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Find video protocols related to scientific articles indexed in Pubmed.
[Application of multispectral animal living imaging technology in evaluating osteoarthritis model].
Zhongguo Gu Shang
PUBLISHED: 09-23-2014
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To observe application value of multispectral animal living imaging technology in rats model of osteoarthritis.
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Systematic investigation on topological properties of layered GaS and GaSe under strain.
J Chem Phys
PUBLISHED: 09-01-2014
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The topological properties of layered ?-GaS and ?-GaSe under strain are systematically investigated by ab initio calculations with the electronic exchange-correlation interactions treated beyond the generalized gradient approximation (GGA). Based on the GW method and the Tran-Blaha modified Becke-Johnson potential approach, we find that while ?-GaSe can be strain-engineered to become a topological insulator, ?-GaS remains a trivial one even under strong strain, which is different from the prediction based on GGA. The reliability of the fixed volume assumption rooted in nearly all the previous calculations is discussed. By comparing to strain calculations with optimized inter-layer distance, we find that the fixed volume assumption is qualitatively valid for ?-GaS and ?-GaSe, but there are quantitative differences between the results from the fixed volume treatment and those from more realistic treatments. This work indicates that it is risky to use theoretical approaches like GGA that suffer from the band gap problem to address physical properties, including, in particular, the topological nature of band structures, for which the band gap plays a crucial role. In the latter case, careful calibration against more reliable methods like the GW approach is strongly recommended.
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Different aggregation dynamics of benzene-water mixtures.
Phys Chem Chem Phys
PUBLISHED: 06-21-2014
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All-atom molecular dynamics simulations for benzene-water mixtures are performed, aiming to explore the relationship between the microscopic structures and the thermodynamic properties, in particular, the transformation dynamics from the mutually soluble state to the phase-separated state. We find that the molecular aggregation of benzene in the water-rich mixture is distinctly different from that of water in the benzene-rich mixture. This aggregation difference is attributed to the different intermolecular interactions: the clustering of benzene molecules in the water-rich mixture is primarily driven by weak short-distance ?-? interactions; while the formation of water clusters in the benzene-rich solution is triggered by long-range dipole-dipole electrostatic interactions. Moreover, the molecular aggregations show double-scaled features: firstly assembling in a quasi-plane at a low concentration, then bulking in three dimensions with an increase in concentration.
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Effect of combining traction and vibration on back muscles, heart rate and blood pressure.
Med Eng Phys
PUBLISHED: 06-19-2014
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Eighty-five percentage of the population has ever experienced low back pain (LBP), which would result in decreasing of muscle strength and endurance, functional capacity of the spine and so on. Traction and vibration were commonly used to relieve the low back pain. It was investigated that the effect of the combing traction and vibration on back muscles, heart rate (HR) and blood pressure (BP) in this study. Thirty healthy subjects participated in 12 trials lying supine on the spine combing bed with different tilt angle (0°, 10°, 20° and 30°) and vibration modes (along with the sagittal and coronal axis with 0Hz, 2Hz and 12Hz separately). EMG was recorded during each trial. Power spectral frequency analysis was applied to evaluate muscle fatigue by the shift of median power frequency (MPF). Pulse pressure (PP) was calculated from BP. HR and PP were used to estimate the effect of the combination of traction and vibration on cardio-vascular system. It was shown that vibration could increase HR and decrease PP. The combination of traction and vibration (2Hz vibration along Z-axis and 12Hz vibration along Y-axis) might have no significant effect on cardio-vascular system. The MPF of LES and UT decreased significantly when the angle reached 20° under the condition of 2Hz vibration along Z-axis compared with it of 0°. What's more, the MPF also decreased significantly compared with it of static mode at 20° for LES and at 30° for UT. However at 12Hz vibration along Y-axis, the MPF had significant increase when the angle reached 20° in LES and 30° in UT compared to it of 0°. For LES, the MPF also had significant difference when the angle was added from 10° to 20°. Therefore, when the 2Hz vibration along Z-axis and traction (tilt angles that less than 20°) were combined, it was helpful to reduce muscle fatigue both for LES and UT compared with only vibration or traction. When the 12Hz vibration along Y-axis and traction (tilt angles that more than 10° for LES and more than 20° for UT) were combined, it could provide good treatment with lower muscle fatigue for back pain compared with only vibration or traction. It is helpful to provide biomechanical quantitative basis for the selection of the clinical treatment methods.
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Biomechanical investigation of thoracolumbar spine in different postures during ejection using a combined finite element and multi-body approach.
Int J Numer Method Biomed Eng
PUBLISHED: 04-03-2014
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The aim of this study is to investigate the dynamic response of a multi-segment model of the thoracolumbar spine and determine how the sitting posture affects the response under the impact of ejection. A nonlinear finite element model of the thoracolumbar-pelvis complex (T9-S1) was developed and validated. A multi-body dynamic model of a pilot was also constructed so an ejection seat restraint system could be incorporated into the finite element model. The distribution of trunk mass on each vertebra was also considered in the model. Dynamics analysis showed that ejection impact induced obvious axial compression and anterior flexion of the spine, which may contribute to spinal injuries. Compared with a normal posture, the relaxed posture led to an increase in stress on the cortical wall, endplate, and intradiscal pressure of 43%, 10%, 13%, respectively, and accordingly increased the risk of inducing spinal injuries. Copyright © 2014 John Wiley & Sons, Ltd.
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Transgenic expression of a functional fragment of harpin protein Hpa1 in wheat induces the phloem-based defence against English grain aphid.
J. Exp. Bot.
PUBLISHED: 03-29-2014
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The harpin protein Hpa1 has multiple beneficial effects in plants, promoting plant growth and development, increasing crop yield, and inducing resistance to pathogens and insect pests. For these effects, the 10-40 residue fragment (Hpa1?????) isolated from the Hpa1 sequence is 1.3- to 7.5-fold more effective than the full-length protein. Here it is reported that the expression of Hpa1????? under the direction of an insect-induced promoter induces the phloem-based defence to English grain aphid, a dominant species of wheat aphids. The expression of Hpa1????? was found to compromise the colonization preference of aphids on the plant and further inhibit aphid reproduction in leaf colonies. In Hpa1?????-expressing wheat lines, moreover, aphid feeding from the phloem was repressed in correlation with the phloem-based defence. This defensive mechanism was shown as enhanced expression of wheat genes encoding phloem lectin proteins (PP2-A1 and PP2-A2) and ?-1,3-glucan synthase-like enzymes (GSL2, GSL10, and GSL12). Both PP2-A and ?-1,3-glucan formed high molecular mass polymers to block phloem sieve plate pores and therefore impede aphid feeding from the phloem. However, the phloem-based defence was impaired by treating plants with ethylene signalling inhibitors, suggesting the requirement for the ethylene signalling pathway. In addition, if Hpa1?????-expressing plants were subjected to attack by a small number of aphids, they newly acquired agriculturally beneficial characters, such as enhanced vegetative growth and increased tiller numbers and grain output values. These results suggest that the defensive and developmental roles of Hpa1????? can be integrated into the germplasm of this agriculturally significant crop.
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Downregulation of leaf flavin content induces early flowering and photoperiod gene expression in Arabidopsis.
BMC Plant Biol.
PUBLISHED: 02-12-2014
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Riboflavin is the precursor of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), essential cofactors for many metabolic enzymes that catalyze a variety of biochemical reactions. Previously we showed that free flavin (riboflavin, FMN, and FAD) concentrations were decreased in leaves of transgenic Arabidopsis plants expressing a turtle riboflavin-binding protein (RfBP). Here, we report that flavin downregulation by RfBP induces the early flowering phenotype and enhances expression of floral promoting photoperiod genes.
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Aldehyde dehydrogenase 2 ameliorates doxorubicin-induced myocardial dysfunction through detoxification of 4-HNE and suppression of autophagy.
J. Mol. Cell. Cardiol.
PUBLISHED: 01-03-2014
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Mitochondrial aldehyde dehydrogenase (ALDH2) protects against cardiac injury via reducing production of 4-hydroxynonenal (4-HNE) and ROS. This study was designed to examine the impact of ALDH2 on doxorubicin (DOX)-induced cardiomyopathy and mechanisms involved with a focus on autophagy. 4-HNE and autophagic markers were detected by Western blotting in ventricular tissues from normal donors and patients with idiopathic dilated cardiomyopathy. Cardiac function, 4-HNE and levels of autophagic markers were detected in WT, ALDH2 knockout or ALDH2 transfected mice treated with or without DOX. Autophagy regulatory signaling including PI-3K, AMPK and Akt was examined in DOX-treated cardiomyocytes incubated with or without ALDH2 activator Alda-1. DOX-induced myocardial dysfunction, upregulation of 4-HNE and autophagic proteins were further aggravated in ALDH2 knockout mice while they were ameliorated in ALDH2 transfected mice. DOX downregulated Class I and upregulated Class III PI3-kinase, the effect of which was augmented by ALDH2 deletion. Accumulation of 4-HNE and autophagic protein markers in DOX-induced cardiomyocytes was significantly reduced by Alda-1. DOX depressed phosphorylated Akt but not AMPK, the effect was augmented by ALDH2 knockout. The autophagy inhibitor 3-MA attenuated, whereas autophagy inducer rapamycin mimicked DOX-induced cardiomyocyte contractile defects. In addition, rapamycin effectively mitigated Alda-1-offered protective action against DOX-induced cardiomyocyte dysfunction. Our data further revealed downregulated ALDH2 and upregulated autophagy levels in the hearts from patients with dilated cardiomyopathy. Taken together, our findings suggest that inhibition of 4-HNE and autophagy may be a plausible mechanism underscoring ALDH2-offered protection against DOX-induced cardiac defect. This article is part of a Special Issue entitled "Protein Quality Control, the Ubiquitin Proteasome System, and Autophagy".
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High-glucose inhibits human fibroblast cell migration in wound healing via repression of bFGF-regulating JNK phosphorylation.
PLoS ONE
PUBLISHED: 01-01-2014
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One of the major symptoms of diabetes mellitus (DM) is delayed wound healing, which affects large populations of patients worldwide. However, the underlying mechanism behind this illness remains elusive. Skin wound healing requires a series of coordinated processes, including fibroblast cell proliferation and migration. Here, we simulate DM by application of high glucose (HG) in human foreskin primary fibroblast cells to analyze the molecular mechanism of DM effects on wound healing. The results indicate that HG, at a concentration of 30 mM, delay cell migration, but not cell proliferation. bFGF is known to promote cell migration that partially rescues HG effects on cell migration. Molecular and cell biology studies demonstrated that HG enhanced ROS production and repressed JNK phosphorylation, but did not affect Rac1 activity. JNK and Rac1 activation were known to be important for bFGF regulated cell migration. To further confirm DM effects on skin repair, a type 1 diabetic rat model was established, and we observed the efficacy of bFGF on both normal and diabetic rat skin repair. Furthermore, proteomic studies identified an increase of Annexin A2 protein nitration in HG-stressed fibroblasts and the nitration was protected by activation of bFGF signaling. Treatment with FGFR1 and JNK inhibitors delayed cell migration and increased Annexin A2 nitration levels, indicating that Annexin A2 nitration is modulated by bFGF signaling via activation of JNK. Together with these results, our data suggests that the HG-mediated delay of cell migration is linked to the inhibition of bFGF signaling, specifically through JNK suppression.
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(+)-rumphiin and polyalthurea, new compounds from the stems of Polyalthia rumphii.
Nat Prod Commun
PUBLISHED: 12-21-2013
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Two new compounds, (+)-rumphiin (3) and polyalthurea (7), together with seven known ones, 3,4,5-trimethoxy benzoic acid (1), (-)-seselinone (2), cannabisin D (4), allantoin (5), oxostephanine (6) and a mixture of beta-sitosterol (8) and stigmasterol (9) were isolated from the stems of Polyalthia rumphii. The chemical structures of 3 and 7 were elucidated by the combination of spectroscopic data, and the absolute configuration of 3 at C-2 was determined by the matrix method to be R. All compounds were evaluated for their cytotoxicity on four human cancer cell lines, which demonstrated that 3 was a moderate bioactive lignan, and 6 showed significant anticancer activity against SPC-A-1 and BEL-7402 cell lines with IC50 values of 1.47 and 1.73 microg/mL, respectively.
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[Different biological characteristics between nucleus pulposus and annulus fibrosus cells in rabbits].
Zhongguo Gu Shang
PUBLISHED: 09-11-2013
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To compare biological characteristics between nucleus pulposus and annulus fibrosus cells in vitro model.
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The effect of different intensities of treadmill exercise on cognitive function deficit following a severe controlled cortical impact in rats.
Int J Mol Sci
PUBLISHED: 08-30-2013
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Exercise has been proposed for the treatment of traumatic brain injury (TBI). However, the proper intensity of exercise in the early phase following a severe TBI is largely unknown. To compare two different treadmill exercise intensities on the cognitive function following a severe TBI in its early phase, rats experienced a controlled cortical impact (CCI) and were forced to treadmill exercise for 14 days. The results revealed that the rats in the low intensity exercise group had a shorter latency to locate a platform and a significantly better improvement in spatial memory in the Morris water maze (MWM) compared to the control group (p < 0.05). The high intensity exercise group showed a longer latency and a mild improvement in spatial memory compared to the control group rats in the MWM; however, this difference was not statistically significant (p > 0.05). The brain-derived neurotrophic factor (BDNF) and p-CREB protein levels in the contralateral hippocampus were increased significantly in the low intensity exercise group. Our results suggest that 2 weeks of low intensity of treadmill exercise is beneficial for improving cognitive function and increasing hippocampal BDNF expression after a severe TBI in its early phase.
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[Reseach of oxidative stress induces aging in rabbit intervertebral disc nucleus pulposus cells injured by H2O2].
Zhongguo Gu Shang
PUBLISHED: 07-13-2013
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To study the effect of H2O2 on the morphological pattern,vitality,proliferation,cycle period of rabbit intervertebral disc nucleus pulposus cells.
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[Research progress on proteomics in femur head necrosis].
Zhongguo Gu Shang
PUBLISHED: 06-26-2013
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Appearance of proteomics technology can fleetly filt and reveal specificity biomarkers of disease, this will help to reveal the pathogenesis of femur head necrosis and help early diagnosis, find more effective methods and therapeutic targets. At present, they are hot spots that find out the occurred mechanism,related proteins of early diagnosis and early treatment and its functional identification; set up the early related database; optimize the protein extraction methods for research of femur head necrosis. This article reviews the application of study technology of related proteins of femur head necrosis on bone tissue, serum,related animal model,and in order to provide further research ideas.
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Proteomic study on the protective mechanism of fibroblast growth factor 21 to ischemia-reperfusion injury.
Can. J. Physiol. Pharmacol.
PUBLISHED: 06-25-2013
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Fibroblast growth factor (FGF)-21 is a novel regulator of insulin-independent glucose transport in 3T3-L1 adipocytes and has glucose and triglyceride lowering effects in rodent models of diabetes. In this study, we found that FGF-21 can significantly attenuate ischemia-reperfusion (I/R) induced damage in H9c2 cells (rat heart). However, it is unclear which signal transduction pathway is involved in the cardioprotective effect of FGF-21. Thus, this study was designed to investigate the potential mechanism induced by FGF-21. The results showed that FGF-21 treatment prevented the oxidative stress and apoptosis associated with I/R damage by reducing the levels of superoxide anions, inhibiting glycogen synthase kinase (GSK) 3? by activating Akt phosphorylation, and recovering the levels of ATP synthase pyruvate kinase isozymes M1 and protein kinase C, thereby improving energy supply. In summary, we conclude that FGF-21 protects H9c2 cells against I/R injury mainly through the Akt-GSK-3?-caspase-3 dependent pathway, preventing oxidative stress, and recovery of the energy supply.
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Prevalence and clinical profile of vitiligo in China: a community-based study in six cities.
Acta Derm. Venereol.
PUBLISHED: 05-29-2013
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Vitiligo is a common skin disease, the prevalence of which varies between races and countries. In China, no population-based study has been reported, although there have been some epidemiological studies on single cities or regions. The objective of this study was to obtain the prevalence and clinical profile of vitiligo in China. The study was conducted in 6 cities. Cluster sampling was used in selecting communities. Residents were visited at home and were asked to complete questionnaires and receive dermatological examinations. A total of 19,974 residents were visited and 17,345 valid questionnaires were obtained. The overall prevalence of vitiligo was 0.56%. Men were affected more than women (0.71% vs. 0.45%, p < 0.01). The prevalence of vitiligo increased with age. The most common type was focal vitiligo (36.1%). A positive family history was found in 9.8% of patients. Thirty-two percent of patients reported a negative impact of vitiligo on their quality of life.
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[Effects of Yougui recipe on the behavioral changes in rat of steroid-induced avascular necrosis of the femoral head].
Zhongguo Gu Shang
PUBLISHED: 04-27-2013
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To explore the effect of Yougui Recipe, a kidney-supplementing and yang-activating formula which on the behavioral changes of rat of steroid-induced avascular necrosis of the femoral head (SANFH).
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Early exercise improves cerebral blood flow through increased angiogenesis in experimental stroke rat model.
J Neuroeng Rehabil
PUBLISHED: 04-22-2013
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Early exercise after stroke promoted angiogenesis and increased microvessles density. However, whether these newly formatted vessels indeed give rise to functional vascular and improve the cerebral blood flow (CBF) in impaired brain region is still unclear. The present study aimed to determine the effect of early exercise on angiogenesis and CBF in ischemic region.
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Two- and three-body dissociation dynamics of temporary negative ion NF3(-).
J Phys Chem A
PUBLISHED: 04-09-2013
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Dissociation dynamics of temporary negative ion NF3(-) formed in the low-energy (0.5 to 4.5 eV) electron attachment is investigated by the anion velocity slice imaging spectroscopy. The kinetic and angular distributions of the F(-) fragment indicate that this fragment is produced via two distinctly different dissociation channels, namely, two-body and three-body fragmentations, at the higher electron attachment energies. The anisotropic distributions of the fast F(-) ions are interpreted as the two-body dissociations relevant to the (2)E resonant state of NF3(-), whereas the slow F(-) can be produced via various three-body dissociations with the products of NF(X (3)?(-)) + F + F(-), NF(b (1)?(+)) + F + F(-), or N + F2 + F(-), depending on the electron attachment energy.
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Early Exercise Protects the Blood-Brain Barrier from Ischemic Brain Injury via the Regulation of MMP-9 and Occludin in Rats.
Int J Mol Sci
PUBLISHED: 04-03-2013
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Early exercise within 24 h after stroke can reduce neurological deficits after ischemic brain injury. However, the mechanisms underlying this neuroprotection remain poorly understood. Ischemic brain injury disrupts the blood-brain barrier (BBB) and then triggers a cascade of events, leading to secondary brain injury and poor long-term outcomes. This study verified the hypothesis that early exercise protected the BBB after ischemia. Adult rats were randomly assigned to sham, early exercise (EE) or non-exercise (NE) groups. The EE and NE groups were subjected to ischemia induced by middle cerebral artery occlusion (MCAO). The EE group ran on a treadmill beginning 24 h after ischemia, 30 min per day for three days. After three-days exercise, EB extravasation and electron microscopy were used to evaluate the integrity of the BBB. Neurological deficits, cerebral infarct volume and the expression of MMP-9, the tissue inhibitors of metalloproteinase-1 (TIMP-1), and occludin were determined. The data indicated that early exercise significantly inhibited the ischemia-induced reduction of occludin, and an increase in MMP-9 promoted TIMP-1 expression (p < 0.01), attenuated the BBB disruption (p < 0.05) and neurological deficits (p < 0.01) and diminished the infarct volume (p < 0.01). Our results suggest that the neuroprotection conferred by early exercise was likely achieved by improving the function of the BBB via the regulation of MMP-9 and occludin.
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Early exercise training improves ischemic outcome in rats by cerebral hemodynamics.
Brain Res.
PUBLISHED: 03-07-2013
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This study examined whether very early initiated physical rehabilitation (VEIPR), as a recommended therapy for postischemia, could improve motor performance and cerebral blood flow (CBF). Adult male rats with ischemic injury caused by middle cerebral artery occlusion (MCAO) were trained to run on a treadmill for 30min per day at 12m/min. Through such exercise training for 3 days, the ischemic rats exhibited increased motor function and decreased infarct volume, as measured by a behavioral score and 2,3,5-triphenyltetrazolium chloride (TTC) staining method, as well as accelerated CBF, as detected with laser speckle imaging (LSI). Furthermore, to determine whether the observed improved CBF provided the protective factor for motor function recovery, we investigated the apoptosis of ischemic rat brain microvascular endothelial cells (rBMECs), which accepted the mechanical force of CBF directly, under flow intervention. The findings indicated that a modest flow decreased cell apoptosis in the ischemic condition and that this effect is magnitude dependent, as excessive flow increased apoptosis.
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Antitumor activity of bacterial exopolysaccharides from the endophyte Bacillus amyloliquefaciens sp. isolated from Ophiopogon japonicus.
Oncol Lett
PUBLISHED: 02-20-2013
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The endophytic bacterium, MD-b1, was isolated from the medicinal plant Ophiopogon japonicas and identified as the Bacillus amyloliquefaciens sp. with 99% similarity based on the partial sequence analysis of 16S rDNA. Exopolysaccharides were extracted from the endophyte for the evaluation of its antitumor activity against gastric carcinoma cell lines (MC-4 and SGC-7901). 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays and microscopy were performed to estimate the cell viability and morphological changes of the MC-4 and SGC-7901 cells following treatment with the exopolysaccharides at 14, 22 and 30 ?g/?l. The results revealed that the exopolysaccharides displayed concentration-dependent inhibitory effects against the MC-4 and SGC-7901 cells, with an IC50 of 19.7 and 26.8 ?g/?l, respectively. The exopolysaccharides also induced morphological abnormalities in the cells. These effects indicated the the exopolysaccharides had an antitumoral mechanism of action associated with the mitochondrial dysfunction of the treated cells. This is the first study to investigate the endophytic microorganism isolated from O. japonicas and also the first discovery of such antitumoral exopolysaccharides derived from the genus Bacillus. This provides a promising and reproducible natural product source with high therapeutic value for anticancer treatment, thereby facilitating the development of new anticancer agents.
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Shear stress inhibits apoptosis of ischemic brain microvascular endothelial cells.
Int J Mol Sci
PUBLISHED: 01-25-2013
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As a therapeutic strategy for ischemic stroke, to restore or increase cerebral blood flow (CBF) is the most fundamental option. Laminar shear stress (LS), as an important force generated by CBF, mainly acts on brain microvascular endothelial cells (BMECs). In order to study whether LS was a protective factor in stroke, we investigated LS-intervented ischemic apoptosis of rat BMECs (rBMECs) through PE Annexin V/7-AAD, JC-1 and Hoechst 33258 staining to observe the membranous, mitochondrial and nuclear dysfunction. Real-time PCR and western blot were also used to test the gene and protein expressions of Tie-2, Bcl-2 and Akt, which were respectively related to maintain membranous, mitochondrial and nuclear norm. The results showed that LS could be a helpful stimulus for ischemic rBMECs survival. Simultaneously, membranous, mitochondrial and nuclear regulation played an important role in this process.
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[Effects and mechanism of Sibiraea angustata on lipid metabolism in hight-fatted rats].
Zhong Yao Cai
PUBLISHED: 10-25-2011
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To investigate the effect and mechanism of Sibiraea angustata on lipid metabolism in hight-fatted SD rats.
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Positive and negative photoion spectroscopy study of monochlorothiophenes.
J Phys Chem A
PUBLISHED: 09-21-2011
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Photolysis dynamics of monochlorothiophenes (2- and 3-chlorothiophenes) is investigated using positive and negative photoion mass spectrometry combined with the synchrotron vacuum ultraviolet radiation. A dozen of the daughter cations are observed in the time-of-flight mass spectra, and their appearance energies are determined by the photoion efficiency spectroscopy measurements. At the energetic threshold, the concerted process rather than a stepwise reaction for C(4)H(3)SCl(+) ? C(2)HSCl(+) + C(2)H(2) and the ring-open isomers of the dehydrogenated thiophene cations (C(4)H(3)S(+) and C(4)H(2)S(+)) formed in C(4)H(3)SCl(+) ? C(4)H(3)S(+) + Cl and C(4)H(2)S(+) + HCl are proposed on the basis of the B3LYP/6-311+G(3df,3pd) calculations. The chlorine anion (Cl(-)) is observed as the product of the photoion-pair dissociations in the energy range of 10.70-22.00 eV. A set of valence-to-Rydberg state transitions 12a ? np (n = 6, 7, 8, 9, 10, etc.) and several series of vibrational excitations are tentatively assigned in the Cl(-) spectrum of 2-chlorothiophene in the lower energy range of 10.90-12.00 eV.
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Resonant dissociative electron attachments to cysteine and cystine.
Phys Chem Chem Phys
PUBLISHED: 07-25-2011
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Shape-resonant electron attachments to cysteine and cystine and the subsequent dissociation dynamics are investigated with the single-center expansion potential scattering calculations. Selectivity of the direct bond cleavage at a given resonant state or by the specific resonant state coupling is demonstrated with the one-dimensional complex potential energy curves of the temporary anion (cysteine)(-). The wave function of the lowest shape resonant state of the temporary anion (cystine)(-) distinctly shows the localized anti-bond (S-S)* character, implying that this disulfide bond can be easily broken due to the low-energy electron resonant attachment.
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[Study on 31 cases with cesarean scar pregnancy treated by transvaginal surgery].
Zhonghua Fu Chan Ke Za Zhi
PUBLISHED: 06-29-2011
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To study clinical efficacy on cesarean scar pregnancy (CSP) treated by transvaginal surgery.
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Identification of a MYB3R gene involved in drought, salt and cold stress in wheat (Triticum aestivum L.).
Gene
PUBLISHED: 06-12-2011
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Abiotic stress seriously affects crop growth and productivity. To better understand the mechanisms plant uses to cope with drought, cold and salt stress, it is necessary to isolate and characterize important regulators response to these stresses. In this study, we cloned a MYB gene from wheat (Triticum aestivum L.) and designated it as TaMYB3R1 based on its conserved three repeats in MYB domain. The sequence of TaMYB3R1 protein shares high identity to other plant MYB3R proteins. Subcellular localization experiment in onion epidermal cells proved that TaMYB3R1 localized in the nucleus. Trans-activation essays in yeast cells confirmed that TaMYB3R1 was a transcriptional activator, and only C-terminal region was able to activate the expression of ?-galactosidase. DNA-binding test showed the MSA cis element-binding activity of TaMYB3R1. After exogenous application of phytohormone ABA, the expression of TaMYB3R1 was induced, and its transcripts accumulated up to 24h; this is also the case for MeJA treatment, but after it peaked at 4h, it decreased to low levels. However, either SA or ET had no obvious effect on the expression of TaMYB3R1. Furthermore, the TaMYB3R1 was initially expressed at low levels and was gradually induced following treatment with salt, and continued to increase up to 72 h. This was similar for the cold treatment. In contrast, the peak appeared at 6h of the PEG treatment, and then gradually decreased to low levels. Our results suggest that TaMYB3R1 is potentially involved in wheat response to drought, salt and cold stress.
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A PVP-extract fungal protein of Omphalia lapideacens and its antitumor activity on human gastric tumors and normal cells.
Oncol. Rep.
PUBLISHED: 06-09-2011
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Omphalia lapidescens is an important medicinal fungus as well as traditional Chinese medicine used for disease treatment. It is mainly used as a vermifuge for anthelmintic therapy, but it has not been hitherto reported to possess antitumor activity. In this study, a purified bioactive protein in O. lapidescens (pPeOp) was obtained using polyvinylpyrrolidone (PVP) followed by gel filtration chromatography. To evaluate the in vitro antitumor activity of pPeOp in human gastric tumor cells (MC-4 and SGC-7901) and normal cells (MC-1), MTT assay and FCM assay were used and the morphological changes, cell viability, cell death rate and cell apoptosis rate of MC-4, SGC-7901 and MC-1 cells were estimated. The results showed that pPeOp could significantly reduce the cell viability of MC-4 and SGC-7901 cells in a concentration-dependent manner, with IC50 values of 236.05 and 156.28 µg/ml, respectively. The morphological observation also indicated a similar result. In FCM assays, a significant increase of cell death rate and cell apoptosis rate of the tumor cells were observed, indicating probable necrosis-inducing effects and/or apoptosis-inducing effects of pPeOp. Importantly, there was no significant effect of pPeOp on MC-1 cells in each assay, showing that pPeOp has no adverse effects on the normal cells. In conclusion, pPeOp is a newly discovered bioactive protein in O. lapidescens and this is the first report on antitumor activity of such a fungal protein. This may provide a meaningful basis for developing a new protein drug for treatment against cancer, especially gastric cancer.
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[A family associated outbreak of Mycoplasma pneumoniae infection in a hospital ward].
Zhonghua Liu Xing Bing Xue Za Zhi
PUBLISHED: 05-12-2011
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To describe the epidemiological and serological features on a family associated outbreak caused by Mycoplasma pneumoniae (MP) infection occurred in Beijing in August 2007.
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Vacuum ultraviolet negative photoion spectroscopy of chloroform.
J Phys Chem A
PUBLISHED: 04-01-2011
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Negative ions Cl(-), Cl(2)(-), CCl(-), CHCl(-), and CCl(2)(-) are observed in vacuum-ultraviolet ion-pair photodissociations of chloroform (CCl(3)H) using the Hefei synchrotron radiation facility, and their ion production efficiency curves are recorded in the photon energy range of 10.00-21.50 eV. Two similar spectra of the isotope anions (35)Cl(-) and (37)Cl(-) indicate the following: Besides the strong bands corresponding to the electron transitions from valence to Rydberg orbitals converging to the ionic states, some additional peaks can be assigned with the energetically accessible multibody fragmentations; a distinct peak at photon energy 14.55 eV may be due to a cascade process (namely, the Cl(2) neutral fragment at the highly excited state D2(3)?(g) may be produced in the photodissociation of CCl(3)H, and then the Cl(-) anions are produced in the pulsed-field induced ion-pair dissociations of Cl(2) (D2(3)?(g))); two vibrational excitation progressions, n?(2)(+) and n?(2)(+) + ?(3)(+), and n?(4)(+) and n?(4)(+) + ?(2)(+), are observed around C? (2)E and D? (2)E ionic states, respectively. The enthalpies of the multibody fragmentations to Cl(2)(-), CCl(-), CHCl(-), and CCl(2)(-) are calculated with the thermochemistry data available in the literature, and these multibody ion-pair dissociation pathways are tentatively assigned in the respective anion production spectra.
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Shape resonance states of the low-energy electron attachments to DNA base tautomers.
Phys Chem Chem Phys
PUBLISHED: 02-25-2011
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Two different types of shape resonance states, ?* and ?*, formed in the low-energy electron attachments to the low-lying tautomers of DNA bases (adenine, guanine, thymine, and cytosine) in the gas phase are investigated using the quantum scattering method with the non-empirical model potentials in a symmetry-adapted, single-center expansion. Four and three ?* states are predicted for purines and pyrimidines, respectively. Comparing the different tautomers of a certain DNA base, we find distinct differences both in the resonance energies and the resonant wave function patterns of ?* states. As for the lowest three ?* states, the energetic values predicted in this work are also compared with the theoretical and experimental results available in the literature.
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Congenital syphilis: refining newborn evaluation and management in Shenzhen, southern China.
Sex Transm Infect
PUBLISHED: 06-24-2010
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Consistent definitions of congenital syphilis are critical for determining true incidences and setting up targets of elimination. This study aimed to assess the evaluation and management of infants at high risk of congenital syphilis with an antenatal syphilis-screening programme in the Shenzhen SEZ and to develop feasible definitions for the detection of congenital syphilis in China.
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Propene oxidation on V4O11- cluster: reaction dynamics to acrolein.
J Phys Chem A
PUBLISHED: 05-27-2010
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Oxidation dynamics of propene (CH(3)CH=CH(2)) to acrolein (CH(2)=CHCHO) on the anionic vanadium oxide cluster V(4)O(11)(-) is investigated with the first-principle density functional calculations, providing an interpretation to V(4)O(11)(-) + propene --> V(4)O(10)H(2)(-) + C(3)H(6)O observed in the photochemical reactions (Li, S.; Mirabal, A.; Demuth, J.; Wöste, L.; Siebert, T. J. Am. Chem. Soc. 2008, 130, 16832). The complicated energy surface of the reaction between V(4)O(11)(-) and propene is explored, and the stepwise dynamic processes for propene to acrolein are proposed. Initially, propene is captured by V(4)O(11)(-) with a hydrogen bond CH (methyl group in propene)...O (dioxo group in V(4)O(11)(-)), then undergoes dehydrogenation along this hydrogen bond to form a pi-allyl radical. After the redehydrogenation of the pi-allyl and oxygen transfer from the vanadium oxide cluster, acrolein is eventually produced together with four isomers of V(4)O(10)H(2)(-) in the different reaction paths. During this process, the negative charge is found to transfer between the hydrocarbon and the vanadium oxide moieties.
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Molecular dynamics study of solvation differences between cis- and transplatin molecules in water.
J Chem Phys
PUBLISHED: 05-13-2010
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The classical molecular dynamics (MD) simulations for the solvation properties of cis- and transplatins in water are performed with the Lennard-Jones plus Coulomb electrostatic potential parameters that are optimized with ab initio potential energies of the water-platin systems. Two hydration shells are found both for cis- and transplatins. The first shell of water molecules is closer to transplatin than cisplatin. The average number and lifetime of the intermolecular hydrogen bonds (HBs) estimated from the MD trajectories indicate that the Cl and NH(3) ligands are the main groups involved in the intermolecular HBs with water. In comparison with cisplatin, there are more HBs around transplatin and these HBs show the longer lifetime. The distinctly different solvation structures between cis- and transplatins are further revealed with the spatially anisotropic distributions of the first hydration shells.
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Evaluation of the biocontrol potential of various Metarhizium isolates against green peach aphid Myzus persicae (Homoptera: Aphididae).
Pest Manag. Sci.
PUBLISHED: 03-05-2010
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Twenty-three isolates of Metarhizium anisopliae (Metschnikof) Sorokin and M. acridum (Driver & Milner) JF Bischoff, Rehner & Humber from non-aphid host insects around the globe were evaluated for their aphid biocontrol potential, which is not well known.
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Photoelectron spectroscopy of homogeneous nucleic acid base dimer anions.
Phys Chem Chem Phys
PUBLISHED: 02-11-2010
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We report the photoelectron spectra of homogeneous dimer anions of the nucleobases: uracil, thymine, cytosine, adenine, and guanine, i.e., U(2)(-), T(2)(-), C(2)(-), A(2)(-), and G(2)(-) along with DFT calculations on U(2)(-) and T(2)(-). Based on these calculations the photoelectron spectrum of T(2)(-) was assigned as being due to both a proton transferred and a non-proton transferred isomer, while the photoelectron spectrum of U(2)(-) was assigned in terms of a single dominant barrier-free proton transferred isomer. Photoelectron spectra were also measured with a different source and on a different type of photoelectron spectrometer for U(2)(-), T(2)(-), A(2)(-), (1-MeT)(2)(-) and (1,3-Me(2)U)(2)(-).
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Hydrophobicity-related protein contents and surface areas of aerial conidia are useful traits for formulation design of fungal biocontrol agents.
Mycopathologia
PUBLISHED: 02-02-2010
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To clarify the potential use of hydrophobicity-related traits of aerial conidia in formulation design of fungal biocontrol agents, hydrophobicity rates (H (r)) and surface areas (S (a)) of aerial conidia were assessed with 48 strains of Beauveria bassiana, Isaria fumosorosea and Metarhizium spp. Inter- or intra-specific variation was large in H (r) (59.7-92.2%) and S (a) (7.9-25.3 microm(2) conidium(-1)) measurements, which were significantly correlated (r (2) = 0.55). Six isolates of the three fungi with distinguished H (r) and S (a) were further studied. Conidial wall proteins of these isolates were sequentially extracted with sodium dodecyl sulfate (SDS), formic acid (FA) and trifluoroacetic acid (TFA). Their H (r) values were significantly correlated to the contents (P (c)) of TFA-soluble, but FA-insoluble, proteins (2.7-44.8 microg per 10(7) conidia; r (2) = 0.79) and reduced drastically by the FA/TFA treatments, which eliminated the hydrophobin-based rodlet layers of conidial surfaces. However, the SDS treatments had no effect on either H (r) or rodlet layers. The dispersancy of a tested emulsifier to oil formulations of the six isolates in water was adversely correlated to their H (r) (r (2) = 0.94). The results indicate that both P (c) and S (a) are inherent hydrophobicity-related traits and can be utilized to select fungal biocontrol candidates for improved formulation and application.
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Modulation of tropoelastin and fibrillin-1 by infrared radiation in human skin in vivo.
Photodermatol Photoimmunol Photomed
PUBLISHED: 11-13-2009
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The heat produced by exposure to infrared radiation (IR) has been demonstrated to modulate the expression of tropoelastin and fibrillin-1, the two main components of elastic fibers in human skin in vivo. However, the effect of IR range of radiations on tropoelastin and fibrillin-1 expression has not been thoroughly investigated.
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A new dimeric phenylpropanoid and cytotoxic norditerpene constituents from Podocarpus nakaii.
J Asian Nat Prod Res
PUBLISHED: 06-09-2009
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A new dimeric phenylpropanoid namely podonaka A (1), along with the 13 known compounds including diterpenes (2 and 3), norditerpenes (4 and 5), benzenoids (6-10), steroids (11 and 12), chalcone (13), and megastigmane (14), was isolated from the EtOH extract of Podocarpus nakaii Hayata. The structure of 1 was elucidated on the basis of spectroscopic analysis including 1D and 2D NMR and MS techniques. Biological evaluation showed that norditerpenes, inumakilactone B (4), and podolactone E (5) have potent cytotoxic activities against Daoy, WiDr, KB, and HeLa tumor cell lines. Moreover, low dosage of 5 may induce early apoptosis in KB cells before 12 h.
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Monoanion BH4(-) can stabilize zwitterionic glycine with dihydrogen bonds.
Chemphyschem
PUBLISHED: 05-12-2009
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Unusual strength: In the complex glycine-BH(4)(-), unconventional dihydrogen bonds are predicted. An ultrashort dihydrogen bond B-H...H-N and a very strong interaction of about -41 kcal mol(-1)) are found in complex 3 (see structures), in which the zwitterionic glycine is stabilized with a big margin.
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A new non-hydrophobic cell wall protein (CWP10) of Metarhizium anisopliae enhances conidial hydrophobicity when expressed in Beauveria bassiana.
Appl. Microbiol. Biotechnol.
PUBLISHED: 03-22-2009
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A cell wall protein, CWP10, resolved from the conidial formic acid extract of a Metarhizium anisopliae isolate, was characterized as a new 9.9-kDa protein with a 32-aa signal peptide with a central hydrophobic region (ca. 10 residues) at its N-terminus. This protein was proven neither to be hydrophobic nor glycosylated and encoded by a 363-bp, single-copy gene with three introns. CWP10 was existent in the conidial extracts of seven of 18 tested M. anisopliae isolates and much more abundant (immunogold-labeled) on conidial walls than in cytoplasm. Integrating the gene into a CWP10-absent strain of Beauveria bassiana led to excellent expression of CWP10 in aerial conidia, increasing net conidial hydrophobicity by 10.8% or adhesion to hydrophobic Teflon by 1.3-fold. However, the expressed protein had no effect on conidial tolerance to thermal and ultraviolet stresses. This is the first report on a non-hydrophobic cell-wall protein enhancing conidial hydrophobicity and adhesion of the fungal species.
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Thermal stabilities of the microhydrated zwitterionic glycine: a kinetics and dynamics study.
J Phys Chem A
PUBLISHED: 03-11-2009
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Thermal stabilities of the zwitterionic glycine (zg) combined with water molecules are investigated by both ab initio/RRKM calculations and the thermostatic molecular dynamics (MD) simulations. The microhydrated zg clusters, zg-nw (n = 2, 3; w = water), can transfer to the canonical clusters cg-nw through the rapid intramolecular proton transfers (PT), while the proton is shifted via the intermolecular hydrogen bonds for zg-4w --> cg-4w. Both the MD/solution model simulations and the RRKM calculations indicate that the zg and cg conformers hydrated with more water molecules have their respective higher stabilties and the transformation needs to overcome a certain energy barrier. The thermostatic MD simulations show that the dynamic PT processes are significantly influenced by both the temperatures used in the trajectory simulations and the hydrogen bonding arrangements between glycine and water molecules.
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Isotopic dilution study of the water/vapor interface by phase-sensitive sum-frequency vibrational spectroscopy.
J. Am. Chem. Soc.
PUBLISHED: 02-13-2009
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Phase-sensitive sum-frequency vibrational spectroscopy (PS-SFVS) has been used to probe the isotopically diluted water/vapor interfaces in the spectral regions of OD (2200-2800 cm(-1)) and OH (3000-3800 cm(-1)) stretches. The experimentally measured Im chiS(2) spectra, where chiS(2) is the surface nonlinear susceptibility, permit direct characterization of resonances of the interfaces. The Im chiS(2) spectrum of the HDO/vapor interface that is intrinsically simpler to analyze can be deduced from the result of isotopic dilution. It exhibits in the bonded-OH region a broad band comprising two parts with opposite signs, in contrast to those deduced earlier from fitting of the |chiS(2)|2 spectra and those calculated by MD simulation, but consistent with that obtained for the H2O/vapor interface.
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Effect of kappa elastin on melanogenesis in A375 human melanoma cells and its related mechanism.
Chin. Med. J.
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Elastin derived peptides can regulate melanocyte precursor development. Ultraviolet irradiation, infrared radiation and heat can increase the synthesis of tropoelastin in human skin epidermis. The aim of this study was to investigate whether the over expressed tropoelastin in epidermis has some role in melanogenesis of melanocytes.
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Communication: Imaging the indirect dissociation dynamics of temporary negative ion: N2O- ? N2 + O-.
J Chem Phys
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We reported an imaging study of the dissociation dynamics of temporary negative ion N(2)O(-) formed in the low-energy electron attachment, e(-) + N(2)O ? N(2)O(-) ? N(2) + O(-). With the help of ab initio molecular dynamics calculations, the evolution of momentum distributions of the O(-) fragment in terms of the electron attachment energy is identified as the result of a competition between two distinctly different indirect pathways, namely, climbing over and bypassing the energy ridge after the molecular structure bending. These two pathways prefer leaving the N(2) fragment at the high vibrational and rotational states, respectively.
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Oxidative stress and activities of caspase-8, -9, and -3 are involved in cryopreservation-induced apoptosis in granulosa cells.
Eur. J. Obstet. Gynecol. Reprod. Biol.
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The aim of this study is to determine whether the oxidative stress and the activities of caspase-8, -9, and -3 are involved in cryopreservation-induced apoptosis in granulosa cells.
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Prevalence of psoriasis in China: a population-based study in six cities.
Eur J Dermatol
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Although psoriasis occurs worldwide, the prevalence varies considerably between different peoples and regions. In China, a questionnaire-based study was carried out in 1987 and the prevalence of psoriasis was found to be 0.12%. Since then, no large-scale, population-based study has been reported.
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Quantum entanglement and criticality of the antiferromagnetic Heisenberg model in an external field.
J Phys Condens Matter
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By Lanczos exact diagonalization and the infinite time-evolving block decimation (iTEBD) technique, the two-site entanglement as well as the bipartite entanglement, the ground state energy, the nearest-neighbor correlations, and the magnetization in the antiferromagnetic Heisenberg (AFH) model under an external field are investigated. With increasing external field, the small size system shows some distinct upward magnetization stairsteps, accompanied synchronously with some downward two-site entanglement stairsteps. In the thermodynamic limit, the two-site entanglement, as well as the bipartite entanglement, the ground state energy, the nearest-neighbor correlations, and the magnetization are calculated, and the critical magnetic field h(c) = 2.0 is determined exactly. Our numerical results show that the quantum entanglement is sensitive to the subtle changing of the ground state, and can be used to describe the magnetization and quantum phase transition. Based on the discontinuous behavior of the first-order derivative of the entanglement entropy and fidelity per site, we think that the quantum phase transition in this model should belong to the second-order category. Furthermore, in the magnon existence region (h < 2.0), a logarithmically divergent behavior of block entanglement which can be described by a free bosonic field theory is observed, and the central charge c is determined to be 1.
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Photoion-pair dissociation dynamics of polyatomic molecules with synchrotron radiation.
Phys Chem Chem Phys
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Positive-negative photoion pairs can be formed in the photoexcitation of molecules in the broad energy range from vacuum ultraviolet to soft X-ray. Synchrotron radiation is the most suitable photon source and state-of-the-art mass spectrometry techniques have been successfully applied in the experimental studies of such ion-pair photodissociation dynamics. This perspective will briefly review the recent progress on this topic and provide a general description of the mechanisms of ion-pair photodissociation dynamics of polyatomic molecules. Challenges in the understanding of ion-pair photodissociation in the higher photon energy range are also discussed.
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Positive/negative ion velocity mapping apparatus for electron-molecule reactions.
Rev Sci Instrum
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In molecular dissociative ionization by electron collisions and dissociative electron attachment to molecule, the respective positively and negatively charged fragments are the important products. A compact ion velocity mapping apparatus is developed for the angular distribution measurements of the positive or negative fragments produced in the electron-molecule reactions. This apparatus consists of a pulsed electron gun, a set of ion velocity mapping optic lenses, a two-dimensional position detector including two pieces of micro-channel plates, and a phosphor screen, and a charge-coupled-device camera for data acquisition. The positive and negative ion detections can be simply realized by changing the voltage polarity of ion optics and detector. Velocity sliced images can be directly recorded using a narrow voltage pulse applied on the rear micro-channel plate. The efficient performance of this system is evaluated by measuring the angular distribution of O(-) from the electron attachments to NO at 7.3 and 8.3 eV and O(+) from the electron collision with CO at 40.0 eV.
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