Other articles by René van Lien on PubMed

• Tailoring the Coupling Between Localized and Propagating Surface Plasmons: Realizing Fano-like Interference and High-performance Sensor Optics Express. Apr, 2013  |   Pubmed ID: 23609734 Surface plasmon modes originated from various metallic nanostructures possess unique features of strong nanoscale light confinement and enhancement with tunable energy, which make them attractive and promising for a variety of applications such as sensing, solar cell, and lasing. Here, we have investigated the interaction between localized and propagating surface plasmons in a structure consisting of a gold nanobar array and a thick gold film, separated by a silica dielectric spacer layer. It is found that the reflection spectrum of the designed plasmonic structure can be readily tailored by changing the gold nanobar size, array period and the spacer layer thickness. Moreover, the strong coupling between the localized and propagating modes can result in an anticrossing behavior and even induce a Fano-like asymmetric lineshape. Importantly, the sensitivity and the figure of merit (FoM) of this plasmonic system can reach as high as 936 nm/RIU and 112, respectively. Our study offers a new, simple, efficient and controllable way to design the plasmonic systems with desired modes coupling and spectral lineshapes for different applications.
• 4-Hydroxy-3-methyl-6-(1-methyl-2-oxoalkyl)pyran-2-one Synthesis by a Type III Polyketide Synthase from Rhodospirillum Centenum Chembiochem : a European Journal of Chemical Biology. Apr, 2013  |   Pubmed ID: 23609937 The purple photosynthetic bacterium Rhodospirillum centenum has a putative type III polyketide synthase gene (rpsA). Although rpsA was known to be transcribed during the formation of dormant cells, the reaction catalyzed by RpsA was unknown. Thus we examined the RpsA reaction in vitro, using various fatty acyl-CoAs with even numbers of carbons as starter substrates. RpsA produced tetraketide pyranones as major compounds from one C10-14 fatty acyl-CoA unit, one malonyl-CoA unit and two methylmalonyl-CoA units. We identified these products as 4-hydroxy-3-methyl-6-(1-methyl-2-oxoalkyl)pyran-2-ones by NMR analysis. RpsA is the first bacterial type III PKS that prefers to incorporate two molecules of methylmalonyl-CoA as the extender substrate. In addition, in vitro reactions with (13) C-labeled malonyl-CoA revealed that RpsA produced tetraketide 6-alkyl-4-hydroxy-1,5-dimethyl-2-oxocyclohexa-3,5-diene-1-carboxylicacids from C14-20 fatty acyl-CoAs. This class of compounds is likely synthesized through aldol condensation induced by methine proton abstraction. No type III polyketide synthase that catalyzes this reaction has been reported so far. These two unusual features of RpsA extend the catalytic functions of the type III polyketide synthase family.
• Carbon Nanotubes-coated Macroporous Poly(N-isopropylacrylamide) Hydrogel and Its Electro-sensitivity ACS Applied Materials & Interfaces. Apr, 2013  |   Pubmed ID: 23611527 A facile method of fabricating novel CNTs-coated macroporous PNIPAAm hydrogel composite was proposed. The method was based on the deposition of a dense and compact CNTs layer on the pore walls of the preformed macroporous PNIPAAm hydrogel scaffold. The resulted hydrogel composite exhibited an electric current sensitivity resulting from electro-thermal conversion. When an external electric current was applied, this hydrogel composite could be electrically heated and then showed a thermally-induced shrink.
• A Simple and Sensitive Fluorescence Biosensor for Detection of Organophosphorus Pesticides Using H2O2-sensitive Quantum Dots/bi-enzyme Biosensors & Bioelectronics. Apr, 2013  |   Pubmed ID: 23612061 In this paper, we have developed a simple, fast, convenient and sensitive method for determination of organophosphorus pesticides in real samples based on inhibition mechanism of acetylcholinesterase (AChE). The biosensor is composed of enzymes (AChE and ChOx (choline oxidase)), QDs and acetylcholine (ACh), without any complex process of assembly for biosensor. After the experimental conditions are optimized, the limit of detection (LOD) for dichlorvos (DDVP) is found to be 4.49nM. Two linear ranges allow a wide determination of DDVP concentration from 4.49nM to 6780nM. Furthermore, a possible mechanism is put forward to explain the fluorescence quenching of CdTe QDs in the presence of H2O2. More importantly, the obtained biosensor is proven to be suitable for the detection of residues of organophosphorus pesticides (OPs) in real examples. The excellent performance of this biosensor will facilitate future development of rapid and high-throughput detection of organophosphorus pesticides.
• Controllable Synthesis of Recyclable Core-shell γ-Fe2O3@SnO2 Hollow Nanoparticles with Enhanced Photocatalytic and Gas Sensing Properties Physical Chemistry Chemical Physics : PCCP. Apr, 2013  |   Pubmed ID: 23612776 Composite materials containing different components with well-defined structures may cooperatively enhance their performance and extend their applications. In this work, core-shell γ-Fe2O3@SnO2 hollow nanoparticles (NPs) were synthesized by a low-cost and environmentally friendly seed-mediated hydrothermal method. Firstly, the γ-Fe2O3 hollow NPs were synthesized by a template-free method. Then they were used as the cores for the growth of SnO2 shells. The thickness of the shell can be simply tailored by controlling the reaction time. Various techniques, including SEM, XRD, TEM and HRTEM, were employed to investigate the morphology, structure and formation process of the special core-shell hollow structures. The combination of magnetic semiconductor (γ-Fe2O3) and wide band-gap semiconductor (SnO2) endowed them with great potential to be used as recyclable photocatalysts. Experiments on photo-degradation of Rhodamin B (RhB) dye in the presence of the samples showed that the hybrid structures possessed higher photocatalytic activities than the monomer structures of SnO2 and γ-Fe2O3 materials indicating a strong coupling enhancement effect between the wide and narrow band-gap semiconductors. Moreover, the gas sensing tests of the γ-Fe2O3@SnO2 hollow NPs revealed that the samples exhibited fast response and recovery rates, which enable them to be promising materials for gas sensors.
• Overexpression of Six1 Gene Suppresses Proliferation and Enhances Expression of Fast-type Muscle Genes in C2C12 Myoblasts Molecular and Cellular Biochemistry. Apr, 2013  |   Pubmed ID: 23613228 Sine oculis homeobox 1 (Six1) homeodomain transcription factor is implicated in the genesis of muscle fiber type diversity, but its regulatory mechanisms on the formation of muscle fiber type are still poorly understood. To elucidate the biological roles of Six1 gene in muscle fiber formation, we established C2C12 cell line overexpressing Six1 and determined the effects of forced Six1 expression on muscle-specific genes expression, cell proliferation, and cell cycles. Our results indicated that Six1 overexpression could significantly promote the expression of fast-type muscle genes Atp2a1, Srl, and Mylpf. Furthermore, Six1 overexpressing C2C12 cells displayed a relative lower proliferative potential, and cell cycle analysis showed that Six1 exerted its role in cell cycle primarily through the regulation of G1/S and G2/M phases. In conclusion, Six1 plays an essential role in modulation of the fast-twitch muscle fiber phenotype through up-regulating fast-type muscle genes expression, and it could suppress the proliferation of muscle cells.
• Elevated Serum Levels of Human Relaxin-2 in Patients with Esophageal Squamous Cell Carcinoma World Journal of Gastroenterology : WJG. Apr, 2013  |   Pubmed ID: 23613637 To assess the prognostic value of serum human relaxin 2 (H2 RLN) level in patients with esophageal squamous cell carcinoma (ESCC).
• Topological Dangling Bonds with Large Spin Splitting and Enhanced Spin Polarization on the Surfaces of Bi2Se3 Nano Letters. Apr, 2013  |   Pubmed ID: 23614400 We investigate the topological surface state properties at various surface cleaves in the topological insulator Bi2Se3, via first principles calculations and scanning tunneling microscopy/spectroscopy (STM/STS). While the typical surface termination occurs between two quintuple layers, we report the existence of a surface termination within a single quintuple layer where dangling bonds form with giant spin splitting owing to strong spin-orbit coupling. Unlike Rashba split states in a 2D electron gas, these states are constrained by the band topology of the host insulator with topological properties similar to the typical topological surface state, and thereby offer an alternative candidate for spintronics usage. We name these new states "topological dangling-bond states". The degree of the spin polarization of these states is greatly enhanced. Since dangling bonds are more chemically reactive, the observed topological dangling-bond states provide a new avenue for manipulating band dispersions and spin-textures by adsorbed atoms or molecules.
• A Comparison of Different Murine Models for Cytomegalovirus-Induced Sensorineural Hearing Loss The Laryngoscope. Apr, 2013  |   Pubmed ID: 23616191 OBJECTIVES/HYPOTHESIS: To compare three different inoculation techniques for the development of cytomegalovirus (CMV)-induced sensorineural hearing loss (SNHL) in a mouse model. STUDY DESIGN: A prospective experimental animal study. METHODS: BALB/c mice underwent inoculation using green fluorescent protein-expressing mouse cytomegalovirus (mCMV-GFP) via transtympanic (TT), intraperitoneal (IP), or intracranial (IC) routes. Control mice received an equal volume of saline. Hearing thresholds were measured using both distortion product otoacoustic emissions (DPOAE) and evoked auditory brainstem response studies (ABR). Cochleas were harvested for histological examination and cytocochleogram. RESULTS: No mice in the TT or IP groups showed significant hearing loss. All infected mice in the IC group showed significantly elevated ABR and DPOAE thresholds at 4 weeks of age. Ten mice (55%) had profound hearing loss (≥80 dB) at 4 weeks of age, while the other eight mice (45%) initially showed moderate hearing loss (≤20 dB), which progressed to profound hearing loss by 6 to 8 weeks. Asymmetric hearing loss was seen in 40% of the mice. Temporal bone histology showed diffuse loss of outer hair cells (OHC). Green fluorescent protein (GFP)-labeled virus was abundant in the spiral ganglion and adjacent to the scala tympani at the basal region of the cochlea at 7 days postinjection, and devoid of GFP labeling by 14 days postinfection. CONCLUSIONS: Intracerebral injection of mCMV preferentially causes mCMV-mediated hearing loss relative to IP or TT injections. These results are consistent with the hearing loss reported in human congenital infection and may have implications for understanding the pathophysiology of CMV-mediated labyrinthitis. LEVEL OF EVIDENCE: N/A. Laryngoscope, 2013.
• Analysis of the Secretome and Identification of Novel Constituents from Culture Filtrate of Bacillus Calmette-Guerin Using High-resolution Mass Spectrometry Molecular & Cellular Proteomics : MCP. Apr, 2013  |   Pubmed ID: 23616670 Tuberculosis (TB) is an infectious bacterial disease that causes morbidity and mortality, especially in developing countries. Although the efficacy against TB has displayed a high degree of variability (0-80%) in different trials, Mycobacterium bovis bacillus Calmette-Guerin (BCG) has been recognized as an important weapon for preventing TB worldwide for over 80 years. Because secreted proteins often play vital roles in the interaction between bacteria and host cells, the secretome of mycobacteria is considered to be an attractive reservoir of potential candidate antigens for the development of novel vaccines and diagnostic reagents. In this study, we performed a proteomic analysis of BCG culture filtrate proteins using SDS-PAGE and high-resolution Fourier transform mass spectrometry. In total, 239 proteins (1555 unique peptides) were identified, including 185 secreted proteins or lipoproteins. Furthermore, 17 novel protein products not annotated in the BCG database were detected and validated by RT-PCR at the transcriptional level. Additionally, the translational start sites of 52 proteins were confirmed, and 22 proteins were validated by extension of the translational start sites based on N-terminus-derived peptides. Compared with previous studies on the mycobacterial secretome, there are 103 secreted proteins that have not been reported that are unique to our study. The physicochemical characteristics of the secreted proteins were determined. Major components from the culture supernatant, including low-molecular-weight antigens, lipoproteins, PE and PPE family proteins and Mce family proteins, were discussed; some components represent potential predominant antigens in the humoral and cellular immune responses.
• Genetic Analysis of a Chinese Han Family with Multiple Endocrine Neoplasia Type 2A Indian Journal of Biochemistry & Biophysics. Feb, 2013  |   Pubmed ID: 23617071 Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant disorder that can be distinguished as three different syndromes: multiple endocrine neoplasia type 2A (MEN2A), MEN2B and familial medullary thyroid carcinoma (FMTC). This disorder is usually caused by the mutations of the rearranged during transfection protooncogene gene (RET) or the neurotrophic tyrosine kinase receptor type 1 gene (NTRK1). To investigate the genetic cause in a Chinese Han family with MEN2A and the genotype-phenotype correlations, nine members belonging to 3 generations of MEN2A family with 5 affected subjects underwent genetic analysis. Standard GTG-banded karyotype analysis and sequencing of the RET and NTRK1 genes were performed to identify the genetic cause of this family. A heterozygous mutation p.Cys634Arg in the RET gene was identified in 5 patients with MEN2A and one asymptomatic family member. The phenotype of patients was that of classic MEN2A, characterized by medullary thyroid carcinoma and phaeochromocytoma. The clinical features of all cases with RET mutations varied greatly, including onset age of clinical manifestations, severity and comorbidities. Thus, this study not only identified the hereditary nature of the MEN2A in the cases, but also discovered a family member harboring the same p.Cys634Arg mutation, who was unaware of his condition. These finding may provide new insights into the cause and diagnosis of MEN2A and have implications for genetic counseling.
• [Manipulative Reduction and Small Splint Fixation for Treatment of Three-part Fractures of Proximal Humerus: a Case-control Study] Zhongguo Gu Shang = China Journal of Orthopaedics and Traumatology. Jan, 2013  |   Pubmed ID: 23617133 To study Chinese medicine treatment in the three-part of the proximal humerus fractures.
• Inverse Planning Optimization Method for Intensity Modulated Radiation Therapy Technology in Cancer Research & Treatment. Apr, 2013  |   Pubmed ID: 23617286 In order to facilitate the leaf sequencing process in intensity modulated radiation therapy (IMRT), and design of a practical leaf sequencing algorithm, it is an important issue to smooth the planned fluence maps. The objective is to achieve both high-efficiency and high-precision dose delivering by considering characteristics of leaf sequencing process. The key factor which affects total number of monitor units for the leaf sequencing optimization process is the max flow value of the digraph which formulated from the fluence maps. Therefore, we believe that one strategy for compromising dose conformity and total number of monitor units in dose delivery is to balance the dose distribution function and the max flow value mentioned above. However, there are too many paths in the digraph, and we don't know the flow value of which path is the maximum. The maximum flow value among the horizontal paths was selected and used in the objective function of the fluence map optimization to formulate the model. The model is a traditional linear constrained quadratic optimization model which can be solved by interior point method easily. We believe that the smoothed maps from this model are more suitable for leaf sequencing optimization process than other smoothing models. A clinical head-neck case and a prostate case were tested and compared using our proposed model and the smoothing model which is based on the minimization of total variance. The optimization results with the same level of total number of monitor units (TNMU) show that the fluence maps obtained from our model have much better dose performance for the target/non-target region than the maps from total variance based on the smoothing model. This indicates that our model achieves better dose distribution when the algorithm suppresses the TNMU at the same level. Although we have just used the max flow value of the horizontal paths in the diagraph in the objective function, a good balance has been achieved between the dose conformity and the total number of monitor units. This idea can be extended to other fluence map optimization model, and we believe it can also achieve good performance.
• The Complete Mitochondrial Genome of Liriomyza Huidobrensis and Comparison with L. Trifolii and L. Sativae (Diptera: Agromyzidae) Mitochondrial DNA. Apr, 2013  |   Pubmed ID: 23617371 Abstract Liriomyza huidobrensis, L. trifolii and L. sativae (Diptera: Agromyzidae) are serious horticultural pests. The three species are very similar and difficult to discriminate from each other. In this study, we report the mitochondrial genome of L. huidobrensis and compare with L. trifolii and L. sativae. The mitochondrial genome of L. huidobrensis is 16,239 bp long, and it contains 37 genes and one A + T-rich region as do the sequenced liriomyza species. The sequence and structure of H51-H100 region in srRNA is significantly different from that of L. trifolii and L. sativae. The greatest sequence differences among the three leafminers are located in the region including ND2, ND3, ND6, ATP6, ATP8, CYTb and A+T region, which can be considered as candidate regions for molecular identification or SNP markers.
• Ultrastructure of Germ Cells, Sertoli Cells and Mitochondria During Spermatogenesis in Mature Testis of the Chinese Taihang Black Goats (Capra Hircus) Micron (Oxford, England : 1993). Apr, 2013  |   Pubmed ID: 23618746 The objective of this study was to describe the ultrastructure of germ cells, Sertoli cells and mitochondria in mature testis of the Chinese Taihang black goat. The characteristics of germ cell nucleus and mitochondria changing during spermatogenesis were investigated by transmission electron microscopy (TEM). The results showed that the spermatogonium was elliptical, and its nucleus was about 4-5μm. The round mitochondria can be observed throughout the cytoplasm around the nucleus. Small patches of heterochromatin were distributed throughout the nucleus. Spermatocyte was oval-shaped with a nucleus of about 4-4.5μm in diameter. The heterochromatin began to attach to the inner surface of the nuclear membrane. Spermatid was about 4μm and oval in shape. Its nucleus was oval or round and approximately 2-3μm in diameter. The borderline between nucleus membrane and karyoplasm was distinct. During spermiogenesis, spermatid nucleus was condensed and elongated, and chromatin reached the highest condensation in the mature spermatozoon. The mid-piece was surrounded by mitochondria at the neck region. The sperm tail showed the typical "9+2″ structure, contained axoneme and central singlet microtubules. The nuclei of the Sertoli cells were irregular shaped and showed indentations in the membrane. In the mature testes of goat bucks, abundant mitochondria were around the germ cells and Sertoli cells. The scattered mitochondria were aggregated around the base of the flagellum (axoneme) during the spermatid differentiation stage. In conclusion, the present study showed that the spermatogenic process of Taihang black goat followed the pattern of mammals with some specific.
• A B3LYP and MP2(full) Theoretical Investigation into the Cooperativity Effect Between Dihydrogen-bonding and H-M∙∙∙π (M = Li, Na, K) Interactions Among HF, MH with the Ï€-electron Donor C2H 2, C 2H 4 or C 6H 6 Journal of Molecular Modeling. Apr, 2013  |   Pubmed ID: 23620226 The DFT-B3LYP/6-311++G(3df,2p) and MP2(full)/6-311++G(3df,2p) calculations were carried out on the binary complex formed by HM (M = Li, Na, K) and HF or the Ï€-electron donor (C2H2, C2H4, C6H6), as well as the ternary system FH∙∙∙HM∙∙∙C2H2/C2H4/C6H6. The cooperativity effect between the dihydrogen-bonding and H-M∙∙∙π interactions was investigated. The result shows that the equilibrium distances R H∙∙∙H and R M∙∙∙π in the ternary complex decrease and both the H∙∙∙H and H-M∙∙∙π interactions are strengthened when compared to the corresponding binary complex. The cooperativity effect of the dihydrogen bond on the H-M∙∙∙π interaction is more pronounced than that of the M∙∙∙π bond on the H∙∙∙H interaction. Furthermore, the values of cooperativity effect follow the order of FH∙∙∙HNa∙∙∙π > FH∙∙∙HLi∙∙∙π > FH∙∙∙HK∙∙∙π and FH∙∙∙HM∙∙∙C6H6 > FH∙∙∙HM∙∙∙C2H4 > FH∙∙∙HM∙∙∙C2H2. The nature of the cooperativity effect was revealed by the analyses of the charge of the hydrogen atoms in H∙∙∙H moiety, atom in molecule (AIM) and electron density shifts methods.
• Pluronic Mixed Micelles Overcoming Methotrexate Multidrug Resistance: in Vitro and in Vivo Evaluation International Journal of Nanomedicine. 2013  |   Pubmed ID: 23620663 A Pluronic polymeric mixed micelle delivery system was developed in this study by using Pluronic P105 and F127 block copolymers to encapsulate the antitumor compound, methotrexate (MTX). The MTX-loaded Pluronic P105/F127 mixed micelle exhibited the spherical shape with about 22 nm in diameter, high encapsulation efficiency (about 85%) and pH-dependent in vitro drug release. In this study, A-549 and KBv cell lines were selected as multidrug resistance tumor cell models, while H-460 and KB cell lines were chosen as sensitive tumor cells. The MTX-loaded Pluronic P105/F127 mixed micelle exhibited significant higher in vitro cytotoxicity in multidrug resistant tumor cells than that of control (MTX injection) mainly because of higher cellular uptake of MTX. The pharmacokinetic studies indicated that the Pluronic micelles significantly prolonged systemic circulation time of MTX compared to MTX injection. Moreover, a much stronger antitumor efficacy in KBv tumor xenografts nude mice was observed in the MTX-loaded Pluronic P105/F127 mixed micelle group, than MTX. Collectively, Pluronic P105/F127 mixed micelles could significantly enhance the antitumor activity of MTX and might be a promising drug delivery platform for multidrug resistance modulation.
• Characterization and Comparative Profiling of MicroRNAs in a Sexual Dimorphism Insect, Eupolyphaga Sinensis Walker PloS One. 2013  |   Pubmed ID: 23620723 BACKGROUND: MicroRNAs are now recognized as key post-transcriptional regulators in animal ontogenesis and phenotypic diversity. Eupolyphaga sinensis Walker (Blattaria) is a sexually dimorphic insect, which is also an important source of material used in traditional Chinese medicine. The male E. sinensis have shorter lifecycles and go through fewer instars than the female. Furthermore, the males have forewings, while the females are totally wingless. RESULTS: We used the Illumina/Solexa deep sequencing technology to sequence small RNA libraries prepared from the fourth-instar larvae of male and female E. sinensis. 19,097,799 raw reads were yielded in total: 7,817,445 reads from the female library and 11,280,354 from the male, respectively. As a result, we identified 168 known miRNAs belonging to 55 families as well as 204 novel miRNAs. Moreover, 45 miRNAs showed significantly different expression between the female and the male fourth-instar larvae, and we validated 10 of them by Stem-loop qRT-PCR. Some of these differentially expressed miRNAs are related to metamorphosis, development and phenotypic diversity. CONCLUSIONSSIGNIFICANCE: This is the first comprehensive description of miRNAs in E. sinensis. The results provide a useful resource for further in-depth study on molecular regulation and evolution of miRNAs. These findings not only enrich miRNAs for hemimetabolans but also lay the foundation for the study of post-transcriptional regulation on the phenomena of sexual dimorphism.
• The Association Between COX-2 Polymorphisms and Hematologic Toxicity in Patients with Advanced Non-Small-Cell Lung Cancer Treated with Platinum-Based Chemotherapy PloS One. 2013  |   Pubmed ID: 23620771 Overexpression of COX-2 is proved to contribute to tumor promotion and carcinogenesis through stimulating cell proliferation, inhibiting apoptosis and enhancing the invasiveness of cancer cells. Apoptosis-related molecules are potential predictive markers for survival and toxicity in platinum treatment. This study aimed at investigating the association between COX-2 polymorphisms and the occurrence of grade 3 or 4 toxicity in advanced non-small cell lung cancer patients treated with platinum-based chemotherapy.
• Does Chloroplast Size Influence Photosynthetic Nitrogen Use Efficiency? PloS One. 2013  |   Pubmed ID: 23620801 High nitrogen (N) supply frequently results in a decreased photosynthetic N-use efficiency (PNUE), which indicates a less efficient use of accumulated Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). Chloroplasts are the location of Rubisco and the endpoint of CO2 diffusion, and they play a vital important role in photosynthesis. However, the effects of chloroplast development on photosynthesis are poorly explored. In the present study, rice seedlings (Oryza sativa L., cv. 'Shanyou 63', and 'Yangdao 6') were grown hydroponically with three different N levels, morphological characteristics, photosynthetic variables and chloroplast size were measured. In Shanyou 63, a negative relationship between chloroplast size and PNUE was observed across three different N levels. Here, plants with larger chloroplasts had a decreased ratio of mesophyll conductance (gm) to Rubisco content (gm/Rubisco) and a lower Rubisco specific activity. In Yangdao 6, there was no change in chloroplast size and no decline in PNUE or gm/Rubisco ratio under high N supply. It is suggested that large chloroplasts under high N supply is correlated with the decreased Rubisco specific activity and PNUE.