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In JoVE (1)
- A Microfluidic System with Surface Patterning for Investigating Cavitation Bubble(s)–Cell Interaction and the Resultant Bioeffects at the Single-cell Level
Other Publications (25)
- [Zhonghua Yan Ke Za Zhi] Chinese Journal of Ophthalmology
- Emerging Infectious Diseases
- Emerging Infectious Diseases
- Journal of Hazardous Materials
- Hawaii Medical Journal
- Hawaii Medical Journal
- Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
- Health Care for Women International
- Journal of Affective Disorders
- Biophysical Journal
- Child Abuse & Neglect
- Hawai'i Journal of Medicine & Public Health : a Journal of Asia Pacific Medicine & Public Health
- Biophysical Journal
- American Journal of Public Health
- Childhood Obesity (Print)
- Food and Chemical Toxicology : an International Journal Published for the British Industrial Biological Research Association
- American Journal of Human Biology : the Official Journal of the Human Biology Council
- Childhood Obesity (Print)
- The Review of Scientific Instruments
- Hawai'i Journal of Medicine & Public Health : a Journal of Asia Pacific Medicine & Public Health
- Journal of Nutrition Education and Behavior
- BMC Research Notes
- Food Chemistry
Articles by Fenfang Li in JoVE
A Microfluidic System with Surface Patterning for Investigating Cavitation Bubble(s)–Cell Interaction and the Resultant Bioeffects at the Single-cell Level
Fenfang Li1, Fang Yuan2, Georgy Sankin1, Chen Yang1, Pei Zhong1
1Mechanical Engineering and Materials Science, Duke University, 2Huacells Corp
Other articles by Fenfang Li on PubMed
[Zhonghua Yan Ke Za Zhi] Chinese Journal of Ophthalmology. Apr, 2002 | Pubmed ID: 12133384
To compare the effectiveness of therapeutic regimen in Vogt-Koyanagi-Harada (VKH) syndrome and determine the reasonable regimen for different patients.
Emerging Infectious Diseases. Aug, 2005 | Pubmed ID: 16102308
The emergence of methicillin-resistant Staphylococcus aureus (MRSA) has generated considerable concern among medical and public health professionals. We used a statewide, population-based antimicrobial resistance surveillance system to examine epidemiologic trends for MRSA from outpatients and inpatients in Hawaii. Pediatric and adult patient populations were compared to assess characteristics of MRSA isolates specific for each group. From 2000 to 2002, 8,206 (26%) of 31,482 total S. aureus isolates were MRSA. During this period, the proportion of MRSA isolates increased in both outpatient and inpatient clinical settings (p<0.01). When stratified by age, annual trends showed a significant increase in the proportion of MRSA in adult patients (from 24% to 30%, p<0.01) but not in pediatric patients (from 25% to 27%, p>0.05). Although MRSA isolates from adults demonstrated high resistance to most non-beta-lactams, most MRSA isolates from pediatric outpatients remained susceptible to most non-beta-lactams.
Emerging Infectious Diseases. Oct, 2005 | Pubmed ID: 16318695
The effect of duplicate isolate removal strategies on Staphylococcal aureus susceptibility to oxacillin was compared by using antimicrobial test results for 14,595 isolates from statewide surveillance in Hawaii in 2002. No removal was compared to most resistant and most susceptible methods at 365 days and to the National Committee for Clinical Laboratory Standards (NCCLS) and Cerner algorithms at 3-, 10-, 30-, 90-, and 365-day analysis periods. Overall, no removal produced the lowest estimates of susceptibility. Estimates with either NCCLS or Cerner differed by <2% when the analysis period was the same; with either method, the difference observed between a 90- and a 365-day period was <1%. The effect of duplicate isolate removal was greater for inpatient than outpatient settings. Considering the ease of implementation and comparability of results, we recommend using the first isolate of a given species per patient to calculate susceptibility frequencies for S. aureus to oxacillin.
Mechanism of the Enhanced Degradation of Pentachlorophenol by Ultrasound in the Presence of Elemental Iron
Journal of Hazardous Materials. Oct, 2006 | Pubmed ID: 16762499
Ultrasound combined with elemental iron (US/Fe(0)) is effective in oxidizing organic contaminants in water. The sonolysis degradation of pentachlorophenol (PCP) was significantly enhanced by a factor of 4.2 with the addition of elemental iron, mainly via reaction with hydroxyl radicals (OH radicals), and the synergistic mechanism of the enhancement in the combined system was investigated. Experiments were performed with (1) sole ultrasonic treatment; (2) ultrasound in presence of iron; (3) ultrasound combined with copper powder as the same particle size as iron powder; (4) ultrasound in presence of Fe(II). It was observed that PCP degradation and OH radicals production were both enhanced in these combined methods, and the pitting on the sonicated iron surface was apparent. These results indicated that the rate enhancements in US/Fe(0) system were attributed to (1) the iron solid effect and the catalysis of Fe(II) produced from corroded-iron with promoting the production of OH radicals; (2) the increased surface area of iron particles by acoustic cavitation with promoting the adsorption process.
Epidemiology of Methicillin-resistant Staphylococcus Aureus Among Incarcerated Population in Hawai'i, 2000-2005
Hawaii Medical Journal. Apr, 2010 | Pubmed ID: 20481235
It is estimated in this study the proportion and incidence of MRSA among the entire state of Hawai'i inmate population over a period of six years, using a statewide, population-based antimicrobial resistance surveillance system. Trend analyses were conducted on both MRSA proportion and MRSA incidence rates including MRSA patterns of antimicrobial resistance to other antibiotics. During the period from 2000 to 2005, 521 (69%) of 753 S. aureus isolates were MRSA. A significant increase in the proportion of MRSA were identified from both jail and prison inmates (p < 0.01). A significant increase in MRSA incidence was also observed among jail inmates (p = 0.005) but not among prison inmates (p = 0.18). A majority of non-beta-lactams, including clindamycin, tetracycline, and trimethoprim-sulfamethoxazole remained as a good choice for the treatment of MRSA infections among inmate population in Hawai'i. Active surveillance of MRSA infection in the inmate population is an important public health tool and should be continued.
Hawaii Medical Journal. May, 2010 | Pubmed ID: 20533756
Residing in long-term care facilities has long been identified as a risk factor for methicillin-resistant Staphylococcus aureus (MRSA) carriage and infection. The objective of this study was to describe MRSA epidemiology among residents in skilled nursing and intermediate care facilities (SNF/ICF) in Hawai'i, using a statewide, population-based antimicrobial resistance surveillance system. From 2000 to 2005, proportions of MRSA increased significantly during the 6-year study period, from 35.0% in 2000 to 58.6% in 2005 (p < 0.001). High levels of MRSA resistance to several commonly used antibiotics were observed, e.g., the level of MRSA resistance to clindamycin, ciprofloxacin, and erythromycin was at 77%, 90%, and 89% respectively. Nevertheless, there is a significant difference in the MRSA resistance pattern against certain antimicrobials in different geographic areas. For example, the level of MRSA resistance to trimethoprim-sulfamethoxazole was close to zero in Hawai'i County, but 13% in Kaua'i County. In contrast, the MRSA resistance to tetracycline was 46% in Hawai'i County, but 5% in Kaua'i County. Multi-drug resistant MRSA was well-established among nursing homes in Hawai'i. Regional antibiograms are important in the assistance of empirical therapy.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics. Dec, 2010 | Pubmed ID: 21230738
We demonstrate the dynamics of arrays of transient cavitation bubbles exposed to a sound field in a planar geometry. Single, double, and complex configurations of cavitation bubbles are obtained by shaping a pulsed laser beam with a digital hologram and focusing it into a thin gap of liquid. The liquid is driven with an oscillating pressure field of variable phase and amplitude. We compare the dynamics of a single bubble recorded with high-speed photography with a two-dimensional Rayleigh model. For multibubble configurations we observe bubble-bubble interaction and coalescence which depends on the phase of the acoustic field. Larger clusters demonstrate drastically enhanced collapse for high-amplitude driving, enabling the study of artificial cavitation clusters under strong driving.
Health Care for Women International. 2012 | Pubmed ID: 22946591
To compare the self-assessed health status (SAHS) of female caregivers of older adults across the United States (N = 1,496), China (N = 485), and the United Kingdom (N = 252), data from three data sets were analyzed to isolate significant predictors of SAHS using an adapted meta-analytic technique. Higher income and full-time employment were predictors of higher SAHS; chronic health condition and emotional strain predicted lower SAHS. Female gender was a predictor of lower SAHS. The health status of women was negatively impacted by the caregiving experience. National policies, such as those in the United Kingdom, may result in higher SAHS for women caregivers.
Nanoscale. Jan, 2013 | Pubmed ID: 23223666
The rapid development in nanoparticle production and application during the past decade requires an easy, rapid, and predictive screening method for nanoparticles toxicity assay. In this study, the toxicological effects and the source of toxicity of copper nanoparticles (CuNPs) are investigated based on a stress-responsive bacterial biosensor array. According to the responses of the biosensing strains, it is found that CuNPs induce not only oxidative stress in E. coli, but also protein damage, DNA damage, and cell membrane damage, and ultimately cause cell growth inhibition. Through enzyme detoxification analysis, the toxicological effects of CuNPs are traced to H(2)O(2) generation from CuNPs. Rapid copper release from CuNPs and Cu(I) production are observed. The oxidation of the released Cu(I) has a close relation to H(2)O(2) production, as tris-(hydroxypropyltriazolylmethyl) amine, the specific Cu(I) chelator, can largely protect the cells from the toxicity of CuNPs. In addition, the TEM study shows that CuNPs can be adsorbed and incepted fast by the cells. Comparatively, copper microparticles are relatively stable in the system and practically non-toxic, which indicates the importance of toxic estimation of materials at the nanoscale. In addition, the Cu(II) ion can induce protein damage, membrane damage, and slight DNA damage only at a relatively high concentration. The current study reveals the preliminary mechanism of toxicity of CuNPs, and suggests that the stress-responsive bacterial biosensor array can be used as a simple and promising tool for rapid screening in vitro toxicity of nanoparticles and studying the primary mechanism of the toxicity.
Evaluating PTSD Prevalence and Resilience Factors in a Predominantly Asian American and Pacific Islander Sample of Iraq and Afghanistan Veterans
Journal of Affective Disorders. Sep, 2013 | Pubmed ID: 23769294
This study examined the prevalence, and risk and resilience correlates of posttraumatic stress disorder (PTSD) in ethno-racially diverse Operation Enduring Freedom, Iraqi Freedom, and New Dawn (OEF/OIF/OND) Veterans in Hawai'i.
Biophysical Journal. Aug, 2013 | Pubmed ID: 23972839
Deformability while remaining viable is an important mechanical property of cells. Red blood cells (RBCs) deform considerably while flowing through small capillaries. The RBC membrane can withstand a finite strain, beyond which it ruptures. The classical yield areal strain of 2-4% for RBCs is generally accepted for a quasi-static strain. It has been noted previously that this threshold strain may be much larger with shorter exposure duration. Here we employ an impulse-like forcing to quantify this yield strain of RBC membranes. In the experiments, RBCs are stretched within tens of microseconds by a strong shear flow generated from a laser-induced cavitation bubble. The deformation of the cells in the strongly confined geometry is captured with a high-speed camera and viability is successively monitored with fluorescence microscopy. We find that the probability of cell survival is strongly dependent on the maximum strain. Above a critical areal strain of ∼40%, permanent membrane damage is observed for 50% of the cells. Interestingly, many of the cells do not rupture immediately and exhibit ghosting, but slowly obtain a round shape before they burst. This observation is explained with structural membrane damage leading to subnanometer-sized pores. The cells finally lyse from the colloidal osmotic pressure imbalance.
Early Childhood Maltreatment and Trajectories of Behavioral Problems: Exploring Gender and Racial Differences
Child Abuse & Neglect. Mar, 2014 | Pubmed ID: 23993147
The current study aimed to examine the trajectory of child behavior problems over time as a function of early maltreatment. We anticipated that early alleged maltreatment would have a substantial impact on both internalizing and externalizing behaviors. The impact of gender and racial differences in the trajectories were also examined. Using the LONGSCAN archived data, a total of 484 children were selected for the study from varying sites. Two groups were formed: children with early allegations of maltreatment from birth to age 4 and children without any report. Children included did not have further allegations of maltreatment from ages 4 to 12. Additionally, they must have completed a behavioral assessment using the Child Behavior Checklist at the age 4 baseline interview. Multilevel modeling using the SAS PROC MIXED procedure was used to examine the effects of early allegations of maltreatment on the trajectories of both internalizing and externalizing problems. Although race was not significant, gender was found to differ in trajectory of behavioral problems among children with early allegations of maltreatment. For boys, the impact of early maltreatment was strongest at the most proximal assessment of behavioral outcomes and then decreased gradually over the course of subsequent periods. For girls, although no significant impact was observed at each measurement point, the impact of early maltreatment increased and became pronounced over time. Findings support the importance of early intervention/prevention to decrease the likelihood of presenting behavioral problems in later childhood years with consideration to gender.
An Exploration of Ethnic, Immigration and Acculturation Differences on Tobacco Smoking Among Public High School Girls in Hawai'i
Hawai'i Journal of Medicine & Public Health : a Journal of Asia Pacific Medicine & Public Health. Jan, 2014 | Pubmed ID: 24470981
This cross-sectional study explores the differences in ethnicity, sex, immigration (place of birth of student and parents), and acculturation (based on language spoken at home) on current cigarette smoking among public high school students in Hawai'i, and especially examine if this affected smoking among girls. Previous behavior risk surveys of youth in Hawai'i showed higher smoking rates among girls, although these were not found to be statistically significant differences. Multiple years of data were compiled from the Hawai'i Youth Tobacco Survey (YTS) for years 2005, 2007, 2009, and 2011, for a total sample size of N=5,527. Multivariate logistic regression analysis was conducted to evaluate the likelihood of current cigarette smoking (in the past 30 days) in relation to a variety of factors. The analysis revealed that Hawai'i-specific ethnicity, grade, and sex were all significant predictors of smoking. Girls whose mothers were born in Hawai'i or in another United States state were more likely to smoke than those whose mothers were born in a foreign country. The model showed girls were more likely to smoke than boys. Eleventh and twelfth graders were more likely to smoke than ninth graders. Whites, Filipinos, Native Hawaiians, Pacific Islanders, and Other ethnic groups were more likely to smoke than those who identified themselves as Japanese.
Rebuttal to a Comment by Richard E. Waugh on Our Article "Yield Strength of Human Erythrocyte Membranes to Impulsive Stretching"
Biophysical Journal. Apr, 2014 | Pubmed ID: 24739182
Systematic Review of Prevalence of Young Child Overweight and Obesity in the United States-Affiliated Pacific Region Compared With the 48 Contiguous States: The Children's Healthy Living Program
American Journal of Public Health. Jan, 2015 | Pubmed ID: 25393168
We estimated overweight and obesity (OWOB) prevalence of children in US-Affiliated Pacific jurisdictions (USAP) of the Children's Healthy Living Program compared with the contiguous United States. We searched peer-reviewed literature and government reports (January 2001-April 2014) for OWOB prevalence of children aged 2 to 8 years in the USAP and found 24 sources. We used 3 articles from National Health and Nutrition Examination Surveys for comparison. Mixed models regressed OWOB prevalence on an age polynomial to compare trends (n = 246 data points). In the USAP, OWOB prevalence estimates increased with age, from 21% at age 2 years to 39% at age 8 years, increasing markedly at age 5 years; the proportion obese increased from 10% at age 2 years to 23% at age 8 years. The highest prevalence was in American Samoa and Guam.
Pacific Kids DASH for Health (PacDASH) Randomized, Controlled Trial with DASH Eating Plan Plus Physical Activity Improves Fruit and Vegetable Intake and Diastolic Blood Pressure in Children
Childhood Obesity (Print). Apr, 2015 | Pubmed ID: 25671796
Pacific Kids DASH for Health (PacDASH) aimed to improve child diet and physical activity (PA) level and prevent excess weight gain and elevation in blood pressure (BP) at 9 months.
Acute and Sub-chronic Toxicity of Glucose-cysteine Maillard Reaction Products in Sprague-Dawley Rats
Food and Chemical Toxicology : an International Journal Published for the British Industrial Biological Research Association. Jun, 2015 | Pubmed ID: 25817020
Maillard reaction products (MRPs) derived from glucose-cysteine reactions have excellent anti-browning ability. However, there is a lack of information about their acute and sub-chronic toxicities. To our knowledge, the present study is the first to evaluate the acute and sub-chronic toxicities of MRPs in experimental animals. Acute toxicity testing and analysis by Horn's method showed that the median lethal oral dose (LD50) of MRPs in rats was 6.81 g/kg body weight. The sub-chronic toxicity test involved feeding rats with diet containing 0, 0.43, 0.85, or 1.70% (w/w) MRPs for 90 days. These treatments did not affect mortality, gross pathology, histology, hematology, or blood chemistry, and there were no dose-dependent changes in feed consumption. Based on these results, the dietary no-observed-adverse-effect level (NOAEL) for 90-day exposure was 1.29 and 1.51 g MRPs/kg body weight/day for male and female rats, respectively.
Anthropometric Measurement Standardization in the US-affiliated Pacific: Report from the Children's Healthy Living Program
American Journal of Human Biology : the Official Journal of the Human Biology Council. May, 2016 | Pubmed ID: 26457888
Anthropometric standardization is essential to obtain reliable and comparable data from different geographical regions. The purpose of this study is to describe anthropometric standardization procedures and findings from the Children's Healthy Living (CHL) Program, a study on childhood obesity in 11 jurisdictions in the US-Affiliated Pacific Region, including Alaska and Hawai'i.
Head Start Wellness Policy Intervention in Hawaii: A Project of the Children's Healthy Living Program
Childhood Obesity (Print). Feb, 2016 | Pubmed ID: 26771119
The increased prevalence of childhood overweight and obesity across the United States and the Pacific has become a serious public health concern, with especially high prevalence among Native Hawaiian and Pacific Islander (NHPI) children. This study aimed to measure the effect of a Head Start (HS) policy intervention for childhood obesity prevention.
Pixel Multiplexing Technique for Real-time Three-dimensional-imaging Laser Detection and Ranging System Using Four Linear-mode Avalanche Photodiodes
The Review of Scientific Instruments. Mar, 2016 | Pubmed ID: 27036763
The avalanche-photodiode-array (APD-array) laser detection and ranging (LADAR) system has been continually developed owing to its superiority of nonscanning, large field of view, high sensitivity, and high precision. However, how to achieve higher-efficient detection and better integration of the LADAR system for real-time three-dimensional (3D) imaging continues to be a problem. In this study, a novel LADAR system using four linear mode APDs (LmAPDs) is developed for high-efficient detection by adopting a modulation and multiplexing technique. Furthermore, an automatic control system for the array LADAR system is proposed and designed by applying the virtual instrumentation technique. The control system aims to achieve four functions: synchronization of laser emission and rotating platform, multi-channel synchronous data acquisition, real-time Ethernet upper monitoring, and real-time signal processing and 3D visualization. The structure and principle of the complete system are described in the paper. The experimental results demonstrate that the LADAR system is capable of achieving real-time 3D imaging on an omnidirectional rotating platform under the control of the virtual instrumentation system. The automatic imaging LADAR system utilized only 4 LmAPDs to achieve 256-pixel-per-frame detection with by employing 64-bit demodulator. Moreover, the lateral resolution is ∼15 cm and range accuracy is ∼4 cm root-mean-square error at a distance of ∼40 m.
Validation of the Actical Accelerometer in Multiethnic Preschoolers: The Children's Healthy Living (CHL) Program
Hawai'i Journal of Medicine & Public Health : a Journal of Asia Pacific Medicine & Public Health. Apr, 2016 | Pubmed ID: 27099804
This study aimed to determine the validity and reliability of the Actical accelerometer for measuring physical activity (PA) in preschool children of mixed ethnicity, compared with direct observation via a modified System for Observing Fitness Instruction Time (SOFIT) protocol and proxy parental reports (PA Logs). Fifty children in Hawai'i wore wrist-mounted accelerometers for two 7-day periods with a washout period between each week. Thirty children were concurrently observed using SOFIT. Parents completed PA Logs for three days. Reliability and validity were measured by intra-class correlation coefficient and proportions of agreement concurrently. There was slight agreement (proportion of agreement: 82%; weighted Kappa=.17, P <.001) between the accelerometer and SOFIT as well as between the accelerometer and the PA Logs (proportions of agreement: 40%; weighted Kappa=0.15, P <.001). PA logs underestimated the PA levels of the children, while the Actical was found to be valid and reliable for estimating PA levels of multiethnic, mixed ethnicity preschoolers. These findings suggest that accelerometers can be objective, valid, and accurate physical activity assessment tools compared to conventional PA logs and subjective reports of activity for preschool children of mixed ethnicity.
Influence of Teachers' Personal Health Behaviors On Operationalizing Obesity Prevention Policy in Head Start Preschools: A Project of the Children's Healthy Living Program (CHL)
Journal of Nutrition Education and Behavior. May, 2016 | Pubmed ID: 27169640
To quantify the Head Start (HS) teacher mediating and moderating influence on the effect of a wellness policy intervention.
Quality Assurance of Data Collection in the Multi-site Community Randomized Trial and Prevalence Survey of the Children's Healthy Living Program
BMC Research Notes. Sep, 2016 | Pubmed ID: 27590179
Quality assurance plays an important role in research by assuring data integrity, and thus, valid study results. We aim to describe and share the results of the quality assurance process used to guide the data collection process in a multi-site childhood obesity prevalence study and intervention trial across the US Affiliated Pacific Region.
Prevalence of Obesity and Acanthosis Nigricans Among Young Children in the Children's Healthy Living Program in the United States Affiliated Pacific
Medicine. Sep, 2016 | Pubmed ID: 27631218
Estimate prevalence of obesity and acanthosis nigricans (AN) among children in United States Affiliated Pacific (USAP) jurisdictions.Cross-sectional measurement of weight, height, and AN in 5775, 2 to 8 years old in 51 communities-Hawai'i, Alaska, Commonwealth of the Northern Mariana Islands, Guam, American Samoa, Palau, Republic of the Marshall Islands (RMI), 4 Federated States of Micronesia (Pohnpei, Yap, Kosrae, Chuuk). Analyses weighted to jurisdiction-specific sex and age distributions accounting for clustering of communities within jurisdictions.Prevalence of obesity was 14.0%, overweight 14.4%, healthy weight 68.9%, and underweight 2.6%, higher in males (16.3%) than females (11.6%), higher among 6 to 8 years old (16.3%) than 2 to 5 years old (12.9%), highest in American Samoa (21.7%), and absent in RMI. In total, 4.7% of children had AN, with no sex difference, higher in 6 to 8 years old (6.8%) than 2 to 5 years old (3.5%) and highest in Pohnpei (11.9%), and absent in Alaska. Obesity was highly associated with AN (odds ratio = 9.25, 95% confidence interval = 6.69-12.80), with the strongest relationships among Asians, followed by Native Hawaiians and Pacific Islanders (NHPI).Obesity, age, and Asian and NHPI race were positively associated with AN.
Salting-out Extraction of Allicin from Garlic (Allium Sativum L.) Based on Ethanol/ammonium Sulfate in Laboratory and Pilot Scale
Food Chemistry. Feb, 2017 | Pubmed ID: 27664612
Salting-out extraction (SOE) based on lower molecular organic solvent and inorganic salt was considered as a good substitute for conventional polymers aqueous two-phase extraction (ATPE) used for the extraction of some bioactive compounds from natural plants resources. In this study, the ethanol/ammonium sulfate was screened as the optimal SOE system for the extraction and preliminary purification of allicin from garlic. Response surface methodology (RSM) was developed to optimize the major conditions. The maximum extraction efficiency of 94.17% was obtained at the optimized conditions for routine use: 23% (w/w) ethanol concentration and 24% (w/w) salt concentration, 31g/L loaded sample at 25°C with pH being not adjusted. The extraction efficiency had no obvious decrease after amplification of the extraction. This ethanol/ammonium sulfate SOE is much simpler, cheaper, and effective, which has the potentiality of scale-up production for the extraction and purification of other compounds from plant resources.