[Analysis of the complete genome characterization of 11 human astrovirus strains in Shandong Province]

Objective: To study the complete genome characterization of Human Astrovirus (HAstV) in Shandong Province. Methods: Stool samples from acute flaccid paralysis (AFP) surveillance in Shandong Province from 2020 to 2022 were collected, and HAstV nucleic acid was examined by real-time quantitative PCR (qPCR). Next-generation sequencing (NGS) was conducted for the positive samples to obtain complete genome sequences and identify the genotype. Homology comparison and phylogenetic analysis were performed by using BioEdit and Mega software. Results: A total of 667 samples were examined by qPCR, of which 14 were HAstV-positive (2.1%), including HAstV-1 (n=6), MLB1 (n=6), MLB2 (n=1), and VA2 (n=1). The complete genome sequences were obtained from 11 samples. The six HAstV-1 sequences of this study had 98.2% to 99.9% nt similarities with each other and 87.6% to 98.6% with those from other regions. The four MLB1 sequences of this study had 99.1% to 99.9% nt similarities with each other and 92.2% to 99.4% with those from other regions. The VA2 sequence of this study had 96.0% to 96.3% nt similarities with those from other regions. Phylogenetic analysis based on ORF2 region showed that the local HAstV-1 sequences were most closely related to Japanese strains, and had distinct topology with phylogenies based on ORF1a and ORF1b regions. Conclusion: The complete genome sequences of 11 HAstV strains are obtained, and the VA2 complete genome is found.

[Analysis of influencing factors and clinical value of anterior peritoneal reflection for patients with rectal cancer]

Objectives: To investigate the factors influencing the height of anterior peritoneal reflection (APR) for patients with rectal cancer, and to analyze the relationship between the APR and the lateral lymph node metastasis. Methods: Clinical data of 432 patients with tumor located within and below APR were retrospectively collected from the rectal cancer database at the Department of General Surgery, Peking Union Medical College Hospital from August 2020 to September 2022. Ninty-eight non-rectal cancer patients were also enrolled as a control group. There were 308 males and 124 females in the tumor group, aged (M(IQR)) 62 (16) years (range: 24 to 85 years) and 53 males and 45 females in the control group, aged 60 (22) years (range: 27 to 87 years). The APR height, pelvis, and tumor-related parameters were measured by MRI. A multifactor linear regression model was established to analyze the dependent correlation factors of APR height. These factors of the two groups were matched by propensity score matching and their APR heights were compared after matching. An ordinal Logistic regression model was established to explore the relationship between APR-related parameters and radiographic lateral lymph node metastasis. Results: The APR height of the tumor group was (98.7±14.4) mm (range: 43.3 to 154.0 mm) and the control group was (95.1±12.7) mm (range: 68.0 to 137.9 mm). Multivariable linear regression revealed that the greater the weight (B=0.519, 95%CI: 0.399 to 0.640, P<0.01), the anterior pelvic depth (B=0.109, 95%CI: 0.005 to 0.213, P=0.039) and the smaller the bi-ischial diameter (B=-0.172, 95%CI:-0.294 to -0.049, P=0.006), the higher the APR height. The tumor group had a higher APR height than the control group after propensity score matching ((98.3±14.2) mm vs. (95.1±12.7) mm, t=-1.992, P=0.047). Ordinal Logistic regression indicated that the longer segment of the tumor invade the nonperitoneal rectum was an independent influencing factor of radiographic lateral lymph node metastasis (OR=1.016, 95%CI: 1.002 to 1.030, P=0.021), while the distance between the anal verge and the tumor was not (OR=0.986, 95%CI: 0.972 to 1.000, P=0.058). Conclusions: The higher the weight, the deeper and narrower the pelvis, the higher the APR height. There is a certain relationship between APR and lateral lymph node metastasis on imaging.

Effects of Testosterone Replacement Therapy on Muscle Strength in Older Men with Low to Low-Normal Testosterone Levels: A Systematic Review and Meta-Analysis

BACKGROUND

Previous studies and meta-analyses have explored the relationship among testosterone, muscle strength, and physical function, to the best of our knowledge, no meta-analysis has investigated the effects of testosterone replacement therapy (TRT) on subgroup of relatively hypogonadal older men.

OBJECTIVE

The aim of this study was to evaluate the effect of TRT in older men with low testosterone levels.

METHODS

PubMed, Embase, and Web of Science were systematically searched for articles published between January 1990 and April 2020. We included randomized controlled studies that investigated the effect of TRT and included older men (age >60 years) with relatively low testosterone levels. Studies were extracted following the PRISMA flowchart, and the included randomized controlled trials were evaluated using RoB 2.0. Our main outcome was muscle strength changes after TRT evaluated using a metaregression of confounding factors. Secondary outcomes included changes in physical performance and the risk ratio of adverse events. Random-effects meta-analyses of TRT on muscle strength and physical function were performed.

RESULTS

Thirteen studies with 2,043 patients were included. The mean age of subjects in various studies ranged from 65.9 years to 76 years. Transdermal testosterone dosages ranged from 5 to 10 g/day, while intramuscular options were 125 mg/week or 200 mg every 2 weeks. Oral testosterone supplementation was given at 160 mg/day in one study. Pooled meta-analyses revealed greater muscle strength improvement after TRT compared with placebo (Hedges' g = 0.21; 95% CI: = 0.15-0.28). Intramuscular administration of TRT had greater efficacy (Hedges' g = 0.74; 95% CI: = 0.34-1.14) than transdermal and oral TRT (p < 0.001). A metaregression revealed that baseline serum total testosterone was associated with muscle strength improvement (β = -0.004, p = 0.002). The risk ratios of adverse events, including elevated prostate-specific antigen, acute coronary syndrome, and prostate cancer, were not significantly different.

CONCLUSION

TRT improved muscle strength in older, relatively hypogonadal men. The effect was more pronounced in populations with lower baseline testosterone levels.

The Intra-Hospital Medical Dispute Burden and Capacities: A Nationwide Survey in Taiwan

(1) Background: Medical disputes have long been resolved via lawsuits. Alternative dispute resolutions have been promoted for their benefits and win-win results. This study aims to investigate Taiwanese hospital medical dispute capacities and burdens. (2) Methods: This study used 2015 nationwide questionnaire data. The number and value of medical disputes that occurred in 2014 was examined to evaluate hospitals' capabilities. Poisson regressions were used to determine the impact of coping abilities on the incidence of disputes and the associated compensation. (3) Results: The response rate of the questionnaire was 90%. Hospital features associated with higher medical disputes incidence included those of a scale ≤ 100 or 200-499 and having a dispute-inform process of over 4 h. In contrast, hospitals whose compensation fund was solely based on medical liability insurance reported less medical dispute incidence. The features associated with higher compensation were lack of continuing training and having a dispute-inform process over 4 h. In contrast, hospitals with standard operating procedures for in-hospital mediation and solicitude paid lower compensation. (4) Conclusions: Hospitals with quicker response times experienced fewer medical disputes and paid lower compensation. Dispute coping skills, other than reaction time, were more visible in compensation bargaining, but were not significantly correlated with incidence.

Exploring the Potential Performance of Fibroscan for Predicting and Evaluating Metabolic Syndrome using a Feature Selected Strategy of Machine Learning

Metabolic syndrome (MetS) includes several conditions that can increase an individual's predisposition to high-risk cardiovascular events, morbidity, and mortality. Non-alcoholic fatty liver disease (NAFLD) is a predominant cause of cirrhosis, which is a global indicator of liver transplantation and is considered the hepatic manifestation of MetS. FibroScan^® provides an accurate and non-invasive method for assessing liver steatosis and fibrosis in patients with NAFLD, via a controlled attenuation parameter (CAP) and liver stiffness measurement (LSM or E) scores and has been widely used in current clinical practice. Several machine learning (ML) models with a recursive feature elimination (RFE) algorithm were applied to evaluate the importance of the CAP score. Analysis by ANOVA revealed that five symptoms at different CAP and E score levels were significant. All eight ML models had accuracy scores > 0.9, while treebags and random forest had the best kappa values (0.6439 and 0.6533, respectively). The CAP score was the most important variable in the seven ML models. Machine learning models with RFE demonstrated that using the CAP score to identify patients with MetS may be feasible. Thus, a combination of CAP scores and other significant biomarkers could be used for early detection in predicting MetS.

Cost-Effectiveness Analysis of Personalized Hypertension Prevention

BACKGROUND

While a population-wide strategy involving lifestyle changes and a high-risk strategy involving pharmacological interventions have been described, the recently proposed personalized medicine approach combining both strategies for the prevention of hypertension has increasingly gained attention. However, a cost-effectiveness analysis has been hardly addressed. This study was set out to build a Markov analytical decision model with a variety of prevention strategies in order to conduct an economic analysis for tailored preventative methods.

METHODS

The Markov decision model was used to perform an economic analysis of four preventative strategies: usual care, a population-based universal approach, a population-based high-risk approach, and a personalized strategy. In all decisions, the cohort in each prevention method was tracked throughout time to clarify the four-state model-based natural history of hypertension. Utilizing the Monte Carlo simulation, a probabilistic cost-effectiveness analysis was carried out. The incremental cost-effectiveness ratio was calculated to estimate the additional cost to save an additional life year.

RESULTS

The incremental cost-effectiveness ratios (ICER) for the personalized preventive strategy versus those for standard care were -USD 3317 per QALY gained, whereas they were, respectively, USD 120,781 and USD 53,223 per Quality-Adjusted Life Year (QALY) gained for the population-wide universal approach and the population-based high-risk approach. When the ceiling ratio of willingness to pay was USD 300,000, the probability of being cost-effective reached 74% for the universal approach and was almost certain for the personalized preventive strategy. The equivalent analysis for the personalized strategy against a general plan showed that the former was still cost-effective.

CONCLUSIONS

To support a health economic decision model for the financial evaluation of hypertension preventative measures, a personalized four-state natural history of hypertension model was created. The personalized preventive treatment appeared more cost-effective than population-based conventional care. These findings are extremely valuable for making hypertension-based health decisions based on precise preventive medication.

New Surveillance Metrics for Alerting Community-Acquired Outbreaks of Emerging SARS-CoV-2 Variants Using Imported Case Data: Bayesian Markov Chain Monte Carlo Approach

BACKGROUND

Global transmission from imported cases to domestic cluster infections is often the origin of local community-acquired outbreaks when facing emerging SARS-CoV-2 variants.

OBJECTIVE

We aimed to develop new surveillance metrics for alerting emerging community-acquired outbreaks arising from new strains by monitoring the risk of small domestic cluster infections originating from few imported cases of emerging variants.

METHODS

We used Taiwanese COVID-19 weekly data on imported cases, domestic cluster infections, and community-acquired outbreaks. The study period included the D614G strain in February 2020, the Alpha and Delta variants of concern (VOCs) in 2021, and the Omicron BA.1 and BA.2 VOCs in April 2022. The number of cases arising from domestic cluster infection caused by imported cases (Dci/Imc) per week was used as the SARS-CoV-2 strain-dependent surveillance metric for alerting local community-acquired outbreaks. Its upper 95% credible interval was used as the alert threshold for guiding the rapid preparedness of containment measures, including nonpharmaceutical interventions (NPIs), testing, and vaccination. The 2 metrics were estimated by using the Bayesian Monte Carlo Markov Chain method underpinning the directed acyclic graphic diagram constructed by the extra-Poisson (random-effect) regression model. The proposed model was also used to assess the most likely week lag of imported cases prior to the current week of domestic cluster infections.

RESULTS

A 1-week lag of imported cases prior to the current week of domestic cluster infections was considered optimal. Both metrics of Dci/Imc and the alert threshold varied with SARS-CoV-2 variants and available containment measures. The estimates were 9.54% and 12.59%, respectively, for D614G and increased to 14.14% and 25.10%, respectively, for the Alpha VOC when only NPIs and testing were available. The corresponding figures were 10.01% and 13.32% for the Delta VOC, but reduced to 4.29% and 5.19% for the Omicron VOC when NPIs, testing, and vaccination were available. The rapid preparedness of containment measures guided by the estimated metrics accounted for the lack of community-acquired outbreaks during the D614G period, the early Alpha VOC period, the Delta VOC period, and the Omicron VOC period between BA.1 and BA.2. In contrast, community-acquired outbreaks of the Alpha VOC in mid-May 2021, Omicron BA.1 VOC in January 2022, and Omicron BA.2 VOC from April 2022 onwards, were indicative of the failure to prepare containment measures guided by the alert threshold.

CONCLUSIONS

We developed new surveillance metrics for estimating the risk of domestic cluster infections with increasing imported cases and its alert threshold for community-acquired infections varying with emerging SARS-CoV-2 strains and the availability of containment measures. The use of new surveillance metrics is important in the rapid preparedness of containment measures for averting large-scale community-acquired outbreaks arising from emerging imported SARS-CoV-2 variants.

[Genetic characteristics of varicella zoster virus in Shandong province from 2020 to 2021]

Objective: To investigate the genetic characteristics of varicella zoster virus (VZV) in Shandong province from 2020 to 2021. Methods: From April 2020 to December 2021, 85 herpes fluid samples from suspected varicella patients in Shandong province were collected. The qPCR was used to detect viral DNA and screen suspected samples. Six single nucleotide polymorphisms (SNPs) of ORF22 fragment and ORF38 fragment in positive samples were examined via PCR and Sanger sequencing to identify the viral genotypes. Four SNPs of ORF38 and ORF62 were examined to identify the vaccine and wild-type strains. The sequences were analyzed with Sequencher and MEGA7 software, using the VZV reference strain sequences from GenBank. Results: In the 85 samples suspected of varicella, 80 were VZV positive and wild-type strains belonging to Clade 2. Compared with clade 2 representative strains, the nucleotide and amino acid similarities of ORF22 fragment were 99.5%-100% and 98.5%-100%, respectively. SD20-1, SD20-5, SD20-6, SD20-8, SD20-9, SD20-10, SD20-11, SD20-12, SD20-13, SD20-30 and SD20-31 had a A➝G nucleotide mutation at 37990, causing amino acid change from glutamine to arginine. SD21-1 had a C➝A nucleotide mutation at 38059, causing threonine to asparagine during coding. Conclusions: From 2020 to 2021, all VZV strains in Shandong province are the wild-type strains belonging to Clade 2.

Association between liver stiffness measurement by transient elastography and chronic kidney disease

ABSTRACT

Transient elastography or elastometry (TE) is widely used for clinically cirrhosis and liver steatosis examination. Liver fibrosis and fatty liver had been known to share some co-morbidities that may result in chronic impairment in renal function. We conducted a study to analyze the association between scores of 2 TE parameters, liver stiffness measurement (LSM) and controlled attenuation parameter (CAP), with chronic kidney disease among health checkup population.This was a retrospective, cross-sectional study. Our study explored the data of the health checkup population between January 2009 and the end of June 2018 in a regional hospital. All patients were aged more than 18 year-old. Data from a total of 1940 persons were examined in the present study. The estimated glomerular filtration rate (eGFR) was calculated by the modification of diet in renal disease (MDRD-simplify-GFR) equation. Chronic kidney disease (CKD) was defined as eGFR < 60 mL/min/1.73 m2.The median of CAP and LSM score was 242, 265.5, and 4.3, 4.95 in non-CKD (eGFR > 60) and CKD (eGFR < 60) group, respectively. In stepwise regression model, we adjust for LSM, CAP, inflammatory markers, serum biochemistry markers of liver function, and metabolic risks factors. The P value of LSM score, ALT, AST, respectively is .005, <.001, and <.001 in this model.The LSM score is an independent factor that could be used to predict renal function impairment according to its correlation with eGFR. This result can further infer that hepatic fibrosis may be a risk factor for CKD.

Effects of obesity on pulmonary function considering the transition from obstructive to restrictive pattern from childhood to young adulthood

Adults with obesity exhibit a restrictive pattern, whereas children with obesity exhibit an obstructive pattern. However, the transition process remains unclear. We performed a systematic search for studies reporting on body mass index and pulmonary function in children. The main outcomes were forced expiratory volume in 1 s (FEV₁ ), forced vital capacity (FVC), and their ratio (FEV₁ /FVC). We compared individuals with overweight or with obesity with individuals with normal weight. Random-effects models were used to calculate pooled estimates. A total of 17 studies were included. Individuals with obesity had a lower FEV₁ /FVC ratio (mean difference [MD] = -3.61%; 95% confidence interval [CI] = -4.58%, -2.64%) and a higher percent-predicted FVC (MD = 3.33%; 95% CI = 0.79%, 5.88%) than those with normal weight. Obesity impaired pulmonary function in the obstructive pattern during childhood to young adulthood, and the maximum obstruction was observed at the age of 16 years in boys and 20 years in girls. The effects attenuated at approximately 30 years and then shifted to the restrictive pattern after 35 years of age in men and 40 years in women. The effects of obesity on pulmonary function change from the obstructive pattern in childhood to the restrictive pattern in adulthood.

Impact of COVID-19 pandemic on accessibility of Taiwanese medical care

OBJECTIVES

Whether and how the COVID-19 pandemic affected utilization of routine medical care in areas with low infection risk, such as Taiwan, has not been widely addressed. We aimed to evaluate the impact of the COVID-19 pandemic on access to medical care.

STUDY DESIGN

Before and after exposure (COVID-19 pandemic) design with a historical control group for comparison of clinical visits based on a retrospective cohort of 6722 customary patients of a community hospital in Zhunan, Taiwan.

METHODS

Repeated measurements of medical utilization in 4-month periods (January to April) of 2019 and 2020 in light of the emerging COVID-19 pandemic were collected. Access to medical care was defined as the mean frequencies of clinical visits. The impacts of the COVID-19 pandemic on access in the overall and specific groups were quantified with a multivariable Poisson regression model.

RESULTS

The overall outpatient visits per month declined by 39% (rate ratio [RR], 0.61; P < .0001) after adjusting for demographics. A notable reduction in visits was observed in foreign patients (RR, 0.50; P < .0001). The visits of the elderly (≥ 80 years) were the most frequent before the COVID-19 pandemic but were reduced by 44% (RR, 0.56; P < .0001) after it began. Most disease categories revealed a declining trend, but the size of reduction varied by International Classification of Diseases codes.

CONCLUSIONS

The COVID-19 pandemic prevented some individuals from keeping regular medical appointments even in an area with a low infection risk. Our findings imply that more research is required to mitigate the effects of delayed medical care for patients who infrequently utilized medical care during and after the long-lasting pandemic period.

[The diagnostic value of chromosome microarray analysis technique in the genetic causes of children with intellectual disability or global developmental delay]

Objective: To study the value of chromosome microarray analysis (CMA) application in children with developmental delay (DD), intellectual disability (ID), autistic spectrum disorder (ASD) and multiple congenital anomalies (MCA). Methods: Genomic DNA was extracted from peripheral blood samples. Array-based comparative genomic hybridization (array-CGH) analysis and single nucleotide polymorphism array (SNP-array) were performed in 1 320 children with DD/ID, ASD, with or without epilepsy and MCA who were admitted to Peking University First Hospital from 2014 to 2019. The results of genetic etiology test of CMA in children with mental retardation or global DD was summarized. Results: Of 1 320 samples, there were 10 cases of aneuploid abnormality, 6 cases of uniparental disomy and one case of mosaicism, respectively. Pathogenic copy number variations (CNVs) were found in 320 cases and pathogenic CNVs were detected in 23 cases, with a combined detection rate of 26% (343/1 320). CNVs of uncertain clinical significance occurred in 107 cases, accounting for 8.1% (107/1 320). There were 25 cases of possible benign CNVs, accounting for 2% (25/1 320), while benign CNVs were reported in 20 cases, accounting for 1.5% (20/1 320). The detection rate of MCA with DD/ID was 39.8% (130/327). Conclusions: CMA has the advantages of high resolution and covering the whole genome. It can detect the chromosomal abnormalities, microdeletions and duplications seen under the microscope, thus the genetic etiology of children with mental retardation or global DD can be diagnosed.

Effect of metabolic syndrome on incidence of oral potentially malignant disorder: a prospective cohort study in Taiwan

OBJECTIVES

We aimed to assess the effect of metabolic syndrome (MetS) on incident oral potentially malignant disorder (OPMD).

DESIGN

We conducted a prospective cohort study of the Changhua community-based integrated screening (CHCIS) programme and nationwide oral cancer screening programme during the period between 2005 and 2014.

SETTING

CHCIS, Taiwan.

PARTICIPANTS

We enrolled 17 590 participants aged 30 years and older.

MAIN OUTCOMES AND MEASURES

We assessed the impact of MetS on the outcome measured by incident OPMD.

RESULTS

The incidences of OPMD among subjects with and without MetS were 7.68 ‰ and 5.38 ‰, respectively. After adjusting for confounders, subjects with MetS exhibited a statistically greater risk of developing OPMD compared with those who were free of MetS by 33% (adjusted rate ratio, aRR=1.33, 95% CI 1.14 to 1.55). Individual components of MetS still remained significant, including central obesity (aRR=1.22, 95% CI 1.04 to 1.44), hypertriglyceridaemia (aRR=1.26, 95% CI 1.07 to 1.49) and hyperglycaemia (aRR=1.20, 95% CI 1.02 to 1.41). Central obesity and hypertriglyceridaemia were also statistically associated with a subtype of OPMD, namely, leukoplakia.

CONCLUSION

The temporal influence of MetS on the risk of incident OPMD was noted in our prospective cohort study. Therefore, promoting an MetS prevention and control programme might reduce the occurrence of OPMD and oral cancer.

Simultaneous multi-slice accelerated diffusion-weighted imaging with higher spatial resolution for patients with liver metastases from neuroendocrine tumours

AIM

To evaluate the imaging characteristics of simultaneous multi-slice (SMS) accelerated diffusion-weighted imaging (DWI) with decreased section thickness, with and without motion correction, in comparison to conventional DWI (cDWI) for the detection of lesions in patients with neuroendocrine tumour (NET) liver metastases.

MATERIALS AND METHODS

Fifteen patients with NET liver metastases underwent cDWI (section thickness [SL]=4 mm) and SMS-DWI (SL=2 mm). Non-linear motion-corrected (Moco)-SMS-DWI was generated in addition to the original series. Qualitative imaging characteristics (five-point Likert scale), the number of high signal lesions, and the detectability and delineation of lesions were evaluated and compared using the Friedman and the Dunn-Bonferroni tests. The test-retest variability (TRV) of the cDWI and SMS-DWI techniques was investigated among 11 healthy volunteers who underwent cDWI (SL=4 mm) and SMS-DWI (SL=4 mm) twice. The Friedman and the Dunn-Bonferroni post-hoc tests were used to compare the mean apparent diffusion coefficient (ADC) and the TRV in different liver regions between the three series.

RESULTS

Moco-SMS-DWI demonstrated significantly superior overall image quality (p<0.001) with significantly fewer artefacts (p=0.003) than cDWI. The number of lesions detected by cDWI, SMS-DWI, and Moco-SMS-DWI were 348, 504, and 523, respectively. The detectability and delineation of the lesions and the ADC values were significantly higher on the SMS-DWI and Moco-SMS-DWI images than on the cDWI images (all p<0.001). Moco-SMS-DWI showed significantly higher TRV than cDWI in regions near the liver edge (p=0.018).

CONCLUSIONS

SMS-DWI achieves higher spatial resolution than cDWI within the same acquisition time, detects more lesions, and provides better lesion delineation. By applying motion correction, the TRV of DWI could be enhanced in regions near the liver edge.

Skeletal Muscle Ratio: A Complete Mediator of Physical Activity and HbA1C in Type 2 Diabetes

BACKGROUND

An increase in the physical activity level reduces body weight, decreases body fat, increases skeletal muscle mass, and improves serum glucose; however, the influence of body composition parameters on the relationship between physical activity and serum glucose remains unclear.

OBJECTIVE

This study investigated whether skeletal muscle and visceral fat affect the relationship between high physical activity and long-term serum glucose goals.

METHOD

This cross-sectional study recruited patients with type 2 diabetes. The Chinese version of the International Physical Activity Questionnaire was used for estimating the physical activity level, and a bioimpedance device was used to measure the skeletal muscle ratio (skeletal muscle mass/total body weight, %) and visceral fat area (cm²). Hierarchical logistic regression models and mediation tests were conducted according to Hayes' procedures.

RESULTS

Of the total 543 Chinese individuals with type 2 diabetes enrolled, HbA1C levels of fewer than half (n = 243, 44.8%) met the target of ≤7.0%. The skeletal muscle ratio was found to be a complete mediator (OR = 0.920, 95% CI: 0.848 to 0.998; indirect effect: -0.238, 95% CI: -0.525 to -0.020) of the relationship between high physical activity and the target HbA1C level after controlling for visceral fat area (indirect effect: -0.013, 95% CI: -0.183 to 0.156), age, time since diabetes diagnosis, and rice intake.

CONCLUSION

Nurses should include an increase in the skeletal muscle ratio as an objective in physical activity interventions for patients with type 2 diabetes to help them achieve their long-term serum glucose goals.

Predicting Metabolic Syndrome With Machine Learning Models Using a Decision Tree Algorithm: Retrospective Cohort Study

Background

Metabolic syndrome is a cluster of disorders that significantly influence the development and deterioration of numerous diseases. FibroScan is an ultrasound device that was recently shown to predict metabolic syndrome with moderate accuracy. However, previous research regarding prediction of metabolic syndrome in subjects examined with FibroScan has been mainly based on conventional statistical models. Alternatively, machine learning, whereby a computer algorithm learns from prior experience, has better predictive performance over conventional statistical modeling.

Objective

We aimed to evaluate the accuracy of different decision tree machine learning algorithms to predict the state of metabolic syndrome in self-paid health examination subjects who were examined with FibroScan.

Methods

Multivariate logistic regression was conducted for every known risk factor of metabolic syndrome. Principal components analysis was used to visualize the distribution of metabolic syndrome patients. We further applied various statistical machine learning techniques to visualize and investigate the pattern and relationship between metabolic syndrome and several risk variables.

Results

Obesity, serum glutamic-oxalocetic transaminase, serum glutamic pyruvic transaminase, controlled attenuation parameter score, and glycated hemoglobin emerged as significant risk factors in multivariate logistic regression. The area under the receiver operating characteristic curve values for classification and regression trees and for the random forest were 0.831 and 0.904, respectively.

Conclusions

Machine learning technology facilitates the identification of metabolic syndrome in self-paid health examination subjects with high accuracy.

Rapid Zeeman atomic absorption determination of copper in serum and urine

In this simple, quick procedure for determining copper in human serum and urine, the serum and urine specimens were analyzed directly after dilution with a solution of HNO3 and Triton X-100, 1 mL/L each. We calibrated with aqueous standards for quantitation in Zeeman background atomic absorption spectrometry. By modifying the drying and pyrolysis stages of the graphite furnace atomic absorption spectrometer, we reduced the analytical time to 30 s per determination. The within-run imprecision (CV) is 2.6% and 3.4% and the between-run imprecision is 0.9% and 2.5% for serum and urine copper at concentrations of 30.4 and 2.70 mumol/L, respectively. The accuracy of this fast method was verified by analyzing the National Institute of Standards and Technology Standard Reference Materials SRM 1598 bovine serum and SRM 2670 urine (agreement with certified values within 0.1 mumol/L for serum and within 0.02 mumol/L for urine), by analytical recovery studies (98% recovered in serum, 100% recovered in urine), and by comparison with our normal routine method. We also used the Quebec Interlaboratory Comparison Program to validate the analytical performance. From the precision and accuracy studies, we conclude that this fast-furnace program is a rapid, simple, and reliable method for determining copper in serum and urine.

Reduction of AHI1 in the serum of Taiwanese with probable Alzheimer's disease

OBJECTIVE

The development of blood-based biomarkers for early diagnosis and treatment of Alzheimer's disease (AD) is desirable. In AD model mouse brain and neuronal cells, Abelson helper integration site-1 (AHI1) protein is reduced. AHI1 facilitates intracellular amyloid precursor protein (APP) translocation to inhibit amyloidogenic pathology of AD, and thus may be an AD biomarker.

METHODS

This study was conducted among 32 AD patients and 54 healthy control (HC) subjects. AHI1-related protein levels from initially collected serum samples in each group were screened using Western blotting. The protein concentrations of AHI1 and amyloid-β (Aβ), peptide(s) derived from APP, from all serum samples were analyzed using ELISA.

RESULTS

In AD serum, AHI1 and a large truncated C-terminal APP fragment were significantly reduced. The average concentrations of serum AHI1 and Aβ in AD were significantly lower than those in HC. Notably, AHI1 concentration in HC serum was decreased in an age-dependent manner, while it was consistently low in AD serum and had no correlation with Aβ or mini-mental state examination score. The receiver operating characteristic analysis on all subjects demonstrated an area under curve (AUC) value of 0.7 for AHI1 on AD diagnosis, while the AUC increased to 0.82 on the subjects younger than 77 years old, suggesting a good diagnostic performance of serum AHI1 for AD especially at relatively young age.

CONCLUSION

An early event of AHI1 reduction in the body of AD patients was observed. Serum AHI1 may be valuable for early diagnosis of AD.

[Etiologic surveillance and analysis of acute meningitis and encephalitis syndrome in Jinan city in 2013-2016]

Objective: To characterize the etiology and epidemiological characteristics of the acute meningitis and encephalitis syndrome (AMES) in Jinan city in 2013-2016. Methods: The epidemiological data, clinical diagnosis, serum and cerebrospinal fluid (CSF) specimens were collected from 3 577 AMES cases in 6 sentinel hospitals in Jinan city in 2013-2016. Samples of all cases were made sero-diagnosis for Immunoglobulin (Ig) M antibody to Japanese encephalitis virus (JEV) and negative cases of JEV for enterovirus (EV), mumps virus (MuV) and herpes simplex virus (HSV) by enzyme-linked immunosorbent assay (ELISA). Virus isolation and molecular identification were performed. Positive rates were analyzed by Chi-square test. Results: In 2013-2016, the positive rates of JEV, EV, MuV and HSV were 9.0% (322/3 577 cases), 22.1% (643/2 916 cases), 9.9% (289/2 916 cases), 26.9% (783/2 916), respectively. Of these, the positive rates of JEV were 32.9% (261/794), 1.2% (14/1 175), 1.0% (8/807) and 4.9% (39/801 cases); EV: 19.5% (91/466), 35.1% (342/974 cases), 15.5% (115/743) and 13.0% (95/733); MuV: 9.2% (43/466), 14.4% (140/974), 9.0% (67/743) and 5.3% (39/733). HSV: 35.4% (165/466), 38.5% (375/974), 25.7% (191/743) and 7.1% (52/733). There were significant differences in positive rates of 4 kinds of viruses in 2013-2016 (P<0.001). A total of 81 EV strains belonging to 8 serotypes were isolated from 1 020 CSF specimens. The positive rates were 4.8% (6 cases), 13.1% (55 cases), 4.1% (7 cases) and 4.2% (13 cases) from 2013 to 2016. Coxsackievirus (CV) B5, echovirus (E) 6 and E30 accounted for 46% (37 isolates), 22% (18 isolates) and 21% (17 isolates) of all strains. Conclusion: The AMES cases in Jinan city in 2013-2016 were mainly caused by HSV, EV, MuV, JEV. CVB5, E6 and E30 were the dominant serotypes of EV associated with AMES cases in Jinan city.

Impact of oral potentially malignant disorder subtypes on all-cause and cause-specific mortality in males

OBJECTIVES

To quantify the effect of oral potentially malignant disorder (OPMD) subtypes on mortality from oral cancer and type 2 diabetes among areca nut chewers and/or cigarette smokers.

MATERIALS AND METHODS

A retrospective cohort design was devised to follow 14,749 men attending community-based screening program for oral cancer between 1998 and 2000 and followed until 2010. The Cox proportional hazards regression model was applied to assess the effect of OPMD on death.

RESULTS

A total of 1,291(8.75%) patients were detected as OPMD. Among those free of T2DM at baseline, the elevated risk for death from T2DM was noted for OSF (aHR = 3.62, 95% CI: 1.25-10.51) and erythroplakia (aHR = 5.01, 95% CI: 1.17-21.45). The elevated risk for all-cause death for OPMD was mainly explained by deaths from oral cancer and T2DM but not other causes of death.

CONCLUSIONS

Oral potentially malignant disorder, particularly OSF and erythroplakia, in male cigarette smokers and/or areca nut chewers led to an incremental elevated risk of T2DM mortality in the way of being distal to the occurrence of T2DM, implying that early detection and prevention of OPMD may not only reduce oral cancer mortality but also result in the reduction of T2DM mortality.

Circ-ITCH regulates triple-negative breast cancer progression through the Wnt/β-catenin pathway

Recent studies indicate that circular RNA (circRNA) is involved in tumorigenesis, but its role in triple-negative breast cancer (TNBC) remains largely unknown. In this study, we characterized the role of circ-ITCH in TNBC and found that circ-ITCH was significantly down-regulated in TNBC tissues and cell lines and closely associated with poor prognosis. We therefore constructed the MDA-MB-231 and BT-549 TNBC cell lines stably expressing circ-ITCH by lentiviral vectors to determine its underlying mechanisms in TNBC progression. Most importantly, over-expression of circ-ITCH remarkably inhibited TNBC proliferation, invasion and metastasis both in vitro and in vivo. Mechanistically, we found that circ-ITCH acts as a sponge for miR-214 and miR-17 to increase expression of its ITCH linear isoform, thereby inactivating Wnt/β-catenin signaling. Our combined results show for the first time that circ-ITCH is a tumor suppressor, a promising prognostic biomarker in TNBC and that its restoration could well be a successful strategy in TNBC.

Cost-effectiveness analysis of universal influenza vaccination: Application of the susceptible-infectious-complication-recovery model

OBJECTIVES

Despite the fact that vaccination is an effective primary prevention strategy for the containment of influenza outbreaks, health policymakers have shown great concern over the enormous costs involved in universal immunization, particularly when resources are limited.

METHODS

A two-arm cost-effectiveness analysis (CEA) was conducted that took into account the aspect of herd immunity. The analysis used a study cohort of 100000 residents with a demographic make-up identical to that of the underlying population in Taipei County, Taiwan, during the epidemic influenza season of 2001-2002. The parameters embedded in the dynamic process of infection were estimated through the application of the newly proposed susceptible-infection-complication-recovery (SICR) model to the empirical data, in order to compute the number of deaths and complications averted due to universal vaccination compared to no vaccination. Incremental cost-effectiveness ratios (ICERs) and the cost-effectiveness acceptability curve (CEAC) given maximum amount of willingness-to-pay (WTP) were calculated to delineate the results of the two-arm CEA.

RESULTS

The incremental costs involved in the vaccinated group as compared to the unvaccinated group were $1195 to reduce one additional complication and $805 to avert one additional death, allowing for herd immunity. The corresponding figures were higher for the results without considering herd immunity. Given the ceiling ratio of WTP equal to $10000 (approximately two-thirds of GDP), the probability of the vaccination being cost-effective for averting death was 100% and for averting complications was 96.7%.

CONCLUSIONS

Universal vaccination against seasonal influenza was found to be very cost-effective, particularly when herd immunity is considered. The probability of being cost-effective was almost certain given the maximum amount of WTP within two-thirds of the GDP.

[The 453rd case: diarrhea, weight loss and diabetes mellitus]

Chronic diarrhea is a common complaint in gastroentology department, which is classified into a variety of types. While as eosinophilic gastroenteritis is a rare cause. A 50-year-old male patient was admitted with a 2-year history of diarrhea worsened for 10 months. Fasting could alleviate the diarrhea. Laboratory findings demonstrated anemia, low vitamins and minerals, fat malabsorption and abnormal D-xylose absorption test, delayed gastric emptying. According to the endoscopic biopsy of gastrointestinal mucosa, the diagnosis of eosinophilic gastroenteritis was made. Diabetic neuropathy may aggravate the symptom. The diarrhea resolved after the administration of steroids.

Arterial Stiffness Index and Coronary Artery Plaques in Patients with Subclinical Coronary Atherosclerosis

BACKGROUND

Arterial stiffness is a physiologic quantitative value used to measure arterial compliance. It is predictive of coronary atherosclerosis in patients with intermediate to high cardiovascular risk. However, a correlation between arterial stiffness and subclinical coronary atherosclerosis has yet to be established. Therefore, the purpose of this study was to evaluate arterial stiffness using an arterial stiffness index (ASI) and investigate its association with coronary artery plaque in patients with subclinical coronary atherosclerosis.

METHODS

Our study enrolled 156 consecutive subjects who underwent health screening using a 64-slice cardiac computed tomography angiography (CCTA). Their arterial stiffness index was assessed noninvasively by CardioVision(®) MS-2000. The atheroma on the coronary vessel walls was analyzed.

RESULTS

Of the 156 patients, 53 displayed at least one > 50% stenotic lesion over the coronary arteries in CCTA images. The patients with at least one > 50% coronary stenotic plaque were older and had higher systolic blood pressure and ASI values than patients without > 50% coronary stenotic plaque. After dividing the study population into 2 groups by those patients over and under 50 years of age, the ASI positively correlated with the presentation of at least one > 50% coronary stenotic plaque in patients aged ≥ 50 years (odds ratio = 1.02, 95% confidence interval: 1.00-1.04, p = 0.03).

CONCLUSIONS

The ASI could play a role in risk stratification systems for coronary artery disease in patients with subclinical coronary atherosclerosis, and is a useful clinical marker for the correlation of early coronary plaque.

KEY WORDS

Arterial stiffness; Arterial stiffness index; Atherosclerosis; Coronary artery plaque.

Screening of the residual normal ovarian tissue adjacent to orthotopic epithelial ovarian carcinomas in nude mice

The objective of this study was to explore the feasibility and methods of screening the residual normal ovarian tissue adjacent to orthotopic ovarian carcinomas in nude mice. Human epithelial ovarian cancer cells (OVCAR3) were subcutaneously implanted for a tumor source and ovarian orthotopic transplantation. The cancer tissue, proximal paraneoplastic tissue, middle paraneoplastic tissue, remote paraneoplastic tissue, and normal ovarian tissue were removed. CK-7, CA125, p53, survivin, MMP-2, and TIMP-2 expression was detected by reverse transcription polymerase chain reaction. We obtained 35 paraneoplastic residual ovarian tissues with normal biopsies from 40 cases of an orthotopic epithelial ovarian carcinoma model (87.5%). CK-7, CA125, p53, survivin, MMP-2, and TIMP-2 expression was lower in proximal paraneoplastic tissue than in cancer tissue (P < 0.05) and higher than in middle and remote paraneoplastic tissue (P < 0.01). There was no statistically significant difference between the expression of these genes in middle and proximal paraneoplastic tissue as well as among residual normal ovarian tissues with different severity (P > 0.05). In ovarian tissues of 20 normal nude mice, the expression of CK- 7, CA125, p53, survivin, MMP-2, and TIMP-2 was negative. Overall, the expression levels of CK-7, CA125, p53, survivin, MMP-2, TIMP-2, and other molecular markers showed a decreasing trend in the non-cancer tissue direction. The expression levels can be used as standards to screen residual normal ovarian tissue. We can obtain relatively safe normal ovarian tissues adjacent to epithelial ovarian cancer.

Mass measurements of the neutron-deficient 41Ti, 45Cr, 49Fe, and 53Ni nuclides: first test of the isobaric multiplet mass equation in f p-shell nuclei

Isochronous mass spectrometry has been applied to neutron-deficient 58Ni projectile fragments at the HIRFL-CSR facility in Lanzhou, China. Masses of a series of short-lived T(z)=-3/2 nuclides including 41Ti, 45Cr, 49Fe, and 53Ni have been measured with a precision of 20-40 keV. The new data enable us to test for the first time the isobaric multiplet mass equation (IMME) in fp-shell nuclei. We observe that the IMME is inconsistent with the generally accepted quadratic form for the A=53, T=3/2 quartet. We perform full space shell model calculations and compare them with the new experimental results.

Dynamic epidemic model for influenza with clinical complications

OBJECTIVE

To incorporate clinical complications in the susceptible-infectious-recovered model to estimate parameters needed in dynamic changes of infectious diseases and to further evaluate the impact of disease-controlling methods.

METHODS

We developed a new extended epidemic model that incorporates of disease-related complications. This model was applied to empirical data on influenza during the epidemic season of 2001-2002 in Taipei County, Taiwan, to estimate the transmission parameters that were converted to the basic reproductive rate (R(0)). The proposed model, in conjunction with estimated parameters, was applied in quantifying the efficacy of different preventive strategies.

RESULTS

During the study period there were 5 outbreaks of influenza. The estimated transmission probability for outbreak 1 was 0.135, with corresponding estimate of R(0), 2.7; for outbreak 2, 0.165, with estimated R(0), 3.3; for outbreak 3, 0.15, with R(0), 4.5; for outbreak 4, 0.165, with R(0), 5; and for outbreak 5, 0.165, with R(0), 5. The efficacy of antiviral prophylaxis to reduce the total episodes was 18% (95% CI, 15%-21%) under the coverage rate of 30%, 31% (95% CI, 26%-36%) under the coverage rate of 50%, and 73% (95% CI, 59%-90%) under the coverage rate of 80%. The corresponding figures for the efficacy of vaccination were 17% (95% CI, 15%-20%), 41% (95% CI, 35%-48%), and 76% (95% CI, 61%-95%). Combination of both methods would yield efficacy of 32% (95% CI, 28%-38%), 59% (95% CI, 49%-71%), and 88% (95% CI, 66%-118%), respectively.

CONCLUSIONS

We demonstrate how to apply a novel extended model to empirical surveillance data of an influenza study for estimating parameters pertaining to dynamic changes in the infection process. These parameters were further used to evaluate the impact of antiviral prophylaxis alone, vaccination alone, or the use of both methods.

Characterization of a chiral phase in an achiral bent-core liquid crystal by polarization studies of resonant x-ray forbidden reflections

The chiral antiferroelectric structure of an achiral bent-core liquid crystal is characterized by resonant x-ray scattering at chlorine K edge. The "forbidden" reflections resulting from the glide or screw symmetry elements are restored by the anisotropy of the tensor structure factor, which we calculate for two possible structural models. A careful analysis of the polarization states of the restored "forbidden" reflections enables an unambiguous identification of a chiral structure (i.e., the so-called anticlinic, antiferroelectric smectic-C or Sm-C(A)P(A)) coexisting with the achiral synclinic antiferroelectric smectic-C or Sm-C(S)P(A). The method proves to be quite powerful as it identifies the chiral structure within coexisting phases despite an imperfect orientation of the sample. The volume fraction of the chiral phase and the distribution of alignment are extracted from the data.

Effect of enantiomeric excess on the phase behavior of antiferroelectric liquid crystals

Null transmission ellipsometry and resonant x-ray diffraction are employed to study the effect of enantiomeric excess (EE) on the phase behavior of antiferroelectric liquid crystal 10OTBBB1M7. Phase sequence, layer spacing, and pitch of the helical structures of the smectic-C(α)* and smectic-C* phases are studied as a function of temperature and EE. Upon reducing EE, a liquid-gas-type critical point of the smectic-C(α)* to smectic-C* transition is observed, as well as the disappearance of the smectic-C(d4)* and the smectic-C(d3)* phases. Results are analyzed in a mean-field model.

Direct mass measurements of short-lived A=2Z-1 nuclides (63)Ge, (65)As, (67)Se, and (71)Kr and their impact on nucleosynthesis in the rp process

Mass excesses of short-lived A=2Z-1 nuclei (63)Ge, (65)As, (67)Se, and (71)Kr have been directly measured to be -46,921(37), -46,937(85), -46,580(67), and -46,320(141)  keV, respectively. The deduced proton separation energy of -90(85)  keV for (65)As shows that this nucleus is only slightly proton unbound. X-ray burst model calculations with the new mass excess of (65)As suggest that the majority of the reaction flow passes through (64)Ge via proton capture, indicating that (64)Ge is not a significant rp-process waiting point.

Evolution of a rare sequence of surface transitions with temperature and film thickness

In free-standing smectic films, layers near the surfaces of the film often contain molecules tilted away from the layer normal, while in the bulk of the film the magnitude of the tilt decays exponentially with distance from the surface. We have identified the detailed molecular tilt orientations in the surface layers of films for one antiferroelectric liquid crystal compound. A series of five surface structures exists with different nonplanar tilt arrangements for each structure. The molecular orientations in the surface layers evolve with temperature. The polarization of the film also evolves with temperature, corresponding to the tilt arrangements. Using ellipsometric data, we reconstruct the changes in the magnitude and azimuthal direction of the tilt as functions of temperature. We have also studied films of several different thicknesses. We present a phase diagram for the five surface structures showing the dependence on temperature and film thickness.

Nonplanar tilts in very thin smectic films of one liquid-crystal compound

Surface effects cause tilted molecular arrangements in smectic layers near the surface of a free-standing liquid-crystal film in which the bulk of the film is in the smectic- A phase. One recent work has shown that the tilt directions in adjacent surface layers may be nonplanar. In this paper we study films with thicknesses of two to six smectic layers. Surface effects dominate in these very thin films. We show that the molecular tilts are nonplanar even in these very thin films.

Recovery of a reversed phase sequence in one ternary liquid-crystal-mixture system

The nOHFBBB1M7 (n=10) compound, 10OHF, shows a reversed SmC{FI2}-SmC phase sequence, unique among all known antiferroelectric liquid crystals. This reversed phase sequence is stabilized when 10OHF is doped with 9OTBBB1M7(C9) or 11OTBBB1M7(C11). In contrast, doping of the homologous members ( n=9 , 11, or 12) eliminates the SmC{FI2} phase. One 10OHF/11OHF mixture without the SmC{FI2} phase was selected for further studies. By adding C9 into this particular mixture, the reversed phase sequence is revived. To our surprise, even though 11OHF destabilizes the SmC_{FI2} phase in binary mixtures with 10OHF, it significantly increases the SmC_{FI2} temperature range in the 10OHF/11OHF/C9 ternary mixtures.

A preliminary investigation of the association between serum uric acid and impaired renal function

BACKGROUND

Hemodialysis for end-stage renal disease (ESRD) incurs huge medical costs in Taiwan. We set out to determine if it is possible to help control chronic renal disease with early treatment of hyperuricemia.

METHODS

Data from Taipei Medical University Hospital (TMUH) health center from January 2004 to December 2006 were analyzed to correlate renal function and blood uric acid concentration. Patients were divided into 5 groups according to their serum uric acid concentration (< 4; 4 approximately 5.9; 6 approximately 7.9; 8 approximately 9.9, and > 10 mg/dl). According to our laboratory data, elevated serum creatinine levels (> 1.3 mg/dL) indicated impaired renal function.

RESULTS

In total, there were 5722 patients, including 2816 (49.2%) men and 2906 (50.8%) women, with a median age of 67. Impaired renal function was noted in 307 (5.4%) cases. Serum uric acid was significantly correlated with blood urea nitrogen and serum creatinine. Groups with a higher serum uric acid level had an increased risk of impaired renal function.

CONCLUSION

Our purpose in this preliminary observation was to try to define a starting point for the early control of serum uric acid, in order to avoid the development of impaired renal function. We found that serum uric acid level to < 6 mg/dl seemed to be associated with less renal function impairment.

Effects of doping on an unusual smectic- C*alpha-smectic-C*FI2-smectic-C* phase sequence

The compound 10OHF has a partially inverted phase sequence, unique among the series of nOHF homologous compounds and all other known liquid crystals, with the smectic-C*FI2 (SmC*FI2) phase occurring at higher temperature than the smectic-C* (SmC*) phase. We present ellipsometric data to identify the phase sequences of 9OHF, 10OHF, 11OHF, and 12OHF. Binary mixtures of 10OHF with C11, a compound with the typical phase sequence among the smectic phases, show that the unusual phase sequence of 10OHF stabilizes upon mixing and that SmC*FI2 predominates over SmC* throughout the entire mixing phase diagram. In thin films of some mixtures, surface interactions induce a reentrant SmC*FI2-SmC*-SmC*FI2 transition in the rest of the film.

In situ x-ray reflectivity studies on the formation of substrate-supported phospholipid bilayers and monolayers

We conducted time-dependent, in situ x-ray reflectivity measurements on the formation of substrate-supported lipid monolayers and bilayers at solid-liquid interfaces, buried under an aqueous buffer with various concentrations (5, 10, 20, 40, and 50 microg/ml ) of lipid 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). The DOPC bilayer is formed on the hydrophilic surface of a bare Si substrate, while the DOPC monolayer is formed on a hydrophobic octadecylthricholorsilane (OTS) monolayer-coated Si substrate. The evolution of the reflectivity curves from the lipid bilayers is well described by lateral growth of bilayer islands, consistent with the rupture and fusion model for the adsorption of lipid vesicles to solid-liquid interfaces. By contrast, the formation of the lipid monolayer on OTS-coated Si occurs through a relatively fast coverage of the entire interfacial area, followed by an increase in the monolayer thickness. For both monolayers and bilayers, the rate of lipid layer growth increases with increasing lipid concentration in the buffer solution.

Polarization studies of resonant forbidden reflections in liquid crystals

We report the results of resonant x-ray diffraction experiments performed on thick films of a biaxial liquid crystal made of achiral bent-core molecules. Polarization properties of forbidden reflections are observed as a function of the sample rotation angle phi about the scattering vector Q for the first time on a fluid material. The experimental data are successfully analyzed within a tensor structure factor model by taking the nonperfect alignment of the liquid crystal into account. The local structure of the B2 mesophase is hence determined to be SmC_{S}P_{A}.

Unique pitch evolution in the smectic-C+alpha phase

Employing resonant x-ray diffraction, we observed unique pitch evolutions in the smectic-C*(alpha) phase in mixtures of two antiferroelectric liquid crystals. Our results show that the pitch in this phase continuously evolves across 4 layers, contradicting a theoretical model that predicts that the smectic-C*(FI2) phase intervenes in the smectic-C*(alpha) phase. The phase sequences we found can be explained by another model that includes one type of long-range interaction among smectic layers.

Smectic-C*alpha phase with two coexistent helical pitch values and a first-order smectic-C*alpha to smectic-C* transition

Previous results from Kundu using dielectric relaxation have suggested a reentrant antiferroelectric-ferroelectric-antiferroelectric transition in the compound LN36. Our comprehensive studies of this compound using differential optical reflectivity, nonadiabatic scanning calorimetry, null transmission ellipsometry, and resonant x-ray diffraction show that in fact LN36 exhibits the usual phase sequence for chiral smectic liquid crystals: SmA*-SmC*alpha-SmC*-SmC*FI1-SmC*A . Moreover, the SmC*alpha-SmC* transition is a first-order transition, characterized by a discontinuous change in the helical pitch. At temperatures just above the SmC*alpha-SmC* transition, two different values for the helical pitch are simultaneously observed for the first time.

Optical studies on the surface-induced tilted layers in freestanding films of two no-layer-shrinkage liquid crystal compounds

Null transmission ellipsometry has been employed to study the molecular arrangements in freestanding films of two no-layer-shrinkage liquid crystal homologous compounds above the bulk smectic A-smectic C* (Sm C*) transition temperature. An unusual nonplanar-parallel or nonplanar-antiparallel-parallel transition has been observed in both compounds under a proper electric field. With the addition of one CH2 group, while the SmC* phase is more stable thermally, the magnitude of the critical field needed to induce a parallel-antiparallel transition decreases dramatically.

Smectic-Calpha*-smectic-C* phase transition and critical point in binary mixtures

We have investigated the smectic-Calpha*-smectic-C* (SmCalpha*-SmC*) transition in a series of binary mixtures with resonant x-ray diffraction, differential optical reflectivity, and heat capacity measurements. Results show that the phases are separated by a first-order transition that ends at a critical point. We report the observation of such a critical point. We have proposed the appropriate order parameter and obtained values of two critical exponents associated with this transition. The values of the critical exponents suggest that long-range interactions are present in the SmCalpha*-SmC* critical region.

Surface-induced multiple reentrant transitions

We have studied tilted surface layers in the bulk SmA temperature window of one liquid crystal using null transmission ellipsometry. Five distinct nonplanar surface structures were observed. We present analyses of the tilt and azimuthal profiles of the structures and examine the transitions between the structures. The transitions are identified as a double reentrant synclinic-anticlinic-synclinic-anticlinic transition. Meanwhile, the transitions also display reentrant ferroelectric-antiferroelectric-ferroelectric behavior.

Optical and resonant X-ray diffraction studies confirm a SmC*FI2-SmC* liquid crystal phase sequence reversal

Employing both null transmission ellipsometry and resonant x-ray diffraction, we confirmed the SmC*FI2-SmC* phase sequence reversal in one liquid crystal compound and specially prepared binary mixtures. This phase sequence reversal was predicted by two recent theoretical advances. Moreover, the temperature range for the SmC*FI2 phase increases significantly in the mixture suggesting that such a phase sequence may exist in other compounds.

Economic evaluation of vaccination against influenza in the elderly: an experience from a population-based influenza vaccination program in Taiwan

Due to viral strains, influenza season, and consultations and admission rates varying from country to country, the continued economic evaluation of influenza vaccination for the elderly people aged 65 years and above is paramount, particularly in areas with dense population. Efficacy and cost-effective analysis of influenza vaccination in reducing all-cause mortality and hospitalization was therefore elucidated based on a prospective and population-based study targeted to 226,997 elderly people aged 65 years and above residing in Taipei county, Taiwan between 1 October 2000 and 31 March 2001. Vaccination against influenza for the elderly persons can lead to a 29% (95% CI: 23-35%) significant reduction of all-cause deaths. Approximately, 20% (95% CI: 9-30%) significant reduction in hospitalization was observed for average-risk group but 4% (95% CI: -4-11%) non-significant reduction for high-risk group. Community-based influenza vaccination program for elderly people aged 65 years and above was demonstrated to be effective in reducing mortality in all elderly people but not significantly in reducing hospitalization. Universal vaccination program for the elderly people seems cost-effective in averting death or gaining life years.

Calorimetric investigations of liquid-crystal compounds exhibiting almost no layer-shrinkage behavior through the smectic-A-smectic- C* transition

Heat-capacity measurements have been made on liquid-crystal compounds exhibiting almost no layer-shrinkage (NLS) behavior through the Sm-A-Sm- C(*) phase transition. The transition was found to be second order for two of the substances studied. It was found that the heat-capacity anomaly accompanying a second-order Sm-A-Sm- C(*) transition with NLS behavior is quite similar to that observed for typical antiferroelectric liquid crystals of the 4-(1-methylheptyloxycarbonyl)phenyl 4'-octyloxybiphenyl-4-carboxylate (MHPOBC) group, showing three-dimensional (3D) XY behavior in the vicinity of the transition. On the other hand, for one compound which shows a weakly first-order transition, the anomaly is almost symmetric above and below T(c) , with a significant fluctuation effect in the Sm-A phase. For this compound, the critical behavior of the heat-capacity anomaly is almost tricritical in the immediate vicinity of T(c) , while away from T(c) the behavior can be explained with the 3D XY model. This suggests that the underlying transition with the 3D XY critical behavior is driven to almost being tricritical but remaining weakly first order. No indication of low-dimensional character in the critical behavior was found in both cases.

Temperature variation of film tension above the bulk smectic-A-isotropic transition in freestanding liquid-crystal films

We have measured the temperature variation of film tension above the bulk smectic-A-isotropic transition in freestanding films of two liquid-crystal compounds. Above the transition, the tension increases sharply with temperature, and the slope is proportional to the film's thickness regardless of whether or not the compound exhibits regular layer-by-layer thinning. The data can be interpreted in the context of theoretical models for layer thinning.

Increased plasma concentration of nitric oxide in type 2 diabetes but not in nondiabetic individuals with insulin resistance

OBJECTIVE

Insulin resistance (IR) is a key element in the pathogenesis of type 2 diabetes. The results of recent experiments on insulin-mediated vasodilatation have suggested that vascular insensitivity is a component of IR. However, it is still controversial that patients with type 2 diabetes have a decreased ability of insulin to increase endothelial nitric oxide (NO) release.

METHOD

Plasma concentration of NO was examined in 26 patients with type 2 diabetes and 78 nondiabetic volunteers during an insulin suppression test. The test measured the efficacy of insulin in promoting disposal of the infused glucose load, in which the steady state plasma glucose (SSPG) during the 150-180 min of the test was used as an index of IR. Plasma NO levels were assayed by measurement of the stable end products of their metabolism. Comparison of plasma NO levels between groups were performed by Mann-Whitney test and relationships between SSPG and different variables were analyzed by partial correlations.

RESULTS

Our results showed that the plasma NO levels were significantly higher in the diabetic group. When the nondiabetic subjects were analyzed according to their SSPG levels, there was no difference of plasma NO levels between those with SSPG>160 mg/dl and those with SSPG<160 mg/dl. There were also no difference of NO levels between those with a family history of type 2 diabetes and those without. In the nondiabetic group, SSPG correlated with BMI, fasting insulin, triglyceride and HDL-cholesterol, but neither with plasma NO levels nor fasting plasma glucose.

CONCLUSION

Our data suggests that the impairment of NO activity in patients with type 2 diabetes is due to an impaired effect rather than its production. This altered NO signaling pathway is not an early event in insulin resistant individuals. Any such changes will not be apparent until type 2 diabetes with overt hyperglycemia develops.