Pseudomonas aeruginosa AlgF is a protein-protein interaction mediator required for acetylation of the alginate exopolysaccharide.

Enzymatic modifications of bacterial exopolysaccharides enhance immune evasion and persistence during infection. In the Gram-negative opportunistic pathogen Pseudomonas aeruginosa, acetylation of alginate reduces opsonic killing by phagocytes and improves reactive oxygen species scavenging. Although it is well known that alginate acetylation in P. aeruginosa requires AlgI, AlgJ, AlgF, and AlgX, how these proteins coordinate polymer modification at a molecular level remains unclear. Here, we describe the structural characterization of AlgF and its protein interaction network. We characterize direct interactions between AlgF and both AlgJ and AlgX in vitro and demonstrate an association between AlgF and AlgX, as well as AlgJ and AlgI, in P. aeruginosa. We determine that AlgF does not exhibit acetylesterase activity and is unable to bind to polymannuronate in vitro. Therefore, we propose that AlgF functions to mediate protein-protein interactions between alginate acetylation enzymes, forming the periplasmic AlgJFXK (AlgJ-AlgF-AlgX-AlgK) acetylation and export complex required for robust biofilm formation.

Depression and Anxiety Symptoms and Treatment Utilization, and Associated HIV Outcomes among Adults with HIV in Rural Florida.

Persons living with HIV (PLWH) and depression or anxiety in the rural South may have suboptimal HIV outcomes. We sought to examine the proportion of PLWH from rural Florida with symptoms of depression or anxiety, the proportion who received depression or anxiety treatment, and the relationship between untreated and treated symptoms of depression or anxiety and HIV outcomes. Cross-sectional survey data collected between 2014 and 2018 were analyzed. Among 187 PLWH residing in rural Florida (median age 49 years, 61.5%, male 45.5% Black), 127 (67.9%) met criteria for symptoms of depression and/or anxiety. Among these 127 participants, 60 (47.2%) were not on depression or anxiety treatment. Participants with untreated symptoms of depression and anxiety (OR 3.2, 95% CI 1.2-9.2, p = 0.03) and treated depression and anxiety with uncontrolled symptoms (OR 1.4, 95% CI 0.5-4.0, p = 0.52) were more likely to have viral non-suppression compared to those without depression or anxiety in an unadjusted bivariate analysis. Only the association between untreated symptoms of depression and anxiety and viral non-suppression was statistically significant, and when adjusting for social and structural confounders the association was attenuated and was no longer statistically significant. This suggests that social and structural barriers impact both mental health and HIV outcomes. Our findings support the need for increased mental health services and resources that address the social and structural barriers to care for PLWH in the rural South.

Body mass index and body shape before treatment and nasopharyngeal carcinoma prognosis: A population-based patient cohort study in southern China.

A concern of reverse causation exists about the association between nasopharyngeal carcinoma (NPC) prognosis and body mass index (BMI) at diagnosis, while the prognostic impact of BMI measured years before diagnosis is unknown. Therefore, we investigated associations of prediagnosis and pretreatment BMI and body shape on NPC mortality. From a population-based patient cohort in southern China between 2010 and 2013, we included 2526 incident NPC cases with prospective follow-up through 2018. We assessed the associations of BMI and body shape at age 20 years, 10 years before diagnosis, and at diagnosis with NPC mortality, combining strategies of stratification and statistical adjustment to minimize reverse causation. We observed 25% lower all-cause mortality (hazard ratio [HR] 0.75, 95% confidence interval [CI]: 0.64-0.89) and 25% lower NPC-specific mortality (HR 0.75, 95% CI: 0.61-0.91) among overweight vs normal-weight NPC cases at diagnosis. Lean body shapes 1 and 2 at diagnosis were associated with 68% and 23% higher all-cause mortality, respectively, compared to normal body shape 3. No effect modification by cancer stage was detected for associations with all-cause or NPC-specific mortality. Associations with BMI and body shape 10 years before diagnosis were similar but attenuated, while body size and shape at age 20 were not associated with mortality. Being overweight at diagnosis decreased mortality, and thinner body shape increased mortality, compared to normal weight/body shape. These associations may be due to poorer nutrition and treatment intolerance, resulting in treatment discontinuation and worse survival outcomes.

Mental health, substance use, and risky sexual behaviors among women living with HIV.

INTRODUCTION: Risky sexual behavior has been explored in women living with HIV (WLHIV) internationally but is not well studied in WLHIV in the United States (U.S.). This merits further investigation due to the negative reproductive and HIV health outcomes associated with risky sexual behavior, such as the increased risk for HIV transmission and infertility from sexually transmitted infections (STIs). The aims of this study are to (1) describe sexual behaviors in a cohort of WLHIV in Florida, (2) determine whether demographic characteristics, substance use, and mental health symptoms are associated with risky sexual behavior in a cohort of WLHIV in Florida, and (3) explore whether the relationship between substance use and mental health symptoms and risky sexual behavior differs in reproductive-age (age 18-49), compared to non-reproductive-age WLHIV (age 50+). DESIGN: This was a cross-sectional analysis of data from a multisite cohort study done in Florida. METHODS: Data were collected from a sample of 304 participants who were recruited into the Florida Cohort Study from 9 clinical and community sites in Florida between 2014 to 2017. The predictor variables of interest were mental health symptoms, substance use, and demographic variables. The outcome variable of interest was risky sexual behavior which was defined as reporting ≥1 of the following: (1) at least one STI diagnosis in the past 12 months, (2) two or more sexual partners in the past 12 months, or (3) any inconsistent condom use in the past 12 months. Descriptive statistics, bivariate analysis, and logistic regression (p < 0.1) were conducted on the variables of interest. RESULTS: The mean age of the sample was 47.8 years, and approximately half (51.6%) of the sample was of reproductive-age. Reporting ≥1 risky sexual behavior was reported in over half (51.6%) of the reproductive-age WLHIV in the sample and 32% of the non-reproductive-age WLHIV in the sample. Binge drinking, alcohol-related problems, marijuana use, and age were all significantly associated with self-reporting ≥1 risky sexual behaviors in all WLHIV. Self-reporting binge drinking, marijuana use, and a high alcohol-related problems score respectively were associated with increased odds of self-reporting ≥1 risky sexual behavior in all WLHIV. Neither mental health symptoms nor race/ethnicity or education were significantly associated with self-reporting ≥1 risky sexual behavior in all WLHIV. Self-reporting severe anxiety symptoms and high alcohol-related problems scores respectively were associated with increased odds of self-reporting ≥1 risky sexual behavior only in reproductive-age WLHIV from the sample. CONCLUSION: Marijuana use, binge drinking, and alcohol-related problems appear to have a relationship with risky sexual behavior in WLHIV regardless of age. Reproductive-age also appears to influence risky sexual behavior in WLHIV, and specific reporting severe anxiety symptoms and high alcohol-related problems in reproductive-age WLHIV increases the odds of engaging in risky sexual behavior. CLINICAL SIGNIFICANCE: This study holds clinical significance for nurses and other clinicians working in reproductive health settings and clinics with WLHIV. Results indicate that it could be beneficial to do more screening for mental health symptoms (particularly anxiety) and alcohol use in younger reproductive-age WLHIV.

Correction: Efficient and stable electrorheological fluids based on chestnut-like cobalt hydroxide coupled with surface-functionalized carbon dots.

Correction for 'Efficient and stable electrorheological fluids based on chestnut-like cobalt hydroxide coupled with surface-functionalized carbon dots' by Yudai Liang et al., Soft Matter, 2022, DOI: 10.1039/D2SM00176D.

Efficient and stable electrorheological fluids based on chestnut-like cobalt hydroxide coupled with surface-functionalized carbon dots.

Intrinsically polarized electrorheological fluids (ERFs) have better thermal stability than ERFs with polar molecules, so they have a broader application prospect. However, the electrorheological efficiency of the common intrinsically polarized ERF is still lower than 1500, which is related to the poor wettability between polarized materials and the continuous phase. Carbon dots (CDs) exhibit good stability, semiconductor properties and low toxicity. We prepared biomimetic chestnut-like cobalt hydroxide coupled with surface-functionalized CD particles (Co(OH)2@CDs) by a simple hydrothermal method. Then we prepared an ERF by mixing Co(OH)2@CDs with silicone oil and studied the effect of CDs on its rheology and electrorheology properties. The synergistic effect of the lipophilic groups on the surface of CDs and the biomimetic chestnut-like structure makes Co(OH)2@CDs exhibit good wettability with silicone oil, and the optimal zero-field viscosity of Co(OH)2@CDs-ERF is only 0.46 Pa s (particle mass fraction of 40%). Exceptional electrorheological efficiency (about 10 000, shear rate 0.1 s-1, 5 kV mm-1) and dynamic shear stress stability of optimal Co(OH)2@CDs-ERF can be attributed to the dielectric enhancement of the biomimetic chestnut-like structure coupled with the semiconductor properties of CDs. In addition, Co(OH)2@CDs-ERF has excellent anti-settling performance, outstanding thermal stability and low current density.

The Correlations among Circulating Tumor Cells, Epstein-Barr Virus Status, and Epidemiology in Patients with Nasopharyngeal Carcinoma.

BACKGROUND: Studies have shown that circulating tumor cells (CTCs) can be detected in nasopharyngeal carcinoma (NPC). However, the relationship between CTCs and tumor stage is still controversial. This study aims to investigate the correlations among CTCs, Epstein-Barr virus (EBV) status, clinicopathologic features, and epidemiological risk factors in patients with NPC. METHODS: Three hundred and thirty primary NPC patients with complete clinical data and epidemiology information were collected. Analysis of CTCs was performed using the CTCBIOPSY system. The plasma EBV DNA load was detected by quantitative real-time PCR. Detection of VCA-IgA and EA-IgA antibodies titers was conducted by immunoenzymatic assay. EBNA1-IgA and Zta-IgA were measured using an enzyme-linked immunosorbent assay. RESULTS: The presence of CTCs was associated with high EBV DNA load (p < 0.05). The positive rate of CTCs was correlated with T and M classifications of NPC (T: 13.2% vs. 22.9%; M: 17.9% vs. 34.8%, p < 0.05). Compared with never and former smokers, current smokers exhibited a higher positive rate of EBNA1-IgA (83.3% and 81.0% vs. 92.5%, p < 0.05); the patients with pack-years of smoking ≥ 15 displayed a significantly higher positive rate of EBNA1-IgA than those with pack-years of smoking < 15 (98.0% and 92.5% vs. 81.0%, p < 0.05). CONCLUSIONS: CTCs positivity was closely associated with tumor burden and distant metastasis of NPC. Smoking status and smoking cumulative dose of NPC patients might be correlated with EBV activation.

Study on microbes and antibiotic resistance genes in karst primitive mountain marshes - A case study of Niangniang Mountain in Guizhou, China.

Previous research on antibiotic resistance genes and microorganisms centered on those in urban sewage treatment plants, breeding farms, hospitals and others with serious antibiotic pollution. However, at present, there are evident proofs that antibiotic resistance genes (ARGs) indeed exist in a primitive environment hardly without any human's footprints. Accordingly, an original karst mountain swamp ecosystem in Niangniang Mountain, Guizhou, China, including herbaceous swamp, shrub swamp, sphagnum bog and forest swamp, was selected to analyze the physical and chemical parameters of sediments. Moreover, microbial compositions, functions, as well as their connections with ARGs were assayed and analyzed using metagenomic technology. The results showed that there was no significant difference in the dominant microorganisms and ARGs in the four marshes, in which the dominant bacteria phyla were Proteobacteria (37.82 %), Acidobacteriota (22.17 %) and Actinobacteriota (20.64 %); the dominant archaea Euryarchaeota. (1.00 %); and the dominant eukaryotes Ascomycota (0.07 %), with metabolism as their major functions. Based on the ARDB database, the number of ARGs annotated reached 209 including 30 subtypes, and the dominant ARGs were all Bacitracin resistance genes (bacA, 84.77 %). In terms of the diversity of microorganisms and ARGs, the herbaceous swamp ranked the top, and the shrub swamp were at the bottom. Correlation analysis between microorganisms and resistance genes showed that, apart from aac2ic, macB, smeE, tetQ, and tetL, other ARGs were positively correlated with microorganisms. Among them, baca coexisted with microorganisms. Pearson correlation analysis results showed that contrary to ARGs, microorganisms were more affected by environmental factors.

Three-Dimensional Encoding Approach for Wearable Tactile Communication Devices.

In this work, we presented a novel encoding method for tactile communication. This approach was based on several tactile sensory characteristics of human skin at different body parts, such as the head and neck, where location coordinates in the three-dimensional (3D) space were clearly mapped in the brain cortex, and gentle stimulations of vibrational touching with varied strengths were received instantly and precisely. For certain applications, such as playing cards or navigating walk paths for blinded people, we demonstrated specifically designed code lists with different patterns of tactile points in varied temporal sequences. By optimizing these codes, we achieved excellent efficiency and accuracy in our test experiments. As this method matched well with the natural habits of tactile sensory, it was easy to learn in a short training period. The results of the present work have offered a silent, efficient and accurate communication solution for visually impaired people or other users.

Occupational exposures and risk of nasopharyngeal carcinoma in a high-risk area: A population-based case-control study.

BACKGROUND: The potential role of occupational exposures in the development of nasopharyngeal carcinoma (NPC) remains unclear, particularly in high-incidence areas. METHODS: The authors conducted a population-based case-control study, consisting of 2514 incident NPC cases and 2586 randomly selected population controls, in southern China from 2010 to 2014. Occupational history and other covariates were self-reported using a questionnaire. Multivariate logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for the risk of NPC associated with occupational exposures. Restricted cubic splines were used to evaluate potentially nonlinear duration-response relations. RESULTS: Individuals who had exposure to occupational dusts (OR, 1.45; 95% CI, 1.26-1.68), chemical vapors (OR, 1.37; 95% CI, 1.17-1.61), exhausts/smokes (OR, 1.42; 95% CI, 1.25-1.60), or acids/alkalis (OR, 1.56; 95% CI, 1.30-1.89) in the workplace had an increased NPC risk compared with those who were unexposed. Risk estimates for all 4 categories of occupational exposures appeared to linearly increase with increasing duration. Within these categories, occupational exposure to 14 subtypes of agents conferred significantly higher risks of NPC, with ORs ranging from 1.30 to 2.29, including dust from metals, textiles, cement, or coal; vapor from formaldehyde, organic solvents, or dyes; exhaust or smoke from diesel, firewood, asphalt/tar, vehicles, or welding; and sulfuric acid, hydrochloric acid, nitric acid, and concentrated alkali/ammonia. CONCLUSIONS: Occupational exposures to dusts, chemical vapors, exhausts/smokes, or acids/alkalis are associated with an excess risk of NPC. If the current results are causal, then the amelioration of workplace conditions might alleviate the burden of NPC in endemic areas. LAY SUMMARY: The role of occupational exposures in the development of nasopharyngeal carcinoma (NPC) remains unclear, particularly in high-incidence areas. The authors conducted a population-based study with 2514 incident NPC cases and 2586 population controls in southern China and observed that occupational exposures were associated with an increased risk of NPC. Duration-response trends were observed with increasing duration of exposure. These findings provide new evidence supporting an etiologic role of occupational exposures for NPC in a high-incidence region.

Highly stretchable and self-foaming polyurethane composite skeleton with thermally tunable microwave absorption properties.

Stretchable and lightweight polymer composite material possessing tunable microwave absorption (MA) properties under thermal radiations remain a significant challenge. Here, we proposed a facile strategy to fabricate stretchable, magnetic composite skeletons by incorporating the tadpole-like CNTs@Fe3O4nanoparticles into self-foaming polyurethane (PU) matrix and the electromagnetic responsive of CNTs@Fe3O4/PU composite foams with different CNTs contents under heating-cooling cycle in a temperature range of 253 -333 K were carefully investigated. Enhanced complex permittivity and shifting peak frequency were observed at elevated temperatures. For instance, the 70-CNTs@Fe3O4/PU sample with 15 wt% loading content at 333 K exhibits excellent MA properties including a minimum reflection loss (RLm) of -66.9 dB and ultrabroad effective frequency bandwidth (RL ≤ -20 dB) of 9.98 GHz at the thickness of 1.58-3.37 mm. Meanwhile, great recoverability in terms of RL-fprofile was achieved in the process of thermal cooling back to 253 K. Such adjustable MA property was attributed to the well-matched impedance and dramatic attenuation ability, benefiting from the temperature-dependant electrical conductivity, abundant interfacial polarization and interior microcellular structures. Besides, the rising temperature increased the sample elongation and electrical conductivity with a slight sacrifice of maximum tensile strength. This stretchable PU skeleton with a unique assembly of CNTs and Fe3O4nanoparticles are expected to be promising candidates as smart absorbers for application in the harsh environments.

Paeonone A, a novel nonanortriterpenoid from the roots of Paeonia lactiflora.

Paeonone A (1), a unique nonanortriterpenoid, and a new octanortriterpenoid, paeonone B (2), were isolated from the roots of Paeonia lactiflora, together with a known analogue, palbinone (3). Paeonone A (1) is the first example of naturally occurring nonanortriterpenoid with a diketo acid group. Extensive NMR and HRESIMS experiments were applied to identify the structures of 1 and 2, and their absolute configurations were solved by single-crystal X-ray diffraction and ECD data. Biological properties of 1-3 were explored against pancreatic lipase and cancer cell lines.

HIV-related stigma and life goals among people living with HIV (PLWH) in Florida.

PURPOSE: Goals are an important component of quality of life (QoL) as they provide motivation to accomplish tasks we strive to achieve. Stigma has been identified as a factor that may be deleterious to achieving personal goals. People living with HIV(PLWH) continue to face HIV-related stigma. As HIV prevalence continues to grow in the U.S., it is important to focus on factors that can help improve the health and QoL of PLWH. This study aims to examine the association between HIV-related stigma and goal-setting behaviors among PLWH in Florida. METHODS: We used baseline data collected from the Marijuana and Potential Long-term Effects (MAPLE) observational cohort study. We collected life goals data using an abbreviated version of the Personal Projects Analysis inventory. Participants listed up to three goals in five domains and were asked about each goal's difficulty and importance. HIV-related stigma was measured using an abbreviated version of the Herek HIV-related stigma scale. Relative risk estimates and 95% confidence intervals were estimated using multivariate linear regression models. RESULTS: The overall sample (n = 232) was majority male (52.4%), Black (72.4%), and non-Latino (84.9%). HIV-related stigma was positively associated with the total number of listed goals (ß = 0.042[0.003, 0.082]; p = 0.037) and perceived goal difficulty (ß = 0.010[0.003, 0.017]; p = 0.004), but not significantly associated with perceived goal importance (ß = 0.001[- 0.002, 0.004]; p = 0.562). CONCLUSION: The results suggest that HIV-related stigma may be affecting the pursuit of goals among PLWH. There is a need to develop and evaluate QoL interventions that are tailored to PLWH and focused on achieving goals in the face of HIV-related stigma.

[Construction and application of pharmacophore model of human carboxylesterase 2 inhibitors].

According to human carboxylesterase 2(hCE2) inhibitors reported in the literature, the pharmacophore model of hCE2 inhibitors was developed using HipHop module in Discovery Studio 2016. The optimized pharmacophore model, which was validated by test set, contained two hydrophobic, one hydrogen bond acceptor, and one aromatic ring features. Using the pharmacophore model established, 5 potential hCE2 inhibitors(CS-1,CS-2,CS-3,CS-6 and CS-8) were screened from 20 compounds isolated from the roots of Paeonia lactiflora, which were further confirmed in vitro, with the IC_(50) values of 5.04, 5.21, 5.95, 6.64 and 7.94 µmol·L~(-1), respectively. The results demonstrated that the pharmacophore model exerted excellent forecasting ability with high precision, which could be applied to screen novel hCE2 inhibitors from Chinese medicinal materials.

Bioactivity-Guided Discovery of Human Carboxylesterase Inhibitors from the Roots of Paeonia lactiflora.

In a continuing search for potential inhibitors against human carboxylesterases 1A1 and 2A1 (hCES1A1 and hCES2A1), an EtOAc extract of the roots of Paeonia lactiflora showed strong hCES inhibition activity. Bioassay-guided fractionation led to the isolation of 26 terpenoids including 12 new ones (1-5, 7-12, and 26). Among these, sesquiterpenoids 1 and 6, monoterpenoids 10, 11, and 13-15, and triterpenoids 18-20, 22, and 24-26 contributed to the hCES2A1 inhibition, in the IC50 range of 1.9-14.5 µM, while the pentacyclic triterpenoids 18-26 were responsible for the potent inhibitory activity against hCES1A1, with IC50 values less than 5.0 µM. The structures of all the compounds were elucidated using MS and 1D and 2D NMR data, and the absolute configurations of the new compounds were resolved via specific rotation, experimental and calculated ECD spectra, and single-crystal X-ray diffraction analysis. The structure-activity relationship analysis highlighted that the free HO-3 group in the pentacyclic triterpenoids is crucial for their potent inhibitory activity against hCES1A1.

[Basic Research on Neuroprotective Effect of Volatile Oil of Cang Ai after Cerebral Ischemia-Reperfusion Injury Based on Diffusion Tensor Imaging].

OBJECTIVE: To study the neuroprotective effect of inhalation of volatile oil of Cang Ai (VOCA) on cerebral ischemia-reperfusion injury model by MRI diffusion tensor imaging. METHODS: Twenty-four healthy adult male SD rats were randomly divided into sham operation group, model (middle cerebral artery occlusion (MCAO) ) group and VOCA group. Evaluated the degree of neurological impairment of rats in each group immediately after successful establishment of model or 7 d later according to Zea Longa scoring. Coronal diffusion tensor imaging (DTI) scan was performed at 3 h, 3 d, and 7 d after the model successfully established by using 7.0 T magnetic resonance imaging. Measured the apparent diffusion coefficient (ADC) and anisotropy score (FA) of the DTI in the striatal region and the motion flat zone of the maximum infarct level and then calculate the relative apparent diffusion coefficient (rADC) and relative anisotropy score (rFA). TTC staining was used to evaluate the cerebral infarction volume of rats in each group at 7 d post model establishment, and the correlation analysis of rFA, rADC and neural score was performed. RESULTS: No neurological defect was detected in mice in the sham operation group. The MCAO group and the VOCA group showed neurological defect to different degrees. The neurological function score of the VOCA group was obviously lower than that of MCAO group at 7 th day (P<0.05). The DTI scan results showed that the rADC value of striatum of rats in VOCA group was higher than that in MCAO group at 3 h and 3 d after modeling (P<0.05), while there was no significant difference between the three groups at 7 th day. The rADC value of the motor cortex in the VOCA group was higher than that in the MCAO group at 3 h after modeling (P<0.01), and there was no significant difference at 3 rdday and 7 thday. The rFA value of striatum in VOCA group was higher than that in MCAO group at 3 rd day and 7 th day after modeling (P<0.05). There were no significant differences in rFA value between the MCAO and the VOCA group at three time points. TTC staining results showed that there was no infarcted area in the sham operation group, and the infarct volume in the VOCA group was smaller than that of the MCAO group (P<0.05). Correlation analysis showed that the striatum rFA value was highly correlated with neurological scores (r=－0.847, P<0.01). CONCLUSION: For the first time, we found that VOCA can effectively protect the neurological function of MCAO rats by reducing the toxic edema of cells in the ischemic area and accelerating the recovery of nerve fiber bundles after cerebral ischemia and reperfusion. rFA and rADC values can be used as effective indicators to evaluate the recovery of nerve function after cerebral ischemia and reperfusion.

Accurate discrimination of Gastrodia elata from different geographical origins using high-performance liquid chromatography fingerprint combined with boosting partial least-squares discriminant analysis.

Gastrodia elata from different geographical origins varies in quality and pharmacological activity. This study focused on the classification and identification of Gastrodia elata from six producing areas using high-performance liquid chromatography fingerprint combined with boosting partial least-squares discriminant analysis. Before recognition analysis, a principal component analysis was applied to ascertain the discrimination possibility with high-performance liquid chromatography fingerprints. And then, boosting partial least-squares discriminant analysis and conventional partial least-squares discriminant analysis were applied in this study. Experimental results indicated that the adaptive iteratively reweighted penalized least-squares algorithm could eliminate the baseline drift of high-performance liquid chromatography chromatograms effectively. And compared with partial least-squares discriminant analysis, the total recognition rates using high-performance liquid chromatography fingerprint combined with boosting partial least-squares discriminant analysis for the calibration sets and prediction sets were improved from 94 to 100% and 86 to 97%, respectively. In conclusion, high-performance liquid chromatography combined with boosting partial least-squares discriminant analysis, which has such advantages as effective, specific, accurate, non-polluting, has an edge for discrimination of traditional Chinese medicine from different geographical origins. And the proposed methodology is a useful tool to classify and identify Gastrodia elata from different geographical origins.

Comparative Investigation of Phenomenological Modeling for Hysteresis Responses of Magnetorheological Elastomer Devices.

Magnetorheological elastomer (MRE) is a type of magnetic soft material consisting of ferromagnetic particles embedded in a polymeric matrix. MRE-based devices have characteristics of adjustable stiffness and damping properties, and highly nonlinear and hysteretic force-displacement responses that are dependent on external excitations and applied magnetic fields. To effectively implement the devices in mitigating the hazard vibrations of structures, numerically traceable and computationally efficient models should be firstly developed to accurately present the unique behaviors of MREs, including the typical Payne effect and strain stiffening of rubbers etc. In this study, the up-to-date phenomenological models for describing hysteresis response of MRE devices are experimentally investigated. A prototype of MRE isolator is dynamically tested using a shaking table in the laboratory, and the tests are conducted based on displacement control using harmonic inputs with various loading frequencies, amplitudes and applied current levels. Then, the test results are used to identify the parameters of different phenomenological models for model performance evaluation. The procedure of model identification can be considered as solving a global minimization optimization problem, in which the fitness function is the root mean square error between the experimental data and the model prediction. The genetic algorithm (GA) is employed to solve the optimization problem for optimal model parameters due to its advantages of easy coding and fast convergence. Finally, several evaluation indices are adopted to compare the performances of different models, and the result shows that the improved LuGre friction model outperforms other models and has optimal accuracy in predicting the hysteresis response of the MRE device.

Lack of association between cigarette smoking and Epstein Barr virus reactivation in the nasopharynx in people with elevated EBV IgA antibody titres.

BACKGROUND: Subjects with elevated Epstein-Barr virus (EBV) immunoglobulin A (IgA) titers have a higher risk of developing nasopharyngeal carcinoma (NPC), indicating that reactivation of EBV in the local mucosa might be important for NPC carcinogenesis. Cigarette smoking appears to be one of the environmental risk factors for NPC. However, it remains unclear whether smoking-induced nasopharyngeal carcinogenesis acts through reactivating EBV in the nasopharyngeal mucosa. Therefore, this study aims to investigate the association between cigarette smoking and nasopharyngeal EBV reactivation in a NPC high-risk population. METHODS: A NPC high-risk cohort study, established from a population-based NPC screening program of 22,816 subjects, consisted of 1045 subjects with elevated serum IgA antibodies against EBV viral capsid antigen (VCA/IgA). Among high-risk subjects, information on detailed cigarette smoking history was collected among 313 male subjects. The associations between cigarette smoking and EBV antibody levels, EBV DNA load of the nasopharynx were analyzed. RESULTS: No significant association was observed between either nasopharyngeal EBV DNA load or serum VCA/IgA titers and smoking status, age at smoking initiation, daily smoking intensity, smoking duration, cigarette type, or pack-years of smoking. Cigarette smoking characteristics in all subgroups did not correlate with nasopharyngeal EBV DNA positivity or EBV VCA/IgA seropositivity. CONCLUSIONS: In a population at high risk of NPC, our study suggests that cigarette smoking is neither associated with nasopharyngeal EBV DNA load nor serum VCA/IgA antibody level. Smoking-associated NPC carcinogenesis may act through other mechanisms than reactivating nasopharyngeal EBV replication.

Structures and Biological Evaluation of Monoterpenoid Glycosides from the Roots of Paeonia lactiflora.

Fractionation of an aqueous extract of the air-dried roots of a traditional Chinese medicinal plant, Paeonia lactiflora, yielded the new monoterpenoid glycosides 1-10. Their structures were assigned via spectroscopic techniques, and the absolute configurations of 1, 4-6, and 8 were verified via chemical methods, specific rotation, and electronic circular dichroism data. Compounds 1-4 are rare compared to the reported cage-like paeoniflorin derivatives; that is, they comprised two monoterpenoidal moieties. In the in vitro assay, compounds 5, 8, and 9 showed weak inhibitions against lipopolysaccharide-induced nitric oxide production in RAW264.7 macrophages, with IC50 values of 64.8, 60.1, and 97.5 µM, respectively.