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BACKGROUND: Acemannan is an acetylated polysaccharide of Aloe vera extract with antimicrobial, antitumor, antiviral, and antioxidant activities. This study aims to optimize the synthesis of acemannan from methacrylate powder using a simple method and characterize it for potential use as a wound-healing agent. METHODS: Acemannan was purified from methacrylated acemannan and characterized using high-performance liquid chromatography (HPLC), Fourier-transform infrared spectroscopy (FTIR), and 1H-nuclear magnetic resonance (NMR). 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assays were performed to investigate the antioxidant activity of acemannan and its effects on cell proliferation and oxidative stress damage, respectively. Further, a migration assay was conducted to determine the wound healing properties of acemannan. RESULTS: We successfully optimized the synthesis of acemannan from methacrylate powder using a simple method. Our results demonstrated that methacrylated acemannan was identified as a polysaccharide with an acetylation degree similar to that in A. vera, with the FTIR revealing peaks at 1739.94 cm-1 (C = O stretching vibration), 1370 cm-1 (deformation of the H-C-OH bonds), and 1370 cm-1 (C-O-C asymmetric stretching vibration); 1H NMR showed an acetylation degree of 1.202. The DPPH results showed the highest antioxidant activity of acemannan with a 45% radical clearance rate, compared to malvidin, CoQ10, and water. Moreover, 2000 µg/mL acemannan showed the most optimal concentration for inducing cell proliferation, while 5 µg/mL acemannan induced the highest cell migration after 3 h. In addition, MTT assay findings showed that after 24 h, acemannan treatment successfully recovered cell damage due to H2O2 pre-treatment. CONCLUSION: Our study provides a suitable technique for effective acemannan production and presents acemannan as a potential agent for use in accelerating wound healing through its antioxidant properties, as well as cell proliferation- and migration-inducing activities.

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The generation of hepatic spheroids is beneficial for a variety of potential applications, including drug development, disease modeling, transplantation, and regenerative medicine. Natural hydrogels are obtained from tissues and have been widely used to promote the growth, differentiation, and retention of specific functionalities of hepatocytes. However, relying on natural hydrogels for the generation of hepatic spheroids, which have batch to batch variations, may in turn limit the previously mentioned potential applications. For this reason, we researched a way to establish a three-dimensional (3D) culture system that more closely mimics the interaction between hepatocytes and their surrounding microenvironments, thereby potentially offering a more promising and suitable system for drug development, disease modeling, transplantation, and regenerative medicine. Here, we developed self-assembling and bioactive hybrid hydrogels to support the generation and growth of hepatic spheroids. Our hybrid hydrogels (PC4/Cultrex) inspired by the sandcastle worm, an Arg-Gly-Asp (RGD) cell adhesion sequence, and bioactive molecules derived from Cultrex BME (Basement Membrane Extract). By performing optimizations to the design, the PC4/Cultrex hybrid hydrogels can enhance HepG2 cells to form spheroids and express their molecular signatures (e.g., Cyp3A4, Cyp7a1, A1at, Afp, Ck7, Ck1, and E-cad). Our study demonstrated that this hybrid hydrogel system offers potential advantages for hepatocytes in proliferating, differentiating, and self-organizing to form hepatic spheroids in a more controllable and reproducible manner. In addition, it is a versatile and cost-effective method for 3D tissue cultures in mass quantities. Importantly, we demonstrate that it is feasible to adapt a bioinspired approach to design biomaterials for 3D culture systems, which accelerates the design of novel peptide structures and broadens our research choices on peptide-based hydrogels.

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The present study combines high-resolution measurements at various distances from a world-class gigantic petrochemical complex with model simulations to test a method to assess industrial emissions and their effect on local air quality. Due to the complexity in wind conditions which were highly seasonal, the dominant wind flow patterns in the coastal region of interest were classified into three types, namely northeast monsoonal (NEM) flows, southwest monsoonal (SEM) flows and local circulation (LC) based on six years of monitoring data. Sulfur dioxide (SO2) was chosen as an indicative pollutant for prominent industrial emissions. A high-density monitoring network of 12 air-quality stations distributed within a 20-km radius surrounding the petrochemical complex provided hourly measurements of SO2 and wind parameters. The SO2 emissions from major industrial sources registered by the monitoring network were then used to validate model simulations and to illustrate the transport of the SO2 plumes under the three typical wind patterns. It was found that the coupling of observations and modeling was able to successfully explain the transport of the industrial plumes. Although the petrochemical complex was seemingly the only major source to affect local air quality, multiple prominent sources from afar also played a significant role in local air quality. As a result, we found that a more complete and balanced assessment of the local air quality can be achieved only after taking into account the wind characteristics and emission factors of a much larger spatial scale than the initial (20 km by 20 km) study domain.

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BACKGROUND/PURPOSE: Suicide is an important public health problem and one of the leading causes of death worldwide. The present study investigated the prevalence of suicidal ideation (SI) and its associated risk factors in the general population. METHODS: A nationwide community survey was conducted using a computer-aided telephone interview system with residents aged >or= 15 years, who were selected by a stratified, proportional randomization method. The questionnaire comprised demographic variables, five items of psychopathology selected from the Brief Symptom Rating Scale (BSRS-5) and questions about personal experience with suicide. In total, 2054 respondents, 1002 male (48.8%), and 1052 female (51.2%), completed the survey. RESULTS: The weighted prevalence of SI was 2.84% in the past week, 5.50% in the past year, and 18.49% during a lifetime. Significant risk factors for SI in the last week included presence of SI over the past year [odds ratio (OR) =1763.6], SI during the lifetime (OR =267.6), psychiatric morbidity (OR = 30.3), depression (OR =26.1), inferiority (OR =11.2), hostility (OR = 10.9), anxiety (OR = 10.5), insomnia (OR =6.7), history of seeking help for psychological distress (OR = 7.9), divorce (OR =6.4), unemployment (OR = 5.0) and having suicidal behavior in relatives or friends (OR =3.8). Stepwise multiple regression analysis demonstrated that the five symptom items of BSRS-5 and unemployment significantly predicted 25.3% of the variance of SI. Using the BSRS-5 score 3 or 4 as a cut-off to predict SI, the rate of accurate classification was 85.88%, with sensitivity of 0.83 and specificity of 0.86. CONCLUSION: A telephone interview survey containing the BSRS-5 items is an efficient way to identify determinants of SI in the general population.

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All suicides (n=12 497) in Taiwan in 2001-2004 were identified from mortality records retrieved from the National Health Insurance Database. Altogether, 95.1% of females and 84.9% of males had been in contact with healthcare services in the year before their death. Females received significantly more diagnoses of psychiatric disorders (48.0% v. 30.2%) and major depression (17.8% v. 7.4%) than males. Such differences were consistent across different medical settings where contact with hospital-based non-psychiatric physicians was as common as with general practitioners (GPs). However, diagnoses of psychiatric disorders were underdiagnosed in both genders.

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OBJECTIVE: The objective of this study is to examine physicians' awareness of diagnosable psychiatric disorders in suicide cases' last medical contacts (MCs). MATERIALS AND METHODS: The contact rates and proportions of both psychiatric and somatic diagnoses in a national cohort of suicide subjects (N=3468) in Taiwan seeking psychiatric or nonpsychiatric medical services within 1 month and 1 year preceding death were examined. RESULTS: The overall rates of MCs were 72.6% within 1 month and 89.2% within 1 year preceding suicide. While around 99.9% of the suicide subjects who contacted psychiatrists within 1 month preceding death were diagnosed as having psychiatric disorders, only 19.7% of those visiting nonpsychiatric physicians had psychiatric diagnoses. Suicide subjects, however, frequently complained of somatic symptoms, for example, gastrointestinal discomfort, headache/dizziness and back problem during their contacts with nonpsychiatric physicians within 1 month preceding death. CONCLUSIONS: Despite the high rates of MCs preceding suicide, the majority of suicide subjects were not diagnosed. Emphasizing psychosomatic manifestations of psychiatric disorders in physician education programs may help enhance the awareness of psychiatric disorders/suicide risk in clinical settings.

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Suicide mortality rates have been steadily rising in Taiwan, and suicide has been among the top ten causes of death for the last consecutive eight years. In response to this situation, the Taiwan Department of Health assigned the Taiwan Association Against Depression the task of setting up the Taiwan Suicide Prevention Center. The mission of the Center, suicide prevention, is advanced by its establishment of efficient networks nationwide capable of delivering related care services. Suicide prevention strategies can be categorized, based on coverage, as universal, selective or indicated interventions. The Center also plans to standardize the national suicide report format and care delivery system, improve mental health service quality, and organize community support networks. It pursues an encompassing health care mechanism model, where clients are considered the first priority, the family a fundamental supporting unit, and the community a solid foundation. The Center will offer a helping hand for individuals who have attempted suicide by maintaining a spirit of positive values and achieving mutual benefits.

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