A Dynamic Model for Estimating the Retention Duration of Neutralizing Antibody Titers After Vaccination in a COVID-19 Convalescent Population.

We measured neutralizing antibodies (nAbs) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a cohort of 235 convalescent patients (representing 384 analytic samples). They were followed for up to 588 days after the first report of onset in Taiwan. A proposed Bayesian approach was used to estimate nAb dynamics in patients postvaccination. This model revealed that the titer reached its peak (1819.70 IU/mL) by 161 days postvaccination and decreased to 154.18 IU/mL by day 360. Thus, the nAb titers declined in 6 months after vaccination. Protection, against variant B.1.1.529 (ie, Omicron) may only occur during the peak period.

Assessment of the performance regarding confirmatory diagnosis and initiation of antiretroviral therapy under a modified national HIV testing algorithm and pay-for-performance program in Taiwan.

BACKGROUND: A pay-for-performance plan for rapid antiretroviral therapy (ART) commencement was initiated in 2018, while a modified testing algorithm offers immunochromatographic test (ICT) to replace Western blot (WB), and simultaneous testing with ICT and Nucleic Acid Amplification Test (NAAT) for HIV-positive sera was adopted in 2019 in Taiwan. METHODS: Serum specimens collected from 1117 suspected or confirmed HIV infection cases in 2016-2019 were reassessed the performance of WB, ICT, and NAAT. We reviewed the medical records of 10,732 individuals diagnosed with HIV in 2015-2021 to determine the time from screening to confirmatory diagnosis, followed by ART commencement. RESULTS: All 860 WB-positives were also positive by ICT and NAAT. The positive detection percentages were 37.0% by ICT and 51.4% by NAAT for 257 WB-indeterminate and -negative sera. The sensitivity for WB and ICT was 93.8% and 95.5%, respectively. In the people living with HIV (PLHIV) cohort, the median time from initial positive to confirmatory diagnosis decreased from 5 to 6 days before 2019 to 1 day in 2021. The median time from initial positive to ART initiation decreased from 37 days in 2015, 14 days in 2018, to 6 days in 2021. Compared to 2015-2017, the time to ART initiation was 91.48 days lower in 2018 (P < 0.001) and 100.66 days lower in 2019-2021 (P < 0.001) by the adjusted linear regression model. CONCLUSION: A significant decrease in the time to ART initiation was observed after initiation of the pay-for-performance program and optimized testing algorithm in Taiwan.

The Processing and Electrical Properties of Isotactic Polypropylene/Copper Nanowire Composites.

Polypropylene (PP), a promising engineering thermoplastic, possesses the advantages of light weight, chemical resistance, and flexible processability, yet preserving insulative properties. For the rising demand for cost-effective electronic devices and system hardware protections, these applications require the proper conductive properties of PP, which can be easily modified. This study investigates the thermal and electrical properties of isotactic polypropylene/copper nanowires (i-PP/CuNWs). The CuNWs were harvested by chemical reduction of CuCl2 using a reducing agent of glucose, capping agent of hexadecylamine (HDA), and surfactant of PEG-7 glyceryl cocoate. Their morphology, light absorbance, and solution homogeneity were investigated by SEM, UV-visible spectrophotometry, and optical microscopy. The averaged diameters and the length of the CuNWs were 66.4 ± 16.1 nm and 32.4 ± 11.8 µm, respectively. The estimated aspect ratio (L/D, length-to-diameter) was 488 ± 215 which can be recognized as 1-D nanomaterials. Conductive i-PP/CuNWs composites were prepared by solution blending using p-xylene, then melt blending. The thermal analysis and morphology of CuNWs were characterized by DSC, polarized optical microscopy (POM), and SEM, respectively. The melting temperature decreased, but the crystallization temperature increasing of i-PP/CuNWs composites were observed when increasing the content of CuNWs by the melt blending process. The WAXD data reveal the coexistence of Cu2O and Cu in melt-blended i-PP/CuNWs composites. The fit of the electrical volume resistivity (ρ) with the modified power law equation: ρ = ρo (V - Vc)-t based on the percolation theory was used to find the percolation concentration. A low percolation threshold value of 0.237 vol% and high critical exponent t of 2.96 for i-PP/CuNWs composites were obtained. The volume resistivity for i-PP/CuNWs composite was 1.57 × 107 Ω-cm at 1 vol% of CuNWs as a potential candidate for future conductive materials.

Towards the first 90: impact of the national HIV self-test program on case finding and factors associated with linkage to confirmatory diagnosis in Taiwan.

INTRODUCTION: Being aware of one's HIV-positive status can help reduce unprotected sex and promote early treatment seeking. Therefore, HIV self-test (HIVST) programs may help control the HIV epidemic by case finding. The aims of this study were to determine the effect of HIVST programs on HIV case finding, time to confirmatory diagnosis and factors associated with linkage to confirmatory diagnosis in Taiwan. METHODS: The Centers for Disease Control in Taiwan initiated HIVST programs and imported 78,000 self-test kits in 2017 and 2019. Clients paid 7 US dollars for a self-test kit at facilities, vending machines or online. The programs set up an HIVST logistics management system; each kit had a unique barcode for monitoring the programs because purchases were anonymous. When clients provided their test results with photo barcodes online or at HIV/AIDS-designated hospitals, they received full monetary reimbursement. We conducted a quasi-experimental interrupted time-series (ITS) analysis that covered a period of 60 months from 2015 to 2019. We enrolled a retrospective cohort of reported HIV cases with initial positive results from HIVST programs between March 2017 and July 2020. RESULTS: The ITS analysis included data from 10,976 reported HIV cases from 2015 to 2019. The HIVST-positive cohort included 386 reported HIV cases, of whom 99.7% were males and 97% were men who have sex with men (MSM); the median age was 28 years. The ITS analysis showed a positive slope change in the number of reported HIV cases immediately in the beginning implementation month (coefficient: 51.09 in 2017 and 3.62 in 2019), but there was a significant decrease over time. It was a negative slope change by 9.52 cases per month in 2017 and 5.56 cases per month in 2019. In the HIVST-positive cohort, three of five individuals linked to HIV confirmatory diagnosis within 1 month after a positive self-test result, and an early linkage to confirmatory diagnosis was associated with HIVST disclosure (adjusted OR = 6.5; 95% CI: 3.9-10.6). CONCLUSIONS: HIVST programs were associated with an increase in HIV case finding. Our findings suggest that countries with a high incidence of HIV among MSM populations should offer multichannel HIVST services.

Single Cell Effects of Photobiomodulation on Mitochondrial Membrane Potential and Reactive Oxygen Species Production in Human Adipose Mesenchymal Stem Cells.

Photobiomodulation (PBM) has recently emerged in cellular therapy as a potent alternative in promoting cell proliferation, migration, and differentiation during tissue regeneration. Herein, a single-cell near-infrared (NIR) laser irradiation system (830 nm) and the image-based approaches were proposed for the investigation of the modulatory effects in mitochondrial membrane potential (ΔΨm), reactive oxygen species (ROS), and vesicle transport in single living human adipose mesenchymal stem cells (hADSCs). The irradiated-hADSCs were then stained with 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA) and Rhodamine 123 (Rh123) to represent the ΔΨm and ROS production, respectively, with irradiation in the range of 2.5-10 (J/cm2), where time series of bright-field images were obtained to determine the vesicle transport phenomena. Present results showed that a fluence of 5 J/cm2 of PBM significantly enhanced the ΔΨm, ROS, and vesicle transport phenomena compared to the control group (0 J/cm2) after 30 min PBM treatment. These findings demonstrate the efficacy and use of PBM in regulating ΔΨm, ROS, and vesicle transport, which have potential in cell proliferation, migration, and differentiation in cell-based therapy.

High-throughput flowing upstream sperm sorting in a retarding flow field for human semen analysis.

In this paper, we propose a microfluidic device capable of generating a retarding flow field for the sorting and separation of human motile sperm in a high-throughput manner. The proposed sorting/separation process begins with a rapid flow field in a straight-flow zone to carry sperm into a sorting zone to maintain the sperm's mobility. The sorting zone consists of a diffuser-type sperm sorter to differentiate sperm with different motilities based on the flowing upstream nature of human sperm in a retarding flow field. The dead sperm will then be separated from the live ones by passing through a dumbbell flow field to the outlet for disposal. The proposed flowing upstream sperm sorter (FUSS) is designed to imitate the selection mechanism found in the female body when sperm swim into the uterus. The experimental results demonstrate the utility of this device with regard to throughput (approximately 200 000 sperm per minute and a maximum of 200 million cells per mL), efficiency (90% of selected sperm are mobile), and the ability to select sperm with high motility (∼20% of sperm with a velocity exceeding 120 µm s-1). The proposed device is suitable for intrauterine insemination as well as in vitro fertilization thanks to the highly efficient sorting process not interfering with the natural function and energy resource of human sperm.

Silymarin and protein kinase A inhibitor modulate glucose-mediated mouse sperm motility: An in vitro study.

Glucose is suggested to play a key role in motility hyperactivation of mammalian spermatozoa. The current study aimed to investigate the modulatory effects of silymarin and/or a protein kinase A (PKA) inhibitor (H-89) on glucose-mediated motility parameters of mouse spermatozoa. Spermatozoa were incubated in HEPES medium containing normal (NG; 5.5mM) or high (HG; 25 mM) glucose concentration. The results of computer-assisted analysis showed that samples incubated in HG resulted in a larger (p < 0.05) percentage of motile spermatozoa at 120 min (59.5 ± 14.8% vs. 34.0 ± 4.4%) compared to those incubated in NG. The average pathway velocity (VAP), curvilinear velocity (VCL), and straight-line velocity (VSL) exhibited similar patterns at 60 and 120 min when incubated in HG (p < 0.05). Treatments with silymarin (5, 10, 20 µg/mL) did not significantly affect sperm motility under NG conditions, but decreased the HG-enhanced motility, VAP, and VCL at 120 min (p < 0.05). H-89 (30 µM) reduced (p < 0.05) motility at 30 min examined in the NG or HG medium. At 90 min, H-89 also reduced (p < 0.05) the HG-enhanced motility of spermatozoa incubated with or without 20 µg/mL silymarin by 49% or 32%, respectively. In conclusion, the H-89-inhibition of glucose-mediated mouse sperm motility and certain types of velocity suggests that the glycolysis-PKA pathway is involved in the regulation of sperm motility. Silymarin may maintain sperm motility under NG conditions, but it inhibits glucose-activated sperm motility.

Correlation between joint [F-18] FDG PET uptake and synovial TNF-alpha concentration: a study with two rabbit models of acute inflammatory arthritis.

The objective of this study was to verify that the [F-18]FDG PET synovial uptake is correlated with the synovial fluid (SF) TNF-alpha concentration. Two rabbit models of acute inflammatory arthritis induced by human interleukin-8 and lipopolysaccharide were used. Modified standard uptake values (MSUVs) obtained from PET images of the animals were compared with results of SF TNF-alpha measurements. Statistically significant correlations were found between the MSUVs and the SF TNF-alpha ratios. An equation to estimate the TNF-alpha ratio from a MSUV was also derived.