The Effects of Anthropogenic Disturbances on the Spatiotemporal Patterns of Medium-Large Mammals in Tropical Volcanic Landscapes.

A comprehensive understanding of the consequences of human interactions with mammals is a critical factor in supporting and conserving species in landscapes dominated by humans, which are increasingly threatened. This study aimed to identify the spatial and temporal interactions between humans and mammals. A non-parametric statistical approach with kernel density was used to detect human-mammal temporal interactions. The species interaction factor (SIF) was applied to calculate the spatial overlap based on the two-species occupancy detection model. The activity patterns of medium mammals were nocturnal, diurnal, and cathemeral. The human-medium mammal pairs with SIF values that were <1 and statistically significant included the human-long-tailed macaque (Macaca fascicularis) pair, the human-leopard cat (Prionailurus bengalensis) pair, and the human-barking deer (Muntiacus muntjac) pair. Based on their SIF values and the high overlap in their activity times, the human-macaque pairings had a high risk of conflict. Barking deer and leopard cats displayed a coexistence with humans via time-sharing activities. Due to temporal niche variations with human activities, the existence of nocturnal mammals was relatively uninterrupted. This study showed that most mammals are able to adapt spatially and temporally to various human activities. Nonetheless, efforts to mitigate human-wildlife conflict must be maintained, particularly in the case of severely endangered species, such as the Sunda pangolin.

Patient outcomes in public sector hepatitis C treatment programmes: a retrospective cohort analysis across five low- and middle-income countries.

OBJECTIVES: Given limited data on factors associated with hepatitis C virus (HCV) treatment discontinuation and failure in low- and middle-income countries, we aimed to describe patient populations treated for HCV in five countries and identify patient groups that may need additional support. DESIGN: Retrospective cohort analysis using routinely collected data. SETTING: Public sector HCV treatment programmes in India (Punjab), Indonesia, Myanmar, Nigeria (Nasarawa) and Vietnam. PARTICIPANTS: 104 957 patients who initiated treatment in 2016-2022 (89% from Punjab). PRIMARY OUTCOMES: Treatment completion and cure. RESULTS: Patient characteristics and factors associated with outcomes varied across countries and facilities. Across all patients, median age was 40 years (IQR: 29-52), 30.6% were female, 7.0% reported a history of injecting drugs, 18.2% were cirrhotic and 4.9% were coinfected with HIV. 79.8% were prescribed sofosbuvir+daclastasvir. Of patients with adequate follow-up, 90.6% (89,551) completed treatment. 77.5% (69,426) of those who completed treatment also completed sustained virological testing at 12 weeks (SVR12), and of those, 92.6% (64 305) were cured. In multivariable-adjusted models, in most countries, significantly lower treatment completion was observed among patients on 24-week regimens (vs 12-week regimens) and those initiated in later years of the programme. In several countries, males, younger patients <20 years and certain groups of cirrhotic patients were less likely to complete treatment or be cured. In Punjab, treatment completion was also lower in those with a family history of HCV and people who inject drugs (PWID); in other countries, outcomes were comparable for PWID. CONCLUSION: High proportions of patients completed treatment and were cured across patient groups and countries. SVR12 follow-up could be strengthened. Males, younger people and those with decompensated cirrhosis on longer regimens may require additional support to complete treatment and achieve cure. Adequate programme financing, minimal user fees and implementation of evidence-based policies will be critical to close gaps.

The Suitability of Propolis as a Bioactive Component of Biomaterials.

Propolis is a resinous product collected by bees from plant exudates to protect and maintain hive homeostasis. Propolis has been used therapeutically for centuries as folk medicine. Modern research investigating the diversity of the chemical composition and plant sources, biological activity, extraction processes, analytical methods, and therapeutic properties in clinical settings have been carried out extensively since the 1980s. Due to its antimicrobial, anti-inflammatory, and immuno-modulator properties, propolis appears to be a suitable bioactive component to be incorporated into biomaterials. This review article attempts to analyze the potential application of propolis as a biomaterial component from the available experimental evidence. The efficacy and compabitility of propolis depend upon factors, such as types of extracts and types of biomaterials. Generally, propolis appears to be compatible with hydroxyapatite/calcium phosphate-based biomaterials. Propolis enhances the antimicrobial properties of the resulting composite materials while improving the physicochemical properties. Furthermore, propolis is also compatible with wound/skin dressing biomaterials. Propolis improves the wound healing properties of the biomaterials with no negative effects on the physicochemical properties of the composite biomaterials. However, the effect of propolis on the glass-based biomaterials cannot be generalized. Depending on the concentration, types of extract, and geographical sources of the propolis, the effect on the glass biomaterials can either be an improvement or detrimental in terms of mechanical properties such as compressive strength and shear bond strength. In conclusion, two of the more consistent impacts of propolis across these different types of biomaterials are the enhancement of the antimicrobial and the immune-modulator/anti-inflammatory properties resulting from the combination of propolis and the biomaterials.

Modeling Impact Mechanics of 3D Helicoidally Architected Polymer Composites Enabled by Additive Manufacturing for Lightweight Silicon Photovoltaics Technology.

When silicon solar cells are used in the novel lightweight photovoltaic (PV) modules using a sandwich design with polycarbonate sheets on both the front and back sides of the cells, they are much more prone to impact loading, which may be prevalent in four-season countries during wintertime. Yet, the lightweight PV modules have recently become an increasingly important development, especially for certain segments of the renewable energy markets all over the world-such as exhibition halls, factories, supermarkets, farms, etc.-including in countries with harsh hailstorms during winter. Even in the standard PV module design using glass as the front sheet, the silicon cells inside remain fragile and may be prone to impact loading. This impact loading has been widely known to lead to cracks in the silicon solar cells that over an extended period of time may significantly degrade performance (output power). In our group's previous work, a 3D helicoidally architected fiber-based polymer composite (enabled by an electrospinning-based additive manufacturing methodology) was found to exhibit excellent impact resistance-absorbing much of the energy from the impact load-such that the silicon solar cells encapsulated on both sides by this material breaks only at significantly higher impact load/energy, compared to when a standard, commercial PV encapsulant material was used. In the present study, we aim to use numerical simulation and modeling to enhance our understanding of the stress distribution and evolution during impact loading on such helicoidally arranged fiber-based composite materials, and thus the damage evolution and mechanisms. This could further aid the implementation of the lightweight PV technology for the unique market needs, especially in countries with extreme winter seasons.

Kinetic Study of Levulinic Acid from Spirulina platensis Residue.

Microalgae have the potential to emerge as renewable feedstocks to replace fossil resources in producing biofuels and chemicals. Levulinic acid is one of the most promising substances which may serve as chemical building blocks. This work investigated the use of Spirulina platensis residue (solid residue after lipids extraction) to produce LA via acid hydrolysis reaction. In this study, Spirulina platensis residue was set to have a solid-liquid ratio of 5% (w/v). The effect of process parameters on the Spirulina platensis residue to levulinic acid hydrolysis reaction was observed at temperatures ranging from 140 to 180 °C under four acid concentrations, i.e., 0.25, 0.5, 0.8, and 1 M. A simplified kinetic model was also developed to describe the behavior of Spirulina platensis residue conversion to levulinic acid, based on the pseudo-homogeneous-irreversible-1st order reaction. The results showed that the proposed model could capture the experimental data well. The reaction network also considered involvement of intermediate products namely glucose and 5-hydroxymethylfurfural. The results showed that Spirulina platensis residue, with acid catalysts, can be used to produce levulinic acid, and the kinetic model can provide useful information for understanding the Spirulina platensis residue to levulinic acid hydrolysis reaction.

Crystallographic Anisotropy Dependence of Interfacial Sliding Phenomenon in a Cu(16)/Nb(16) ARB (Accumulated Rolling Bonding) Nanolaminate.

Nanolaminates are extensively studied due to their unique properties, such as impact resistance, high fracture toughness, high strength, and resistance to radiation damage. Varieties of nanolaminates are being fabricated to achieve high strength and fracture toughness. In this study, one such nanolaminate fabricated through accumulative roll bonding (Cu(16)/Nb(16) ARB nanolaminate, where 16 nm is the layer thickness) was used as a test material. Cu(16)/Nb(16) ARB nanolaminate exhibits crystallographic anisotropy due to the existence of distinct interfaces along the rolling direction (RD) and the transverse direction (TD). Nanoindentation was executed using a Berkovich tip, with the main axis oriented either along TD or RD of the Cu(16)/Nb(16) ARB nanolaminate. Subsequently, height profiles were obtained along the main axis of the Berkovich indent for both TD and RD using scanning probe microscopy (SPM), which was later used to estimate the pile-up along the RD and TD. The RD exhibited more pile-up than the TD due to the anisotropy of the Cu(16)/Nb(16) ARB interface and the material plasticity along the TD and RD. An axisymmetric 2D finite element analysis (FEA) was also performed to compare/validate nanoindentation data, such as load vs. displacement curves and pile-up. The FEA simulated load vs. displacement curves matched relatively well with the experimentally generated load-displacement curves, while qualitative agreement was found between the simulated pile-up data and the experimentally obtained pile-up data. The authors believe that pile-up characterization during indentation is of great importance to documenting anisotropy in nanolaminates.

Impact-Resistant and Tough 3D Helicoidally Architected Polymer Composites Enabling Next-Generation Lightweight Silicon Photovoltaics Module Design and Technology.

Lightweight photovoltaics (PV) modules are important for certain segments of the renewable energy markets-such as exhibition halls, factories, supermarkets, farms, etc. However, lightweight silicon-based PV modules have their own set of technical challenges or concerns. One of them, which is the subject of this paper, is the lack of impact resistance, especially against hailstorms in deep winter in countries with four seasons. Even if the front sheet can be made sufficiently strong and impact-resistant, the silicon cells inside remain fragile and very prone to impact loading. This leads to cracks that significantly degrade performance (output power) over time. A 3D helicoidally architected fiber-based polymer composite has recently been found to exhibit excellent impact resistance, inspired by the multi-hierarchical internal structures of the mantis shrimp's dactyl clubs. In previous work, our group demonstrated that via electrospinning-based additive manufacturing methodologies, weak polymer material constituents could be made to exhibit significantly improved toughness and impact properties. In this study, we demonstrate the use of 3D architected fiber-based polymer composites to protect the silicon solar cells by absorbing impact energy. The absorbed energy is equivalent to the energy that would impact the solar cells during hailstorms. We have shown that silicon cells placed under such 3D architected polymer layers break at substantially higher impact load/energy (compared to those placed under standard PV encapsulation polymer material). This could lead to the development of novel PV encapsulant materials for the next generation of lightweight PV modules and technology with excellent impact resistance.

Helicoidally Arranged Polyacrylonitrile Fiber-Reinforced Strong and Impact-Resistant Thin Polyvinyl Alcohol Film Enabled by Electrospinning-Based Additive Manufacturing.

In this study, we demonstrate the use of parallel plate far field electrospinning (pp-FFES) based manufacturing system for the fabrication of polyacrylonitrile (PAN) fiber reinforced polyvinyl alcohol (PVA) strong polymer thin films (PVA SPTF). Parallel plate far field electrospinning (also known as the gap electrospinning) is generally used to produce uniaxially aligned fibers between the two parallel collector plates. In the first step, a disc containing PVA/H2O solution/bath (matrix material) was placed in between the two parallel plate collectors. Next, a layer of uniaxially aligned sub-micron PAN fibers (filler material) produced by pp-FFES was directly collected/embedded in the PVA/H2O solution by bringing the fibers in contact with the matrix. Next, the disc containing the matrix solution was rotated at 45∘ angular offset and then the next layer of the uniaxial fibers was collected/stacked on top of the previous layer with now 45∘ rotation between the two layers. This process was continued progressively by stacking the layers of uniaxially aligned arrays of fibers at 45∘ angular offsets, until a periodic pattern was achieved. In total, 13 such layers were laid within the matrix solution to make a helicoidal geometry with three pitches. The results demonstrate that embedding the helicoidal PAN fibers within the PVA enables efficient load transfer during high rate loading such as impact. The fabricated PVA strong polymer thin films with helicoidally arranged PAN fiber reinforcement (PVA SPTF-HA) show specific tensile strength 5 MPa · cm3· g-1 and can sustain specific impact energy (8 ± 0.9) mJ · cm3· g-1, which is superior to that of the pure PVA thin film (PVA TF) and PVA SPTF with randomly oriented PAN fiber reinforcement (PVA SPTF-RO). The novel fabrication methodology enables the further capability to produce even further smaller fibers (sub-micron down to even nanometer scales) and by the virtue of its layer-by-layer processing (in the manner of an additive manufacturing methodology) allowing further modulation of interfacial and inter-fiber adherence with the matrix materials. These parameters allow greater control and tunability of impact performances of the synthetic materials for various applications from army combat wear to sports and biomedical/wearable applications.

Kinetic Investigation for in-situ Epoxidation of Unsaturated Fatty Acid Based on the Pseudo-steady-state-hypothesis (PSSH).

Oleic acid is a mono-unsaturated fatty acid that can be found abundantly in various vegetable oils and potentially attractive to be used as raw material for epoxide chemical. In-situ epoxidation of oleic acid was conducted in batch reactor using peroxy-formic at 30-60°C. Pseudo-steady-state-hypothesis (PSSH) was applied to develop the kinetic model. Heterogeneous liquid-liquid system was chosen and four models which emphasized on the ring opening agent (ROA) and reversibility of the epoxidation reaction were proposed. It has been suggested that reversible model is well suited to represent the experimental data. Activation energy obtained from Arrhenius equation is in the range of 40-195 kJ/mol.

Measuring the Pull-Off Force of an Individual Fiber Using a Novel Picoindenter/Scanning Electron Microscope Technique.

We employed a novel picoindenter (PI)/scanning electron microscopy (SEM) technique to measure the pull-off force of an individual electrospun poly(vinylidene fluoride) (PVDF) fibers. Individual fibers were deposited over a channel in a custom-designed silicon substrate, which was then attached to a picoindenter. The picoindenter was then positioned firmly on the sample stage of the SEM. The picoindenter tip laterally pushed individual fibers to measure the force required to detach it from the surface of substrate. SEM was used to visualize and document the process. The measured pull-off force ranged between 5.8 ± 0.2 µN to ~17.8 ± 0.2 µN for individual fibers with average diameter ranging from 0.8 to 2.3 µm. Thus, this study, a first of its kind, demonstrates the use of a picoindenter to measure the pull-off force of a single micro/nanofiber.

Massively parallel bisulphite pyrosequencing reveals the molecular complexity of breast cancer-associated cytosine-methylation patterns obtained from tissue and serum DNA.

Cytosine-methylation changes are stable and thought to be among the earliest events in tumorigenesis. Theoretically, DNA carrying tumor-specifying methylation patterns escape the tumors and may be found circulating in the sera from cancer patients, thus providing the basis for development of noninvasive clinical tests for early cancer detection. Indeed, using methylation-specific PCR-based techniques, several groups reported the detection of tumor-associated methylated DNA in the sera from cancer patients with varying clinical success. However, by design, such analytical approaches allow assessment of the presence of molecules with only one methylation pattern, leaving the bigger picture unexplored. The limited knowledge about circulating DNA methylation patterns hinders the efficient development of clinical methylation tests and testing platforms. Here, we report the results of a comprehensive methylation pattern analysis from breast cancer clinical tissues and sera obtained using massively parallel bisulphite pyrosequencing. The four loci studied were recently discovered by our group, and demonstrated to be powerful epigenetic biomarkers of breast cancer. The detailed analysis of more than 700,000 DNA fragments derived from more than 50 individuals (cancer and cancer-free) revealed an unappreciated complexity of genomic cytosine-methylation patterns in both tissue derived and circulating DNAs. Both tumor and cancer-free tissues (as well as sera) contained molecules with nearly every conceivable cytosine-methylation pattern at each locus. Tumor samples displayed more variation in methylation level than normal samples. Importantly, by establishing the methylation landscape within circulating DNA, this study has better defined the development challenges facing DNA methylation-based cancer-detection tests.