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Background: Osteosarcopenia is a syndrome characterized by the co-existence of osteoporosis and sarcopenia. This study aimed to examine the relationship between various types of physical activity and osteosarcopenia in community-dwelling Korean adults aged 65 years or older. Methods: This cross-sectional study used raw data from the fourth and fifth editions of the Korean National Health and Nutritional Survey Examination, conducted from 2008 to 2011. The researchers exclusively recruited participants aged 65 years or older for the study. These participants were categorized into four distinct groups based on their clinical factors, namely individuals without osteoporosis or sarcopenia, those with osteoporosis alone, those with sarcopenia alone, and individuals with osteosarcopenia. The International Physical Activity Short-Form was used to calculate the weekly time spent walking, moderate-intensity aerobic physical activity, and vigorous aerobic physical activity. Number of days in performing strengthening or stretching exercises were also surveyed. We used logistic regression analyses to examine the association between various physical activities and occurrence of osteosarcopenia. Results: A total of 1,342 participants (639 men and 703 women) were included in the analysis. No significant difference was observed in the amount and level of aerobic physical activity between the groups. The odds ratios below were based on participants without osteoporosis or sarcopenia as the reference category. The un-adjusted odds ratio of participants who performed stretching (male, 0.179, 95% CI 0.078–0.412; female 0.430, 95% CI 0.217–0.853) and strengthening exercises (male, 0.143, 95% CI 0.051–0.402; female, 0.044, 95% CI 0.006–0.342) at least twice per week was significantly lower in participants with osteosarcopenia compared to those without. In the adjusted analysis (adjusted by age, body mass index, house income, educational level, smoking habits, drinking status, and protein intake), only female patients in the osteosarcopenia group had a significantly lower adjusted odds ratio for performing strengthening exercise compared to female participants without osteoporosis or sarcopenia (0.062, 95% CI 0.007–0.538). Conclusions: After adjusting for confounding factors and protein intake, women aged 65 years and older who suffered osteosarcopenia had considerably lower odds ratio of performing strengthening exercises. [ABSTRACT FROM AUTHOR]

Bioleaching has been regarded as a green alternative to chemical leaching in metal extraction processes. In this study, the bioleaching properties of indigenous acidophilic bacteria for various sulfide minerals were compared and evaluated in terms of pH reduction and metal leaching. The primary minerals in the samples were sphalerite (ZnS) (SP), galena (PbS) (GN1 and GN2), pyrite (FeS2) (PY), and chalcopyrite (CuFeS2) (CCP), and an indigenous acidophilic bacterium, Acidiphilium cryptum (99.56%), was applied for bioleaching experiments. The metal extraction in bioleaching differed according to the mineral content. The leached metal concentration of Zn was higher than that of Pb for the SP sample with a high ZnS content, whereas the concentration of Pb was higher than that of Zn for the GN1 and GN2 samples with a high PbS content. Meanwhile, the leaching rate of Zn was faster than that of Pb for all samples. Corrosion action was observed on the surface of bacterial residues in SP and GN1 samples. These results show that the bioleaching mechanism based on sulfide minerals proceeds through indirect biological oxidation, chemical oxidation, and direct bacterial oxidation. The results of this study can provide basic research data for process optimization when employing bioleaching to extract valuable metals. [ABSTRACT FROM AUTHOR]

Pb contamination in aquatic environments causes severe pollution; therefore, harmless absorbents are required. In this study, we report a novel synthesis of whitlockite (WH, Ca18Mg2(HPO4)2(PO4)12), which is the second most abundant biomineral in human bone, and its application as a high‐performing Pb2+ absorbent. Hydroxyapatite (HAP) and WH are prepared via a simple precipitation method. The Pb2+ absorption performance and mechanism of the synthesized biominerals are investigated in aqueous solutions at neutral pH. The results demonstrate that WH exhibits an excellent Pb2+ absorption capacity of 2339 mg g−1, which is 1.68 times higher than the recorded value for HAP. Furthermore, the absorbed Pb2+ ions are recycled into high‐purity PbI2. This is employed as a precursor for the fabrication of perovskite solar cells (PSCs), resulting in a conversion efficiency of 19.00% comparable to that of commercial PbI2 powder (99.99% purity). Our approach provides an efficient way to remove Pb2+ ions from water and reuse them in the recycling of PSCs. [ABSTRACT FROM AUTHOR]

The high affinity of iron-based byproducts for anion removal can facilitate wastewater treatment using membranes functionalized with such byproducts. In this study, a low-cost functional ceramic membrane (LFCM) based on waste cast iron (WCI) was fabricated and applied to remove selenium from aqueous solutions. The effect of roasting (1250 °C) on the raw material properties was analyzed by X-ray diffraction and specific surface area measurements. Upon roasting, zero-valent iron (Fe0) present in WCI was oxidized to hematite (Fe2O3), while the specific surface area of WCI increased from 2.040 to 4.303 m2/g. Raw WCI exhibited the highest Se(IV) and Se(VI) removal capacity among the prepared materials, and Se(IV) could be removed faster and more efficiently than Se(VI). The selenium removal properties of the synthesized LFCM were similar to those of WCI. This membrane could simultaneously and efficiently remove Se(IV) and turbidity-causing substances through filtration. The results are expected to provide insights into the fabrication of ceramic membranes using industrial byproducts for the removal of ionic contaminants from wastewater. [ABSTRACT FROM AUTHOR]

sEMG-based gesture recognition is useful for human–computer interactions, especially for technology supporting rehabilitation training and the control of electric prostheses. However, high variability in the sEMG signals of untrained users degrades the performance of gesture recognition algorithms. In this study, the hand posture recognition algorithm and radar plot-based visual feedback training were developed using multichannel sEMG sensors. Ten healthy adults and one bilateral forearm amputee participated by repeating twelve hand postures ten times. The visual feedback training was performed for two days and five days in healthy adults and a forearm amputee, respectively. Artificial neural network classifiers were trained with two types of feature vectors: a single feature vector and a combination of feature vectors. The classification accuracy of the forearm amputee increased significantly after three days of hand posture training. These results indicate that the visual feedback training efficiently improved the performance of sEMG-based hand posture recognition by reducing variability in the sEMG signal. Furthermore, a bilateral forearm amputee was able to participate in the rehabilitation training by using a radar plot, and the radar plot-based visual feedback training would help the amputees to control various electric prostheses. [ABSTRACT FROM AUTHOR]

The tendency of persons with hemiplegia to sit for prolonged periods can cause excessive interface pressure (IP) on their buttocks. Due to the different neuromusculoskeletal conditions, different buttock IP relief methods are required for persons with left hemiplegia (LH) and right hemiplegia (RH). Therefore, this study investigates temporal characteristics of IP on the right and left buttocks for RH, LH, and able-bodied individuals (AB) sitting in a wheelchair for 30 min. Thirty-five males participated in the study: 13 LH, 12 RH, and 10 AB. In the initial adjustment phase, the participants maintained an erect sitting posture for 7 min (2 min for posture and 5 min for creep adjustments). After the adjustments, experiments were conducted for 30 min to measure the IP. In the experiments, significant right-sided asymmetries of the mean IP were found for each group (P < 0.05). The right buttocks of LH exhibited significantly more right-sided asymmetry of the mean IP than that of AB (p < 0.01). Moreover, the right buttocks of RH exhibited insignificant asymmetry of the mean IP compared to that of AB (p >0.21). The peak IPs of RH and LH were significantly higher than those of AB (p <0.05), and temporal changes of the mean and peak IP of hemiplegia were significant (p <0.05) and not significant (p >0.05), respectively. The RH exhibited affected-side weight-bearing based on the mean IP. In contrast, the LH relieved the mean IP on the affected-side buttock. Due to the right-sided asymmetric mean and high peak IP, hemiplegia in acute and recovery stages using wheelchairs can cause ulceration. Therefore, different rehabilitation approaches are required for the RH and LH to reduce the peak IP and avoid an uneven distribution of the mean IP. [ABSTRACT FROM AUTHOR]

Apple (Malus domestica (Suckow) Borkh., 1803) is economically important horticultural fruit crop in the world. In this study, the complete chloroplast genome of Korean apple cultivar 'Kamhong' was characterized through the de novo assembly of Illumina sequencing data. The chloroplast genome is a circular molecule of 161,069 bp length with 36.55% GC content and has a total of 112 genes including 78 protein-coding genes, 30 transfer RNA genes, and 4 ribosomal RNA genes. Phylogenetic analysis with protein-coding sequences of chloroplast genome revealed that 'Kamhong' was closely grouped with M. domestica cultivars reported in China. The genomic data generated in this study can extend a molecular basis for phylogenetic relationships of Korean cultivar 'Kamhong' with other M. domestica cultivars bred in other countries. [ABSTRACT FROM AUTHOR]

Prunus Linnaeus 1753 species include many economically important fruit crops, of which plumcot is generated by inter-species crossing between Prunus salicina Lindley 1830 × Prunus armeniaca Linnaeus 1753. In this study, the complete chloroplast genome of Korean plumcot cultivar 'Harmony' was characterized through the de novo assembly of Nanopore and Illumina sequencing data. The chloroplast genome is a circular molecule of 157,916 bp length with 36.75% GC content and has a total of 113 genes including 79 protein-coding genes, 30 transfer RNA genes, and four ribosomal RNA genes. Phylogenetic analysis with protein-coding sequences of chloroplast genome revealed that 'Harmony' showed closer to P. salicina than P. armeniaca. [ABSTRACT FROM AUTHOR]

We study the covert communication over $K$ -user-pair discrete memoryless interference channels (DM-ICs) with a warden. It is assumed that the warden’s channel output distribution induced by $K$ “off” input symbols, which are sent when no communication occurs, is not a convex combination of those induced by any other combination of input symbols (otherwise, the square-root law does not hold). We derive the exact covert capacity region and show that a simple point-to-point based scheme with treating interference as noise is optimal. In addition, we analyze the secret key length required for the reliable and covert communication with the desired rates, and present a channel condition where a secret key between each user pair is unnecessary. The results are extended to the Gaussian case and the case with multiple wardens. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting is a promising means to produce eco‐friendly hydrogen fuels. Inspired by the Mn4CaO5 cluster in nature, substantial works have been performed to develop efficient manganese (Mn)‐based heterogeneous catalysts. Despite improvements in catalytic activity, the underlying mechanism of the oxygen evolution reaction (OER) is not completely elucidated owing to the lack of direct spectroscopic evidence for the active Mn‐oxo moieties. We identify water oxidation intermediates on the surface of Mn3O4 nanoparticles (NPs) in the OER at neutral pH by in situ Raman spectroscopy. A potential‐dependent Raman peak was detected at 760 cm−1 and assigned to the active MnIV=O species generated during water oxidation. Isotope‐labeling experiments combined with scavenger experiments confirmed the generation of surface terminal MnIV=O intermediates in the Mn‐oxide NPs. This study provides an insight into the design of systems for the observation of reaction intermediates. [ABSTRACT FROM AUTHOR]

We consider the problem of covert communication over wireless adhoc networks in which (roughly) $n$ legitimate nodes (LNs) and $n^{\kappa }$ for $\kappa > 0$ non-communicating warden nodes (WNs) are randomly distributed in a square of unit area. Each legitimate source wants to communicate with its intended destination node while ensuring that every WN is unable to detect the presence of the communication. In this scenario, we study the throughput scaling law. Due to the covert communication constraint, the transmit powers are necessarily limited. Under this condition, we introduce a preservation region around each WN. This region serves to prevent transmission from the LNs and to increase the transmit power of the LNs outside the preservation regions. For the achievability results, multi-hop (MH), hierarchical cooperation (HC), and hybrid HC-MH schemes are utilized with some appropriate modifications. In the proposed MH and hybrid schemes, because the preservation regions may impede communication along direct data paths, the data paths are suitably modified by taking a detour around each preservation region. To avoid the concentration of detours resulting extra relaying burdens, we distribute the detours evenly over a wide region. In the proposed HC scheme, we control the symbol power and the scheduling of distributed multiple-input multiple-output transmission. We also present upper bounds on the throughput scaling under the assumption that every active LN consumes the same average transmit power over the time period in which the WNs observe the channel outputs. For $0 < \kappa < 1$ , these upper bounds match with the achievable throughput scalings. [ABSTRACT FROM AUTHOR]

In this study, indigenous acidophilic bacteria living in mine drainage and hot acidic spring were collected and used for bioleaching experiments. The incubated indigenous acidophilic bacteria were inoculated on various minerals. The changes in pH, Eh, and heavy metal concentrations were examined with uninoculated controls to study bioleaching over time. As a result, the aspects of bioleaching varied greatly depending on the origin of microorganisms, the type of minerals, the temperature conditions, etc. We applied an ANN model to express and predict these complex bioleaching trends. Through the application of an ANN model, we developed the ANN models that can predict the changes in concentration of pH, Eh, and heavy metal ion concentrations and further evaluated predictability. Through this, the predictability of bioleaching using the ANN models can be confirmed. However, we also identified limitations, showing that further testing and application of the ANN models in more diverse experimental conditions are needed to improve the predictability of the ANN models. [ABSTRACT FROM AUTHOR]

Ceramic membranes and ion exchangers are effective at removing turbidity and ionic contaminants from water, respectively. In this study, we demonstrate the performance of a hybrid ion-exchange fabric/ceramic membrane system to treat metal ions and turbidity at the same time in synthetic wastewater. The removal rate of As(V) and Zn(II) by the ceramic membrane increased with solution pH, while turbidity was completely removed regardless of the solution pH. The main reaction of As(V) removal was adsorption at solution pH 6 and precipitation at solution pH 8, whereas phase-change was the predominant reaction for Zn(II) removal at both solution pH values. The removal efficiency of the ion-exchange fabric was affected by the solution pH, with the maximum removal capacity of As(V) occurring at solution pH 4. The As(V) adsorption capacity of the ion-exchange fabric reached equilibrium within 120 min. The ion-exchange capacity of the ion-exchange fabric was compared with commercial ion-exchange fibers. The regeneration efficiency of the ion-exchange fabric using 0.1 M NaCl solution was around 95% on average and decreased slightly as the number of regeneration cycles was increased. Over 80% of As(V) and Zn(II) were steadily removed at solution pH 6 by the hybrid ion-exchange fabric/ceramic membrane system. Reduced flow rate and removal capacity were recovered through a backwashing process during continuous treatment with the hybrid ion-exchange fabric/ceramic membrane system. [ABSTRACT FROM AUTHOR]

As the demand for energy has dramatically increased in the past decade, electrochemical water splitting has been regarded as an attractive approach to produce renewable hydrogen energy. However, large overpotentials of oxygen‐evolving reaction (OER) is a key bottleneck for practical application. Thus, water‐oxidizing electrocatalysts with low cost and high efficiency should be developed. Here, 5 nm‐sized Mn3O4 nanoparticles (NPs) are synthesized by a hydrothermal method, which is appropriate for large‐scale production. To further improve their performance, various 3d transition metal elements are successfully doped in Mn3O4 NPs. Ni‐doped Mn3O4 NPs exhibit the highest efficiency among the Mn3O4 NPs doped with various elements. Based on structural analysis, the Ni‐doping process leads to the lattice distortion of their tetragonal spinel structure and it strongly correlates with the enhancement of OER activity. The overpotential at the current density of 10 mA cm–2 is 524 and 458 mV for pristine and 5 at% doped Mn3O4 NPs under neutral condition. The heteroatom‐doping process in sub‐10 nm‐sized nanocatalysts is expected to be a promising methodology to induce distorted structure related to active species. Thus, it can be effective to improve catalytic performance of various heterogeneous nano‐catalysts. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting is one of the ways to produce environmentally‐friendly hydrogen energy. Transition‐metal (TM)‐based catalysts have been attracting attention due to their low cost and abundance, but their insufficient activity still remains a challenge. Here, 4 nm Mn3O4 nanoparticles (NPs) are successfully synthesized and their electrochemical behavior is investigated. Using electrokinetic analyses, an identical water oxidizing mechanism is demonstrated between the 4 and 8 nm Mn3O4 NPs. In addition, it is confirmed that the overall increase in the active surface area is strongly correlated with the superb catalytic activity of the 4 nm Mn3O4 NPs. To further enhance the oxygen evolution reaction (OER) performance, Ni foam substrate is introduced to maximize the entire number of the NPs participating in OER. The 4 nm Mn3O4/Ni foam electrode exhibits outstanding electrocatalytic activity for OER with overpotential of 395 mV at a current density of 10 mA cm−2 under neutral conditions (0.5 m PBS, pH 7). [ABSTRACT FROM AUTHOR]

Electrochemical water splitting is one of the most important ways to produce hydrogen fuel for an environmentally friendly energy system. Low‐cost and efficient electrocatalysts for oxygen evolution reaction (OER) have been studied to overcome the sluggish kinetics of OER, which is considered to be a bottleneck that affects the overall efficiency of water splitting. However, the atomic‐level understanding and control of the catalyst surface still remains elusive. Here, we show that methylamine treatment of manganese oxide nanoparticles can effectively control their surface charge and enhance their OER catalytic activity under neutral condition. Methylamine treatment can reduce the overpotential for OER by nearly 100 mV at the current density 5 mA cm−2. Through spectroscopic studies, potentiometric titration, and zeta potential analysis, we discovered that methylamine does not exist on the surface after methylamine treatment but deprotonates the surface of nanoparticles and induce additional negative charge on the surface. Surprisingly, treatment with not only methylamine but other amines can also improve the OER performance and the catalytic activity of the amine treated nanoparticles is influenced by the pKa values of amines. Underwater stars: After methylamine treatment of OH− ligand exchanged Mn3O4 nanoparticles, oxygen evolving reaction performance is significantly enhanced. Detailed mechanistic study reveals that methylamine deprotonates the surface and generates additional negative charges on the surface. The catalytic performance could also be enhanced with different amines and the decrease in overpotential is associated with pKa of amines. [ABSTRACT FROM AUTHOR]