University research is a vital source of innovation, and government funds are often used to support innovative research programs. As such, universities are pressured to demonstrate returns on ...investments through tangible research outcomes. This study analyzed how university resources affect research productivity, using data from 95 4-year universities in Korea from 2009 to 2017. Explanatory variables were remuneration, performance-based payments, and expenditures on research, experiments, machines, and books. Research productivity indices were the numbers of Korea Citation Index (KCI) and Science Citation Index (SCI) publications, authored books, patents attained, and licensing revenue. Considering that research productivity measures are related, this study used a seemingly unrelated regression (SUR) model. The SUR model analysis showed that SCI, patents, and licensing revenue were correlated and resources differentially affected research productivity. Full-time faculty remuneration, performance-based payments, and research expenditure were significant variables in determining SCI, patents, and licensing revenue. Results of quadratic form regression showed that research productivity increased when full-time faculty remuneration increased, but these gains were limited by the law of marginal diminishing returns. However, the performance-based payment variable showed opposite results, reflecting the law of marginal increasing returns. Combined results will help universities set their strategic direction, efficiently allocate their resources, and promote understanding about university functions.
Among the various materials found inside microplastic pollution, nanosized microplastics are of particular concern due to difficulties in quantification and detection; moreover, they are predicted to ...be abundant in aquatic environments with stronger toxicity than microsized microplastics. Here, we demonstrated a stronger accumulation of nanosized microbeads in the marine rotifer Brachionus koreanus compared to microsized ones, which was associated with oxidative stress-induced damages on lipid membranes. In addition, multixenobiotic resistance conferred by P-glycoproteins and multidrug resistance proteins, as a first line of membrane defense, was inhibited by nanoplastic pre-exposure, leading to enhanced toxicity of 2,2′,4,4′-tetrabromodiphenyl ether and triclosan in B. koreanus. Our study provides a molecular mechanistic insight into the toxicity of nanosized microplastics toward aquatic invertebrates and further implies the significance of synergetic effects of microplastics with other environmental persistent organic pollutants.
The charging process of secondary batteries is always associated with a large volume expansion of the alloying anodes, which in many cases, develops high compressive residual stresses near the ...propagating interface. This phenomenon causes a significant reduction in the rate performance of the anodes and is detrimental to the development of fast‐charging batteries. However, for the Na‐Sn battery system, the residual stresses that develop near the interface are not stored, but are relieved by the generation of high‐density dislocations in crystalline Sn. Direct‐contact diffusion experiments show that these dislocations facilitate the preferential transport of Na and accelerate the Na diffusion into crystalline Sn at ultrafast rates via “dislocation‐pipe diffusion”. Advanced analyses are performed to observe the evolution of atomic‐scale structures while measuring the distribution and magnitude of residual stresses near the interface. In addition, multi‐scale simulations that combined classical molecular dynamics and first‐principles calculations are performed to explain the structural origins of the ultrafast diffusion rates observed in the Na‐Sn system. These findings not only address the knowledge gaps regarding the relationship between pipe diffusion and the diffusivity of carrier ions but also provide guidelines for the appropriate selection of anode materials for use in fast‐charging batteries.
By performing direct‐contact sodiation experiments and multiscale simulations that combined classical molecular dynamics and first‐principle calculations on the Na‐Sn system, it is found that Na diffusion into crystalline Sn induces tensile stresses near the propagating interface, promoting the nucleation of high‐density dislocations. These dislocations facilitate the preferential transport of Na and accelerate the diffusion of these ions into crystalline Sn at ultrafast rates via dislocation‐pipe diffusion.
Direct ink writing (DIW) stands out as a facile additive manufacturing method, minimizing material waste. Nonetheless, developing homogeneous Bingham inks with high yield stress and swift ...liquid‐to‐solid transitions for versatile 3D printing remains a challenge. In this study, high‐performance Bingham inks are formulated by destabilizing silica particle suspensions in acrylate‐based resin. A colloidal network forms in the shear‐free state through interparticle attraction, achieved by disrupting the solvation layer of large resin molecules using polar molecules. The network is highly dense, with evenly distributed linkage strength as monodisperse particles undergo gelation at an ultra‐high fraction. Crucially, the strength is calibrated to ensure a sufficiently large yield stress, while still allowing the network to reversibly melt under shear flow. The inks immediately undergo a liquid‐to‐solid transition upon discharge, while maintaining fluidity without nozzle clogging. The dense colloidal networks develop structural colors due to the short‐range order. This enables the rapid and sophisticated drawing of structurally‐colored 3D structures, relying solely on rheological properties. Moreover, the printed composite structures exhibit high mechanical stability due to the presence of the colloidal network, which expands the range of potential applications.
High‐yield stress colloidal inks for 3D printing of structurally‐colored objects are created through destabilization of ultra‐stable silica suspensions with polar molecules. These inks form dense, uniform colloidal networks and swiftly transition from liquid to solid upon nozzle discharge, facilitating rapid, shrinkage‐free printing. The resulting prints display structural colors and enhanced mechanical properties due to the dense network.
Proopiomelanocortin (POMC) neurons in the arcuate nucleus of the hypothalamus (ARC) respond to numerous hormonal and neural signals, resulting in changes in food intake. Here, we demonstrate that ARC ...POMC neurons express capsaicin-sensitive transient receptor potential vanilloid 1 receptor (TRPV1)-like receptors. To show expression of TRPV1-like receptors in ARC POMC neurons, we use single-cell reverse transcription-polymerase chain reaction (RT-PCR), immunohistochemistry, electrophysiology, TRPV1 knock-out (KO), and TRPV1-Cre knock-in mice. A small elevation of temperature in the physiological range is enough to depolarize ARC POMC neurons. This depolarization is blocked by the TRPV1 receptor antagonist and by Trpv1 gene knockdown. Capsaicin-induced activation reduces food intake that is abolished by a melanocortin receptor antagonist. To selectively stimulate TRPV1-like receptor-expressing ARC POMC neurons in the ARC, we generate an adeno-associated virus serotype 5 (AAV5) carrying a Cre-dependent channelrhodopsin-2 (ChR2)-enhanced yellow fluorescent protein (eYFP) expression cassette under the control of the two neuronal POMC enhancers (nPEs). Optogenetic stimulation of TRPV1-like receptor-expressing POMC neurons decreases food intake. Hypothalamic temperature is rapidly elevated and reaches to approximately 39 °C during treadmill running. This elevation is associated with a reduction in food intake. Knockdown of the Trpv1 gene exclusively in ARC POMC neurons blocks the feeding inhibition produced by increased hypothalamic temperature. Taken together, our findings identify a melanocortinergic circuit that links acute elevations in hypothalamic temperature with acute reductions in food intake.
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An antimicrobial peptide motif (Cys-KR12) originating from human cathelicidin peptide (LL37) was immobilized onto electrospun SF nanofiber membranes using EDC/NHS and thiol-maleimide ...click chemistry to confer the various bioactivities of LL37 onto the membrane for wound care purposes. Surface characterizations revealed that the immobilization density of Cys-KR12 on SF nanofibers could be precisely controlled with a high reaction yield. The Cys-KR12-immobilized SF nanofiber membrane exhibited antimicrobial activity against four pathogenic bacterial strains (Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa) without biofilm formation on the membrane surface. It also facilitated the proliferation of keratinocytes and fibroblasts and promoted the differentiation of keratinocytes with enhanced cell-cell attachment. In addition, immobilized Cys-KR12 significantly suppressed the LPS-induced TNF-α expression of monocytes (Raw264.7) cultured on the membrane. These results suggest that a Cys-KR12-immobilized SF nanofiber membrane, which has multiple biological activities, would be a promising candidate as a wound dressing material.
This research article reports various bioactivities of an antimicrobial peptide on electrospun silk fibroin nanofiber membrane. Recently, human cathelicidin peptide LL37 has been extensively explored as an alternative antibiotic material. It has not only a great antimicrobial activity but also a wide variety of bioactivities which can facilitate wound healing process. Especially, many studies on immobilization of LL37 or its analogues have shown the immobilization technique could improve performance of wound dressing materials or tissue culture matrices. Nevertheless, so far studies have only focused on the bactericidal effect of immobilized peptide on material surface. On the other hand, we tried to evaluate multi-biofunction of immobilized antimicrobial peptide Cys-KR12, which is the shortest peptide motif as an analogue of LL37. We fabricated silk fibroin nanofiber membrane as a model wound dressing by electrospinning and immobilized the antimicrobial peptide. As a result, we confirmed that the immobilized peptide can play multi-role in wound healing process, such as antimicrobial activity, facilitation of cell proliferation and keratinocyte differentiation, and inhibition of inflammatory cytokine expression. These findings have not been reported and can give an inspiration in wound-care application.
This study presents an effective method for recovering unbroken solar cells from photovoltaic (PV) modules. The combustion process is effective at removing ethylene vinyl acetate (EVA) in PV modules. ...However, the solar cell tends to break during the combustion process. We verify that the breakage mechanisms of the solar cell in the module are related to the thermal changes of EVA during the heat treatment process, that is, generated gases form bubbles behind the glass, and the thermal deformation of the rear EVA applies stress to the solar cell. This study investigates the simple pretreatments of glass cracking and EVA patterning to prevent the breakage behavior. An unbroken solar cell was successfully recovered from the module after complete EVA removal using the combustion process. The recovered solar cell was immersed in a mixed acid solution of HNO3 and HF to reclaim the crystalline silicon wafer, which subsequently underwent the solar cell manufacturing process. The PV performances of the solar cells based on the reclaimed wafer and a commercial wafer were evaluated and compared. The PV performance of the solar cell manufactured from the reclaimed wafer was measured at 18.5%, whereas that from the commercial wafer‐based solar cell was measured at 18.7%. Consequently, the considered pretreatment processes yielded solar cells acceptable for use in the PV industry.
The proposed process is capable of recovering unbroken solar cells by applying simple pretreatments on both sides of the PV module that are effective at removing the stress factors during the solar cell recovery process. The unbroken solar cell recovered from the module was immersed in a mixed acid solution to reclaim the crystalline silicon wafer, and a solar cell was remanufactured. The PV performance of the solar cell was evaluated to have a high efficiency of 18.5%.
We report high-performance flexible nanogenerators (NGs) based on a composite thin film, composed of hemispherically aggregated BaTiO3 nanoparticles (NPs) and poly(vinylidene ...fluoride-co-hexafluoropropene) P(VDF-HFP). The hemispherical BTO–P(VDF-HFP) clusters were realized by a solvent evaporation method, which greatly enhanced piezoelectric power generation. The flexible NGs exhibit high electrical output up to ∼75 V and ∼15 μA at the applied force normal to the surface, indicating the important role of hemispherical BTO clusters. Besides, the durability and reproducibility of the NGs were tested by cyclic measurement under bending stage, generating the output of ∼5 V and ∼750 nA. The approach we introduce here is simple, cost-effective, and well-suited for large-scale high-performance flexible NG fabrication.
Obesity, Metabolic Abnormality, and Progression of CKD Yun, Hae-Ryong; Kim, Hyoungnae; Park, Jung Tak ...
American journal of kidney diseases,
September 2018, 2018-09-00, 20180901, Volume:
72, Issue:
3
Journal Article
Peer reviewed
Recent studies have yielded conflicting findings on the association between obesity and progression of chronic kidney disease (CKD). Few studies have evaluated whether metabolic abnormalities may ...accelerate the rate of progression of CKD.
Prospective observational cohort study.
1,940 participants from the Korean Cohort Study for Outcome in Patients With Chronic Kidney Disease (KNOW-CKD)
Obesity and metabolic abnormality. Obesity was defined as body mass index ≥ 25kg/m2. Metabolic abnormality was defined as the presence of 3 or more of the following 5 components: hypertension, fasting glucose level > 125mg/dL or the presence of type 2 diabetes, triglyceride level > 150mg/dL or use of lipid-lowering drugs, high-density lipoprotein cholesterol level ≤ 40mg/dL in men and ≤ 50mg/dL in women, and high-sensitivity C-reactive protein level > 1mg/L.
A composite of a 50% decline in estimated glomerular filtration rate from the baseline value or end-stage kidney disease.
Multivariable cause-specific hazards models implemented to assess the association between obesity, metabolic abnormality, and CKD progression.
During a mean follow-up of 3.1 years, the primary outcome occurred in 395 (20.4%) patients. In multivariable analyses, after adjustment for confounding factors, obesity and metabolic abnormality were significantly associated with 1.41-fold (95% CI, 1.08-1.83; P=0.01) and 1.38-fold (95% CI, 1.03-1.85; P=0.03) increased risk for adverse renal outcomes, respectively. Patients were categorized into 4 groups depending on the presence of obesity and metabolic abnormality. Compared with those with neither obesity nor metabolic abnormality, those with obesity and metabolic abnormality had a greater risk for CKD progression (HR, 1.53; P=0.03). Those with obesity without metabolic abnormality also had a higher rate of CKD progression (HR, 1.97; P=0.01).
Observational study, limited power to detect cardiovascular disease outcomes, unmeasured confounders.
Both metabolic abnormality and obesity are associated with a significantly increased risk for CKD progression. Notably, obese patients without metabolic abnormality also have an elevated risk for CKD progression.
It is of critical importance to improve toughness, strength, and wear-resistance together for the development of advanced structural materials. Herein, we report on the synthesis of unoxidized ...graphene/alumina composite materials having enhanced toughness, strength, and wear-resistance by a low-cost and environmentally benign pressure-less-sintering process. The wear resistance of the composites was increased by one order of magnitude even under high normal load condition (25 N) as a result of a tribological effect of graphene along with enhanced fracture toughness (KIC) and flexural strength (σf) of the composites by ~75% (5.60 MPa·m(1/2)) and ~25% (430 MPa), respectively, compared with those of pure Al2O3. Furthermore, we found that only a small fraction of ultra-thin graphene (0.25-0.5 vol%, platelet thickness of 2-5 nm) was enough to reinforce the composite. In contrast to unoxidized graphene, graphene oxide (G-O) and reduced graphene oxide (rG-O) showed little or less enhancement of fracture toughness due to the degraded mechanical strength of rG-O and the structural defects of the G-O composites.
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