Crystal plane orientation-dependent surface atom diffusion in sub-10-nm Au nanocrystals.

Surface atom diffusion is a ubiquitous phenomenon in nanostructured metals with ultrahigh surface-to-volume ratios. However, the fundamental atomic mechanism of surface atom diffusion remains elusive. Here, we report in situ atomic-scale observations of surface pressure-driven atom diffusion in gold nanocrystals at room temperature using high-resolution transmission electron microscopy with a high-speed detection camera. The topmost layer of atoms on (001) plane initially diffuse in a column-by-column manner. As diffusion proceeds, the remaining atomic columns collectively inject into adjacent underlayer, accompanied by nucleation of a surface dislocation. In comparison, atoms on (111) plane directly diffuse to the base without collective injection. Quantitative calculations indicate that these crystal plane orientation-dependent atom diffusion behaviors contribute to the larger diffusion coefficient of (111) plane compared to (001) plane in addition to the effect of diffusion activation energy. Our findings provide valuable insights into atomic mechanisms of diffusion-dominant morphology evolution of nanostructured metals and guide the design of nanostructured materials with enhanced structural stability.

Increasing Risk of Dementia Among Patients with Subsequent Epilepsy Within 2 Years Post-Traumatic Brain Injury: A Population-Based Case-Control Study.

Background: Although the association between neurodegenerative diseases, such as dementia, and traumatic brain injury (TBI) has long been known, the association between dementia and TBI with epilepsy has been controversial. Aim: This data-driven population-based study is designed to investigate the association between dementia and epilepsy after TBI within a 2-year period. Methods: This case-control cohort study was conducted using the Longitudinal Health Insurance Database 2000 (LHID2000). We included 784 individuals ambulatory or hospitalized for TBI with epilepsy from 2001 to 2011, compared with 2992 patients with TBI without epilepsy who were matched for characteristics including sex, age, and healthcare resource use index date. Every participant was followed up for 5 years to ascertain any dementia development. Data were stratified and analyzed using the Cox proportional hazards regression. Results: Through the 5-year follow-up period, 39 patients (5.21%) with TBI with epilepsy and 55 (1.53%) with TBI without epilepsy developed dementia. TBI with epilepsy was independently associated with a >3.03 times risk of dementia after correcting for age, sex, and comorbidities. Conclusion: These findings suggest an increased risk of dementia in patients with TBI with epilepsy. Our research recommends that individuals with TBI and epilepsy be monitored more intensively.

Atomic-Scale In Situ Observations of Reversible Phase Transformation Assisted Twinning in a CrCoNi Medium-Entropy Alloy.

Twinning is an important deformation mode of face-centered-cubic (FCC) medium- and high-entropy alloys, especially under extreme loading conditions. However, the twinning mechanism in these alloys that have a low or even negative stacking fault energy remains debated. Here, we report atomic-scale in situ observations of the deformation process of a prototypical CrCoNi medium-entropy alloy under tension. We found that the parent FCC phase first transforms into a hexagonal close-packed (HCP) phase through Shockley partial dislocations slipping on the alternate {111} planes. Subsequently, the HCP phase rapidly changes to an FCC twin band. Such reversible phase transformation assisted twinning is greatly promoted by external tensile loads, as elucidated by geometric phase analysis. These results indicate the previously underestimated role of the metastable HCP phase in nanotwin nucleation and early plastic deformations of CrCoNi alloys and shed light on microstructure regulation of medium-entropy alloys with enhanced mechanical properties.

A Three-Dimensional Bioprinted Copolymer Scaffold with Biocompatibility and Structural Integrity for Potential Tissue Regeneration Applications.

The present study was to investigate the rheological property, printability, and cell viability of alginate−gelatin composed hydrogels as a potential cell-laden bioink for three-dimensional (3D) bioprinting applications. The 2 g of sodium alginate dissolved in 50 mL of phosphate buffered saline solution was mixed with different concentrations (1% (0.5 g), 2% (1 g), 3% (1.5 g), and 4% (2 g)) of gelatin, denoted as GBH-1, GBH-2, GBH-3, and GBH-4, respectively. The properties of the investigated hydrogels were characterized by contact angle goniometer, rheometer, and bioprinter. In addition, the hydrogel with a proper concentration was adopted as a cell-laden bioink to conduct cell viability testing (before and after bioprinting) using Live/Dead assay and immunofluorescence staining with a human corneal fibroblast cell line. The analytical results indicated that the GBH-2 hydrogel exhibited the lowest loss rate of contact angle (28%) and similar rheological performance as compared with other investigated hydrogels and the control group. Printability results also showed that the average wire diameter of the GBH-2 bioink (0.84 ± 0.02 mm (*** p < 0.001)) post-printing was similar to that of the control group (0.79 ± 0.05 mm). Moreover, a cell scaffold could be fabricated from the GBH-2 bioink and retained its shape integrity for 24 h post-printing. For bioprinting evaluation, it demonstrated that the GBH-2 bioink possessed well viability (>70%) of the human corneal fibroblast cell after seven days of printing under an ideal printing parameter combination (0.4 mm of inner diameter needle, 0.8 bar of printing pressure, and 25 °C of printing temperature). Therefore, the present study suggests that the GBH-2 hydrogel could be developed as a potential cell-laden bioink to print a cell scaffold with biocompatibility and structural integrity for soft tissues such as skin, cornea, nerve, and blood vessel regeneration applications.

In situ atomic-scale observation of dislocation climb and grain boundary evolution in nanostructured metal.

Non-conservative dislocation climb plays a unique role in the plastic deformation and creep of crystalline materials. Nevertheless, the underlying atomic-scale mechanisms of dislocation climb have not been explored by direct experimental observations. Here, we report atomic-scale observations of grain boundary (GB) dislocation climb in nanostructured Au during in situ straining at room temperature. The climb of a edge dislocation is found to occur by stress-induced reconstruction of two neighboring atomic columns at the edge of an extra half atomic plane in the dislocation core. This is different from the conventional belief of dislocation climb by destruction or construction of a single atomic column at the dislocation core. The atomic route of the dislocation climb we proposed is demonstrated to be energetically favorable by Monte Carlo simulations. Our in situ observations also reveal GB evolution through dislocation climb at room temperature, which suggests a means of controlling microstructures and properties of nanostructured metals.

Correlation between nutrition, oral health, and different sarcopenia groups among elderly outpatients of community hospitals: a cross-sectional study of 1505 participants in China.

BACKGROUND: Studies have rarely explored the association between oral health status and different sarcopenia groups (possible sarcopenia, diagnosed sarcopenia, and severe sarcopenia). Moreover, these studies have not reported any definitive conclusions of their relationship. We aimed to characterize the oral health status, prevalence of sarcopenia, and risk factors in different sarcopenia groups of elderly outpatients of community hospitals. Furthermore, we determined the correlation among nutrition, oral health, and different sarcopenia groups. METHODS: Overall, 1505 elderly participants (aged ≥ 65 years) completed the survey. The Mini Nutritional Assessment short-form (MNA-SF) was used to assess the nutrition status of the elderly. Oral health was assessed using the instrument of the oral health assessment index of the elderly (General Oral Health Assessment Index [GOHAI]), and the number of remaining natural teeth (NRT) was counted. Data on muscle mass, muscle strength, and gait speed were collected, and sarcopenia was classified into three groups (possible sarcopenia, diagnosed sarcopenia, and severe sarcopenia) according to the Asian Working Group for Sarcopenia 2019. Multinomial logistic regression multivariate analysis was used to test their relationships. RESULTS: Eighty-eight (5.8%) participants were identified as having possible sarcopenia; 142 (9.5%), diagnosed sarcopenia; 136 (9.0%), severe sarcopenia; and 1139 (75.7%), no sarcopenia. Of the seven variables, advancing age was typically associated with an increasing prevalence of sarcopenia (odds ratio [OR] = 1.06-1.47, 95% confidence interval [CI] = 1.06-1.47). The results showed that household income (OR = 0.57, 95% CI = 0.33-0.98), education level (OR = 3.32, 95% CI = 1.09-10.07), and chronic diseases (OR = 0.34, 95% CI = 0.19-0.62) were significantly associated with the severe sarcopenia group. Physical activity scores were significantly associated with the diagnosed sarcopenia and severe sarcopenia groups. Participants with < 20 NRT were more likely to have diagnosed sarcopenia (OR = 5.55, 95% CI = 3.80-8.12) or severe sarcopenia (OR = 6.66, 95% CI = 4.13-10.76) than participants with > 20 NRT. The GOHAI score was associated with the diagnosed sarcopenia (OR = 5.55, 95% CI = 3.80-8.12) and severe sarcopenia (OR = 6.66, 95% CI = 4.13-10.78) groups. The MNA-SF score was associated with the different sarcopenia groups. CONCLUSIONS: Assessing early and improving lifestyle with respect to nutrition and oral health may be an effective way to reduce or delay the occurrence of sarcopenia.

Relative Efficacy of Weight Management, Exercise, and Combined Treatment for Muscle Mass and Physical Sarcopenia Indices in Adults with Overweight or Obesity and Osteoarthritis: A Network Meta-Analysis of Randomized Controlled Trials.

Aging and osteoarthritis are associated with high risk of muscle mass loss, which leads to physical disability; this loss can be effectively alleviated by diet (DI) and exercise (ET) interventions. This study investigated the relative effects of different types of diet, exercise, and combined treatment (DI+ET) on muscle mass and functional outcomes in individuals with obesity and lower-limb osteoarthritis. A comprehensive search of online databases was performed to identify randomized controlled trials (RCTs) examining the efficacy of DI, ET, and DI+ET in patients with obesity and lower-extremity osteoarthritis. The included RCTs were analyzed through network meta-analysis and risk-of-bias assessment. We finally included 34 RCTs with a median (range/total) Physiotherapy Evidence Database score of 6.5 (4-8/10). DI plus resistance ET, resistance ET alone, and aerobic ET alone were ranked as the most effective treatments for increasing muscle mass (standard mean difference (SMD) = 1.40), muscle strength (SMD = 1.93), and walking speed (SMD = 0.46). Our findings suggest that DI+ET is beneficial overall for muscle mass in overweight or obese adults with lower-limb osteoarthritis, especially those who are undergoing weight management.

Atomic Ni and Cu co-anchored 3D nanoporous graphene as an efficient oxygen reduction electrocatalyst for zinc-air batteries.

Highly active, cost-effective and durable electrocatalysts for the oxygen reduction reaction (ORR) are critically important for renewable energy conversion and storage. Here we report a 3D bicontinuous nitrogen doped nanoporous graphene electrocatalyst co-anchoring with atomically dispersed nickel and copper atoms ((Ni,Cu)-NG) as a highly active single-atom ORR catalyst, fabricated by the combination of chemical vapor deposition and high temperature gas transportation. The resultant (Ni,Cu)-NG exhibits an exceptional ORR activity in alkaline electrolytes, comparable to the Pt-based benchmarks, from the synergistic effect of the CuNx and NiNx complexes. Endowed with high catalytic activity and outstanding durability under harsh electrochemical environments, rechargeable zinc-air batteries using (Ni,Cu)-NG as the cathodes show excellent energy efficiency (voltage gap of 0.74 V), large power density (150.6 mW cm-2 at 250 mA cm-2) and high cycling stability (>500 discharge-charge cycles at 10 mA cm-2). This study may pave an efficient avenue for designing highly durable single-atom ORR catalysts for metal-air batteries.

Tele-Health Intervention for Carers of Dementia Patients-A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Objective: The purpose of this study is to evaluate the major mental health outcomes on dementia patient carers when using psychoeducational programs and psychotherapeutic interventions. Methods: A meta-analysis was performed with randomized controlled trials of carers' tele-health interventions from the literature inception to December 31, 2019, using PubMed, EMBASE, and CENTRAL databases for articles. Results: The meta-analysis identified 1,043 results, of which 11 were randomized control trials. Among all 11 randomized control trials, only one study addressed face-to-face contact with online modules of interventions, four studies addressed telephone-based interventions, two studies reported on combined face-to-face contact and phone call interventions, two studies focused on web-based interventions, one study used video and telephone interventions, and one study conducted a computer-telephone integration system of intervention. The updated evidence suggested that there was more efficacy via tele-health interventions in lowering depression for carers of people with dementia. We outlined the delivery formation of intervention to evaluate the effectiveness and processes of major mental health improvements, including depression, burden, anxiety, and quality of life. Conclusions: In this study, tele-health intervention was shown to significantly lower depression and also lower the risk of mental health impairment. Although there was a significant decrease of depression, there were no significant differences in burden, anxiety, and quality of life. Future researchers are encouraged to carry out larger-scale studies; also, further analysis using a standardized assessment tool is suggested for future multi-component tele-health interventions.

Anionic redox reaction triggered by trivalent Al3+ in P3-Na0.65Mn0.5Al0.5O2.

P3-Na0.65Mn0.5Al0.5O2 (NMAO) has been synthesized and studied as a cathode for sodium batteries, and shows anionic redox reaction (ARR) and exhibits a first charging capacity of ∼110 mA h g-1. The electrochemical mechanism of NMAO was comprehensively investigated by X-ray absorption spectroscopy (XAS), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and density functional theory (DFT) calculations. The reversible oxygen redox behaviour is triggered by Al3+ through oxygen quasi non-bonding states generated by the relatively ionic interaction of Al and O. Furthermore, the presence of Al3+ can suppress oxygen loss in ARR. This work provides new insights into the design and mechanism of anionic redox active cathode materials.

Dual-Metal Interbonding as the Chemical Facilitator for Single-Atom Dispersions.

Atomically dispersed catalysts, with maximized atom utilization of expensive metal components and relatively stable ligand structures, offer high reactivity and selectivity. However, the formation of atomic-scale metals without aggregation remains a formidable challenge due to thermodynamic stabilization driving forces. Here, a top-down process is presented that starts from iron nanoparticles, using dual-metal interbonds (RhFe bonding) as a chemical facilitator to spontaneously convert Fe nanoparticles to single atoms at low temperatures. The presence of RhFe bonding between adjacent Fe and Rh single atoms contributes to the thermodynamic stability, which facilitates the stripping of a single Fe atom from the Fe nanoparticles, leading to the stabilized single atom. The dual single-atom Rh-Fe catalyst renders excellent electrocatalytic performance for the hydrogen evolution reaction in an acidic electrolyte. This discovery of dual-metal interbonding as a chemical facilitator paves a novel route for atomic dispersion of chemical metals and the design of efficient catalysts at the atomic scale.

Dealloying Kinetics of AgAu Nanoparticles by In Situ Liquid-Cell Scanning Transmission Electron Microscopy.

Understanding the formation and evolution of bicontinuous nanoporous structure during dealloying has been one of the most challenging subjects of dealloying research. However, previous in situ investigations either suffer from insufficient spatial resolution (e.g., X-ray tomography) or lack morphology visualization and mass information (e.g., scanning tunneling microscopy). In this work, we report the kinetics of the whole course of dealloying by utilizing liquid-cell aberration-corrected scanning transmission electron microscopy. With Z-contrast imaging analysis, the in situ sub-nanoscale characterization reveals two new phenomena, an initial period of dealloying indicative of an initial length scale for bulk dealloying and a large volume shrinkage in a nanoscale alloy precursor. We explain the particle-size-dependent volume shrinkage with the formation of a dense shell and quantify the dependence with a simple geometric model. These insights into the mechanisms of dealloying will enable deliberate designs of nanoporous structures.

Bioinspired Fe3C@C as Highly Efficient Electrocatalyst for Nitrogen Reduction Reaction under Ambient Conditions.

Developing highly efficient non-precious-metal catalysts for electrochemical reduction reaction is vital for artificial nitrogen fixation under ambient conditions. Herein, we report a bioinspired Fe3C@C composite as an efficient electrocatalyst for nitrogen reduction. The composite based on a leaf skeleton successfully replicates the natural vein structure with multichannels. The Fe3C@C core-shell structure as the real active center contributes to selective electrocatalytic synthesis of ammonia from nitrogen with Faraday efficiency of 9.15% and production rate of 8.53 µg/(h mgcat) or 12.80 µg/(h cm2) at a low potential of -0.2 V versus reversible hydrogen electrode (vs RHE), which is better than that of recently reported carbon- and iron-based materials, even comparable with that of noble-metal-based catalyst. Experiments with density functional theory calculations reveal that graphene-encapsulated Fe3C nanoparticles can improve charge transfer due to core-shell interaction, beneficial for inducing active sites for N2 adsorption and activation and thereby facilitate ammonia synthesis.

Structural Determination and Nonlinear Optical Properties of New 1T‴-Type MoS2 Compound.

Noncentrosymmetric MoS2 semiconductors (1H, 3R) possess not only novel electronic structures of spin-orbit coupling (SOC) and valley polarization but also remarkable nonlinear optical effects. A more interesting noncentrosymmetric structure, the so-called 1T‴-MoS2 layers, was predicted to be built up from [MoS6] octahedral motifs by theoreticians, but the bulk 1T‴ MoS2 or its single crystal structure has not been reported yet. Here, we have successfully harvested 1T‴ MoS2 single crystals by a topochemical method. The new layered structure is determined from single-crystal X-ray diffraction. The crystal crystallizes in space group P31m with a cell of a = b = 5.580(2) Å and c = 5.957(2) Å, which is a √3 a × âˆš3 a superstructure of 1T MoS2 with corner-sharing Mo3 triangular trimers observed by the STEM. 1T‴ MoS2 is verified to be semiconducting and possesses a band gap of 0.65 eV, different from metallic nature of 1T or 1T' MoS2. More surprisingly, the 1T‴ MoS2 does show strong optical second-harmonic generation signals. This work provides the first layered noncentrosymmetric semiconductor of edge-sharing MoS6 octahedra for the research of nonlinear optics.

Characteristics and clinical outcomes of head-injured cyclists with and without helmets in urban and rural areas of Taiwan: A 15-year study.

OBJECTIVE: Bicycle riding is increasingly popular in Taiwan, but the number of cyclists injured and cyclists' death rates are both increasing. The aim of this study was to investigate the different characteristics and clinical outcomes of traffic accident-related head injuries among cyclists in urban and rural areas. METHODS: Records of 812 patients (533 urban and 279 rural) admitted to 27 hospitals in Taipei City and Hualien County as the result of a traumatic head injury while bicycling between 1998 and 2013 were retrieved for study. Demographics, details about the accident, protective helmet use, and clinical outcomes were then subjected to analysis. RESULTS: Urban victims were more likely to be injured during morning and early evening rush hours and rural victims during the day; most urban victims were between 19 and 34 years of age and injured in the slow lane; rural victims tended to be younger or older and were injured in the fast lane (all P ≤.001). Riders who wore a helmet were less likely to suffer loss of consciousness (odds ratio [OR] = 0.31), amnesia (OR = 0.069), neurological disorders (OR = 0.205), or facial fractures (OR = 0.369). Older age, more severe head injuries, and bicycle-motor vehicle collisions influenced the severity of symptoms on admission and the residual effects at discharge. CONCLUSIONS: Differences in the characteristics of injuries in urban and rural areas and the utilization of protective helmets may help government authorities adopt appropriate policies to promote safer and more enjoyable cycling.

Hazard Ratio and Repeat Injury for Dementia in Patients With and Without a History of Traumatic Brain Injury: A Population-Based Secondary Data Analysis in Taiwan.

The impact of traumatic brain injury (TBI) on the pathogenic hazard ratio (HR) for dementia patients is still controversial. Some studies have supported the association between TBI and dementia, especially for Alzheimer's disease, and our study determined that the HR of dementia patients with and without a history of TBI or repeated TBI (RTBI). We determined the HR for dementia patients with a diagnosis of TBI (n = 12931) and a comparative cohort with age- and gender-matched controls (n = 51724) during 2004-2005, using Taiwan's National Health Insurance Research Database. The adjusted HR (HR = 3.21) for dementia patients with TBI showed that they were more likely to develop dementia than the comparison cohort. The HR for dementia patients with RTBI was increased to 3.62. The results of this large-scale study suggested that TBI increases dementia risk. Future studies using animal models and epidemiological databases could elucidate medical and biological mechanisms linking TBI and the development of dementia.

Reduced power spectra of heart rate variability are correlated with anxiety in patients with mild traumatic brain injury.

Anxiety is one of the most frequently diagnosed emotional disorders after a mild traumatic brain injury (mTBI); however, predictors of anxiety after an mTBI remain uncertain. Recent research indicated that anxiety is associated with abnormalities in the autonomic nervous system (ANS) which can be evaluated by a power spectral analysis of heart rate variability (HRV). In this study, we investigated whether a frequency-domain analysis of HRV could correlate with the occurrence of anxiety in mTBI patients. We recruited 165 Taiwanese patients diagnosed with an mTBI and 82 volunteer healthy controls from three affiliated hospitals of Taipei Medical University during 2010-2014. The Beck Anxiety Inventory (BAI) was assessed at the 1st, 6th, and 12th weeks. We found that mTBI patients were more vulnerable to anxiety compared to healthy controls. The power spectral density of HRV was significantly lower in mTBI patients than in healthy controls. A correlation analysis indicated that anxiety was negatively significantly correlated with low- and high-frequency power at the 6th week. Our study suggests the clinical usefulness of HRV as a potential noninvasive tool for evaluating later anxiety in mTBI patients.

Early dysautonomia detected by heart rate variability predicts late depression in female patients following mild traumatic brain injury.

Depression is one of the frequent complications following a mild traumatic brain injury (mTBI). Recent research indicated that abnormalities in the autonomic nervous system (ANS) can be evaluated by a noninvasive power spectral analysis of the heart rate variability (HRV). In this study, we investigated whether a frequency-domain analysis of HRV was correlated with late depression in mTBI patients. In total, 181 patients diagnosed with mTBI and 83 volunteers as healthy controls were recruited in 2010-2014. Beck Depression Inventory (BDI) scores were used to evaluate depression in the 1st week of assessment and at 1.5-, 3-, 6-, 12-, and 18-month follow-ups. Correlation and logistic regression analyses of the 1st week HRV parameters with BDI scores at 18 months were performed in individual female mTBI patients. Female mTBI patients were more vulnerable to depression accompanied by reduced HRV compared to healthy controls. Over time, depression was aggravated in female mTBI patients but was alleviated in male mTBI patients. A significantly lower parasympathetic proportion of the ANS was noted at 18 months with respect to the 1st week in female mTBI patients. In addition, depression in female mTBI patients at 18 months after injury was significantly correlated with a decrease in the parasympathetic proportion of the ANS in the 1st week (ρ = -0.411; p < .05). Dysautonomia resulted in higher risks of depression in female mTBI patients. We concluded that early dysautonomia following an mTBI contributes to late depression in female mTBI patients.

The effect of various types of motorcycle helmets on cervical spine injury in head injury patients: a multicenter study in Taiwan.

INTRODUCTION: The relationship between cervical spine injury (CSI) and helmet in head injury (HI) patients following motorcycle crashes is crucial. Controversy still exists; therefore we evaluated the effect of various types of helmets on CSI in HI patients following motorcycle crashes and researched the mechanism of this effect. PATIENTS AND METHODS: A total of 5225 patients of motorcycle crashes between 2000 and 2009 were extracted from the Head Injury Registry in Taiwan. These patients were divided into case and control groups according to the presence of concomitant CSI. Helmet use and types were separately compared between the two groups and the odds ratio of CSI was obtained by using multiple logistic regression analysis. RESULTS: We observed that 173 (3.3%) of the HI patients were associated with CSI. The HI patients using a helmet (odds ratio (OR) = 0.31, 95% confidence interval (CI) = 0.19-0.49), full-coverage helmet (0.19, 0.10-0.36), and partial-coverage helmet (0.35, 0.21-0.56) exhibited a significantly decreased rate of CSI compared with those without a helmet. CONCLUSION: Wearing full-coverage and partial-coverage helmets significantly reduced the risk of CSI among HI patients following motorcycle crashes. This effect may be due to the smooth surface and hard padding materials of helmet.