Transfer-free, lithography-free and fast growth of patterned CVD graphene directly on insulators by using sacrificial metal catalyst

Chemical vapor deposited graphene suffers from two problems: transfer from metal catalysts to insulators, and photoresist induced degradation during patterning. Both result in macroscopic and microscopic damages such as holes, tears, doping, and contamination, translated into property and yield dropping. We attempt to solve the problems simultaneously. A nickel thin film is evaporated on SiO2 as a sacrificial catalyst, on which surface graphene is grown. A polymer (PMMA) support is spin-coated on the graphene. During the Ni wet etching process, the etchant can permeate the polymer, making the etching efficient. The PMMA/graphene layer is fixed on the substrate by controlling the surface morphology of Ni film during the graphene growth. After etching, the graphene naturally adheres to the insulating substrate. By using this method, transfer-free, lithography-free and fast growth of graphene realized. The whole experiment has good repeatability and controllability. Compared with graphene transfer between substrates, here, no mechanical manipulation is required, leading to minimal damage. Due to the presence of Ni, the graphene quality is intrinsically better than catalyst-free growth. The Ni thickness and growth temperature are controlled to limit the number of layers of graphene. The technology can be extended to grow other two-dimensional materials with other catalysts

A quasi-Z-source boost DC-DC converter

For problems of traditional boost converter including limited boost ability and high capacitor voltage stress, a boost DC-DC converter was proposed which used two quasi-Z-source networks in cascade. Working process of the converter was analyzed, and expressions of step-up ratio and capacitor voltage stress were derived. Compared with traditional Z-source boost converter, the quasi-Z-source converter can realize larger step-up ratio with small duty cycle, and has lower capacitor voltage stress under the same step-up ratio. The simulation and experimental results verify validity of the theoretical analysis

Elevated thyroid stimulating hormone and metabolic syndrome risk in patients with first-episode and drug-na?ve major depressive disorder: a large-scale cross-sectional study

Background Metabolic syndrome (MetS) is common in major depressive disorder (MDD), but its relationship with thyroid hormones remains unclear. We aimed to examine the association of thyroid hormones and MetS in first-episode drug-na & iuml;ve (FEDN) MDD patients. Methods We recruited 1718 unmedicated MDD patients in this cross-sectional study. MetS was defined based on the 2004 Chinese Diabetes Society Criteria. Serum thyroid hormones including free thyroxine (FT4), free triiodothyronine (FT3), thyroid-stimulating hormone (TSH), thyroid peroxidase antibodies (TPOAb), and anti-thyroglobulin (TGAb) were examined. We used the logistic regression model to determine risk factors for MetS and examined the performance of the regression model by using the Area Under the Curve (AUC). In addition, we performed the trend test to test whether the results were robust. Results The prevalence of MetS in unmedicated MDD patients was 34.4%. MDD patients with MetS had higher levels of serum TSH, TGAb, and TPOAb (all P < 0.001). Concurrently, serum TSH levels were independent risk factors for MetS in MDD patients (OR:1.49, 95%CI: 1.40-1.58), which could also distinguish MDD patients with and without MetS (AUC was 0.77). Additionally, in the trend test, the results also indicated a similar trend when TSH was used as a categorical variable (P for trend < 0.001). Conclusions This study suggests that TSH levels were independent risk factors for MetS in FEDN MDD patients (OR:1.49). The examination of thyroid function may contribute to the early detection of MetS

A New, Efficient Conversion Technology to Transform Ambient CO2 to Valuable, Carbon-Based Fuel via Molten Salt Electrochemistry

Climate warming and environmental problems caused by the excessive consumption of fossil energy and massive CO2 emissions have seriously damaged the human living environment. This paper develops a new green, efficient, and environmentally friendly CO2 capture and conversion method, which is a crucial way to alleviate the greenhouse effect. In this study, alkali metal carbonates (and the corresponding hydroxides) are fused and blended to construct a liquid molten salt electrolyte system with excellent performance, which is applied to synthesize carbon materials or carbon-based fuel gas. By regulating the electrolyte composition and electrolysis parameters, carbon-based fuels with different micro-morphologies and compositions can be prepared in a controllable manner. In pure Li2CO3 electrolyte, carbon nanotubes (CNTs) with a high value are synthesized at 750 &deg;C with, initially, 10 mA/cm2 and, finally, with 100 mA/cm2. Carbon spheres are obtained in Li-Ca-Ba at 750 &deg;C with 200 mA/cm2, while honeycomb carbon is generated in the electrolyte of Li-Na-K at 450 &deg;C with 450 mA/cm2. Syngas (33.6%) or CH4-rich fuel gas (40.1%) can also be obtained by adding LiOH into the electrolyte under 500 &deg;C at 2.0 V and 3.2 V, respectively. This paper provides a new way of utilizing CO2 resources and a new sustainable green development

A New, Efficient Conversion Technology to Transform Ambient CO₂ to Valuable, Carbon-Based Fuel via Molten Salt Electrochemistry

Climate warming and environmental problems caused by the excessive consumption of fossil energy and massive CO2 emissions have seriously damaged the human living environment. This paper develops a new green, efficient, and environmentally friendly CO2 capture and conversion method, which is a crucial way to alleviate the greenhouse effect. In this study, alkali metal carbonates (and the corresponding hydroxides) are fused and blended to construct a liquid molten salt electrolyte system with excellent performance, which is applied to synthesize carbon materials or carbon-based fuel gas. By regulating the electrolyte composition and electrolysis parameters, carbon-based fuels with different micro-morphologies and compositions can be prepared in a controllable manner. In pure Li2CO3 electrolyte, carbon nanotubes (CNTs) with a high value are synthesized at 750 °C with, initially, 10 mA/cm2 and, finally, with 100 mA/cm2. Carbon spheres are obtained in Li-Ca-Ba at 750 °C with 200 mA/cm2, while honeycomb carbon is generated in the electrolyte of Li-Na-K at 450 °C with 450 mA/cm2. Syngas (33.6%) or CH4-rich fuel gas (40.1%) can also be obtained by adding LiOH into the electrolyte under 500 °C at 2.0 V and 3.2 V, respectively. This paper provides a new way of utilizing CO2 resources and a new sustainable green development

Neural mechanisms underlying empathy during alcohol abstinence : evidence from connectome-based predictive modeling

Empathy impairments have been linked to alcohol dependence even during abstinent periods. Nonetheless, the neural underpinnings of abstinence-induced empathy deficits remain unclear. In this study, we employed connectome-based predictive modeling (CPM) by using whole brain resting-state functional connectivity (rs-FC) to predict empathy capability of abstinent alcoholics (n = 47) versus healthy controls (n = 59). In addition, the generalizability of the predictive model (i.e., one group treated as a training dataset and another one treated as a test dataset) was performed to determine whether healthy controls and abstinent alcoholics share common neural fingerprints of empathy. Our results showed that abstinent alcoholics relative to healthy controls had decreased empathy capacity. Although no predictive models were observed in the abstinence group, we found that individual empathy scores in the healthy group can be reliably predicted by functional connectivity from the default mode network (DMN) to the sensorimotor network (SMN), occipital network, and cingulo-opercular network (CON). Moreover, the identified connectivity fingerprints of healthy controls could be generalized to predict empathy in the abstinence group. These findings indicate that neural circuits accounting for empathy may be disrupted by alcohol use and the impaired degree varies greatly among abstinent individuals. The large inter-individual variation may impede identification of the predictive model of empathy in alcohol abstainers

Remnant cholesterol and mild cognitive impairment: A cross-sectional study

ObjectiveEmerging evidence suggests that elevated remnant cholesterol (RC) correlates with several health conditions. To explore the association of plasma RC with MCI incidence and the relationship between plasma RC and different domains of cognition in MCI patients.MethodsThirty-six MCI patients and 38 cognitively healthy controls (HC) were enrolled in the present cross-sectional study. Using total cholesterol (TC) minus high-density lipoprotein cholesterol (HDL-C) minus low-density lipoprotein cholesterol (LDL-C) as the formula for calculating fasting RC. Cognition was assessed using the Chinese version of the Montreal cognitive assessment (MoCA), Auditory Verbal Learning Test (AVLT), Digit Symbol Substitution Test (DSST), Trail Making Test (TMT), and Rey-Osterrieth Complex Figure Test (ROCF).ResultsCompared to healthy controls, MCI patients had a higher level of RC, the median difference in RC levels between these two groups was 8.13 mg/dl (95.0%CI: 0.97–16.1). Concurrently, plasma RC level was positively associated with MCI risk (OR = 1.05, 95%CI: 1.01–1.10). Notably, elevated RC level was correlated with impaired cognition in MCI patients, such as DSST (pr = −0.45, p = 0.008), ROCF- Long Delayed Recall (pr = −0.45, p = 0.008), AVLT-Immediate Recall (pr = −0.38, p = 0.028), and TMT-A (pr = 0.44, p = 0.009). Conversely, no significant correlation was found between RC and the AVLT-Long Delayed Recall test.ConclusionThis study found that plasma remnant cholesterol was associated with MCI. Further large longitudinal studies are needed in the future to confirm the results and clarify the cause-and-effect relationship

Characterization of the Macroscopic Impact of Diverse Microscale Transport Mechanisms of Gas in Micro-Nano Pores and Fractures

The objective of this study is to construct a refined microscopic transport model that elucidates the transport mechanisms of gas flow within micro-nano pores and fractures. The collective impact of various microscopic transport mechanisms was explained through the apparent permeability model, specifically related to gases such as methane and carbon dioxide, within the shale matrix. The apparent permeability models, taking into account microscopic transport mechanisms such as slippage flow, Knudsen diffusion, transition flow, and surface diffusion, were established individually. Subsequently, the influencing factors on apparent permeability were analyzed. The results demonstrate that the apparent permeability of the shale reservoir matrix is significantly influenced by pore pressure, temperature, pore size, and total organic carbon (TOC). As pressure decreases, the apparent permeability of Knudsen diffusion and surface diffusion increases, while the apparent permeability of slippage flow decreases. In addition, the apparent permeability of the reservoir matrix initially decreases and then increases. With increasing temperature, the apparent permeability of slippage flow, Knudsen diffusion, and surface diffusion all increase, as does the apparent permeability of the reservoir matrix. As pore size increases, the apparent permeability of surface diffusion and Knudsen diffusion decreases, while the apparent permeability of slippage flow and the reservoir matrix increases. Furthermore, an increase in TOC leads to no change in the apparent permeability of slippage flow and Knudsen diffusion, but an increase in the apparent permeability of surface diffusion and the reservoir matrix. The model presented in this paper enhances the multi-scale characterization of gas microflow mechanisms in shale and establishes the macroscopic application of these micro-mechanisms. Moreover, this study provides a theoretical foundation for the implementation of carbon capture, utilization, and storage (CCUS) in shale gas production

Investigation and analysis of occupational physical injuries among healthcare staffs during allopatric medical aid for the fight against COVID-19

Background: Occupational health impairment of medical personnel manifested as a prominent problem in COVID-19. The aim of this study is to investigate the occupational physical injuries of front-line medical staffs in Hubei province during the fight against COVID-19. Material and Methods: questionnaire survey was conducted among 476 medical staffs from 3 regions of Hubei Province, including general characteristics and the physical discomfort/damage suffered in the isolation wards during working hours. Results: A total of 457 valid questionnaires were collected. The common physical discomfort/damage included skin injuries (22.76%), conjunctivitis (15.10%), falls (9.19%), intolerant unwell symptoms (8.53%) and sharp injuries (6.13%). Logistic regression analysis showed that: lack of protective work experience (OR = 2.049, 95% CI: 1.071–3.921), continuous working for 4 h (OR = 3.771, 95% CI: 1.858–7.654), and working >4 h (OR = 7.076, 95% CI: 3.197–15.663) were high-risk factors for skin injuries. Working continuously for 4 h (OR = 3.248, 95% CI: 1.484–7.110) and working >4 h (OR = 3.096, 95% CI: 1.232–7.772) were high-risk factors for conjunctivitis. Lack of protective work experience was a high risk factor for falls (OR = 5.508, 95% CI: 1.299–23.354). The high risk factors for intolerant unwell symptoms were continuous working for 4 h (OR = 5.372, 95% CI: 1.239–23.301) and working >4 h (OR = 8.608, 95% CI: 1.843–40.217). Working in a COVID-19 critical care unit (OR = 3.249, 95% CI: 1.344–7.854) and implementation of nursing (OR = 9.766, 95% CI: 1.307–72.984) were high risk factors for sharp injuries. Conclusions: Occupational physical injuries are universal in the COVID-19 ward. Those who take up nursing, work in a critical care ward, with no experience in an isolation ward for infectious diseases, and work continuously for ≥4 h on the same day should get more attention