2,360 research outputs found
Thomson backscattering in combined two laser and magnetic field
The Thomson backscattering of an electron moving in combined fields is
studied by a dynamically assisted mechanism. The combined fields are composed
of two co-propagating laser fields and a magnetic field, where the first laser
field is strong and low-frequency while the second is weak and high-frequency,
relatively. The dependence of fundamental frequency of emission on the ratio of
incident laser high-to-low frequency is presented and the spectrum of
backscattering is obtained. It is found that, with a magnetic field, the peak
of the spectrum and the corresponding radiation frequency are significantly
larger in case of two-laser than that in case of only one laser. They are also
improved obviously as the frequency of the weak laser field. Another finding is
the nonlinear correlation between the emission intensity of the backscattering
and the intensity of the weak laser field. These results provide a new
possibility to adjust and control the spectrum by changing the ratios of
frequency and intensity of the two laser fields.Comment: 13 pages, 4 figure
Fall-related attendance and associated hospitalisation of children and adolescents in Hong Kong: a 12-year retrospective study
Objectives: The present study aimed to examine the trends and characteristics of fall-related attendance in accident and emergency department (AED) by injury type and the trend in associated average length of stay (LOS) among children and adolescents in Hong Kong.
Design: A retrospective approach was adopted.
Setting: AED, involving all local public emergency departments from 2001 to 2012.
Participants: 63 557 subjects aged 0–19 years with fall injury record were included in the analysis.
Primary outcome measures: Fall-related injury number and rates were calculated and reported. Poisson and negative binomial regression models were used to study the trends of injury incidence rate at different body regions.
Results: AED fall-related attendance rate increased significantly with an annual percentage change of 4.45 (95% CI 3.43 to 5.47%, p<0.0001). The attendance number of male subjects was persistently higher than female subjects. The standardised rate of fracture injury increased by 1.31% (95% CI 0.56 to 2.05%, p<0.0001) and that of non-fracture injury increased by 9.23% (95% CI 7.07 to 11.43%, p<0.0001) annually. Upper limb was the most frequently fractured location. It included forearm/elbow, shoulder/upper arm and wrist/hand with descending order of frequency. On the contrary, head was the most frequent non-fracture location, followed by forearm/elbow.
Conclusions: The rates of fall-related attendance have been increasing and still remain high. There were significant increases in non-fracture injuries. Fractures were most frequently found in the upper extremity of a child while the most common non-fracture location was head. It appears that more efforts should be made and preventive measures should be implemented for children and adolescents in Hong Kong
Influences of commuting mode, air conditioning mode and meteorological parameters on fine particle (PM2.5) exposure levels in traffic microenvironments
With the aim of determining the impacts of various factors on commuter exposure to fine particulate matter (PM2.5), a series of field studies were carried out to measure commuter exposure to PM2.5 on six major commuting modes (in-cabin mode: bus, taxi and metro; on-roadway mode: walking, bicycle and motorcycle) in a highly industrialized city in the Pearl River Delta, China. The results showed that the exposure level was greatly influenced by the commuter mode, with the on-roadway mode showing a higher PM2.5 concentration (76 μg/m3). An experiment with the taxi mode suggested that the use of air-conditioning can effectively reduce exposure levels in most cases (by at least 83%). Apart from traffic-related emissions, ambient PM2.5 concentration also had important impacts on exposure levels in most commuting modes, which was further ascertained by the seasonal variations in exposure levels and their significant correlations (p < 0.05) with meteorological parameters (temperature, relative humidity, wind speed and direction). The results of a General Linear Model analysis show that temperature, traffic mode and wind speed were significant factors that explained 27.3% of variability for the in-cabin mode, while relative humidity and wind speed were the significant determinants for the on-roadway mode, which contributed 14.1% of variability. In addition, wind direction was also an important determinant for both in-cabin and on-roadway modes. This study has some valuable implications that can help commuters to adopt appropriate travel behavior to reduce their personal exposure to such pollutants
Par-4 Links Dopamine Signaling and Depression
SummaryProstate apoptosis response 4 (Par-4) is a leucine zipper containing protein that plays a role in apoptosis. Although Par-4 is expressed in neurons, its physiological role in the nervous system is unknown. Here we identify Par-4 as a regulatory component in dopamine signaling. Par-4 directly interacts with the dopamine D2 receptor (D2DR) via the calmodulin binding motif in the third cytoplasmic loop. Calmodulin can effectively compete with Par-4 binding in a Ca2+-dependent manner, providing a route for Ca2+-mediated downregulation of D2DR efficacy. To examine the importance of the Par-4/D2DR interaction in dopamine signaling in vivo, we used a mutant mouse lacking the D2DR interaction domain of Par-4, Par-4ΔLZ. Primary neurons from Par-4ΔLZ embryos exhibit an enhanced dopamine-cAMP-CREB signaling pathway, indicating an impairment in dopamine signaling in these cells. Remarkably, Par-4ΔLZ mice display significantly increased depression-like behaviors. Collectively, these results provide evidence that Par-4 constitutes a molecular link between impaired dopamine signaling and depression
Hybrid passivation for foldable indium gallium zinc oxide thin-film transistors mediated by low-temperature and low-damage parylene-C/atomic layer deposition-AlOx coating
Indium gallium zinc oxide (IGZO) thin‐film transistors (TFTs) are primary components in active integrated electronics, such as displays and sensor arrays, which heavily involve high‐throughput passivation techniques during multilayer fabrication processes. Though oxide compound semiconductors are commonly used for providing uniform and robust passivation, it usually causes performance degradation on IGZO TFTs during passivation process. Herein, a parylene‐C and aluminum oxide (AlOx) hybrid passivation approach are introduced to reduce the damage during AlOx atomic layer deposition (ALD), which results in high‐performance depletion‐mode IGZO TFT to be fabricated on polyethylene naphthalate (PEN) substrate with enhanced bias stability. Compared with parylene‐C passivation, the hybrid‐passivated IGZO TFTs exhibit excellent saturation mobility (7.9 cm2 (V s)−1), ON/OFF ratio (107), hysteresis window (0.73 V), and bias stability (1.44 and −0.27 V threshold voltage shift, Vds = 20 V). Based on systematic Mott–Schottky and X‐ray diffraction characterizations, it is found that TFT performance enhancement is originated from their doping density variation that resulted from a parylene‐C/ALD‐AlOx microstructural hybridization. Finally, this method is implemented to wafer‐scale integrated circuits with high uniformity and a flexible 10 × 10 IGZO TFT backplane matrix on a PEN substrate (2.5 cm × 2.5 cm)
Effects of photoperiod on nutrient digestibility, hair follicle activity and cashmere quality in Inner Mongolia white cashmere goats
Objective This study investigated the effects of photoperiod on nutrient digestibility, hair follicle (HF) activity and cashmere quality in Inner Mongolia white cashmere goats. Methods Twenty-four female (non-pregnant) Inner Mongolia white cashmere goats aged 1 to 1.5 years old with similar live weights (mean, 20.36±2.63 kg) were randomly allocated into two groups: a natural daily photoperiod group (NDPP group:10 to 16 h light, n = 12) and a short daily photoperiod group (SDPP group: 7 h light:17 h dark, n = 12). All the goats were housed in individual pens and fed the same diets from May 15 to October 15, 2015. The digestibility of crude protein (CP), dry matter (DM), and neutral detergent fiber (NDF) were measured in different months, along with secondary hair follicle (SHF) activity, concentration of melatonin (MEL), and cashmere quality. Results Although there was no significant difference in the live weights of goats between the SDPP and NDPP groups (p>0.05), the CP digestibility of goats in the SDPP group was significantly increased compared to the NDPP group in July, September, and October (p<0.05). For the DM and NDF digestibility of goats, a significant increase (p<0.05) was found during in September in the SDPP group. Furthermore, compared to the NDPP group, the SHF activity in July, the MEL concentration in July, and the cashmere fiber length and fiber weight in October were significantly increased in the SDPP group (p<0.05). Conclusion The cashmere production of Inner Mongolia white cashmere goats was increased without obvious deleterious effects on the cashmere fibers in the SDPP group (metabolizable energy, 8.34 MJ/kg; CP, 11.16%; short daily photoperiod, 7 h light:17 h dark)
Association between investigator-measured body-mass index and colorectal adenoma: a systematic review and meta-analysis of 168,201 subjects
The objective of this meta-analysis is to evaluate the odds of colorectal adenoma (CRA) in colorectal cancer screening participants with different body mass index (BMI) levels, and examine if this association was different according to gender and ethnicity. The EMBASE and MEDLINE were searched to enroll high quality observational studies that examined the association between investigator-measured BMI and colonoscopy-diagnosed CRA. Data were independently extracted by two reviewers. A random-effects meta-analysis was conducted to estimate the summary odds ratio (SOR) for the association between BMI and CRA. The Cochran’s Q statistic and I2 analyses were used to assess the heterogeneity. A total of 17 studies (168,201 subjects) were included. When compared with subjects having BMI < 25, individuals with BMI 25–30 had significantly higher risk of CRA (SOR 1.44, 95% CI 1.30–1.61; I2 = 43.0%). Subjects with BMI ≥ 30 had similarly higher risk of CRA (SOR 1.42, 95% CI 1.24–1.63; I2 = 18.5%). The heterogeneity was mild to moderate among studies. The associations were significantly higher than estimates by previous meta-analyses. There was no publication bias detected (Egger’s regression test, p = 0.584). Subgroup analysis showed that the magnitude of association was significantly higher in female than male subjects (SOR 1.43, 95% CI 1.30–1.58 vs. SOR 1.16, 95% CI 1.07–1.24; different among different ethnic groups (SOR 1.72, 1.44 and 0.88 in White, Asians and Africans, respectively) being insignificant in Africans; and no difference exists among different study designs. In summary, the risk conferred by BMI for CRA was significantly higher than that reported previously. These findings bear implications in CRA risk estimation
Effectiveness of a technology-based injury prevention program for enhancing mothers’ knowledge of child safety: protocol for a randomized controlled trial
Background: Provision of anticipatory guidance for parents is recommended as an effective strategy to prevent injuries among young children. Technology-based anticipatory guidance has been suggested to reinforce the effectiveness of injury prevention and improve parents’ knowledge of child safety.
Objective: This study aims to examine the effectiveness of a technology-based injury prevention program with parental anticipatory guidance for enhancing mothers’ knowledge of child safety.
Methods: In this randomized controlled trial, 308 mothers will be recruited from the antenatal clinics and postnatal wards of two major public hospitals in Hong Kong. Participating mothers will be randomly assigned into intervention and control groups. Mothers in the intervention group will be given free access to a technology-based injury prevention program with anticipatory guidance, whereas mothers in the control group will be given a relevant booklet on parenting. The injury prevention program, available as a website or on a mobile app, includes behavioral components based on the Theory of Planned Behavior. The primary outcome measure will be the change in the mother’s knowledge of child safety. The secondary outcome measures will be age-appropriate domestic safety knowledge, attitudes, intentions, perceived behavioral control, and self-reported behavior related to home safety practice. We will also determine dose-response relationships between the outcome measures and the website and mobile app usage.
Results: Enrolment of participants will begin in October 2016. Results are expected by June 2018.
Conclusions: Parents will be able to easily access the domestic injury prevention website to find information regarding child injury prevention. It is anticipated that the technology-based intervention will help parents improve their knowledge of child safety and raise their awareness about the consequences of domestic injuries and the importance of prevention.
Trial Registration: Clinicaltrials.gov
Clinicaltrials.gov NCT02835768; http://clinicaltrials.gov/ct2/show/NCT02835768 (Archived by WebCite at http://www.webcitation/6lbXYM6b9)
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