Ocular surface temperature: a 3D FEM prediction using bioheat equation

Computational and mathematical human eye models from previous studies which were constructed in two-dimensions (2D) did not give a precise representation of the actual human eye. This work is an extension from an earlier published work on the 2D model. In this paper, a 3D FEM model of the human eye is simulated for the steady state temperature distribution during normal condition and during electromagnetic (EM) wave radiation. Results show a discrepancy of 0.49% for a normal condition as opposed to 1.9% of a 2D model when compared to experimental results from open literatures. Investigations on the EM wave radiations found an average power absorption density of 15,151 and 22,145 Wm(-3) for the 750 and 1500 MHz radiation, respectively. A peak temperature of 38.18( composite function)C was predicted for the 750 MHz radiation while 41.19( composite function)C was computed for the 1500 MHz radiation. These temperatures are in reasonable agreement with the simulated results computed by another report in the past.     

Effects of prostaglandins E2 and F2α on electromyogram of cat colonin vitro

Prostaglandins cause diarrhea, and their production by the gut increases in diarrheal states. We studied the effects of PGF₂ and PGE₂ on the electromyogram recorded from the cat colonin vitro to determine if these prostaglandins might produce electromyographic changes similar to those seen in diarrheal states. PGF₂ decreased slow wave frequency and uncoupled slow wave propagation in the proximal colon. It increased the frequency of migrating spike bursts. PGE₂ had no effect on slow waves, but increased the frequency of the migrating spike burst. PGF₂ produced electromyographic changes similar to those recorded from the colon of cats with spontaneous diarrhea or after exposure to diarrhea-producing agents such as ricinoleate or quinidine. Some diarrhea-producing agents are likely to act by increasing prostaglandin production.     

The origin of secondary microseism Love waves

The interaction of ocean surface waves produces pressure fluctuations at the seafloor capable of generating seismic waves in the solid Earth. The accepted mechanism satisfactorily explains secondary microseisms of the Rayleigh type, but it does not justify the presence of transversely polarized Love waves, nevertheless widely observed. An explanation for two-thirds of the worldwide ambient wave field has been wanting for over a century. Using numerical simulations of global-scale seismic wave propagation at unprecedented high frequency, here we explain the origin of secondary microseism Love waves. A small fraction of those is generated by boundary force-splitting at bathymetric inclines, but the majority is generated by the interaction of the seismic wave field with three-dimensional heterogeneity within the Earth. We present evidence for an ergodic model that explains observed seismic wave partitioning, a requirement for full-wave field ambient-noise tomography to account for realistic source distributions.

The surface of the Earth is continuously subjected to perturbing forces that generate seismic waves. Given that 70% of the surface of our planet is covered by oceans, seismic signals due to ocean storms represent the vast majority of seismic data recorded by seismometers on Earth (1). Such data carry information about the energy exchange between different Earth systems, allowing for probing our changing climate (2–4) as well as imaging the internal structure of the Earth (5). The strongest vibrations are called secondary microseisms, excited in the 0.1 to 0.3 Hz frequency range by nonlinear ocean wave–wave interaction (6, 7). They are predominantly composed of seismic surface waves, and Rayleigh waves dominate the vertical component of microseism records (8).The generation mechanism currently accepted for secondary microseisms explains the Rayleigh wave content of vertical-component noise records (9). Secondary microseisms are produced by pressure-like sources at the surface of the ocean. Rayleigh waves are excited below the seafloor due to constructive interference of P and SV body waves. At the ocean–crust interface, they are called Scholte waves when their phase velocity becomes smaller than the minimum phase velocity of the system (10). While at longer periods, ocean waves can directly couple with the seafloor and generate Love waves (11, 12), the generation mechanism of secondary microseisms cannot explain the presence of Love waves on the horizontal components of microseismic records. Observations of secondary microseism Love waves date back to the early (13) and middle (14) 20th century. A few recent studies based on high-quality digital data focused on quantifying the Love-to-Rayleigh ratio in the secondary microseism frequency range (SI Appendix, Table S1). They found that Love-to-Rayleigh ratios are frequency dependent (15) and show a predominance of Rayleigh waves (16, 17), with few exceptions (18).Hypotheses for the generation of secondary microseism Love waves envisage that they can be generated either in the region where the pressure power spectral density (PSD) is strong or along distinct propagation paths within the Earth. The first hypothesis is supported by the presence of bathymetric inclines in the source regions. Such bathymetry may lead to splitting of the vertical second-order pressure force in a component perpendicular to inclines—responsible for Rayleigh waves—and a component tangent to inclines—responsible for Love waves. The second hypothesis is supported by the presence of lateral heterogeneities within the Earth, which can lead to the generation of Love waves due to scattering and focusing/defocusing effects. Ref. 8 observed Love and Rayleigh waves coming from the same direction, concluding that Love waves do originate in the source region. On the other hand, ref. 19 noted that the greater the distance of propagation of Rayleigh waves, the larger the Love wave energy. In addition to these hypotheses, Love waves may originate from Rayleigh-to-Love wave conversion at the ocean–continent boundary, although early numerical simulations suggest that only a few percent of incident Rayleigh wave energy can be converted to Love wave energy (20). To date, no comprehensive theoretical investigations as to which mechanisms can lead to the observed secondary microseism Love waves have been conducted.     

Reference values of ECG parameters derived from 906 echocardiographically confirmed healthy Indian children: A population-based study from Gujarat

Introduction

There are few published studies on reference ranges of ECG parameters in children; some ethnic differences have been described.

超声波、关节松动术联合Thera-Band弹力带主动运动疗法治疗冻结肩的疗效

目的探讨以超声波、关节松动术联合Thera-Band弹力带抗阻主动训练运动疗法为主的综合康复手段对冻结肩的疗效。方法将收治的75例冻结肩患者随机分为超声波、关节松动术联合Thera-Band弹力带抗阻主动训练运动疗法为主的综合康复治疗观察组及自我锻炼对照组进行治疗,分别评价其治疗前、治疗6周后的肩关节疼痛（P）、关节活动度（ROM）、肌力（M）、日常生活能力（ADL）、形态（F）等情况,并将两组病例作对照性研究分析。结果 1治疗前观察组与对照组肩关节功能各单项评分、总评分组间比较,差异无统计学意义（P〉0.05）,治疗6周后观察组及对照组肩关节功能各单项评分及总评分较治疗前均显著提高,其中观察组和对照组肩关节功能总评分分别由治疗前的33.58±12.24、35.03±9.62增加至治疗6周后的88.35±11.13、72.56±10.39,差异有统计学意义（组内比较P〈0.05）;增加值分别为54.77±9.71、37.53±10.14。治疗6周后肩关节功能各单项分值及增加值、总评分及增加值组间比较,观察组均优于对照组,差异有统计学意义（P〈0.05或P〈0.01）。2观察组38例患者治愈28例,治愈率为76.38%;显效7例,显效率为18.42%,治愈显效率为92.11%。对照组37例治愈0例,治愈率为零;显效4例,显效率为10.81%,治愈显效率为10.81%。治愈率及治愈显效率差异有统计学意义（P〈0.01）。结论以超声波、关节松动术联合Thera-Band弹力带抗阻主动训练运动疗法为主的综合康复手段对冻结肩的疗效显著。     

Assessment of muscle stiffness using a continuously scanning laser‐Doppler vibrometer

Introduction: A stand‐alone and low‐cost elastography technique has been developed using a single continuously scanning laser Doppler vibrometer. Methods: This elastography technique is used to measure the propagation velocity of surface vibrations over superficial skeletal muscles to assess muscle stiffness. Results: Systematic variations in propagation velocity depending on the contraction level and joint position of the biceps brachii were demonstrated in 10 subjects. Conclusions: This technique may assist clinicians in characterizing muscle stiffness (or tone) changes due to neuromuscular disorders. Muscle Nerve 50 : 133–135, 2014     

Issues & opinions: Single muscle fiber discharges (insertional activity,end-plate potentials,positive sharp waves,and fibrillation potentials): A unifying proposal

The exact origin and precise morphologic explanation of positive sharp waves (PSWs) are presently lacking. Observing normal needle electromyographic insertional activity reveals two types of waveforms: (1) biphasic negative/positive spikes, and (2) positive spikes followed by a small negative phase. In the end-plate region, it is possible to occasionally observe a biphasic end-plate spike transform into a monophasic positive end-plate waveform. It is postulated that this waveform is simply a form of intracellular recording for the biphasic end-plate spike or a form of extracellularly recorded but blocked single muscle fiber discharge. Similarly, the observed monophasic positive insertional activity may be an intracellularly recorded single muscle fiber discharge or a blocked extracellular discharge originating about the needle electrode. Applying this reasoning to PSWs suggests that they may also be an intracellular recording of a fibrillation potential, or needle-induced extracellular blocked local single muscle fiber discharge. This unifying concept is applied to various clinical situations purported to demonstrate “different” types of PSWs. © 1996 John Wiley & Sons, Inc.     

Carbamates and Benzodiazepines have different effects on detoxified alcoholics' sleep polygraphy

We showed in a previous work that tetrabamate (molecular complex composed of febarbamate, difebarbamate and phenobarbital) induced delta sleep in alcoholics, compared to diazepam. The aim of the present study was to test the hypothesis that the effect of tetrabamate on delta sleep was due to the carbamate part of the drug. We compared the effects of diazepam, tetrabamate, and meprobamate on 32 recently detoxified alcoholic inpatients' sleep polygraphy. Except for sleep duration and wake after sleep onset, tetrabamate and meprobamate groups had a similar polygraphic profile, in contrast to diazepam. Compared to the diazepam group, tetrabamate and meprobamate groups showed a decrease in stage 2 and an increase in stage 4. The effects of tetrabamate and meprobamate on stage 4, compared to diazepam, had comparable amplitudes. We propose the hypothesis that carbamates exert their action on delta sleep through an antagonist effect on 5HT-2 or histamine H1 receptors.     

Modelling of Longitudinal Elastic Wave Propagation in a Steel Rod Using the Discrete Element Method

The paper deals with the issue of modelling elastic wave propagation using the discrete element method (DEM). The case of a longitudinal wave in a rod with a circular cross-section was considered. A novel, complex algorithm consisting of the preparation of models and simulation of elastic waves was developed. A series of DEM models were prepared for simulations, differing in discretisation and material parameters. Additional calculations with the finite element method (FEM) were performed. Numerical wave signals were obtained from each simulation and compared with experimental results to choose the best DEM model based on the correlation between the waveforms. Moreover, dispersion curves were prepared for each model to verify the agreement with the Pochhammer-Chree wave propagation theory. Both experimental and theoretical approaches indicated the same model as the most suitable. The analysis results allowed stating that DEM can be successfully used for modelling wave propagation in structural rods.