MGOS: A library for molecular geometry and its operating system

The geometry of atomic arrangement underpins the structural understanding of molecules in many fields. However, no general framework of mathematical/computational theory for the geometry of atomic arrangement exists. Here we present "Molecular Geometry (MG)'' as a theoretical framework accompanied by "MG Operating System (MGOS)'' which consists of callable functions implementing the MG theory. MG allows researchers to model complicated molecular structure problems in terms of elementary yet standard notions of volume, area, etc. and MGOS frees them from the hard and tedious task of developing/implementing geometric algorithms so that they can focus more on their primary research issues. MG facilitates simpler modeling of molecular structure problems; MGOS functions can be conveniently embedded in application programs for the efficient and accurate solution of geometric queries involving atomic arrangements. The use of MGOS in problems involving spherical entities is akin to the use of math libraries in general purpose programming languages in science and engineering. (C) 2019 The Author(s). Published by Elsevier B.V

고전력 트랜지스터 어레이를 이용한 촉감 전기 자극 시스템

Haptic stimulator; High power transistor; Active-matrix array; IGZO TFTIn recent years, there has been a growing demand for haptic feedback in electronic devices because the haptic device market is expanding rapidly due to the increasing number of applications such as automobile displays or virtual reality systems. Haptic devices can be classified into two categories: a mechanical and an electrical feedback device. Mechanical devices can offer some tactile feedback, but most of them are bulky, heavy, and consume a significant amount of power, making them difficult to use in portable devices. In contrast, an electrical device can be small, lightweight, and consume less power, and therefore, it can be more suitable for portable devices. Moreover, it can provide precise tactile feedback if it can achieve high integration density of electrode with suitable electrical stimulation signals. Unfortunately, it is not easy to achieve the high electrode density by simple dot or matrix electrode design. To address the issue, we propose active-matrix electrode design based a thin film transistor(TFT), which reduces the number of wires and improves spatial resolution. As first approach to get design parameters of TFT, we tried to measure the impedance of finger skin. The impedance value is around 30 kΩ at 100 μsec pulse width and 1 pulse per second(pps) condition. Considering high impedance of human finger skin, the transistor should sustain in high voltage(>40 V) and high current(>0.5 mA) driving conditions. Therefore, we optimized the 5 fabrication parameters to achieve optimal electrical stimulator performance. Quality of gate oxide, channel dimension, contact metal, passivation condition and channel design are the 5 parameters. Among those conditions, 200 nm gate oxide formed by PECVD, 20 nm channel thickness, Aluminum contact, polymer passivation and union design of conducting channel are fixed as optimized parameters for electrical stimulation. For precise electrical stimulation, applying bipolar waveform signals are required. Therefore, we investigated the electrical properties of the TFT in the biphasic signal. Because the voltage difference between a drain and a gate is changed at a positive and a negative pulse, the sustain range of TFT should be increased and we reflected the enquiry to the design of TFTs. The TFT provided enough current to stimulate the tactile receptors in various situations. As proof of suggested concept, we fabricated 64 stimulation sites based on active matrix TFT array in 1.1 x 1.1 cm2 area. The conductance of TFT(on state) can transfer well stimulation signal for fingertip well(50 V, 1.14 mA with 30 kΩ). Tactile perception test by electrical stimulation was conducted. The stimulation shape formed by selected electrodes. The new stimulator gave better tactile perception of object shape recognition to subjects than low resolution dot type design. The proposed electrical stimulator exhibits promising potential to enhance artificial tactile perception. Therefore, it can be applied to various devices.|본 논문은 높은 공간해상도를 가지는 액티브 어레이를 활용한 전기적 햅틱 자극기 시스템을 제안한다. 최근 몇 년간 전자 기기에서 햅틱 피드백에 대한 수요가 증가하고 있다. 자동차 디스플레이 및 가상 현실 시스템 등의 응용 분야가 증가함에 따라 햅틱 시장은 급속하게 확대되고 있다. 햅틱 장치는 기계식 및 전기식으로 분류할 수 있다. 기계식 장치는 풍부한 촉감 피드백을 제공하지만, 보통 부피가 크고 무거우며 상당한 전력을 소비하여 휴대용 장치에서 사용하기 어렵다. 반면에 전기 장치는 작고 가벼우며 전력 소모가 적어 휴대용 장치에 적합하다. 하지만 전기 장치는 공간 해상도가 낮아 정확한 촉감 피드백을 제공하기 어렵다. 이러한 공간 해상도 문제를 해결하기 위해, 8x8 매트릭스 배열 구조를 가진 박막 트랜지스터 기반의 전기 자극기를 제안하였다. 이는 전선의 수를 줄이고 공간 해상도를 향상시킨다. 게이트 산화막, 채널, 소스-드레인, 패시베이션 및 TFT 디자인과 같은 제조 매개 변수를 최적화하여 최적의 전기 자극기 성능을 달성하였다. 결과적으로, 자극기는 1.1 x 1.1 cm2 영역에서 64개의 자극 부위를 만들 수 있었다. 또한, 개별 TFT의 전기적 특성을 조사하였으며, 음극 소스-드레인 바이어스 하에서 불규칙한 동작을 나타냈다. 이 문제를 해결하기 위해, 자극 상황에서의 펄스파 양극성 신호를 인가하였다. TFT는 촉감 수용기를 자극하기에 충분한 전류를 제공하였으며, 펄스 신호에서 임피던스 감소 현상을 나타내었다. 마지막으로, 세 명의 피험자와 함께 지각 실험을 진행하였으며, 자극 부위에서 범퍼와 같은 촉감을 느낀다는 보고가 있었다. 이는 제안된 전기 자극기가 성공적으로 촉감을 재현할 수 있었다는 걸 의미한다.I. Introduction 1 1.1 Overview 1 1.2 Motivation 2 II. Background 3 2.1 Human tactile sensing system 3 2.1.1 Human tactile receptor 3 2.1.2 Human tactile signal 6 2.2 Previous works 9 2.2.1 Mechanical stimulator 9 2.2.2 Electrical stimulator 13 2.3 Principle of TENS 15 2.4 Array stimulator 19 III. Experimental Details 20 3.1 Effort to lowing the contact resistance 20 3.1.1 Electrical characteristic of fingertip 20 3.1.2 Fabrication flow 21 3.1.3 Results 22 3.2 Effort to satisfying electrical characteristic for stimulation 25 3.2.1 Electrical signal to evoke tactile sensation 25 3.2.2 Fabrication flow 27 3.2.3 Results 28 IV. Conclusion 51MasterdCollectio

Spontaneous spinal epidural hematoma of the thoracic spine after herbal medicine: a case report

Abstract Background Spontaneous spinal epidural hematoma (SSEH) is an uncommon disease, but it can lead to acute cord compression with disabling consequences. Identifiable reasons for spontaneous hemorrhage are vascular malformations and bleeding disorders. However, SSEH after taking herbal medicines has not been described yet. Case presentation A 60-year-old female experienced sudden back pain combined with numbness and weakness in the lower limbs for several hours with no trauma, drug use, family history or any disease history. Her deep tendon reflexes were normoactive, and Babinski was negative. An emergent MRI showed a spinal epidural hematoma extending from T3 to T5. She was taken to surgery after immediate clinical and laboratory evaluations had been completed. Emergency decompression with laminectomy was performed and the patient recovered immediately after the surgery. Additional history taken from the patient at outpatient clinic after discharge revealed that she had been continuously taking herbal medicine containing black garlic for 8 weeks. Conclusion To our knowledge, no report has been previously issued on SSEH after taking herbal medicines. Although contradictory evidence is present on bleeding risks with herbal uses, we believe that it’s reasonable to ascertain if patients with SSEP are taking herbal medication before or during spinal surgery

Electrical and Structural Characteristics of Excimer Laser-Crystallized Polycrystalline Si_1−xGe_x Thin-Film Transistors

We investigated the characteristics of excimer laser-annealed polycrystalline silicon−germanium (poly-Si1−xGex) thin film and thin-film transistor (TFT). The Ge concentration was increased from 0% to 12.3% using a SiH4 and GeH4 gas mixture, and a Si1−xGex thin film was crystallized using different excimer laser densities. We found that the optimum energy density to obtain maximum grain size depends on the Ge content in the poly-Si1−xGex thin film; we also confirmed that the grain size of the poly-Si1−xGex thin film is more sensitive to energy density than the poly-Si thin film. The maximum grain size of the poly-Si1−xGex film was 387.3 nm for a Ge content of 5.1% at the energy density of 420 mJ/cm2. Poly-Si1−xGex TFT with different Ge concentrations was fabricated, and their structural characteristics were analyzed using Raman spectroscopy and atomic force microscopy. The results showed that, as the Ge concentration increased, the electrical characteristics, such as on current and sub-threshold swing, were deteriorated. The electrical characteristics were simulated by varying the density of states in the poly-Si1−xGex. From this density of states (DOS), the defect state distribution connected with Ge concentration could be identified and used as the basic starting point for further analyses of the poly-Si1−xGex TFTs

Diagnostic Performance of Cardiac CT and Transthoracic Echocardiography for Detection of Surgically Confirmed Bicuspid Aortic Valve: Effect of Calcium Extent and Valve Subtypes

Purpose This study aimed to compare the diagnostic performance of cardiac CT and transthoracic echocardiogram (TTE) depending on the degree of valvular calcification and bicuspid aortic valve (BAV) subtype. Materials and Methods This retrospective study included 266 consecutive patients (106 with BAV and 160 with tricuspid aortic valve) who underwent cardiac CT and TTE before aortic valve replacement. Cardiac CT was used to evaluate the morphology of the aortic valve, and a calcium scoring scan was used to quantify valve calcium. The aortic valves were classified into fused and two-sinus types. The diagnostic accuracy of cardiac CT and TTE was calculated using a reference standard for intraoperative inspection. Results CT demonstrated significantly higher sensitivity, negative predictive value, and accuracy than TTE in detecting BAV (p < 0.001, p < 0.001, and p = 0.003, respectively). The TTE sensitivity tended to decrease as valvular calcification increased. The error rate of TTE for CT was 10.9% for the twosinus type of BAV and 28.3% for the fused type (p = 0.044). Conclusion Cardiac CT had a higher diagnostic performance in detecting BAV than TTE and may help diagnose BAV, particularly in patients with severe valvular calcification

Impact of early nutrition and feeding route on clinical outcomes of neurocritically ill patients.

Early proper nutritional support is important to critically ill patients. Nutritional support is also associated with clinical outcomes of neurocritically ill patients. We investigate whether early nutrition is associated with clinical outcomes in neurocritically ill patients. This was a retrospective, single-center, observational study including neurosurgical patients who were admitted to the intensive care unit (ICU) from January 2013 to December 2019. Patients who started enteral nutrition or parenteral nutrition within 72 hours after ICU admission were defined as the early nutrition group. The primary endpoint was in-hospital mortality. The secondary endpoint was an infectious complication. Propensity score matching (PSM) and propensity score weighting overlap weights (PSOW) were used to control selection bias and confounding factors. Among 1,353 patients, early nutrition was performed in 384 (28.4%) patients: 152 (11.2%) early enteral nutrition (EEN) and 232 (17.1%) early parenteral nutrition (EPN). In the overall study population, the rate of in-hospital mortality was higher in patients with late nutrition than in those with early nutrition (P0.05). In the overall study population, EEN patients had a low rate of in-hospital mortality and infectious complications compared with those with EPN and late nutrition (P0.05), but EEN was significantly associated with in-hospital mortality and infectious complications (all P<0.05). Eventually, early enteral nutrition may reduce the risk of in-hospital mortality and infectious complications in neurocritically ill patients

Impact of early nutrition and feeding route on clinical outcomes of neurocritically ill patients

Early proper nutritional support is important to critically ill patients. Nutritional support is also associated with clinical outcomes of neurocritically ill patients. We investigate whether early nutrition is associated with clinical outcomes in neurocritically ill patients. This was a retrospective, single-center, observational study including neurosurgical patients who were admitted to the intensive care unit (ICU) from January 2013 to December 2019. Patients who started enteral nutrition or parenteral nutrition within 72 hours after ICU admission were defined as the early nutrition group. The primary endpoint was in-hospital mortality. The secondary endpoint was an infectious complication. Propensity score matching (PSM) and propensity score weighting overlap weights (PSOW) were used to control selection bias and confounding factors. Among 1,353 patients, early nutrition was performed in 384 (28.4%) patients: 152 (11.2%) early enteral nutrition (EEN) and 232 (17.1%) early parenteral nutrition (EPN). In the overall study population, the rate of in-hospital mortality was higher in patients with late nutrition than in those with early nutrition (P0.05). In the overall study population, EEN patients had a low rate of in-hospital mortality and infectious complications compared with those with EPN and late nutrition (P0.05), but EEN was significantly associated with in-hospital mortality and infectious complications (all P<0.05). Eventually, early enteral nutrition may reduce the risk of in-hospital mortality and infectious complications in neurocritically ill patients