Structure and Dynamics of the Instantaneous Water/Vapor Interface Revisited by Path-Integral and Ab-Initio Molecular Dynamics Simulations

The structure and dynamics of the water/vapor interface is revisited by means of path-integral and second-generation Car-Parrinello ab-initio molecular dynamics simulations in conjunction with an instantaneous surface definition [A. P. Willard and D. Chandler, J. Phys. Chem. B 114, 1954 (2010)]. In agreement with previous studies, we find that one of the OH bonds of the water molecules in the topmost layer is pointing out of the water into the vapor phase, while the orientation of the underlying layer is reversed. Therebetween, an additional water layer is detected, where the molecules are aligned parallel to the instantaneous water surface.Comment: 9 pages, 5 figure

Risk assessment of occupational exposure to BTEX in the National Oil Distribution Company in Iran

BACKGROUND: This study evaluated the quantitative, carcinogenic and non-carcinogenic risk of exposure to BTEX using lifetime cancer risk (LCR) and hazard quotient (HQ) in the National Company for Distribution of Petroleum Products in Iran.METHODS: In this risk assessment method, the data were collected in different parts of the company. In order to determine the concentration of BTEX, sampling was carried out in different parts using activated carbon. A Gas Chromatography–Flame Ionization Detector (GC-FID) was used for analysis. Analysis and sampling was conducted according to the NIOSH 1500 method. For carcinogenic risk assessment, LCR was calculated. For non-carcinogenic risk assessment, HQ was calculated.RESULTS: The carcinogenetic risk of benzene was definite for loading and deep handling units, and safety officer, and was probable rank for sealing, inspection gate, security, loading 1, and deep handling units. The carcinogenic risk of ethylbenzene was definite for quality control and loading 1 units, was probable for deep handling and loading 2 units, and safety officer, and was possible for sealing, inspection gates, security units. The non-carcinogenic risk of toluene was acceptable for deep handling, clothing, inspection gates, and sealing units, but was unacceptable for officer safety, quality control, loading 1, and loading 2 units. The non-carcinogenic risk of xylene was acceptable for the inspection gate unit, but was unacceptable for security, sealing, officer safety, quality control, deep handling, loading 1, loading 2 units.CONCLUSIONS: This risk assessment method used was a comprehensive and quantitative method, so it determined risk accurately. Commensurate with the risk level of each part of the company, the appropriate corrective actions must be carried out

Risk assessment of occupational exposure to BTEX in the National Oil Distribution Company in Iran

BACKGROUND: This study evaluated the quantitative, carcinogenic and non-carcinogenic risk of exposure to BTEX using lifetime cancer risk (LCR) and hazard quotient (HQ) in the National Company for Distribution of Petroleum Products in Iran. METHODS: In this risk assessment method, the data were collected in different parts of the company. In order to determine the concentration of BTEX, sampling was carried out in different parts using activated carbon. A Gas Chromatography–Flame Ionization Detector (GC-FID) was used for analysis. Analysis and sampling was conducted according to the NIOSH 1500 method. For carcinogenic risk assessment, LCR was calculated. For non-carcinogenic risk assessment, HQ was calculated. RESULTS: The carcinogenetic risk of benzene was definite for loading and deep handling units, and safety officer, and was probable rank for sealing, inspection gate, security, loading 1, and deep handling units. The carcinogenic risk of ethylbenzene was definite for quality control and loading 1 units, was probable for deep handling and loading 2 units, and safety officer, and was possible for sealing, inspection gates, security units. The non-carcinogenic risk of toluene was acceptable for deep handling, clothing, inspection gates, and sealing units, but was unacceptable for officer safety, quality control, loading 1, and loading 2 units. The non-carcinogenic risk of xylene was acceptable for the inspection gate unit, but was unacceptable for security, sealing, officer safety, quality control, deep handling, loading 1, loading 2 units. CONCLUSIONS: This risk assessment method used was a comprehensive and quantitative method, so it determined risk accurately. Commensurate with the risk level of each part of the company, the appropriate corrective actions must be carried out

Harvard

The compact and harmonious layout of ads and text is a fundamental and costly step in the production of commercial telephone directories ( ¨Yellow Pages¨). We formulate a canonical version of Yellow-Pages pagination and layout (YPPL) as an optimization problem in which the task is to position ads and text-stream segments on sequential pages so as to minimize total page length and maximize certain layout aesthetics, subject to constraints derived from page-format requirements and positional relations between ads and text. We present a heuristic-search approach to the YPPL problem. Our algorithm has been applied to a sample of real telephone-directory data, and produces solutions that are significantly shorter and better than the published ones

Kawasaki Disease Presenting as Acute Clinical Hepatitis

Kawasaki disease is a systemic vasculitis of children. Among gastrointestinal symptoms of this disease jaundice occurs uncommonly. We present a 23 month boy with icter and clinical hepatitis and final diagnosis of kawasaki disease

Ingested Foreign Bodies Removed by Lexible Endoscopy in Pediatric Patients: A 10-year Retrospective Study

Introduction: Determination of type and location of trapped objects and endoscopic observations among children with foreign-body ingestion.   Materials and Methods: We evaluated 105 endoscopic records of patients presenting with foreign-body ingestion from 2001–2011.   Results: Button batteries were the most common objects removed (41%). The lower segment of the esophagus was the most common trapping site. There was significant correlation between type of foreign body and its location of trapping. Abnormal endoscopic observations were reported in 33% patients. There was significant correlation between the type of foreign body and endoscopic observations. There was also a significant correlation between the location of the foreign body and endoscopic observation.   Conclusion:  The pattern of foreign-body ingestion is somewhat different in our center compared with other studies. Awareness among parents about the prevention of this accident is an important step in decreasing the incidence of foreign-body ingestion.

Electrically contractile polymers augment right ventricular output in the heart

Research into the development of artificial heart muscle has been limited to assembly of stem cell-derived cardiomyocytes seeded around a matrix, while nonbiological approaches to tissue engineering have rarely been explored. The aim of the study was to apply electrically contractile polymer-based actuators as cardiomyoplasty for positive inotropic support of the right ventricle. Complex trilayer polypyrrole (PPy) bending polymers for high-speed applications were generated. Bending motion occurred directly as a result of electrochemically driven charging and discharging of the PPy layers. In a rat model (n=5), strips of polymers (3x20mm) were attached and wrapped around the right ventricle (RV). RV pressure was continuously monitored invasively by direct RV cannulation. Electrical activation occurred simultaneously with either diastole (in order to evaluate the polymer\u27s stand-alone contraction capacity; group 1) or systole (group 2). In group 1, the pressure generation capacity of the polymers was measured by determining the area under the pressure curve (area under curve, AUC). In group 2, the RV pressure AUC was measured in complexes directly preceding those with polymer contraction and compared to RV pressure complexes with simultaneous polymer contraction. In group 1, the AUC generated by polymer contraction was 2768 +/- 875U. In group 2, concomitant polymer contraction significantly increased AUC compared with complexes without polymer support (5987 +/- 1334U vs. 4318 +/- 691U, P≤0.01). Electrically contractile polymers are able to significantly augment right ventricular contraction. This approach may open new perspectives for myocardial tissue engineering, possibly in combination with fetal or embryonic stem cell-derived cardiomyocytes