New developments in predicting stage–discharge curves, velocity and boundary shear stress distributions in open channel flow

The stage–discharge curve, depth-averaged velocity and boundary shear stress distributions are required to be determined for flood alleviation schemes. These parameters are hard to predict because of the three-dimensional (3-D) aspects of flow in open channels. This paper proposes a new approach for modelling open channel flow based on the Shiono and Knight Method (SKM), which is a depth-averaged model based on the governing Navier–Stokes equations. The modelling philosophy is applied to natural rivers and artificial channels both in inbank and overbank flow conditions. Accurate results are obtained when compared with field data and experimental measurements. Modelling philosophies are presented for the three calibration coefficients of the SKM. These coefficients represent the most important features of the 3-D flow mechanism.     

Full-Potential Calculation of Structural, Electronic, and Thermodynamic Properties of Fluoroperovskite \text{ CsMF}_{3} (M?=?Be and Mg)

The structural and electronic properties of the cubic fluoroperoveskite $\text{ CsBeF}_{3}$ and $\text{ CsMgF}_{3}$ have been investigated using the full-potential-linearized augmented plane wave method within the density functional theory. The exchange-correlation potential was treated with the local density approximation and the generalized gradient approximation. The calculations of the electronic band structures show that $\text{ CsBeF}_{3 }$ has an indirect bandgap, whereas $\text{ CsMgF}_{3}$ has a direct bandgap. Through the quasi-harmonic Debye model, in which the phononic effects are considered, the effect of pressure $P$ and temperature $T$ on the lattice parameter, bulk modulus, thermal expansion coefficient, Debye temperature, and the heat capacity for $\text{ CsBeF}_{3}$ and $\text{ CsMgF}_{3}$ compounds are investigated for the first time.     

Structural stabilities,elastic and thermodynamic properties of Scandium Chalcogenides via first-principles calculations

The high-pressure structural (B1–B2) phase transition and the elastic properties of ScS and ScSe are studied using the full-potential augmented plane wave plus local orbitals method (FP-APW + LO) with the generalized-gradient approximation (GGA) exchange-correlation functional. The elastic constants and their pressure dependence are calculated following the total energy variation with strain technique. The stability and the ductility mechanisms for these compounds are discussed via the electronic density of states (DOS) and the elastic constants C_ij. The thermodynamic properties of (B1) structure are predicted through the quasi-harmonic Debye model, in which the lattice vibrations are taken into account. The variation of bulk moduli, the thermal expansion coefficient, the heat capacities and the Debye temperature with pressure and temperature are successfully obtained. To our knowledge this is the first quantitative theoretical prediction of the elastic, high pressure and thermal properties for the investigated compounds and still awaits experimental confirmations.     

Changes in the arterial blood pressure, heart rate and normal ECG parameters of rat after envenomation with Egyptian cobra (Naja haje) venom

Haemophilus somnus is able to survive and multiply in bovine blood monocytes (BBM) and alveolar macrophages (BAM), but the mechanisms used by H. somnus to evade killing mechanisms of bovine mononuclear phagocytes are not completely understood. To study the bactericidal ability of bovine mononuclear phagocytes following interaction with H. somnus, in vitro assay systems were developed to detect the luminol-dependent chemiluminescence response (LDCL) and nitric oxide (NO) production of BBM and BAM. Live logarithmically growing or stationary phase H. somnus inhibited the LDCL of BBM and BAM costimulated with opsonized Staphylococcus aureus. Inhibition of the LDCL response of BBM and BAM was not mediated by live H. somnus opsonized with hyperimmune serum, or by killed bacteria. H. somnus stimulated both BBM and BAM to produce NO at levels comparable with Escherichia coli lipopolysaccharide. While NO was being produced, viable H. somnus could still be isolated from the cell cultures. The ability of H. somnus to inhibit LDCL of both BBM and BAM, and resistance to NO killing may be an important mechanism that contributes to survival of the organism following ingestion by bovine mononuclear phagocytes.     

Isolierung, Reinigung and Charakterisierung einer endo-Pectinlyase (endo-PL)

Zusammenfassung In dieser Arbeit wurde mittels Chromatofocussierung eine endo-Pectinlyase (PL) impräparativen Maßstab aus dem technischen Enzympräparat Pectinex Ultra SP-L isoliert and durch die wichtigsten physikalisch-chemischen and biochemischen Eigenschaften charakterisiert. Ihre Reinheit wurde durch analytische isoelektrische Focussierung und typische biochemische Reaktionen nachgewiesen. Für die PL wurden folgende Konstanten bestimmt: IP 3,9;K _m 1,91 mg/ml andV _max 0,88/min. Die pH-Optima lagen bei Verwendung von Apfelpectin mit einem Veresterungsgrad (VE) von 71 % bzw. von hochver estertem Pectin (VE=94%) bei pH 6,0 bzw. bei pH 8,5, die Temperatur-Optima bei 60° C bzw. 65° C. Die PL wies eine relativ hohe Temperatur- und pH-Stabilität auf. Die PL-Aktivität wurde deutlich durch Na⁺-Ionen gesteigert.

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Isolation, purification and characterization of an endo-pectinlyase (endo-PL)

Summary This paper describes an endo-pectinlyase isolated on a preparative scale from the commercial enzyme preparation Pectinex Ultra SP-L by using chromatofocusing. The most important biochemical and physico-chemical properties are presented. The purity of this endo-pectinlyase was proved by analytical isoelectric focusing and by typical biochemical reactions. The following constants were determined: pI 3.9, Km 1.91 mg/ml andV _max0.88 min^–1. The enzyme has a pH optimum of 6.0 with 71 % esterified apple pectin and of 8.5 with a highly (94%) esterified pectin. Temperature optima with these two substrates were 60° C and 65° C respectively. The enzyme showed a relatively high pH and temperature stability. Its activity was increased considerably in the presence of Na⁺ ions.

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Fran Rengang Zhou, landwirtschaftliche Akademie Shijiazhuang Hebei (V.R. China), z. Zt. als Stipendiatin der chinesischen Regie rung an der Universitat Hohenheim

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H. Omran, Suez Canal Universitat Ismailia (Agypten), z. Zt. als Stipendiat der Alexander von Humboldt-Stiftung an der Universitat Hohenheim     

Design and implementation of a low-cost multiple-range digital phase detector

The feasibility of a multiplex system based on the unique properties of solitons hoe been, successfully demonstrated. The system is composed of non-linear LC networks which are equivalent to a one-dimensional anharmonic lattice, and we have investigated experimentally the recurrence phenomena for a pair of soliton trains of which the amplitudes are independently modulated. The recurrence phenomena could be used for secure communications.     

The effects of some physico-chemical factors and pharmaceutical excipients on the bioavailability of nitrofurantoin oily and aqueous suspensions in rats

The effects of some physico-chemical factors and various excipients, i.e., sucrose, aluminum stearate, hydrogenated castor oil, Cab-o-sil, and lecithin, either alone or in combination, from suspensions in fractionated coconut oil and distilled water have been investigated. In vitro drug release studies were performed according to the flask-stirrer method. In addition to adsorption and solubility studies, determination of partition coefficients and rheological measurements have been carried out. The experimental design was based on an 8×8 latin square using rats as the test animals. The results of the study showed that the rate and extent of absorption of nitrofurantoin are decreased significantly by the use of an oily rather than an aqueous vehicle. In vitro drug release data showed some correlation with in vivo parameters, and also with the apparent viscosity of the vehicles. However, no correlation was detectable between in vivo parameters and the apparent viscosity of the vehicles.     

Paraprosthetic regurgitation in aortic prostheses: determination of the hemodynamic significance by pulsed Doppler examination of the subclavian artery flow

Paraprosthetic leaks in aortic prostheses may cause significant aortic regurgitation. Color flow Doppler echocardiography is the method of choice for detecting paraprosthetic leaks, but quantitation of regurgitation is limited by this method. This study investigated the value of pulsed Doppler of the left subclavian artery flow for assessing the hemodynamic significance of paraprosthetic regurgitation in aortic prostheses in 32 patients with, and in 77 control subjects without paraprosthetic leaks. Paraprosthetic leaks were either detected by transthoracic or transesophageal color flow echocardiography. The hemodynamic significance of paraprosthetic regurgitation was determined by means of a dichotomous angiographic classification - significant versus insignificant regurgitation. Pulsed Doppler was performed to measure the maximal diastolic and systolic velocities, and diastolic and systolic velocity-time-integrals (VTI) and their ratios in the subclavian artery flow. The accuracy of these parameters for differentiating significant versus insignificant regurgitation was assessed. Angiography revealed 13 significant and 19 insignificant forms of aortic regurgitation. In all patients, examination of the subclavian artery was feasible by pulsed Doppler. The highest correlation between Doppler derived parameters and regurgitation was calculated for the ratios of diastolic and systolic VTI (r = 0.84), diastolic VTI (r = 0.82) and ratio of diastolic and systolic velocities (r = 0.80). An increase of the ratio of diastolic and systolic VTI (> 45%) and ratio of diastolic to systolic velocity (> 0.4), and increased diastolic VTI (> 60 cm) in the subclavian artery velocity profile identified significant paraprosthetic regurgitation with a sensitivity of 94%, 75% and 87%, and specificity of 87%, 80% and 87%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Salmonella enterica in superficial cervical (prescapular) and ileocecal lymph nodes of slaughtered pigs

Because certain lymph nodes may be incorporated in food products, the presence of Salmonella enterica in these tissues could pose a food safety risk. We designed this two-part study to assess the prevalence of Salmonella in prescapular lymph nodes from normal slaughtered swine. Prescapular lymph nodes were collected from 300 systematically selected pigs in study 1 and, in study 2, from 75 pigs distributed among 10 herds. For study 2, pooled bacterial cultures were also completed on ileocecal lymph nodes, combining tissue from five pigs per pool (n = 60 pools). No Salmonella was detected in study 1 among prescapular lymph nodes (95% confidence interval, 0.0 to 1.16%). Salmonella was not detected in 75 prescapular lymph nodes from study 2, although Salmonella was detected in 5 of 10 herds in ileocecal lymph nodes. We conclude that prescapular lymph nodes posed a limited food safety risk in this population of pigs.