Inhibition of thymidine uptake by staphylococci, a new method for the investigation of phagocytosis

A radioassay employing (3H) thymidine, to measure inhibition of growth of Staphylococcus aures by human phagocytes is presented. The principle of this new method is that viable and dividing staphylococci take up thymidine more rapidly than white cells, so that whereas in control cultures containing staphylococci alone high counts per minute (cpm) are obtained within 90 min of incubation in test cultures both leucocytes and plasma from 25 normal subjects reduced the cpm, following ingestion and killing of staphylococci.     

Author Index

Authors Index

Author Index     

Influence of strain and fermentation time on the production,composition, and properties of xanthan gum

The objective of this study was to monitor the influence of Xanthomonas spp. and fermentation time on the production, properties, and composition of xanthan gum, verifying how these variables affect the biopolymer synthesis and properties. Three strains were monitored for 168 h of fermentation. Every 24 h, a sample was collected to determine cell growth, gum production, and substrate consumption. Fourier transform infrared, X-ray diffraction, rheology, molecular characterization, thermogravimetric analysis, sugars, and acids analyzes were performed to characterize the gums produced and to identify possible differences in these properties and composition. The results showed the influence of strain and the fermentation time in production (Pr₆₄₅ = 0.047 g L⁻¹ h⁻¹, Pr₂₉₀ = 0.039 g L⁻¹ h⁻¹, Pr₁₁₅₅ = 0.149 g L⁻¹ h⁻¹) and gum quality, since the viscosity was highest in the first 48 h for strains 290 (148.71 MPa s⁻¹) and 645 (135.28 MPa s⁻¹), while for Strain 1155, the maximum value identified for this property was 90.48 MPa s⁻¹. These results are of practical importance, since they allow obtaining better quality xanthan, enabling reduction of production costs. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48557.     

Efficient 3D medical image segmentation algorithm over a secured multimedia network

Image segmentation has proved its importance and plays an important role in various domains such as health systems and satellite-oriented military applications. In this context, accuracy, image quality, and execution time deem to be the major issues to always consider. Although many techniques have been applied, and their experimental results have shown appealing achievements for 2D images in real-time environments, however, there is a lack of works about 3D image segmentation despite its importance in improving segmentation accuracy. Specifically, HMM was used in this domain. However, it suffers from the time complexity, which was updated using different accelerators. As it is important to have efficient 3D image segmentation, we propose in this paper a novel system for partitioning the 3D segmentation process across several distributed machines. The concepts behind distributed multimedia network segmentation were employed to accelerate the segmentation computational time of training Hidden Markov Model (HMMs). Furthermore, a secure transmission has been considered in this distributed environment and various bidirectional multimedia security algorithms have been applied. The contribution of this work lies in providing an efficient and secure algorithm for 3D image segmentation. Through a number of extensive experiments, it was proved that our proposed system is of comparable efficiency to the state of art methods in terms of segmentation accuracy, security and execution time.

     

Petrological control on engineering properties of carbonate rocks in arid regions

Bulletin of Engineering Geology and the Environment - Petrological features of carbonate rocks that exert control on their mechanical and physical properties are examined in the study presented...     

Development of meloxicam in situ implant formulation by quality by design principle

Objective: The focus of this study was to develop and optimize in situ implant formulation of meloxicam by quality by design (QbD) principle for long-term management of musculoskeletal inflammatory disorders.

Methods: The formulation was optimized by Box–Behnken design with polylactide-co-glycolide (PLGA) level (X₁), N-methyl pyrrolidone level (X₂) and PLGA intrinsic viscosity (X₃) as the independent variables and initial burst release of drug (Y₁), cumulative release (Y₂), and dissolution efficiency (Y₃) as the dependent variables. The formulation was physicochemically characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and powder X-ray diffraction (PXRD). Pharmacokinetic studies of the optimized formulation were performed on Sprague--Dawley rats.

Results: Y₁ was significantly affected by X₂ and X₃. Y₂ was affected by X₁ and X₃ while Y₃ was affected by all three independent variables employed in the formulations. Responses for the optimized formulation were in close agreement with the values predicted by the model. SEM photomicrographs indicated uniform gel formulation. No chemical interaction between the components of formulation was observed by FT-IR and meloxicam was found to be present in the amorphous form in the gel matrix as revealed by PXRD. The maximum plasma concentration (C_max), time to achieve C_max and area under plasma concentration curve were significantly different from those of the solution formulation used as the control. Plasma concentration of meloxicam was maintained above its IC₅₀ concentration required for COX-2 inhibition for 23 days.

Conclusion: Meloxicam in situ implant may provide long-term management of inflammatory conditions with improved patient compliance and better therapeutic index.     

Axial crushing of tubes as an energy dissipating mechanism for the reduction of acceleration induced injuries from mine blasts underneath infantry vehicles

A novel simple numerical formulation has been developed and implemented as a program to improve the capability of analytical approaches while reducing the dependence on computationally intensive numerical simulations. The formulation is based on an energy balance approach and utilizes explicit time integration of governing analytical energy equations to study the plastic work of the tube and impactor velocity in real time. An impulse–momentum equation yields the time history of the dynamic axial crushing force. The results of the numerical formulation are in excellent agreement with data from various external sources. The geometric and material properties of the tube can be varied to accurately study their effect on the dynamic crushing response, thus eliminating the need for frequent destructive testing. Further, the numerical formulation when properly modified, can predict occupant responses such as lumbar accelerations and compressive forces when used in crashworthiness applications.     

An advanced numerical model in solving thin-wire integral equations by using semi-orthogonal compactly supported spline wavelets

In this paper, the semi-orthogonal compactly supported spline wavelets are used as basis functions for the efficient solution of the thin-wire electric field integral equation (EFIE) in frequency domain. The method of moments (MoM) is used via the Galerkin procedure. Conventional MoM directly applied to the EFIE, leads to dense matrix which often becomes computationally intractable when large-scale problems are approached. To overcome these difficulties, wavelets can be used as a basis set so obtaining the generation of a sparse matrix; this is due to the local supports and the vanishing moments properties of the wavelets. In the paper, this technique is applied to analyze electromagnetic transients in a lightning protection systems schematized as a thin-wire structure. The study is carried out in frequency domain; a discrete fast Fourier transform algorithm can be used to compute time profiles of the electromagnetic interesting quantities. The unknown longitudinal currents are expressed by using multiscale wavelet expansions. Thus, the thin-wire EFIE is converted into a matrix equation by the Galerkin method. Results for linear spline wavelets along with their comparison with conventional MoM that uses triangular basis functions and the point matching procedure are presented, for two case studies. Good agreement has been reached with a strong reduction of the computational complexity.     

Energy and exergy analysis of prosumers in hybrid energy grids

Surplus energy can be a recurrent phenomenon in zero-energy buildings (ZEBs) with onsite generation systems, usually resulting in the export of excess electricity. Yet, converting electricity into heat and exporting it could improve the overall energy balance. This study analyses the energy and exergy performance of a Finnish nearly zero-energy building (nZEB) as a heat and electricity prosumer, and proposes alternative energy topologies to improve energy and exergy levels, primary energy demand and CO₂ emissions. The results show that increasing the installed capacity of the photovoltaic systems would lead to zero energy, exergy, emissions and a balance of primary energy. However, by instead using the surplus electricity to drive a heat pump and export heat, the currently installed capacity would lead to a net energy export of over 4000?kWh/a. Thus, energy conversion could significantly enhance the contribution from heat and electricity prosumers to smart energy grids, though not without affecting other criteria. Two management strategies arise: favouring heat export improves the net energy and CO₂ emissions reduction but lessens the net exergy, while favouring electricity export improves the net exergy and primary energy reduction. The findings highlight that energy conversion can enhance nZEB performance and its exchange with hybrid grids.