Self-Modulated Dynamics of Relativistic Charged Particle Beams in Plasmas

We carry out a theoretical investigation on the self-modulated dynamics of a relativistic, nonlaminar, charged particle beam travelling through a magnetized plasma due to the plasma wake field excitation mechanism. In this dynamics the beam plays the role of driver, but at the same time it experiences the feedback of the fields produced by the plasma. Driving beam and plasma are strongly coupled by means of the EM fields that they produce: the longer the beam (compared to the plasma wavelength), the stronger the self-consistent beam-plasma interaction. The sources of these EM fields are charges and currents of both plasma and driving beam. While travelling through the plasma, the beam experiences the electro-mechanical actions of the wake fields. They have a 3D character and affects sensitively the beam envelope. To provide a self-consistent description of the driving beam dynamics, we first start from the set of governing equations comprising the Lorentz-Maxwell fluid equations for the beam-plasma system. In the unperturbed particle system (i.e., beam co-moving frame) and in quasi-static approximation, we reduce it to a 3D partial differential equation, called the Poisson-type equation. The latter relates the wake potential to the beam density which is coupled with the 3D Vlasov equation for the beam. Therefore, the Vlasov-Poisson-type pair of equations constitute our set of governing equation for the spatiotemporal evolution of the self-modulated beam dynamics. We divide the analysis in two different cases, purely transverse and purely longitudinal. In the purely transverse dynamics, we investigate the envelope self-modulation of a cylindrically symmetric beam by implementing the Vlasov-Poisson-type system with the corresponding virial equations. This approach allows us to find some constant of motions and some ordinary differential equations, called the \textit{envelope equations} that govern the time evolution of the beam spot size. They are easily integrate-able analytically and/or numerically and therefore facilitate the analysis. Additionally, to approach our analysis also from the qualitative point of view, we make use of the so called \textit{pseudo potential} or \textit{Sagdeev potential}, widely used in nonlinear sciences, that is associated with the envelope equations. We first carry out an analysis in two different regimes, i.e., the local regime (where the beam spot size is much greater than the plasma wavelength) and the strongly nonlocal regime (where the beam spot size is much smaller than the plasma wavelength). In both cases, we find several types of self-modulation, such as focusing, defocusing and betatron-like oscillations, and criteria for instability, such as collapse and self-modulation instability. Then, the analysis is extended to the case where the beam spot size and the plasma wavelength are not necessarily constrained as in the local or strongly nonlocal cases. We carry out a full semi-analytical and numerical investigation for the envelope self-modulation. To this end, criteria for predicting stability and self-modulation instability are suitably provided. In the purely longitudinal dynamics, we specialize the 3D Vlasov-Poisson-type equation to the 1D longitudinal case. Then, the analysis is carried out by perturbing the Vlasov-Poisson-type system up to the first order and taking the Fourier transformation to reduce the Vlasov-Poisson system to a set of algebraic equations in the frequency and wavenumber domain. This allows us to easily get a Landau-type dispersion relation for the beam modes, that is fully similar to the one holding for plasma modes. First, we consider the case of a monochromatic beam (i.e., cold beam) for which we find both a purely growing mode and a simple stability criterion. Moreover, by taking into account a non-monochromatic distribution function with finite small thermal correction, the Landau approach leads to obtain both the dispersion relation for the real and imaginary parts. The former shows all the possible beam modes in the diverse regions of the wave number and the latter shows the stable or unstable character of the beam modes, which suggests a simple stability criterion. Finally, within the framework of the 1D longitudinal Vlasov-Poisson-type system of equations, we introduce the concept of coupling impedance in full analogy with the conventional accelerators. It is shown that also here the coupling impedance is a very useful tool for the Nyquist-type stability analysis

Stochastic Effects and Fractal Kinetics in the Pharmacokinetics of Drug Transport

Pharmacokinetics (PK) attempts to model the progression and time evolution of a drug in the human body from administration to the elimination stage. It is the primary quantitative approach used in drug discovery/development (in the pharma industry). The overwhelming majority of PK models are based on equilibrium kinetics with all the reaction kinetics occurring in a well mixed, homogeneous environment. Of course as is well known, the human body is comprised of heterogeneous media with non equilibrium chemical kinetics. As a result, the transport processes and reaction mechanisms are often atypical. In this thesis, we apply ideas from stochastic processes and fractal kinetics in order to better capture the time course of a drug through the body when there is spatial and temporal heterogeneity. We discuss the limitations of the Langevin equation and Bourret’s approximation and apply Van Kampen’s approach to the random differential equations arising from the stochastic formulation of standard one compartmental extra vascular model. Although one compartment models can produce good fits if a drug dispersed rapidly so that equilibrium is achieved (in all tissues) swiftly, in general they are oversimplification of a complex process . Thus we also extend the two compartmental model Kearns et al., to incorporate fractal Michaelis Menten kinetics and compare with experimental data from the literature for paclitaxel. Finally, we conclude with a discussion and appraisal of the contribution in the thesis to the field of pharmacokinetics

An Exertion to Alleviate Stitch Defects During Garments Production

In garments industry sewing is the most critical phase during an apparel production. Different types of sewing and stitching defects are occured in this phase due to various problems. As today’s world each customer is expecting a very high quality garments with product variety, it has become a very challenging task for garments quality management. Here all the data were collected from Gardenia Wears Limited situated at Barmi- Sreepur, Gazipur, Dhaka and data were analyzed for reducing Defects per Hundred Unit (DHU%) and also top 10 stitch defects were identified and analyzed later. Finally the work shows reduction of DHU% from 5.23% to 3.48% and also reduce the top ten stitch defects with comparison to before trial and after trial data of ten days and it is proved that an industry can achieve higher production capability & profitability with improved quality product and also saving cost due to reducing DHU%

CT evaluation of malignant PNS mass and histopathological correlation

Background: Computed tomography (CT) is the gold standard for exact delineation of paranasal sinus(PNS) disease. There are many radiologically important diseases of paranasal sinuses. Objective: to evaluate the malignant PNS mass by computed tomographic image and the findings of this modality were compared with histopathological result.Methods: It was a cross sectional type of study and carried out with suspected PNS mass having patients during January 2009 to Octo­ber 2010.Results: The mean age of the patients was 35.95 ± 18.24 and common complaints of the patients were nasal obstruction (73.7%) and maximum 53.9% patients had PNS mass in maxillary sinuses. Out of 76 cases 21.1 % found malignant mass on CT and after histopathology 19. 7% had malignant mass. Out of all cases 14 were diagnosed as malig­nant PNS mass by CT scan and confirmed by histopathological evaluation and they were true positive. Two cases were diagnosed as malignant PNS mass by CT scan but not confirmed by histopathological findings and they were false positive. Of 60 cases, which were diagnosed by CT scan, one was confirmed as malignant and 59 were benign by histopa­thology. They were false negative and true negative respectively. Sensitivity of CT scan to diagnose malignant PNS mass was 93.3%, specificity 96.7%, positive predictive value 87.5%, negative predictive value 98.3% and accuracy 96.1 %. Conclusion: CT scan of the malignant para nasal sinus mass provides more information and better image quality and CT diagnosis correlate well with the findings of histopathology

Novel chemical degumming process and its effect on structure and properties of mulberry fibres

366-371A novel chemical degumming (Fibre-N) method has been used to extract fibres from the bark of mulberry plant. Fibres obtained by a new method (Fibre-N) are characterized by the X-ray diffraction, scanning electron microscopy, Fourier transform Infrared spectroscopy, residual gum content, fibre yield, and mechanical property measurement. Fibre-N method exhibits 17.71% lower residual gum content, 37.18% higher breaking strength, 18.36% higher breaking elongation and 10.81% higher fibre yield. Fibre-N process used to extract fibres from mulberry plant is more economical and efficient, which could be used as a promising method for producing textile yarns, nonwovens, and composites

Novel chemical degumming process and its effect on structure and properties of mulberry fibres

A novel chemical degumming (Fibre-N) method has been used to extract fibres from the bark of mulberry plant. Fibres obtained by a new method (Fibre-N) are characterized by the X-ray diffraction, scanning electron microscopy, Fourier transform Infrared spectroscopy, residual gum content, fibre yield, and mechanical property measurement. Fibre-N method exhibits 17.71% lower residual gum content, 37.18% higher breaking strength, 18.36% higher breaking elongation and 10.81% higher fibre yield. Fibre-N process used to extract fibres from mulberry plant is more economical and efficient, which could be used as a promising method for producing textile yarns, nonwovens, and composites.

Amoxyclav Resistance Pattern and Aerobic Bacterial Profile in Diabetic Foot Infection Patients in Bangladesh

Introduction: The goal of this study was to determine the frequency of bacterial isolates cultured from diabetic foot infections and to assess their amoxyclav resistance and susceptibility.Methods: A total of 378 diabetic foot lesions were included in this prospective analysis. The antibiotic susceptibility pattern of bacteria isolated from foot lesions was assessed using the Kirby-Bauer disk diffusion method.Results: The most commonly isolated Gram-positive bacteria were Staphylococcus aureus, followed by Enterococcus spp. and CoNS. The most commonly isolated Gram-negative bacteria were Klebsiella spp., Pseudomonas spp., Proteus spp., Escherichia coli, Enterobacter spp., Citrobacter spp., Citrobacter freundii, and Proteus vulgaris. Amoxyclav was found to be 100.00% resistant against Pseudomonas aeruginosa and followed by Enterococcus spp. (89.50%), Proteus spp. (87.50%), Staphylococcus aureus (84.30%), Escherichia coli (81.50%), Klebsiella spp. (70.50%) and Enterobacter spp. (69.20%).Conclusion: The present study confirmed the prevalence of amoxyclav drug resistant pathogens (84.90%) in diabetic foot ulcers. The diverse bacteria infecting the wound must be evaluated, as well as the antibiotic susceptibility patterns of the isolates from the infected lesion. This information is critical for selecting the right medications, eliminating resistance trends, and lowering healthcare costs. Keywords: Diabetic Foot Infection, Polymicrobial Infections, Amoxyclav DOI: 10.7176/JHMN/94-03 Publication date:October 31st 202

Feasibility and effectiveness of electronic vs. paper partograph on improving birth outcomes:A prospective crossover study design

BACKGROUND: The partograph has been endorsed by World Health Organization (WHO) since 1994 which presents an algorithm for assessing maternal and foetal conditions and labor progression. Monitoring labour with a partograph can reduce adverse pregnancy outcomes such as prolonged labor, emergency C-sections, birth asphyxia and stillbirths. However, partograph use is still very low, particularly in low and middle income countries (LMICs). In Bangladesh the reported partograph user rate varies from 1.4% to 33.0%. Recently, an electronic version of the partograph, with the provision of online data entry and user aid for emergency clinical support, has been tested successfully in different settings. With this proven evidence, we conducted and operations research to test the feasibility and effectiveness of implementing an e-partograph, for the first time, in 2 public hospitals in Bangladesh. METHODS: We followed a prospective crossover design. Two secondary level referral hospitals, Jessore and Kushtia District Hospital (DH) were the study sites. All pregnant women who delivered in the study hospitals were the study participants. All nurse-midwives working in the labor ward of study hospitals were trained on appropriate use of both types of partograph along with standard labour management guidelines. Collected quantitative data was analyzed using SPSS 23 statistical software. Discrete variables were expressed as percentages and presented as frequency distribution and cross tabulations. Chi square tests were employed to test the association between exposure and outcome variables. Potential confounding factors were adjusted using multivariate binary logistic regression methods. Ethical approval was obtained from the institutional review board of the International Centre for Diarrheal Disease Research, Bangladesh (icddr,b). FINDINGS: In total 2918 deliveries were conducted at Jessore DH and 2312 at Kushtia DH during one-year study period. Of them, 1012 (506 in each facility) deliveries were monitored using partograph (paper or electronic). The trends of facility based C-section rates was downwards in both the hospitals; 43% to 37% in Jessore and from 36% to 25% in Kushtia Hospital. There was a significant reduction of prolonged labour with e-partograph use. In Kushtia DH, the prolonged labour rate was 42% during phase 1 with the paper version which came down to 29% during phase-2 with the e-partograph use. The similar result was observed in Jessore DH where the prolonged labour rate reduced to 7% with paper partograph from the reported 30% prolonged labour with e-partograph. The e-partograph user rate was higher than the paper partograph during both phases (phase 1: 3.31, CI: 2.04-5.38, p < .001 and in phase 2: 15.20 CI: 6.36-36.33, p < .001) after adjusting for maternal age, parity, gestational age, religion, mother's education, husband's education, and fetal sex. CONCLUSION: The partograph user rate has significantly improved with the e- partograph and was associated with an overall reduction in cesarean births. Use of the e-partograph was also associated with reduced rates of prolonged labour. This study has added to the growing body of evidence on the positive impact of e-partograph use. We recommend implementing e-partograph intervention at scale in both public and private hospitals in Bangladesh. TRIAL REGISTRATION: ClinicalTrials.gov NCT03509103

Factors Associated with Klebsiella

Although Klebsiella bacteremia in children is perceived to be associated with fatal consequences, data are scarce on those children presenting with diarrhea. We evaluated the factors associated with Klebsiella bacteremia in such children. In this retrospective chart analysis, data of all diarrheal children was retrieved from electronic medical record system (named as SHEBA) of Dhaka Hospital of International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), from January 1, 2010, to December 31, 2012, who had their blood culture done. This was a study having a case-control design where comparison of clinical and laboratory characteristics was done among children with Klebsiella bacteremia (cases = 30) and those without any bacteraemia (controls = 90). Controls were selected randomly. The cases more often had fatal outcome (p<0.001). In logistic regression analysis, after adjusting for potential confounders such as young age, severe dehydration, severe wasting, abnormal mentation, hypotension, and fast breathing, the cases were independently associated with hospital-acquired infection and positive stool growth (for all, p<0.05). The study highlights the importance of obtaining blood cultures in hospitalized children under five years old with diarrheal illness in the presence of either hospital-acquired infection or positive stool culture to have better outcome