Design and Development of High Voltage High Pulse Power Supply using FPGA for Dynamic Impedance Matching

High Voltage High Pulse Power Supply (HVHPPS) is designed with the goal to match fixed load, so thatprecise pulse output can be achieved. Generally the loads involve magnetron, klystron, and particle accelerators etc. The HVHPPS output pulse shape changes with load impedance variation due to various reasons. Due to changes in impedance, the performance of Pulse Power Supply degrades and reflects the power at the source end which causes component failure and system shut down. To overcome such problems, a scale down High Voltage High Pulse Power is designed and developed to match the dynamic impedance variations upto 25 % of mismatch. In earlier days, all HVHPPS were designed using microcontrollers where the problem of pulse to pulse monitoring and computational speed was compromised. The availability of variable and self-defined, Field Programmable Gate Array (FPGA) controller, which provided flexibility to design the pulse to pulse shaping and various vital parameter monitoring, made it possible. This paper presents the design and implementation of HVHPPS over an FPGA platform to meet the fast response requirement. This paper provides a solution for impedance mismatch problems associated with such types of power supply, and also presents specifications for major components in a high voltage pulse power system for various types of load ranges. An experimental test hardware was designed and developed for HVHPPS to implement dynamic impedance algorithm and validate the results

De novo HNF1 homeobox B mutation as a cause for chronic, treatment-resistant hypomagnesaemia.

29-year-old female presenting with an 8-year history of unexplained hypomagnesaemia, which was severe enough to warrant intermittent inpatient admission for intravenous magnesium. Urinary magnesium was inappropriately normal in the context of hypomagnesaemia indicating magnesium wasting. Ultrasound imaging demonstrated unilateral renal cysts and computed tomography of kidneys, ureters and bladder showed a bicornuate uterus. Referral to genetic services and subsequent testing revealed a de novo HNF1B deletion. Learning points: HNF1B loss-of-function mutations are one of the most common monogenic causes of congenital anomalies of the kidney and urinary tract.Those with HNF1B mutations may have some of a constellation of features (renal and hepatic cysts, deranged liver function tests, maturity onset diabetes of the young type 5 (MODY5), bicornuate uterus, hyperparathyroidism, hyperuricaemic gout, but presenting features are highly heterogeneous amongst patients and no genotype/phenotype correlation exists. HNF1B mutations are inherited in an autosomal dominant pattern but up to 50% of cases are de novo.HNF1B mutations can be part of the Chr17q12 deletion syndrome, a contiguous gene deletion syndrome.Inorganic oral magnesium replacements are generally poorly tolerated with side effects of diarrhoea. Organic magnesium compounds, such as magnesium aspartate, are better absorbed oral replacement therapies.This work was supported by a Wellcome Trust Clinical Training fellowship to CES (grant number 097970/Z/11/Z)

Evaluation and treatment of neurogenic bowel dysfunction – a review

Neurogenic bowel dysfunction is a severely troubling entity for patients with neurological disease or injury. The complex symptom cluster presents a challenge, not only for the patients but also for the treating clinician. Without intervention, patients are bound to have a reduced quality of life, and experience social impacts and secondary complications that come along with it. A careful initial assessment provides an idea of symptom severity and is crucial for successful rehabilitation. The mainstay of treatment remains a conservative approach of managing faecal incontinence or optimising the mechanics of defecation to improve patient’s quality of life. This article attempts to provide a comprehensive review of existing literature on pathophysiology, assessment and management of neurogenic bowel dysfunction

Gartner duct cyst in pregnancy presenting as a prolapsing pelvic mass

Gartner duct cysts are the remnants of the Wolffian duct and they are rarely seen in adulthood. We present a case of a pregnant patient with a prolapsing vaginal mass. A diagnosis of Gartner duct cyst was made after MRI was performed. The Gartner duct cyst was drained when the patient went into labour allowing vaginal delivery to be performed

Geometry dominated fluid adsorption on sculptured substrates

Experimental methods allow the shape and chemical composition of solid surfaces to be controlled at a mesoscopic level. Exposing such structured substrates to a gas close to coexistence with its liquid can produce quite distinct adsorption characteristics compared to that occuring for planar systems, which may well play an important role in developing technologies such as super-repellent surfaces or micro-fluidics. Recent studies have concentrated on adsorption of liquids at rough and heterogeneous substrates and the characterisation of nanoscopic liquid films. However, the fundamental effect of geometry has hardly been addressed. Here we show that varying the shape of the substrate can exert a profound influence on the adsorption isotherms allowing us to smoothly connect wetting and capillary condensation through a number of novel and distinct examples of fluid interfacial phenomena. This opens the possibility of tailoring the adsorption properties of solid substrates by sculpturing their surface shape.Comment: 6 pages, 4 figure

Multicolour correlative imaging using phosphor probes

Correlative light and electron microscopy exploits the advantages of optical methods, such as multicolour probes and their use in hydrated live biological samples, to locate functional units, which are then correlated with structural details that can be revealed by the superior resolution of electron microscopes. One difficulty is locating the area imaged by the electron beam in the much larger optical field of view. Multifunctional probes that can be imaged in both modalities and thus register the two images are required. Phosphor materials give cathodoluminescence (CL) optical emissions under electron excitation. Lanthanum phosphate containing thulium or terbium or europium emits narrow bands in the blue, green and red regions of the CL spectrum; they may be synthesised with very uniform-sized crystals in the 10- to 50-nm range. Such crystals can be imaged by CL in the electron microscope, at resolutions limited by the particle size, and with colour discrimination to identify different probes. These materials also give emissions in the optical microscope, by multiphoton excitation. They have been deposited on the surface of glioblastoma cells and imaged by CL. Gadolinium oxysulphide doped with terbium emits green photons by either ultraviolet or electron excitation. Sixty-nanometre crystals of this phosphor have been imaged in the atmospheric scanning electron microscope (JEOL ClairScope). This probe and microscope combination allow correlative imaging in hydrated samples. Phosphor probes should prove to be very useful in correlative light and electron microscopy, as fiducial markers to assist in image registration, and in high/super resolution imaging studies

The Spin Structure of the Nucleon

We present an overview of recent experimental and theoretical advances in our understanding of the spin structure of protons and neutrons.Comment: 84 pages, 29 figure

Effects of hydroxyapatite and PDGF concentrations on osteoblast growth in a nanohydroxyapatite-polylactic acid composite for guided tissue regeneration

The technique of guided tissue regeneration (GTR) has evolved over recent years in an attempt to achieve periodontal tissue regeneration by the use of a barrier membrane. However, there are significant limitations in the currently available membranes and overall outcomes may be limited. A degradable composite material was investigated as a potential GTR membrane material. Polylactic acid (PLA) and nanohydroxyapatite (nHA) composite was analysed, its bioactive potential and suitability as a carrier system for growth factors were assessed. The effect of nHA concentrations and the addition of platelet derived growth factor (PDGF) on osteoblast proliferation and differentiation was investigated. The bioactivity was dependent on the nHA concentration in the films, with more apatite deposited on films containing higher nHA content. Osteoblasts proliferated well on samples containing low nHA content and differentiated on films with higher nHA content. The composite films were able to deliver PDGF and cell proliferation increased on samples that were pre absorbed with the growth factor. nHA–PLA composite films are able to deliver active PDGF. In addition the bioactivity and cell differentiation was higher on films containing more nHA. The use of a nHA–PLA composite material containing a high concentration of nHA may be a useful material for GTR membrane as it will not only act as a barrier, but may also be able to enhance bone regeneration by delivery of biologically active molecules