Solution-blown nanofiber mats from fish sarcoplasmic protein

In the present work, solution-blowing was adopted to form nanofibers from fish sarcoplasmic proteins (FSPs). Nanofiber mats containing different weight ratios (up to 90/10) of FSP in the FSP/nylon 6 blended nanofibers were formed from formic acid solutions, and compared to electrospun fibers made from the same solutions. The nanofiber mats produced by the two methods were characterized in terms of FSP content, fiber diameter distribution, fiber mat porosity, and mass of the fibers collected. The mechanical strength of the solution-blown fibers was also measured. Overall, fibers made by the two techniques were similar, but with some exceptions. The fiber diameter of the electrospun fibers was slightly smaller than those made using solution-blowing, however in both cases the fiber diameter increased with increasing FSP content. Interestingly, for uniform fibers the stretchability of the fibers increased with increasing FSP content, indicated by an increased strain at rupture. Moreover, the mechanical tests showed that up to 50% of nylon 6 could be replaced with FSP without compromising the mechanical properties, compared to pure nylon 6 nanofibers. Comparison of the yield showed that the production rate of solution-blowing was increased 30-fold in relation to electrospinning. Overall, this study reveals FSP as an interesting biopolymeric alternative to synthetic polymers, and the introduction of FSP to nylon 6 provides a composite with controlled properties

A search for radio pulsars in five nearby supernova remnants

Most neutron stars are expected to be born in supernovae, but only about half of supernova remnants (SNRs) are associated with a compact object. In many cases, a supernova progenitor may have resulted in a black hole. However, there are several possible reasons why true pulsar-SNR associations may have been missed in previous surveys: The pulsar's radio beam may not be oriented towards us; the pulsar may be too faint to be detectable; or there may be an offset in the pulsar position caused by a kick. Our goal is to find new pulsars in SNRs and explore their possible association with the remnant. The search and selection of the remnants presented in this paper was inspired by the non-detection of any X-ray bright compact objects in these remnants when previously studied. Five SNRs were searched for radio pulsars with the Green Bank Telescope at 820 MHz with multiple pointings to cover the full spatial extent of the remnants. A periodicity search plus an acceleration search up to 500 m/s^2 and a single pulse search were performed for each pointing in order to detect potential isolated binary pulsars and single pulses, respectively. No new pulsars were detected in the survey. However, we were able to re-detect a known pulsar, PSR J2047+5029, near SNR G89.0+4.7. We were unable to detect the radio-quiet gamma-ray pulsar PSR J2021+4026, but we do find a flux density limit of 0.08 mJy. Our flux density limits make our survey two to 16 times more sensitive than previous surveys, while also covering the whole spatial extent of the same remnants. We discuss potential explanations for the non-detection of a pulsar in the studied SNRs and conclude that sensitivity is still the most likely factor responsible for the lack of pulsars in some remnants.Comment: Accepted for publication in A&A on 14/01/202

Long-term result of Memokath urethral sphincter stent in spinal cord injury patients

BACKGROUND: Memokath urethral sphincter stents are used to facilitate bladder emptying in patients with spinal cord injury, but long term follow-up has not been reported. METHODS: Case series of ten men with spinal cord injury who underwent insertion of Memokath stents and were followed for up to nine years. RESULTS: Within four years, the stent had to be removed in nine out of ten patients because of: extensive mucosal proliferation causing obstruction to the lumen of the stent; stone around the proximal end of the stent, incomplete bladder emptying, and recurrent urinary infections; migration of the stent into the bladder related to digital evacuation of bowels; large residual urine; concretions within the stent causing obstruction to flow of urine, and partial blockage of the stent causing frequent episodes of autonomic dysreflexia. In one patient the stent continued to function satisfactorily after nine years. CONCLUSIONS: The Memokath stent has a role as a temporary measure for treatment of detrusor-sphincter dyssynergia in selected SCI patients who do not get recurrent urinary infection and do not require manual evacuation of bowels

A study of cytokeratin 20 immunostaining in the urothelium of neuropathic bladder of patients with spinal cord injury

BACKGROUND: Normal urothelium is characterised by terminally differentiated superficial cells, which express cytokeratin 20 in the cytoplasm. In contrast, cultured human stratified urothelium, which does not undergo complete terminal differentiation of its superficial cells, does not express cytokeratin 20. If spinal cord injury (SCI) affects urothelial differentiation or induces squamous or other metaplastic change undetected by histological analysis, the superficial urothelial cells of the neuropathic bladder might be expected to show absence of immunostaining for cytokeratin 20. PATIENTS AND METHODS: We studied immunostaining for cytokeratin 20 in bladder biopsies taken from 63 consecutive SCI patients. Immunostaining was performed on paraffin-embedded tissue using a mouse monoclonal antibody (clone: Ks20.8). RESULTS: Of 63 biopsies, the epithelium was scarce in two. Eight biopsies showed squamous metaplasia and immunostaining for cytokeratin 20 was absent in all the eight biopsies. Of the remaining 53 cases, in which the umbrella cell layer of the urothelium was intact, immunostaining for cytokeratin 20 was seen only in ten biopsies. CONCLUSION: Superficial cells in the transitional epithelium showed immunostaining for cytokeratin 20 in 10 of 53 bladder biopsies taken from SCI patients. The reasons for this could be either that there is an underlying metaplasia or that changes in the neuropathic bladder affect urothelial differentiation. Taken with evidence from other systems, such as loss of cytokeratin 20 expression from static organ cultures of urothelial tissue, this might suggest that other factors, such as impairment of voluntary voiding in SCI patients, could affect expression of markers such as cytokeratin 20

Nanoengineered condenser surfaces for enhancing transport in thermal desalination by air gap membrane distillation

Thermal desalination is a technique that uses heat or thermal energy to desalinate water, unlike reverse osmosis. Membrane distillation (MD) is a type of thermal desalination technology having various configurations. Air gap membrane distillation (AGMD) is one of the more energy efficient MD configurations, being especially advantageous over other configurations at high salinity. However, the large mass transfer resistance of the air gap dramatically reduces the permeate flux, impairing performance. Higher condensation performance can be achieved by using a smaller air gap size, but typical film-wise condensation flow patterns flood the air gap at the optimal gap size (\u3c1 mm). Experiments show that dropwise and jumping-droplet condensation regimes, achieved using hydrophobic and superhydrophobic condensing surfaces respectively, can improve droplet shedding, allowing for thinner gap sizes. A systemlevel numerical model is used to demonstrate that these surfaces could thereby enable improved energy efficiency (2.1× increase of gained output ratio) while avoiding flooding at gap sizes as small as 0.2 mm. Superhydrophobic surfaces with directional jumping of droplets, specifically in the direction of gravity, are also tested and compared to droplets that jump normal to the condensing surface. Novel condensing surfaces that include a combination of the superhydrophobic and superhydrophilic patterns create flow regimes having pathways for faster permeate removal. Other condensing surfaces, including SLIPS (slippery liquidinfused porous surfaces) and laser-ablated superhydrophobic patterned surfaces are tested to the check the extent to which they improve the permeate removal rate while exhibiting different condensation regimes that merit further exploration

The method of bladder drainage in spinal cord injury patients may influence the histological changes in the mucosa of neuropathic bladder – a hypothesis

BACKGROUND: In spinal cord injury (SCI) patients, no correlation was found between the number of bladder infections per year, the period since injury, the neurologic level of the spinal cord lesion and the histopathology of the urinary bladder mucosa. The use of chronic indwelling urethral and/or suprapubic catheters in SCI patients is often associated with inflammatory and proliferative pathological conditions in neuropathic bladder. PRESENTATION OF THE HYPOTHESIS: We propose a hypothesis that the type of bladder drainage in SCI patients influences the histological changes in the mucosa of neuropathic bladder. This hypothesis implies that SCI patients with long-term indwelling urinary catheters develop certain histological changes in bladder mucosa, which are seen less frequently in SCI patients, who do not use long-term indwelling catheters. The latter group includes patients, who perform regular intermittent catheterisation and those, who wear a penile sheath and empty their bladders satisfactorily by reflex voiding. We hypothesise that the following histological lesions are seen more frequently in the neuropathic bladder of SCI patients with long-term indwelling catheters. (1) Papillary or polypoid cystitis; (2) widespread cystitis glandularis; (3) moderate to severe, acute and chronic inflammatory changes in bladder mucosa; (4) follicular cystitis; (5) squamous metaplasia; and (6) urothelial dysplasia As per this hypothesis, it is postulated that the above pathological conditions are seen less often in SCI patients, who achieve complete, low-pressure emptying of the neuropathic bladder by regular intermittent catheterisation, and SCI patients with penile sheath drainage, who empty their bladders satisfactorily by reflex voiding. TESTING THE HYPOTHESIS: A large prospective study of bladder biopsies in SCI patients practising different methods of bladder drainage is required to validate this hypothesis that the histological changes in bladder mucosa are related to the method of bladder drainage in SCI patients. IMPLICATIONS OF THE HYPOTHESIS: We propose a hypothesis that the method of bladder drainage in SCI patients influences histological changes in the bladder mucosa. If this hypothesis is validated, methods of bladder drainage such as intermittent catheterisation, which do not require the use of chronic indwelling catheters, should be recommended, in order to minimise adverse histological changes in the mucosa of neuropathic bladder of spinal cord injury patients

ESTIMATION OF INSTANTANEOUS EVAPOTRANSPIRATION USING REMOTE SENSING BASED ENERGY BALANCE TECHNIQUE OVER PARTS OF NORTH INDIA

Evapotranspiration (ET) is an essential element of the hydrological cycle and plays a significant role in regional and global climate through the hydrological circulation. Estimation and monitoring of actual crop evapotranspiration (ET) or consumptive water use over large-area holds the key for better water management and regional drought preparedness. In the present study, the remote sensing based energy balance (RS-EB) approach has been used to estimate the spatial variation of instantaneous evapotranspiration (ETinst). The (ETinst) is evaluated as the residual value after computing net radiation, soil heat flux and sensible heat flux using multispectral remote sensing data from Landsat-8 for the post-monsoon and summer season of 2016–2017 over the parts of North India. Cloud free temporal remote sensing data of October 12, 2016; November, 13, 2016; March 05, 2017 and May 24, 2017 were used as primary data for this study. The study showed that normalized difference vegetation index and LST are closely related and serve as a proxy for qualitative representation of (ETinst)

Klippel-Feil syndrome – the risk of cervical spinal cord injury: A case report

BACKGROUND: Klippel-Feil syndrome is defined as congenital fusion of two or more cervical vertebrae and is believed to result from faulty segmentation along the embryo's developing axis during weeks 3–8 of gestation. Persons with Klippel-Feil syndrome and cervical stenosis may be at increased risk for spinal cord injury after minor trauma as a result of hypermobility of the various cervical segments. Persons with Klippel-Feil Syndrome often have congenital anomalies of the urinary tract as well. CASE PRESENTATION: A 51-year male developed incomplete tetraplegia in 1997 when he slipped and fell backwards hitting his head on the floor. X-rays of cervical spine showed fusion at two levels: C2 and C3 vertebrae, and C4 and C5 vertebrae. Intravenous urography (IVU) revealed no kidneys in the renal fossa on both sides, but the presence of crossed, fused renal ectopia in the left ilio-lumbar region. This patient had a similar cervical spinal cord injury about 15 years ago, when he developed transient numbness and paresis of the lower limbs following a fall. DISCUSSION AND CONCLUSION: 1) Persons with Klippel-Feil syndrome should be made aware of the increased risk of sustaining transient neurologic deterioration after minor trauma if there is associated radiographic evidence of spinal stenosis. 2) Patients with Klippel-Feil syndrome often have congenital anomalies of the urinary tract. Our patient had crossed, fused, ectopia of kidney. 3) When patients with Klippel-Feil syndrome sustain tetraplegia they have increased chances of developing urinary tract calculi. Treatment of kidney stones may pose a challenge because of associated renal anomalies. 4) Health professionals caring for cervical spinal cord injury patients with Klippel-Feil syndrome and renal anomalies should place emphasis on prevention of kidney stones. A large fluid intake is recommended for these patients, as a high intake of fluids is still the most powerful and certainly the most economical means of prevention of nephrolithiasis

Bladder stones – red herring for resurgence of spasticity in a spinal cord injury patient with implantation of Medtronic Synchromed pump for intrathecal delivery of baclofen – a case report

BACKGROUND: Increased spasms in spinal cord injury (SCI) patients, whose spasticity was previously well controlled with intrathecal baclofen therapy, are due to (in order of frequency) drug tolerance, increased stimulus, low reservoir volume, catheter malfunction, disease progression, human error, and pump mechanical failure. We present a SCI patient, in whom bladder calculi acted as red herring for increased spasticity whereas the real cause was spontaneous extrusion of catheter from intrathecal space. CASE PRESENTATION: A 44-year-old male sustained a fracture of C5/6 and incomplete tetraplegia at C-8 level. Medtronic Synchromed pump for intrathecal baclofen therapy was implanted 13 months later to control severe spasticity. The tip of catheter was placed at T-10 level. The initial dose of baclofen was 300 micrograms/day of baclofen, administered by a simple continuous infusion. During a nine-month period, he required increasing doses of baclofen (875 micrograms/day) to control spasticity. X-ray of abdomen showed multiple radio opaque shadows in the region of urinary bladder. No malfunction of the pump was detected. Therefore, increased spasticity was attributed to bladder stones. Electrohydraulic lithotripsy of bladder stones was carried out successfully. Even after removal of bladder stones, this patient required further increases in the dose of intrathecal baclofen (950, 1050, 1200 and then 1300 micrograms/day). Careful evaluation of pump-catheter system revealed that the catheter had extruded spontaneously and was lying in the paraspinal space at L-4, where the catheter had been anchored before it entered the subarachnoid space. A new catheter was passed into the subarachnoid space and the tip of catheter was located at T-8 level. The dose of intrathecal baclofen was decreased to 300 micrograms/day. CONCLUSION: Vesical calculi acted as red herring for resurgence of spasticity. The real cause for increased spasms was spontaneous extrusion of whole length of catheter from subarachnoid space. Repeated bending forwards and straightening of torso for pressure relief and during transfers from wheel chair probably contributed to spontaneous extrusion of catheter from spinal canal in this patient