Effect of climate on electrical performance of finned phase change material integrated solar photovoltaic

This is the final version. Available on open access from Elsevier via the DOI in this recordIn support of open access research, all underlying article materials (such as data, samples or models) can be accessed upon request via email to the corresponding author.Photovoltaic (PV) cells absorb the incident solar radiation while operation of which, majority part causes heating leading to the hampered electrical efficiency. PVs can be integrated with phase change material (PCM) to maintain cell temperature within desired limits and the effect can be improved by deploying fins. The current work aims at analysing the effect of climate on the electrical performance of finned PCM integrated PV. Modelling of system has been done which has been validated using experimental results. For the study, fins with various spacings, thicknesses and lengths are used. The main conclusions of the study are, (a) for less alterative climate, the improvement in the PV electrical output (using finned PCM) is 9.7%, 10.8%, 11.3%, 11.6% and 11.6% respectively for a spacing of 1 m, 1/2 m, 1/3 m, 1/4 m and 1/5 m. For highly alterative climate, the respective values reduce to 6.6%, 7.6%, 8.1%, 8.4% and 8.4%, (b) for warmer climate, the output increases by 10.1%, 11.3%, 11.8%, 12.1% and 12.1% while for colder climate, it increases only by 5.4%, 6.1%, 6.5%, 6.7% and 6.7%, (c) for windy climate, the power increments are significantly lesser as compared to the other case, (d) climate having higher wind azimuth results in better performance of finned PCM, and (e) for clear sky climate, performance of finned PCM is better.Engineering and Physical Sciences Research Council (EPSRC

Optimization of finned solar photovoltaic phase change material (finned pv pcm) system

This is the final version. Available on open access from the publisher via the DOI in this recordHeat generation during the operation of the photovoltaic (PV) cell raises its temperature and results in reduced electrical output. The heat produced in the process can be removed by attaching phase change material (PCM) at the back of the PV panel which can contain the PV temperature substantially and increase its efficiency. Fins can be used inside the PCM container to enhance the heat transfer. In literature, it is observed that as soon as PCM is melted completely, the heat extraction rate of PCM reduces which again leads to increase in PV temperature. However, the study carrying out the optimization of Finned-PV-PCM system to keep PV temperature low during operation for different solar irradiance levels is not available in literature. Thus, in the current study, the most suitable depth of PCM container is calculated for different solar irradiance levels. In addition, how it is affected with spacing between successive fins, fin length and fin thickness has been studied. The best fin dimensions are also calculated. The results show that the most suitable depth of PCM container is 2.8 cm for ∑I T = 3 kWh/m 2 /day and 4.6 cm for ∑I T = 5 kWh/m 2 /day for the chosen parameters. The best spacing between successive fins (to keep PV temperature low) is 25 cm, best fin thickness is 2 mm and best fin length is the one when it touches the bottom of the container. PV, PV-PCM and Finned-PV-PCM systems are also compared. For PV-PCM system (without fins), the most suitable depth of PCM container is 2.3 cm for ∑I T = 3 kWh/m 2 /day and 3.9 cm for ∑I T = 5 kWh/m 2 /day.The authors gratefully acknowledge the financial support from EPSRC-DST funded Reliable and Efficient System for Community Energy Solution - RESCUES project (EP/K03619X/1

Optimization of fins fitted phase change material equipped solar photovoltaic under various working circumstances

This is the final version. Available on open access from Elsevier via the DOI in this recordData availability: in support of open access research, all underlying article materials (such as data, samples or models) can be accessed upon request via email to the corresponding author.The present work aims at the optimization of fins fitted phase change material equipped photovoltaic system under different working circumstances for proper power enhancement. Setup has been modelled and the best deepness of fins fitted phase change material enclosure has been computed for a range of daily collective solar flux at photovoltaic panel surface, wind pace, wind azimuth, surroundings temperature, melting point, successive fins distance, fins deepness and fins width in order to analyse the influence of working circumstances. It is shown that the change in wind pace from 0.2 m/s to 6 m/s results in reduction of best deepness of phase change material enclosure from 5.2 cm to 3.7 cm, 5.6 cm to 4.0 cm, 5.8 cm to 4.2 cm, 5.9 cm to 4.3 cm and 5.9 cm to 4.3 cm for successive fins distance of 1 m, 1/2 m, 1/3 m, 1/4 m and 1/5 m respectively for daily collective solar flux at photovoltaic panel as 5000Wh/m2. The change in wind azimuth from 0° to 75° results in increment in the best deepness of enclosure from 3.9 cm to 4.8 cm, 4.3 cm to 5.2 cm, 4.5 cm to 5.4 cm, 4.6 cm to 5.5 cm and 4.6 cm to 5.5 cm for respective fins distances. The power production is increased from 125 W/m2 to 137 W/m2, 140 W/m2, 142 W/m2, 143 W/m2 and 143 W/m2 with fins width of 0 mm, 0.5 mm, 1 mm, 2 mm and 4 mm respectively.Engineering and Physical Sciences Research Council (EPSRC

Tuberculosis of the breast with erythema nodosum: a case report

<p>Abstract</p> <p>Introduction</p> <p>There has been an increasing number of tuberculosis cases worldwide, but tuberculosis of the breast remains rare. In rare cases this is seen with a cutaneous manifestation of erythema nodosum.</p> <p>Case presentation</p> <p>We report the case of a 33-year-old Chinese woman with tuberculosis of the left breast accompanied by erythema nodosum on the anterior aspect of both lower legs. Due to her poor clinical response to conventional therapy, and the histopathological findings of fine needle aspiration cytology, there were strong indications of tuberculosis. Her clinical diagnosis was confirmed by molecular detection of <it>Mycobacterium tuberculosis </it>complex by polymerase chain reaction. The diagnosis was further confirmed by a second polymerase chain reaction test of erythema nodosum which tested positive for <it>Mycobacterium tuberculosis</it> complex. She received anti-tuberculous therapy for 18 months, and finally underwent residual lumpectomy. During her follow-up examination after 12 months, no evidence of either residual or recurrent disease was present.</p> <p>Conclusion</p> <p>Histopathological features and a high index of clinical suspicion are necessary to confirm a diagnosis of tuberculosis of the breast. Anti-tuberculous therapy with or without simple surgical intervention is the core treatment.</p

The association between histamine 2 receptor antagonist use and Clostridium difficile infection: a systematic review and meta-analysis.

Background Clostridium difficile infection (CDI) is a major health problem. Epidemiological evidence suggests that there is an association between acid suppression therapy and development of CDI. Purpose We sought to systematically review the literature that examined the association between histamine 2 receptor antagonists (H2RAs) and CDI. Data source We searched Medline, Current Contents, Embase, ISI Web of Science and Elsevier Scopus from 1990 to 2012 for all analytical studies that examined the association between H2RAs and CDI. Study selection Two authors independently reviewed the studies for eligibility. Data extraction Data about studies characteristics, adjusted effect estimates and quality were extracted. Data synthesis Thirty-five observations from 33 eligible studies that included 201834 participants were analyzed. Studies were performed in 6 countries and nine of them were multicenter. Most studies did not specify the type or duration of H2RAs therapy. The pooled effect estimate was 1.44, 95% CI (1.22–1.7), I2 = 70.5%. This association was consistent across different subgroups (by study design and country) and there was no evidence of publication bias. The pooled effect estimate for high quality studies was 1.39 (1.15–1.68), I2 = 72.3%. Meta-regression analysis of 10 study-level variables did not identify sources of heterogeneity. In a speculative analysis, the number needed to harm (NNH) with H2RAs at 14 days after hospital admission in patients receiving antibiotics or not was 58, 95% CI (37, 115) and 425, 95% CI (267, 848), respectively. For the general population, the NNH at 1 year was 4549, 95% CI (2860, 9097). Conclusion In this rigorous systematic review and meta-analysis, we observed an association between H2RAs and CDI. The absolute risk of CDI associated with H2RAs is highest in hospitalized patients receiving antibiotics

Macrocyclic colibactin induces DNA double-strand breaks via copper-mediated oxidative cleavage.

Colibactin is an assumed human gut bacterial genotoxin, whose biosynthesis is linked to the clb genomic island that has a widespread distribution in pathogenic and commensal human enterobacteria. Colibactin-producing gut microbes promote colon tumour formation and enhance the progression of colorectal cancer via cellular senescence and death induced by DNA double-strand breaks (DSBs); however, the chemical basis that contributes to the pathogenesis at the molecular level has not been fully characterized. Here, we report the discovery of colibactin-645, a macrocyclic colibactin metabolite that recapitulates the previously assumed genotoxicity and cytotoxicity. Colibactin-645 shows strong DNA DSB activity in vitro and in human cell cultures via a unique copper-mediated oxidative mechanism. We also delineate a complete biosynthetic model for colibactin-645, which highlights a unique fate of the aminomalonate-building monomer in forming the C-terminal 5-hydroxy-4-oxazolecarboxylic acid moiety through the activities of both the polyketide synthase ClbO and the amidase ClbL. This work thus provides a molecular basis for colibactin's DNA DSB activity and facilitates further mechanistic study of colibactin-related colorectal cancer incidence and prevention

Refractive Status at Birth: Its Relation to Newborn Physical Parameters at Birth and Gestational Age

Refractive status at birth is related to gestational age. Preterm babies have myopia which decreases as gestational age increases and term babies are known to be hypermetropic. This study looked at the correlation of refractive status with birth weight in term and preterm babies, and with physical indicators of intra-uterine growth such as the head circumference and length of the baby at birth.All babies delivered at St. Stephens Hospital and admitted in the nursery were eligible for the study. Refraction was performed within the first week of life. 0.8% tropicamide with 0.5% phenylephrine was used to achieve cycloplegia and paralysis of accommodation. 599 newborn babies participated in the study. Data pertaining to the right eye is utilized for all the analyses except that for anisometropia where the two eyes were compared. Growth parameters were measured soon after birth. Simple linear regression analysis was performed to see the association of refractive status, (mean spherical equivalent (MSE), astigmatism and anisometropia) with each of the study variables, namely gestation, length, weight and head circumference. Subsequently, multiple linear regression was carried out to identify the independent predictors for each of the outcome parameters.Simple linear regression showed a significant relation between all 4 study variables and refractive error but in multiple regression only gestational age and weight were related to refractive error. The partial correlation of weight with MSE adjusted for gestation was 0.28 and that of gestation with MSE adjusted for weight was 0.10. Birth weight had a higher correlation to MSE than gestational age.This is the first study to look at refractive error against all these growth parameters, in preterm and term babies at birth. It would appear from this study that birth weight rather than gestation should be used as criteria for screening for refractive error, especially in developing countries where the incidence of intrauterine malnutrition is higher

Functional Analysis of Retinitis Pigmentosa 2 (RP2) Protein Reveals Variable Pathogenic Potential of Disease-Associated Missense Variants

Genetic mutations are frequently associated with diverse phenotypic consequences, which limits the interpretation of the consequence of a variation in patients. Mutations in the retinitis pigmentosa 2 (RP2) gene are associated with X-linked RP, which is a phenotypically heterogenic form of retinal degeneration. The purpose of this study was to assess the functional consequence of disease-associated mutations in the RP2 gene using an in vivo assay. Morpholino-mediated depletion of rp2 in zebrafish resulted in perturbations in photoreceptor development and microphthalmia (small eye). Ultrastructural and immunofluorescence analyses revealed defective photoreceptor outer segment development and lack of expression of photoreceptor-specific proteins. The retinopathy phenotype could be rescued by expressing the wild-type human RP2 protein. Notably, the tested RP2 mutants exhibited variable degrees of rescue of rod versus cone photoreceptor development as well as microphthalmia. Our results suggest that RP2 plays a key role in photoreceptor development and maintenance in zebrafish and that the clinical heterogeneity associated with RP2 mutations may, in part, result from its potentially distinct functional relevance in rod versus cone photoreceptors

Using Hydrophilic Ionic Liquid, [bmim]BF4 – Ethylene Glycol System as a Novel Media for the Rapid Synthesis of Copper Nanoparticles

In this work, we present a novel method for the synthesis of copper nanoparticles. We utilize the charge compensatory effect of ionic liquid [bmim]BF4 in conjunction with ethylene glycol for providing electro-steric stabilization to copper nanoparticles prepared from copper sulphate using hydrazine hydrate as a reducing agent. The formed copper nanoparticles showed extended stability over a period of one year. Copper nanoparticles thus prepared were characterized by powder X-ray diffraction measurements (pXRD), transmission electron microscopy (TEM) and quasi elastic light scattering (QELS) techniques. Powder X-ray diffraction (pXRD) analysis revealed relevant Bragg's reflection for crystal structure of copper. Powder X-ray diffraction plots also revealed no oxidized material of copper nanoparticles. TEM showed nearly uniform distribution of the particles in methanol and confirmed by QELS. Typical applications of copper nanoparticles include uses in conductive films, lubrication and nanofluids. Currently efforts are under way in our laboratory for using these nanoparticles as catalysts for a variety of organic reactions