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Paenibacillus durus strain ATCC 35681T is a Gram‐positive diazotroph that displayed capability of fixing nitrogen even in the presence of nitrate or ammonium. However, the nitrogen fixation activity was detected only at day 1 of growth when cultured in liquid nitrogen‐enriched medium. The transcripts of all the nifH homologues were present throughout the 9‐day study. When grown in nitrogen‐depleted medium, nitrogenase activities occurred from day 1 until day 6 and the nifH transcripts were also present during the course of the study albeit at different levels. In both studies, the absence of nitrogen fixation activity regardless of the presence of the nifH transcripts raised the possibility of a post‐transcriptional or post‐translational regulation of the system. A putative SigA box sequence was found upstream of the transcription start site of nifB1, the first gene in the major nitrogen fixation cluster. The upstream region of nifB2 showed a promoter recognizable by SigE, a sigma factor normally involved in sporulation. [ABSTRACT FROM AUTHOR]

In this work, an electromagnetic energy harvesting device using a sprung eccentric rotor has been designed, optimized and characterized to harvest power from pseudo-walking signals (a single frequency sinusoidal signal derived from motion of a driven pendulum that approximates the swing of a human-arm during walking). Our analysis shows that a rotor with an eccentric mass suspended by a torsional spring enhances the mechanical energy captured from low-frequency excitations (e.g., those produced during human walking, running/jogging). An electromagnetic transducer in the sprung eccentric rotor structure converts the captured mechanical energy into electrical energy. An electromechanical dynamic model of a sprung eccentric rotor has been developed and an optimization routine was performed to maximize output power under pseudo-walking excitation. The structure of the electromagnetic transducer was refined using Finite Element Analysis (FEA) simulations. A prototype energy harvester was fabricated and tested in a pseudo wrist-worn situation (by mounting on a mechanical swing-arm) to mimic the low-frequency excitation produced during human walking. A series of pseudo-walking motions was created by varying the swing profile (angle and frequency). The prototype with optimal spring stiffness generates a maximum 61.3 μW average power at ±25° rotational amplitude and 1 Hz frequency which is about 6-times higher than its unsprung counterpart under same excitation condition. The experimental results are in good agreement with the simulation results. [ABSTRACT FROM AUTHOR]

Experimental and numerical investigation of the triple concentric-tube heat exchanger with inserted ribs has been carried out. The purpose is to evaluate the performance characteristics of the triple tube heat exchanger with rib inserts. The investigation key design parameters involve water mass flow rate, flow pattern, temperature variation, rib height and rib pitch. Numerical CFD modeling is developed using FLUENT commercial code and validation criteria is done to extend the study parameters with extra ranges. The results revealed that, the insertion of ribs to the inner annulus fluid flow of the triple tube heat exchanger participate a significant enhancement of the convective heat transfer. Higher performance index is obtained at higher rib pitch and lower rib height. A set of empirical expressions with the dimensionless design parameters have been predicted based on the obtained data. [ABSTRACT FROM AUTHOR]

Abstract: Forty-six deep groundwater samples from highly arsenic affected areas in Bangladesh were analyzed in order to evaluate the processes controlling geochemical constituents in the deep aquifer system. Spatial trends of solutes, geochemical modeling and principal component analysis indicate that carbonate dissolution, silicate weathering and ion exchange control the major-ion chemistry. The groundwater is dominantly of Na–Cl type brackish water. Approximately 17% of the examined groundwaters exhibit As concentrations higher than the maximum acceptable limit of 10μg/L for drinking water. Strong correlation (R 2 =0.67) of Fe with dissolved organic carbon (DOC) and positive saturation index of siderite suggests that the reductive dissolution of Fe-oxyhydroxide in presence of organic matter is considered to be the dominant process to release high content of Fe (median 0.31mg/L) in the deep aquifer. In contrast, As is not correlated with Fe and DOC. Boron concentration in the 26% samples exceeds the standard limit of 500μg/L, for water intended for human consumption. Negative relationships of B/Cl ratio with Cl and boron with Na/Ca ratio demonstrate the boron in deep groundwater is accompanied by brackish water and cation exchange within the clayey sediments. [Copyright &y& Elsevier]

Abstract: Background: We studied early sirolimus (SRL) therapy in renal transplant recipients at high risk after administration of antithymocyte globulin or interleukin-2 receptor blockade induction. Patients and Methods: In 45 patients, SRL therapy was started within 1 month after transplantation. The primary indications for conversion of treatment from calcineurin inhibitors (CNIs)–mycophenolate mofetil (MMF)–steroid to SRL-MMF-steroid were biopsy-proved rejection (after treatment), CNI toxicity, CNI elimination, and acute tubular necrosis. Pediatric, geriatric, and other patients with medical comorbidities were not excluded. Results: Post-SRL rejection episodes were reported in 22.2% of recipients including 15.6% who were resistant to steroid therapy. Mean (SD) follow-up after SRL therapy was 59.9 (8.1) months. Proteinuria greater than 2 g/d (P = .001), leukopenia (P < .001), hyperlipidemia (P < .001), and transaminases values (P = .02) increased significantly after SRL therapy. Graft survival was 88.8%, and patient survival was 93.3%. There was significant improvement in serum creatinine concentration and estimated creatinine clearance by the end of the study (P < .001). A high incidence of adverse effects and infections was noted post-SRL therapy, and the drug was discontinued in 31% of patients because of multiple adverse effects. At multivariate analysis, age, hypertension, nutritional status, bone marrow suppression, hyperlipidemia, and graft dysfunction were identified as risk factors for worse graft and patient outcome. Conclusion: Early treatment with combined SRL-MMF-steroid may be effective as a CNI-free immunosuppression regimen in patients at high risk; however, there is a high rate of adverse effects during long-term follow-up. [Copyright &y& Elsevier]

Abstract: While conversion of stable renal transplant recipients (RTR) from calcineurin inhibitors (CNI) to sirolimus (SRL) is safe and effective, it is still under investigation for recent, high-risk cases. We studied the long-term effects of conversion of high-risk subjects maintained on a CNI, mycophenolate mofetil, plus steroid regimen to SRL, mycophenolate mofetil, plus steroid on graft and patient outcomes. We retrospectively reviewed the first 100 RTR converted to SRL treatment over approximately 5 years. The main indications for conversion were biopsy-proven acute rejection (BPAR), CNI toxicity, CNI elimination, and acute-tubular necrosis (ATN). Exclusion criteria were limited to bone marrow suppression. The overall mean ± SD age was 38.5 ± 15.6 years, including pediatric and geriatric age groups. Mean ± SD body mass index (BMI) was 28.99 ± 8.0 and 40% had a BMI > 30. There were 40% RTR from deceased donors and 60% showed 4 to 6 HLA mismatches. Preconversion total BPAR and steroid-resistant rejection incidences were 35% and 14%, respectively. Mean ± SD time to start of SRL was 11.9 ± 22.8 months posttransplantation. Proteinuria > 2 g/d, leukopenia, and hyperlipidemia increased significantly after conversion (P = .001, P = .0003, and P = .0001, respectively). Patient and graft survivals were 95% and 90%, respectively. There was significant improvement in graft function postconversion (P < .0001). There was a high incidence of side effects and cases of SRL discontinuation. Multivariate analysis demonstrated the influence of bone marrow suppression, obesity, hyperlipidemia, nutritional status, proteinuria, and graft function on graft and patient outcomes. We concluded that conversion from CNI to SRL was effective among high-risk RTR, but with a high incidence of adverse events during long-term follow-up. [Copyright &y& Elsevier]

Abstract: Geochemical composition and the level of Arsenic (As) contamination of groundwater in the Ganges Delta Plain, southwestern Bangladesh were elucidated. Hydrogeochemical data of tube well samples suggested that the groundwater is mostly Ca–Mg–HCO3 type with bicarbonate (HCO3 −) as the dominant anion, though other type waters are also observed. In contrast, the elevated EC, Cl− and high content of Na+ relative to Ca2+, Mg2+ and K+ in six groundwater samples suggest their saline origin. Low concentrations of NO3 − and SO4 2−, and high concentrations of dissolved organic carbon (DOC), HCO3 − and PO4 3− indicate the reducing conditions of subsurface aquifer where sediments are deposited with abundant organic matter. The total As concentration in the analyzed samples is very high (0.0431–1.352mg/L) along with high Fe (2.791–17.058mg/L) and relatively low Mn (0.134–1.972mg/L) at different depths. Distinct relationship of As with Fe and Mn, and strong correlation with DOC suggests that the biodegradation of organic matter and reductive dissolution of Fe-oxyhydroxide is considered to be the dominant processes to release As in aquifers. Moreover, negative correlation between As and SO4 2− demonstrates the As may not be directly mobilized from sulfide minerals like arsenopyrite. [Copyright &y& Elsevier]

[Display omitted] • Suspended spherical and cylindrical bodies were investigated in an air stream. • Two scenarios of body axis as parallel and normal to flow stream were studied. • Increasing body length resulted in improved heat transfer coefficient. • General correlations with identified constants were suggested. The present study solely relies on experimental research to examine forced convection heat transfer from suspended spherical and cylindrical entities to an air stream. By looking to the body's primary axis, two flow directions are parallel/perpendicular. The findings showed that a cylindrical body with a Reynolds number of 2 × 104 to 7.3 × 105 and a spherical body with a Reynolds number of 3 × 104 to 3 × 105 are both used in the situation of air flowing parallel position. The ranges of Reynolds numbers used for spherical bodies ranged from 2.7 × 104 to 2 × 105 and cylindrical bodies ranged from 2 × 104 to 2.3 × 105 for airflow perpendicular position. According to the findings for cylindrical bodies, increasing body length resulted in improved heat transmission. The enhancement of the convictive heat transfer coefficient (CHTC) reaches about 87.4% for sphere diameter = 150 mm, when air velocity increases from 11 to 32 m/s. For the cylindrical body with = 50 mm diameter and increase of air velocity from 11 to 32 m/s, the CHTC is improved by about 113.2% and 101.7% for l/d = 1 and 2 based on parallel and perpendicular flow respectively. The correlation between the Nusselt and Reynolds numbers served as a representation of the outcomes. The current findings are crucial for understanding the heat exchange with air flow around building, food and fluid transporters, refrigerated cars, heated liquid wagons, and air-conditioned train coaches. [ABSTRACT FROM AUTHOR]

Suggests a novel method of starting a three-phase wound rotor induction motors by inserting a parallel combination of resistance, inductance and capacitance in the rotor circuit. Reference to the development of a frequency-domain quasi-steady state; Findings of experiments conducted; Methodology used in experiments.

Describes a nonconventional method for fast starting of three phase wound rotor induction motors. Shunting of stator and rotor windings for a short period; Development and simulation of a state space mathematical model; Basic principles of interaction between magnetic fields.

Abstract: Background: High levels of soluble CD30 (sCD30), a marker for T-helper 2-type cytokine-producing T cells, pre or post–renal transplantation serves as a useful predictor of acute rejection episodes. Over the course of 1-year, we evaluated the accuracy of serial sCD30 tests to predict acute rejection episodes versus other pathologies that affect graft outcomes. Patients and methods: Fifty renal transplant recipients were randomly selected to examine sCD30 on days 0, 3, 5, 7, 14, and 21 followed by 1, 3, 6, and 12 months. The results were analyzed for development of an acute rejection episode, acute tubular necrosis (ATN), or other pathology as well as the graft outcome at 1 year. Results: Compared with pretransplantation sCD30, there was a significant reduction in the average sCD30 immediately posttransplantation from day 3 onward (P < .0001). Patients were divided into four groups: (1) uncomplicated courses (56%); (2) acute rejection episodes (18%); (3) ATN (16%); and (4) other diagnoses (10%). There was a significant reduction in sCD30 immediately posttransplantation for groups 1, 2, and 3 (P < .0001, .004, and .002 respectively) unlike group 4 (P = .387). Patients who developed an acute rejection episode after 1 month showed higher pretransplantation sCD30 values than these who displayed rejection before 1 month (P = .019). All groups experienced significant improvement in graft function over 1-year follow-up without any significant differences. Conclusion: Though a significant drop of sCD30 posttransplantation was recorded, serial measurements of sCD30 did not show a difference among subjects who displayed acute rejection episodes, ATN, or other diagnoses. [Copyright &y& Elsevier]

Abstract: Objective: To assess the efficacy of leflunomide, intravenous immunoglobulins, and ciprofloxacin as active treatment of postrenal transplant BK virus nephropathy (BKVN) in graft outcome at 1 year. Patients and Methods: Renal transplant recipients with positive results of 2 BK virus polymerase chain reaction tests of urine and blood underwent graft biopsy to confirm BKVN. If BKVN was diagnosed, antimetabolite therapy (mycophenolate mofetil or azathioprine) was changed to leflunomide therapy accompanied by a course of immunoglobulin and oral ciproflxacin. Results: Of 18 patients evaluated, 72% were men. Nine patients received cadaveric organs, with a mean of 3.6 HLA mismatches. All patients received induction thereapy (61% thymoglobulin), and 61% received antirejection therapy before BKVN was diagnosed. Maintenance immunosuppression therapy was primarily with prednisolone (94%); mycophenolate mofetil, 2 g/d (94%); and tacrolimus (61%). At baseline, mean (SD) creatinine clearance was 35.6 (11.5) mL/min/1.732, which decreased to 29.3 (17.3) mL/min/1.732 at 1 year (P = .01). Patients were divided into 2 groups of 9 each according to creatinine clearance values. In group 1, baseline value was 44.5 (6.6) mL/min/1.732, compared with 25.36 (7.8) mL/min/1.732 in group 2, which decreased to 42.66 (12.8) mL/min/1.732 (P = .23) and 16.76 (9.0) mL/min/1.732 (P = .009), respectively, at 1 year. Three grafts (16.7%) were lost by the end of the study, all in group 2 (P = .03). Conclusion: Late diagnosis and intensive immunosuppression predispose to BKVN. Early active treatment of BKVN may improve graft outcome at 1 year posttransplantation. [Copyright &y& Elsevier]

Abstract: Cyclosporine (CsA) microemulsion has been the mainstay immunosuppressive agent for renal transplant recipients for years. A single daily dosing of cyclosporine (SD) is rarely used. The objective of this study was to evaluate the efficacy of SD versus twice daily dosing of CsA. Retrospective evaluation of SD use was conducted for 44 renal transplant recipients for 12 months (study group). Equal numbers of matched recipients were selected for age, sex, HLA mismatch, donor type, and immunosuppressive regimen (control group). We measured CsA trough (C0) and peak (C2) blood levels, 12-hour CsA profile, and the area under the concentration-time curve (AUC). There were significant differences in C0, C2, and calculated AUC after shifting to SD. In the study group, the mean AUC was 4619 ng/mL/h before versus 6567 ng/mL/h after shifting to SD (P = .004). This became more therapeutic and identical to the mean AUC in the control group, which was 6551 ng/mL/h. Total daily CsA dose was significantly lower in the study group compared with the control group (P < .0001). A significantly higher incidence of hepatitis was observed among the study group (P = .011). There were significantly fewer adverse effects in patients in the study group than the control group. There were no significant differences in graft and patient outcomes between the groups. We concluded that CsA dose should be individualized in renal transplant recipients especially if they have viral hepatitis. SD has the advantage of decreasing dosage and CsA-related adverse effects while maintaining optimal graft function. [Copyright &y& Elsevier]

Abstract: Introduction: Cyclosporine microemulsion has been the mainstay immunosuppressive agent in renal transplantation for years. Since single daily dosing of cyclosporine is rarely used, the objective of this investigation was to evaluate the efficacy of a single daily dose versus twice daily dosing of cyclosporine in renal transplant recipients. Methods: Retrospective evaluation of single-dose cyclosporine use was conducted for 15 renal transplant recipients for 12 months (study group). Equal numbers of matched renal transplant recipients were selected for age, sex, human leukocyte antigen mismatch, donor type, and immunosuppressive regimen (control group). Cyclosporine trough level and peak cyclosporine blood levels, 12-hour cyclosporine profile, and the area under the concentration-time curve were measured. Results: There was a significant difference in cyclosporine peak blood level and calculated area under the curve after shifting to single-dose cyclosporine (P = .001). In the study group, the mean area under the curve was significantly below the average therapeutic range before (3154 ng/mL/ho) versus 5532 ng/mL/h after shifting to the single-dose regimen (which was therapeutic). This value was 5749 ng/mL/h in the control group. Total daily cyclosporine dose was lower in the study group when compared with the control group at 6 and 12 months (P = .01). There were significantly fewer adverse effects in patients in the study group than in patients in the control group. Conclusion: We conclude that although cyclosporine dose should be individualized in renal transplant recipients, a single dose of cyclosporine has the added advantage of decreasing dosages and cyclosporine-related adverse effects while maintaining optimal graft function. [Copyright &y& Elsevier]

Abstract: Objective: The area under the concentration-time curve of cyclosporine microemulsion is the best measure of the absorption and beneficial effects in renal transplant recipients. We sought to determine the best method of monitoring cyclosporine levels in these patients. Methods: Prospective evaluation of peak cyclosporine blood levels and area under the curve monitoring were performed for 1 year in 65 renal transplant recipients (study group). Cyclosporine trough levels and peak cyclosporine blood levels were correlated with the calculated area under the curve. Cyclosporine trough levels were monitored in equal numbers of matched controls. Results: There were no significant differences in the incidence of acute rejection, cyclosporine nephrotoxicity, proteinuria, serum creatinine levels, or graft and patient outcomes between the groups (P = .1). Peak cyclosporine blood levels guided by calculating the area under the curve were found to be 27% to 32% lower than previously reported. The correlation coefficient was <70% for cyclosporine trough levels (P < .02) and >90% for peak cyclosporine blood levels (P < .001) when related to the calculated area under the curve. The calculated area under the curve was approximately 6000 ng/mL/h following transplantation, gradually decreasing to approximately 3000 ng/mL/h at 1 year. Both appeared to the acceptable therapeutic values. Conclusion: Calculating the area under the curve using trough and peak blood levels versus using isolated readings for either of these levels alone is the most effective method of monitoring cyclosporine in recipients undergoing renal transplant. [Copyright &y& Elsevier]

Abstract: The prevalence of inflammatory bowel disease (IBD) after renal transplantation is affected by the immune tolerance and the modality of immunosuppression. Mycophenolate mofetil (MMF) may have a promoting effect on the development of posttransplantation erosive enterocolitis and a Crohn’s disease-like pattern of colitis. We have presented a 40-year-old man with end-stage renal disease due to chronic glomerulonephritis who commenced hemodialysis for 2 months before receipt of a live unrelated renal transplant. He developed early posttransplantation diabetes mellitus and an anti graft rejection episode, which responded to a methylprednisolone pulse and OKT3 treatment. His immunosuppressive regimen included prednisolone, MMF, and tacrolimus. Three years after transplantation, he developed mild constitutional symptoms, mouth ulcerations, and chronic intermittent bloody diarrhea. Colonoscopy showed active segmental colitis with aphthous ulcers, involving the proximal descending colon and the splenic flexure. Colonic biopsies showed distended and branched crypts in the ascending colon, moderate active chronic colitis with regenerative atypia, skipping appearance, and ulceration in the splenic flexure and descending colon. The edematous crypts were associated with ulcerations in the sigmoid colon and rectum. The features were highly suggestive of Crohn’s disease. He was successfully treated with high-dose steroids and 5-aminosalicylic acid. Subsequently, he developed chronic transplant glomerulopathy and restarted hemodialysis. We concluded that de novo Crohn’s disease may develop in renal transplant recipients despite immunosuppressive therapy especially with MMF immunosuppression. [Copyright &y& Elsevier]

Presents an obstetric case report on successive pregnancy of a 25 year old patient with a transplanted heart. Medical history of the patient; Reason why pregnancy is not recommended for heart transplant women.

• The width of the scrape-off-layer (SOL) has been a critical issue in the design of fusion reactors. • The plasma parameters for the small-size divertor tokamak are solved using the B2SOLPS5.02D code at different locations. • SOL width is significantly influenced by the sheath transmission coefficient, Larmor radius, and safety factor. • SOL width was found to be uneven along the poloidal coordinate. • Diffusion coefficient, heat flux density, impurities, and the creation of edge transport barriers significantly affect SOL width. The width of the scrape-off-layer has been a critical issue in the design of fusion reactors. This width has been derived using Braginskii electron energy balance and electron momentum balance equations. The most significant influence on the edge plasma profiles, especially on the divertor heat flux, was the drift element. Therefore, the drift mechanisms are used to find the width of scrape-off-layer. The derivation of these formulas with some presumptions leads to the width of scrape-off-layer ∼ qρ ci , where q is a safety factor, and ρ ci is an ion Larmor radius. The plasma parameters for the small-size divertor tokamak are solved using the B2SOLPS5.02D code at different locations. Then, they are applied in the scrape-off-layer width relation to correlate the width with these variables. In these locations, the scrape-off-layer width was found to be uneven. The results show that the diffusion coefficient, heat flux density, impurities, and the creation of edge transport barriers significantly affect scrape-off-layer width. [ABSTRACT FROM AUTHOR]

Deposits of salts and extraneous materials occur during water desalination by heating, forming an insulating layer, which is known as fouling. Fouling reduces the rate of heat transfer between the heating medium and the water, subsequently decreases the desalination efficiency gradually and sometimes can lead to operation failure. The thermal shock is a fouling mitigation technique in water desalination units, which could be due to sudden decrease or increase in the heat transfer process. The objective of this research is to study the removal of fouling layers by the thermal shock in case of (i) smooth tubes, (ii) rough tubes and (iii) finned-rough tubes. It has been found that it is possible to remove the fouling layer by the thermal shock technique in case of smooth and rough tubes, but not in case of finned tubes. The thermal shock blows off the fouling layer in case of plain tubes, and the fouling process resumes after the thermal shock without any delays, i.e. no more induction period. Fins assist the sticking of crystals to the heat exchanger tubes and prevent its removal by thermal shock. Fins act as a heat sink during the thermal shock, which reduces the dissipation of heat to the surrounding water, i.e. cooling of the tubes, and prevent cracking of the fouling layer. [ABSTRACT FROM AUTHOR]

Paschen curves were studied using different cathode materials such as magnesium, zinc, and carbon graphite by discharge in argon gas of a pressure range between 0.08 and 3 Torr using a parallel plates configuration. The first and second Townsend coefficients (α and γ, respectively) and the ionization efficiency (η) of different cathode materials were deduced from Paschen curves as a function of the reduced field (E/P). The minimum breakdown voltage was found to be about 242 V for Mg material, which has the lowest work function, while carbon graphite has a higher breakdown voltage of 283 V due to its higher work function. The second coefficient γ was increased as a function of E/P and has higher values for materials of lower work functions, and a similar trend of γ is obtained as a function of the ion mean energy. On the other hand, the first coefficient α has a reverse behavior with both E/P and the work function of the cathode materials compared with the second coefficient. The ionization efficiency of the three cathode materials is identical, as η depends only on the gas properties and not the cathode material. η has a maximum value of about 0.025 V−1 for an E/P of about 185 Vcm−1Torr−1, corresponding to the maximum ionizing ability of electrons. The validation of the breakdown results has been confirmed by conferring with other published experimental measurements. [ABSTRACT FROM AUTHOR]

The continuous increase in the level of greenhouse gas (GHG) emissions and the increase in fuel prices are the main driving force to utilize various source of renewable energy. Among the clean energy technologies, solar energy is recognized as one of the most promising choice since it is free and provides clean and environmentally friendly energy. The objective of this paper is to improve the heating capabilities of evacuated tubes solar cookers that operates based on a closed loop thermosyphon action, and utilize thermal oil as the heating medium. Two identical evacuated tube solar cookers have been designed and built to study the influence of inserting metallic wires or nanographene particles on the thermal performance of the cooker. Also, the study was based on the thermal transfer of natural convection of the thermal oil movement within the evacuated tubes. The metallic wires and the nanographene particles are inserted inside the evacuated tube, which is filled with the heat exchange oil. One cooker is always tested without any modifications, i.e. taken as a reference point. The other cooker is the developed cooker, i.e. with wires or particles. Steel, aluminum and copper wires have been examined, and the number of wires has been varied between 5, 10 and 15. It has been found that the copper wires improve the rate of heat transfer compared with steel wires, aluminum wires and the nanographene particles. It has been also obtained that there is a critical number of wires, i.e. 10 wires, above that the rate of heat transfer by natural convection decreases and this is due to the increased friction which resists the natural convection currents. Finally, adding nanographene particles increases the viscosity of the oil, which increases the resistance to natural convection currents and consequently decreases the rate of heat transfer by natural convection. • Thermal performance of closed loop solar cookers with evacuated tubes was improved. • Metallic wires inserted in the evacuated tube were investigated. • The influence of adding nanographene particles to thermal oil on the solar cooker was studied. • The critical number of wires inserted inside the evacuated tube of solar cookers were investigated. [ABSTRACT FROM AUTHOR]

The continuous increase in the level of greenhouse gas (GHG) emissions and the increase in fuel prices are the main driving force to utilize various source of renewable energy. Among the clean energy technologies, solar energy is recognized as one of the most promising choice since it is free and provides clean and environmentally friendly energy. The objective of this paper is to improve the heating capabilities of evacuated tubes solar cookers that operates based on a closed loop thermosyphon action, and utilize thermal oil as the heating medium. Two identical evacuated tube solar cookers have been designed and built to study the influence of inserting metallic wires or nanographene particles on the thermal performance of the cooker. Also, the study was based on the thermal transfer of natural convection of the thermal oil movement within the evacuated tubes. The metallic wires and the nanographene particles are inserted inside the evacuated tube, which is filled with the heat exchange oil. One cooker is always tested without any modifications, i.e. taken as a reference point. The other cooker is the developed cooker, i.e. with wires or particles. Steel, aluminum and copper wires have been examined, and the number of wires has been varied between 5, 10 and 15. It has been found that the copper wires improve the rate of heat transfer compared with steel wires, aluminum wires and the nanographene particles. It has been also obtained that there is a critical number of wires, i.e. 10 wires, above that the rate of heat transfer by natural convection decreases and this is due to the increased friction which resists the natural convection currents. Finally, adding nanographene particles increases the viscosity of the oil, which increases the resistance to natural convection currents and consequently decreases the rate of heat transfer by natural convection. • Thermal performance of closed loop solar cookers with evacuated tubes was improved. • Metallic wires inserted in the evacuated tube were investigated. • The influence of adding nanographene particles to thermal oil on the solar cooker was studied. • The critical number of wires inserted inside the evacuated tube of solar cookers were investigated. [ABSTRACT FROM AUTHOR]

Recently, tubular solar still (TSS) is considered as one of the preferable options for pure acquisition water, particularly, for small applications located in coastal and arid regions. Such areas are usually doesn't have a sufficient power source for water desalination or infrastructure to transport pure water. This paper presents an improvement in the daily rate of water production by offering TSS integrated with cover cooling. The system consists of a transparent solar tube to increase the amount of solar irradiance, which is combined with a black basin to enhance the absorption and improve the water evaporation. TSS was manufactured using lightweight materials, gaining strong and durable weight, from locally available materials. In this study, different basin water depth (0.5, 1, 2, and 3 cm) were investigated to obtain the best water depth. Furthermore, trying various water cover cooling flow rate (1, 2, 3, and 4 L/h) to get the optimal water-cooling flow rate. The experimental results show that the TSS with lower water depth gives the best performance, where the productivity was reached to 4.5 L/m2, while with the large water depth at 3 cm give a daily productively of 3 L/m2. Also, the best cooling water flow rate was obtained at 2 L/h. Under the best conditions corresponding to 0.5 cm water depth and 2 L/h cooling water flow rate, the maximum efficiency was achieved, which was about 54.9%. In comparison with TSS without cooling, the proposed TSS successfully improved the yield and efficiency of the TSS by about 31.4% and 32.6%, respectively. Moreover, the daily thermal exergy efficiency increased by about 9%. From an economic point of view, the cost per liter of clean water output was found to be 0.023 $ and 0.019 $ for TSS without and with cover cooling, respectively. • Evaluating the thermal performance of tubular solar still with and without cover cooling. • Investigating the freshwater production of tubular solar still with different water depth. • Examining the freshwater production of tubular solar still with various cooling flow rate. • Estimating the price per liter for the different modification in tubular solar still. [ABSTRACT FROM AUTHOR]

The present research inspected the thermal and flow behavior of finned coiled tube heat exchangers in crossflow for chilled water air conditioning systems. The investigation variables cover the impacts of several variables, such as fin dimple shape, the number of fins, and the Reynolds number of water and air sides on the thermal-hydraulic aspects of a finned cooling coiled tube heat exchanger. The goal is to enhance this famous finned cooling coiled tube heat exchanger using dimples concerning the same coiled tube heat exchanger without dimples. Six test specimens were fabricated, three with fin dimple geometries as sharp-sided triangle dimples, curved-sided triangle dimples, and teardrop dimples. The other specimens with three different fin numbers 140, 155, and 170. The test runs were experimented in a transparent air duct with air Reynolds numbers ranging from 1540 to 6205, while the chilled water flow side has experimented with Reynolds numbers ranging from 3350 to 16250. The findings revealed that a higher Nusselt number and flow area goodness factor is achieved by a heat exchanger (D) with a curved-sided triangle fin dimple shape. The energy efficiency ratio for a cooling coil with a fin number of 170 is higher than that of cooling coils with fin numbers 140 and 155 by approximately 24.68% and 12.94%, respectively. Correlations of energy efficiency ratio, effectiveness, flow area goodness factor, and friction factor are extracted according to the experimental results with deviations. [Display omitted] • The performance of the dimpled air conditioning cooling coil is investigated. • Three different patterns of dimples have been proposed. • A curved-sided triangle fin dimple shape achieves a higher flow area goodness factor. • A maximum energy efficiency ratio is acquired with a fin number of 170. • Correlations of EER, Ꜫ, α, and f are extracted according to the experimental results. [ABSTRACT FROM AUTHOR]

Abstract: This work focused on the fabrication of p-type ZnO material by Ag–N co-doping using spray pyrolysis technique and the characterization of structural, surface morphology and opto-electrical properties. Hall measurements reveal that Ag–N co-doped ZnO thin films are p-type materials and highest mobility is obtained for 2.5mol% of Ag doping, keeping the concentration of N unchanged. The resistivity of the films depends on doping level and shows a minimum value (ρ~1.59Ω-cm) with a carrier concentration of 4.09×1016 cm−3 for 2.5mol% of Ag doping at the deposition temperature of 400°C. X-ray diffraction study shows a single phase of ZnO up to 2.5mol% of Ag doping level and after that a phase of silver oxide arises, which confirms that 2.5mol% of Ag doping level is the optimum condition. The aging effect does not affect the p-type characteristics of the Ag–N co-doped ZnO films. [Copyright &y& Elsevier]

To overcome the discontinuity between the axial phase and the radial phase in the plasma focus, a new model (the Masoud model) has been developed. It is assumed that, according to the snowplough model, the radial phase moves in the angular direction with continuity between the axial and the radial phases. This model is based on the introduction of an angle of motion in all equations of motion and circuit. Then, the plasma sheath position and velocity were calculated numerically from the previous equations. A slug model has been used to calculate the shock wave velocity, and hence the electron temperature. Values of the discharge current, the axial speed, the axial position, the spike voltage, the radial piston speed, the radial piston position, the plasma column length and the plasma temperature have been obtained using the new model. The values calculated by using this model show good agreement with the published experimental results. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Calcineurin inhibitor (CNI) induced HUS, although rare, can be a serious complication of renal transplantation. Classical syndrome of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal injury may not be fully manifested. Methods: We retrospectively analyzed our data in 950 kidney recipients under follow-up in our center (1994 – 2008). We reviewed the kidney biopsies performed for these patients to exclude conflicting diagnoses like antibody mediated rejection. Results: HUS was diagnosed in 12 patients (1.26%). None of them had HUS as the original kidney disease. Cyclosporine was the primary immunosuppression in 9 and tacrolimus in 3 patients. The median day of onset was 7 days. Manifestations were anemia (100%), thrombocytopenia (75%), elevated reticulocyte count (62.5%), fragmented red blood cells (8.3%), elevated lactate dehydrogenase (LDH) enzyme (83.3%), increased fibrin degradation product (FDP) (83.3%), reduced haptoglobin level (42.9%) and hyperbilirubinemia (25%). CNI elimination was the first step in the management. Transfusion of fresh frozen plasma (FFP) was used in 10 patients and plasma exchange with FFP in the other two. All grafts recovered function. Cyclosporine or tacrolimus were reintroduction in two patients after complete clinical and laboratory recovery. Both patients developed recurrence of HUS. While the former did not the latter did recover on further treatment of HUS. Conclusion: Anemia, thrombocytopenia, elevated LDH and FDP are the most frequent manifestations of HUS. Early CNI elimination and fresh plasma transfusion can revert CNI induced HUS and save the graft. Reintroduction of CNI may be deleterious to the graft and should be avoided. [Copyright &y& Elsevier]

Abstract: Background: Prophylaxis against cytomegalovirus (CMV) is a regular practice in organ transplantation. Oral valgancyclovir appears to be an interesting alternative to the usual intravenous form. Patients and Methods: We prospectively compared the response of intravenous gancyclovir for 2 weeks (GAN; n = 41) to oral valgancyclovir for 2 weeks (VAL2w; n = 23) or 3 months (VAL3m; n = 46) in kidney transplant recipients receiving induction immunosuppression. CMV antigenemia assay and/or polymerase chain reaction (PCR) were used for viral detection. Patients were followed for a minimum of 6 months posttransplantation. SPSS software was used for statistical analysis using a cutoff of significance as P < .05. Results: There was no statistical difference in the demographic features among the study groups. However, human leukocyte antigen (HLA) match was better in the VAL3m group and the patients of this group received less ATG induction immunosuppression (41.3%) compared with the GAN group (100%). The incidence of acute rejection was not different among the study groups. There was a higher incidence of fever with positive CMV tests in the VAL2w group (P = .035) compared with the other groups, while leukopenia with a negative CMV test was significantly higher in the VAL3m group (P = .04). The incidence of CMV disease was higher in the VAL2w group (30.4%) compared with the GAN group (14.6%) or the VAL3m group (8.7%). Renal function was significantly worse in the VAL2w group at 3 and 6 months (P = .011 and .02, respectively). Conclusions: Three months oral valgancyclovir prophylaxis for CMV was a more effective regimen compared with intravenous gancyclovir for 2 weeks. Shorter courses were associated with a higher incidence of CMV infection and poorer graft function. Leukopenia observed in patients receiving valgancyclovir may be a drug-related side effect. [Copyright &y& Elsevier]

Abstract: Introduction: Invasive fungal sinusitis is a rare but often fatal infection in immunocompromised patients. Aggressive antifungal treatment is mandatory, but is not without risk. Caspofungin, an antifungal agent that is a member of the echinocandin family, an inhibitor of glucan synthesis in the fungal wall, is active against Aspergillus and Candidae infections. Although it works on the fungal wall, it does not affect mammalian cells; hence, its toxicity is minimal. Case Summary: This report describes a case of invasive Aspergillus sinusitis in a kidney transplant recipient with diabetes mellitus. The infection involved the apex of the right orbit causing optic nerve compression. The patient was treated with transnasal endoscopic decompression of the optic nerve and intravenous AmBisome (liposomal amphotericin B) for 2 weeks without clinical improvement. The combination of caspofungin and AmBisome administered for another 2 weeks yielded partial improvement. The AmBisome had to be discontinued due to deterioration of renal and hepatic function, but the patient completed a further 7-week course of caspofungin alone. Retro-orbital biopsy confirmed a complete response to treatment; the patient’s renal and hepatic function returned to normal. Conclusion: This case indicates that caspofungin is effective to treat invasive Aspergillus sinusitis in kidney transplant recipients. This agent is well tolerated and safe with respect to renal and hepatic function. [Copyright &y& Elsevier]

Abstract: Introduction: BK virus nephropathy (BKVN) is a significant cause of graft loss among renal transplant recipients. The treatment outcomes of BKVN have been variably reported in the literature. Patients and methods: We prospectively investigated BKV infection and BKVN among a population of renal transplant recipients with suspected BKV infection. The 42 subjects who all had acute allograft dysfunction, were categorized in three groups: those with clinical, laboratory, and histological findings that did not suggest acute rejection, drug toxicity, or obstruction (group 1, n = 24); those with findings that suggested probable acute cellular rejection but did not respond to antirejection treatment (group 2, n = 10); and those whose renal histology suggested BKVN (group 3, n = 8). Polymerase chain reaction analysis was done to detect BKV DNA in urine and blood samples from each subject. BKV DNA was detected in 19 (45%) urine samples with 11 of these subjects (26.1% of total) having BK viremia as well. Results: No evidence of BKVN was detected histologically in seven subjects with isolated BK viruria, while the others proved to be JC virus infections. Among the 11 subjects with BK viremia, eight had BKVN based on renal histology at the time of diagnosis with BKV infection, while the other three subsequently developed histological features of BKVN. BKVN developed after 5.3 ± 2.5 (2 to 44) months after transplantation. The serum creatinine at time of BKVN diagnosis was 158.9 ± 58 (87 to 285) μmol/L. All subjects were initially treated with a 50% reduction in immunosuppressive drug doses. Further decreases in immunosuppression were performed in all patients with close monitoring of renal function. All subjects were followed up for a of 18.2 ± 5 (12 to 26) months. Two grafts were lost not due to BKVN, and one patient was lost to follow-up during this period. The latest serum creatinine in eight recipients is 113 + 20 (81 to 138) μmol/L, which is better than the renal function at diagnosis. Conclusion: The prevalence of BKVN in suspected BKV infection was 26%. Although the study period was short (30 months), BK viremia strongly correlated with BKVN, which seemed to be successfully treated with reduction in immunosuppression. [Copyright &y& Elsevier]

Abstract: Background: Renal allograft transplantation with multiple arteries (MRA) was always avoided as much as possible as it is technically demanding and carries a higher MSK for complications. This was a single-center study to explore the graft outcomes of kidney transplantation with MRA. Patients and Methods: We retrospectively reviewed the medical records of 35 patients who received kidney grafts with MRA for the surgical technique, surgical complications, graft function, and graft survival. The results were compared with those achieved in recipients of kidney grafts with a single renal artery (SRA). Results: Of 35 grafts, there were 2 renal arteries in 30 grafts, and 3 renal arteries in 5 grafts. In the MRA group, there were 7 instances of surgical complications, the mean serum creatinine levels were 122, 139, and 156 μmol/L at 1 month, 1 year, and 5 years, respectively, and the actuarial graft survival rates were 94.3%, 88.6%, and 83% at 1, 5, and 10 years, respectively. In the SRA group, there were 56 instances of surgical complications, the mean serum creatinine levels were 115, 121, and 141 μmol/L at 1 month, 1 year, and 5 years, respectively, and the actuarial graft survival rates were 93.7%, 88.1%, and 84.4% at 1, 5, and 10 years, respectively. Conclusion: Although transplantation of MRA grafts might carry a relatively higher risk for complications, it is justified because it gives results comparable with those achieved in SRA. [Copyright &y& Elsevier]

Abstract: Background: Hyperinfection strongyloidiasis is a potentially fatal syndrome associated with conditions of depressed host cellular immunity. A high degree of suspicion is required to detect cases early and thereby avoid a fatal outcome. Patients and Methods: Three consecutive cadaveric kidney transplant recipients died within 2 months from hyperinfections with strongyloides. All members of the transplant team were involved in a campaign to localize the source of infection, identify and treat affected patients, and provide adequate prophylaxis to other transplant recipients. We reviewed cadaveric donor files and screened 61 hospital personnel, 27 hospital inpatients, and the 87 hospital outpatients transplanted in a year’s time before that event for a possible source. The screening test included analysis of fresh stool samples on 3 consecutive days for strongyloides larvae. The anti-helminthic drug albendazol was administered to all patients during screening. They were followed for possible development of the disease during the infectivity period. Results: The first 2 recipients received their kidneys from 1 cadaveric donor, while the third received it from a different donor. Both donors came from areas endemic for strongyloidiasis. The 3 recipients were on tacrolimus-based immunosuppression. The twin recipient of the second kidney was on cyclosporine and did not manifest a disease. All stool samples taken for screening were negative for the infective larvae. None of the other recipients developed the disease. Conclusions: Cadaveric donors were the possible source for this outbreak. Cyclosporine probably has a protective effect against strongyloides. In our setting, screening of cadaveric donors for strongyloides is mandatory before accepting them for donation, and oral prophylaxis is required for all recipients. [Copyright &y& Elsevier]

Abstract: Introduction: Early acute rejection episodes (ARE) have deleterious effects on graft outcomes. The incidence of ARE in the first 3 months has been reported to be <20%. In a recent audit of ARE among 100 renal transplants, we observed the rates to be high (30%). We retrospectively collected details of donor type, induction therapy, immunosuppression medications, drug levels, HLA mismatches, acute tubular necrosis (ATN), and delayed graft function (DGF) to correlate with ARE and response to therapy. Results: Thirty rejection episodes occurred after a mean period of 14.3 days after transplantation. Ninety-one patients had induction treatment with either antithymocyte globulin (ATG) or interleukin 2 receptor antibodies (IL2 Rab). The drugs included cyclosporine, mycophenolate, sirolimus, azathioprine, and prednisolone in these patients. There was no significant difference in ARE among the different drug protocols (30.7%–35.2%). Subjects with 4 or more HLA mismatches displayed more ARE (40.3%) compared with those with 3 or less (23%). Subjects with ATN or DGF immediately posttransplantation had a higher incidence of ARE (39.2%) than those without them (26.3%). Deceased donor recipients had a higher episode of ARE (45.1%) compared with live related donor recipients (25%). On stratifying the known risk factors for ARE, subjects with no risk factors had the least (22.2%) ARE compared with those with one (32.5%) or two (47.6%) risk factors. Subjects who failed to achieve adequate cyclosporine (C2) levels showed significantly higher rates of ARE (86.9%) than those with adequate or higher levels (8.6%). Conclusion: Higher HLA mismatches, DGF, deceased donor, and failure to achieve adequate cyclosporine levels were observed to be major risk factors for the development of ARE. [Copyright &y& Elsevier]