A new cleaning method for solar panels inspired from the natural vibrations of tree branches and leaves.

Photovoltaic (PV) panels are similar in many aspects to the leaves of trees, both are standing in the Sun to capture the sunlight, however, PV panels get soiled especially in desert areas, while the leaves remain clean to a very good extent. The question is, why leaves remain clean while PV panels get soiled quite easily? The leaves are hanging on the stem of trees and these stems are flexible to motion, such that if the wind blows in any direction over the stem it vibrates allowing any deposited particle to fall off the surface. The objective of this research is to develop a fixation method for PV panels similar to the stems of trees, such that the panel can vibrate as the wind blows in order to minimize dust accumulation. Different fixation methods for the PV panel are designed, and the air flow around the panel is simulated using the CFD package Ansys Fluent. It has been found that a PV panel pivoted at its lower edge, such that it can revolve around the lower edge, together with a vertical wind shield attached to its upper edge and a spring attached at the middle of its backside has the largest vibration amplitude due to the applied wind compared to the other designs. Experiments have been done to infer the influence of the new fixation method of the PV panel on dust accumulation over the panel. After 6 weeks of operation, it has been found that the efficiency of the PV panel that is flexibly fixed has dropped by only 5%, while the efficiency of the panel that is rigidly fixed has dropped by 25%. It can be concluded that a PV panel operating a light post should be fixed on a flexible base that allows the panel to vibrate as the wind blows over it in order to mitigate dust.

Ventilation practices in the neonatal intensive care units in Saudi Arabia, survey of the utilization of volume-targeted ventilation among practicing neonatologists.

OBJECTIVE: To assess the current practice in using volume-targeted ventilation among neonatologists working at the Neonatal Intensive Care Units (NICU) of Saudi Arabia. METHODS: The questionnaire was provided electronically to 153 practicing Neonatologists working in 39 NICUs. The survey's results were received and statistically analyzed. RESULTS: One hundred nineteen (119) responses were received with, a 78% response rate. Volume Targeted Ventilation (VTV) was used routinely by 67.2%, whereas 21.8% still use only pressure control (PC)/pressure limited (PL) mode. During the acute phase of ventilation support, Assist Control was the most popular synchronized mode, whereas Synchronized Intermittent Mandatory Ventilation (SIMV) with pressure support (PS) or PSV were the two most common modes during the weaning phase, 31.8%, and 31% respectively. The majority of the neonatologists used a tidal volume of 4 ml/kg as the lowest and 6 ml/kg as the highest. The major reasons for not implementing VTV were the limited availability of ventilator devices that have an option of VTV, followed by lack of experience. CONCLUSION: VTV is the predominant ventilation practice approach among neonatologists working in the KSA. Limited availability and lack of experience in using are the main challenges. Efforts to equip NICUs with the most advanced ventilation technology, enhance practitioners' experience and sufficient training in its use are warranted.

Ochromobactrum intermedium: an emerging opportunistic pathogen-case of recurrent bacteraemia associated with infective endocarditis in a haemodialysis patient.

We describe the first clinical case report of infective endocarditis related to Ochrobactrum intermedium infection. The case involved a 23-year-old man receiving dialysis via an internal jugular long-term haemodialysis catheter. He improved with a prolonged course of meropenem and minocycline. Ochrobactrum spp. are recognized as rare emerging opportunistic pathogens.

Angiogenin and vascular endothelial growth factor in pregnancies complicated by preeclampsia.

OBJECTIVE: To investigate the role of the angiogenic factors, vascular endothelial growth factor (VEGF) and angiogenin in the pathophysiology of preeclampsia and how their concentrations correlate with the severity of the disease and fetal outcome. PATIENTS AND METHODS: A prospective study was carried out on 71 pregnant patients with preeclampsia and 20 pregnant normotensive controls. Maternal serum levels of VEGF and angiogenin were determined in all cases by enzyme immunoassay. Assessment of fetal well-being using the Biophysical Profile Score (BPS), umbilical and uterine artery Doppler velocimetry, and infant birthweight were carried out. RESULTS: Maternal serum VEGF and angiogenin levels were significantly increased in cases of mild and severe preeclampsia compared to controls. Their increase was positively correlated with elevated systolic and diastolic blood pressure, as well as poor BPS, abnormal Doppler velocimetry, and low birthweight. CONCLUSION: Elevated levels of both VEGF and angiogenin could confirm the existence of vascular reactivity and endothelial disturbance in preeclampsia. Measurement of these angiogenic factors in maternal serum may be a useful as biomarkers for the assessment of the severity of the disease and of fetal outcome.

Hypertension prevalence, awareness, treatment, and control in Egypt. Results from the Egyptian National Hypertension Project (NHP). NHP Investigative Team.

This report from the Egyptian National Hypertension Project presents national estimates of the prevalence of hypertension and the extent to which high blood pressure is being detected, treated with medications, and controlled in the Egyptian population. The results are based on findings from a national probability survey of adults > or = 25 years of age conducted in six Egyptian governorates. With the use of a stratified multistage probability design, 6733 people (85% response rate) were examined. Hypertension was defined as systolic pressure > or = 140 mm Hg, and/or diastolic pressure > or = 90 mm Hg, and/or reported treatment with one or more antihypertensive medications. Overall, the estimated prevalence of hypertension in Egypt was 26.3%. Hypertension prevalence increased progressively with age, from 7.8% in 25- to 34-year-olds to 56.6% in those 75 years or older. Hypertension was slightly more common in women than in men (26.9% versus 25.7%, respectively). Overall, 37.5% of hypertensive individuals were aware that they had high blood pressure, 23.9% were being treated with antihypertensive medications, and 8.0% were under control (systolic pressure < 140 mm Hg and diastolic pressure < 90 mm Hg). Hypertension prevalence as well as awareness, treatment, and control rates varied by region, with Cairo having the highest prevalence (31.0%) and the Coastal Region having the highest control rate (15.9%). Rates of awareness, treatment, and control tended to be lowest in areas of lower socioeconomic status. Our results indicate that hypertension is highly prevalent in Egypt and that the rates of hypertension is awareness, treatment, and control are relatively low.(ABSTRACT TRUNCATED AT 250 WORDS)

Nitrogen balance and protein turnover during the growth failure in newly born low-birth-weight infants.

Weight gain, nitrogen balance, protein turnover, and energy and protein intakes were measured during the first week of life of 14 low-birth-weight (LBW) infants, 5 small-for-gestational-age (SGA) infants and 9 appropriate-for-gestational-age (AGA) infants enterally fed at rates determined by the infants ability to assimilate feed. Mean gross intakes were 334 KJ and 1.75 g/kg protein; 4 infants were increasing and 10 were losing weight at rates proportional to gross energy and protein intakes and to nitrogen balance (0.031 g protein balance/g wt gain). Rates of protein synthesis and degradation measured by an intragastric infusion of [1-13C]leucine, averaged 14.5 and 15.9 g protein.kg-1.d-1, some 50% higher than previously reported in older preterm infants and not correlated with nitrogen balance. The growth failure of these infants was not associated with inadequate overall rates of protein turnover, but appeared to reflect an influence of the insufficient energy and protein intakes on the high rates of protein turnover, inducing changes in protein balance in either direction through relatively small changes in protein synthesis and/or degradation.

Marked resistance of normal subjects to tube-feeding-induced diarrhea: the role of magnesium.

The tolerance of healthy subjects to increasing rates of tube feeding was studied to better understand the etiology of diarrhea among tube-fed patients. Five volunteers were fed Osmolite HN by continuous duodenal infusion beginning at 314 kJ (75 kcal).kg body wt-1 x d-1 and progressing each 24 h until no longer tolerated. The five subjects were able to tolerate maximum 24-h infusions of 331-511 kJ.kg-1 x d-1 (198-340 mL/h). Diarrhea developed in only three subjects. Compared with nondiarrheal stools, the high-speed supernatant of the diarrheal stools had significantly higher concentrations of magnesium (192 +/- 22 mmol/L vs 139 +/- 17 mmol/L, P = 0.005), lower concentrations of potassium and phosphorus, and similar concentrations of calcium. The mean carbohydrate, fat, and nitrogen contents were not significantly different. We conclude that normal adult males are remarkably tolerant to duodenal infusion of this typical, isotonic tube-feeding product. The diarrhea that occurred in three of the volunteers at very high infusion rates appeared to be osmotic and attributable predominantly to magnesium.

Cclooxygenase-2 (COX-2) Protein Expression by Western Blotting.

Most epidemiological studies (1-7) support a protective role of aspirin and nonsteroidal antiinflammatory drugs (NSAIDs) against colorectal cancer. People who (by their report) take aspirin regularly have about a 50% decrease in the incidence (3,4) and mortality (1,2) from colorectal cancer compared to those who reported no aspirin use. In addition, hospital-based case control studies suggest a protective effect of aspirin use on the development of large-bowel adenomas (5-7). On the other hand, the Physician's Health Study failed to detect any protective effect for aspirin against the subsequent development of colorectal cancer over 12 years of follow up, although this may be due to the short period of follow up (8,9).

Renal cell carcinoma metastatic to the pituitary gland: clinical manifestations and successful treatment with transsphenoidal resection.

OBJECTIVE: To describe two cases of metastatic involvement of the pituitary gland by renal cell carcinoma (RCCA) and review the medical literature regarding this entity. METHODS: We present two case reports and discuss the published literature to illustrate the clinical findings, radiographic features, and recommended management of RCCA metastatic to the pituitary gland. RESULTS: During a 12-month period, we encountered two patients, one with visual deficits and both with anterior pituitary dysfunction, who had large sellar lesions that were histologically proved to be RCCA. Both patients were successfully treated with transsphenoidal surgical resection of the lesion, one of whom is alive and well more than 2 years later. A pituitary metastatic tumor is an uncommon complication of RCCA; it may be difficult to diagnose and potentially fatal. Anterior pituitary dysfunction and visual disturbances are more common initial features than is diabetes insipidus, in contrast to pituitary metastatic involvement from other tumors. CONCLUSION: Transsphenoidal resection is a safe and effective method of treatment of RCCA metastatic to the pituitary gland.

[Doppler echocardiographic evaluation of functional parameters of mechanical and biological valve prostheses]. / Valutazione tramite ecocardiografia-Doppler dei parametri funzionali di protesi valvolari meccaniche e biologiche.

We studied and compared functional parameters in 314 valvular prostheses. The following parameters have been calculated: mean transvalvular gradients for aortic and mitral prostheses and functional area by Pht (pressure half time) for mitral prostheses. All patients with important depression in myocardial function, tachycardia or malfunctioning prostheses were excluded. 173 prostheses were in aortic position and 141 in mitral position. Mitral prostheses were: 31 biological and 110 mechanical. We subdivided mechanical prostheses in monoleaflet (Omnicarbon, Sorin-Carbocast and Allcarbon, Medtronic, Bjork-Shiley) and bileaflet (Sorin-Bicarbon, St. Jude). These three groups were compared: mean transvalvular gradients and area showed no differences. Aortic prostheses were: 33 biological and 140 mechanical; mechanical prostheses were subdivided in two groups: monoleaflet (Sorin Allcarbon e Carbocast, Bjork-Shiley, Medtronic, Omnicarbon) and bileaflet (Sorin-Bicarbon, St. Jude). Mean transvalvular gradients of these three groups were compared within each group for every size: bileaflet prostheses demonstrated inferior gradients than biological and monoleaflet for 19-21 and 23 sizes; in superior sizes there were no significant differences. Further analysis showed a significant correlation among gradients and body surface area in the 21 size prostheses (p = 0.004). Bileaflet prostheses in this subgroup showed less increase in mean gradient with surface area than mechanical and biological ones.

Regulation of dendritic cell interleukin-12 secretion by tumour cell necrosis.

Dendritic cells (DCs) play a key role in the induction and regulation of antigen-specific immunity. Studies have shown that, similar to infection, cellular necrosis can stimulate DC maturation. However, the ability of necrotic cell death to modulate DC cytokine secretion has yet to be explored. We investigated the regulation of interleukin (IL)-12 secretion by human DCs in response to tumour cell necrosis in an in vitro culture model. Two human tumour cell lines (K562 and JAr) were induced to undergo necrosis using heat injury and repeated cycles of freezing and thawing. Both types of tumour cells tested in this study, when injured, induced secretion of monomeric IL-12p40 by monocyte-derived DCs. Furthermore, priming DCs with necrotic cells augmented IL-12p70 secretion significantly in conjunction with CD40 cross-linking. This was physiologically relevant because cell death-pulsed DCs were more potent than non-pulsed DCs at stimulating T cells to proliferate and secrete interferon (IFN)-gamma. The Toll-like receptor 4 (TLR4) played a role in mediating the DC response to heat-killed, but not freeze/thaw-killed necrotic cells. For both methods of injury, proteins contributed to the effect of necrosis on dendritic cells, whereas DNA was involved in the effect of freeze/thawed cells only. These findings indicate that necrotic tumour cell death is not sufficient to induce bioactive IL-12p70, the Th1 promoting cytokine, but acts to augment its secretion via the CD40/CD40L pathway. The results also highlight that the mode of cell death may determine the mechanism of dendritic cell stimulation.

Low endogenous prostaglandin E2 predisposes to relapsing inflammation in experimental rat enterocolitis.

Intramural injection of peptidoglycan-polysaccharide (PG-PS) induces acute enterocolitis that spontaneously relapses in Lewis but not Fischer rats. Interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF-alpha) induce prostaglandin E2 (PGE2) secretion, which inhibits secretion of these cytokines by macrophages, suggesting an inhibitory feedback mechanism. We postulate that Lewis rat susceptibility to relapse is due to an imbalance between protective prostaglandins and cytokines. Female Fischer and Lewis rats were injected with PG-PS (37.5 microg/g) or human serum albumin intramurally. Tissue IL-1alpha and PGE2 immunoreactivities and myeloperoxidase (MPO) activity were determined. Relapsing rats had lower PGE2 and PGE2/IL-1alpha ratios than nonrelapsing rats (P < 0.05). In Fischer rats, 2 mg/kg/day of indomethacin potentiated cecal MPO and IL-1alpha concentrations above PG-PS alone (P < 0.05). Misoprostol treatment blocked PG-PS induced IL-1alpha and MPO and inhibited the potentiating effect of indomethacin on MPO and IL-1alpha (P < 0.05). In conclusion, increased endogenous PG may be protective against relapsing inflammation in PG-PS induced enterocolitis, at least partially via inhibition of proinflammatory cytokines. Imbalance between protective prostaglandins and proinflammatory cytokines may be involved in the pathogenesis of chronic relapsing inflammation in genetically susceptible hosts.

Tumour necrosis factor alpha changes porcine intestinal ion transport through a paracrine mechanism involving prostaglandins.

Prostaglandins stimulate electrogenic anion secretion and inhibit sodium chloride absorption in cryptosporidium induced pig diarrhoea. Because tumour necrosis factor alpha (TNF alpha) is an early mediator of inflammation and stimulates prostaglandin secretion, we investigated its effect on intestinal ion transport. Cryptosporidium infected pig ileum showed higher macrophage infiltration and tissue TNF alpha-like activity than uninfected tissues (p < 0.05, n = 4 and p < 0.05, n = 12, respectively). TNF alpha treatment of control porcine ileal mucosa increased the short circuit current (Isc), a measurement of net anion secretion in this model (p < 0.001, n = 23). This effect was blocked by 10(-6) M indomethacin and Cl- replacement. Neither acute treatment nor preincubation of colonic intestinal epithelial cell monolayers (T84) with TNF alpha stimulated the Isc. However, co-mounting of TNF alpha preincubated pig jejunal fibroblasts (P2JF) monolayers back to back with untreated T84 monolayers dose-dependently induced an indomethacin sensitive increase in Isc compared with values in untreated co-mounted monolayers (p < 0.001, n = 11). These data suggest that in infectious diarrhoea, TNF alpha may induce Cl- secretion through a paracrine mechanism involving prostaglandin release from subepithelial cells, for example fibroblasts.

Low endogenous prostaglandin E2 predisposes to relapsing inflammation in experimental rat enterocolitis.

Intramural injection of peptidoglycan-polysaccharide (PG-PS) induces acute enterocolitis that spontaneously relapses in Lewis but not Fischer rats. Interleukin-1 (IL-1) and tumor-necrosis factor-alpha (TNF-alpha) induce prostaglandin E2 (PGE2) secretion, which inhibits secretion of these cytokines by macrophages, suggesting an inhibitory feedback mechanism. We postulate that Lewis rat susceptibility to relapse is due to an imbalance between protective prostaglandins and cytokines. Female Fischer and Lewis rats were injected with PG-PS (37.5 microg/g) or human serum albumin intramurally. Tissue IL-1alpha and PGE2 immunoreactivities and myeloperoxidase (MPO) activity were determined. Relapsing rats had lower PGE2 and PGE2:IL-1alpha ratios than nonrelapsing rats (P < 0.05). In Fischer rats, 2 mg/kg/day indomethacin potentiated cecal MPO and IL-1alpha concentrations above PG-PS alone (P < 0.05). Misoprostol treatment blocked PG-PS-induced IL-1alpha and MPO and inhibited the potentiating effect of indomethacin on MPO and IL-1alpha (P < 0.05). In conclusion, increased endogenous PG may be protective against relapsing inflammation in PG-PS induced enterocolitis, at least partially via inhibition of proinflammatory cytokines. An imbalance between protective prostaglandins and proinflammatory cytokines may be involved in the pathogenesis of chronic relapsing inflammation in genetically susceptible hosts.

Henna (Lawsonia inermis Linn.) inducing haemolysis among G6PD-deficient newborns. A new clinical observation.

Over a 10-year period, 15 glucose-6-phosphate dehydrogenase (G6PD)-deficient male newborns were admitted to Al-Jahra Hospital with acute haemolysis a few days after applying henna dye over the body, which is a unique Bedouin tribal practice to celebrate the arrival of the first-born boy. Laboratory investigations revealed significant anaemia, reticulocytosis and indirect hyperbilirubinaemia among the index newborns as compared with controls (p < 0.001). The mean (SD) haemoglobin concentration in index patients was 113.4 (13.4) g/l vs 171.2 (11.2) g/l in controls, reticulocytic count 13.8% (4.2%) vs 1.4% (0.74%), and indirect bilirubin 382.8 (58.7) mumol/l vs 63.7 (61.4) mumol/l. G6PD-deficient newborns with haemolysis linked to henna application had delayed age at presentation and a higher reticulocytic count and hyperbilirubinaemia compared with non-henna-induced haemolysis (p < 0.05). Percutaneous henna absorption is well recognized and clinical findings support the harmful effect of henna on G6PD-deficient red blood cells. A local health education programme has been established to prevent the use of henna dye in infancy.

Cyclooxygenase-2 expression in Barrett's esophagus.

Barrett's epithelium is a recognized premalignant condition for esophageal adenocarcinoma. Nonsteroidal antiinflammatory drugs (NSAIDs) decrease the relative risk of colon cancer in humans and the esophageal tumor load in carcinogen-treated mice. Previous studies provided conflicting results for COX-2 activity in Barrett's mucosa. Pinch mucosal biopsies were collected from Barrett's and adjacent normal esophageal mucosa from 17 patients with Barrett's esophagus. Low-grade dysplasia was found in seven patients. COX-2 protein was undetectable in normal esophageal mucosa. COX-1 protein expression did not vary between normal and Barrett's epithelium. Increased COX-2 protein was detected in Barrett's epithelium in seven patients (41%) but did not differ with or without dysplasia (43% vs 40%). In conclusion, COX-2 protein is increased in 41% of patients with Barrett's epithelium compared to normal esophageal mucosa but did not differ with or without dysplasia. COX-2 induction may be an early event in the development of Barrett's esophagus.

Regurgitant jet size by transesophageal compared with transthoracic Doppler color flow imaging.

Combined echocardiography and Doppler color flow mapping from transthoracic imaging windows has become the standard method for the noninvasive assessment of valvular regurgitation. This study compared regurgitant jet areas by Doppler color flow imaging derived from the newer transesophageal approach with measurements obtained from conventional transthoracic apical views. Maximal regurgitant jet area determinations and an overall visual estimate of lesion severity were obtained from 42 patients who underwent color flow examination by both techniques. Seventy-three regurgitant lesions were visualized by transesophageal flow imaging: 34 mitral, 22 aortic, and 17 tricuspid jets. Transthoracic studies in the same patients revealed fewer regurgitant lesions for each valve; 20 mitral, 16 aortic, and 12 tricuspid (p = 0.0009). A comparison of maximal jet areas determined by transesophageal and transthoracic studies showed a good overall correlation (r = 0.85, SEE = 2.8 cm2) and a systematic overestimation by the transesophageal technique (TEE = 0.96 TTX + 2.7). For the subgroup with mitral insufficiency, valve lesions visualized by both techniques were larger by the transesophageal approach (n = 18, 6.0 versus 3.6 cm2, p = 0.008). Semiquantitative visual grading of individual valve lesions by two independent observers revealed a higher grade of regurgitation with more jets classified as mild (38 versus 25), moderate (18 versus 13), and severe (17 versus 10) by esophageal imaging than by transthoracic imaging. Thus, transesophageal color flow mapping techniques yield a higher prevalence of valvular regurgitation than do transthoracic techniques in the same patients. Jet area and the overall estimate of regurgitant lesion severity were also greater by transesophageal color Doppler imaging compared with standard transthoracic imaging.(ABSTRACT TRUNCATED AT 250 WORDS)