Design Methodology for a Medium Voltage Single Stage LLC Resonant Solar PV Inverter

An inverter is generally employed with MV LFT to connect to the grid in a grid-tied PV system. However, in some single-stage topologies, the LFTs are replaced by HFT combined with an unfolder inverter. Generally, these topologies have limited use at high-power MV grids due to high switching losses on the primary side. This study proposes an LLC resonant converter-based single-stage inverter design procedure. Resonant converters make use of ZVS to reduce switching losses. The design includes both the resonant tank as well as output filter components. The design is verified by simulations in MATLAB/Simulink for various loads and input voltages at 13.8kV grid output voltage. THD simulations validate the filter design

p16INK4a hypermethylation and p53, p16 and MDM2 protein expression in Esophageal Squamous Cell Carcinoma

<p>Abstract</p> <p>Background</p> <p>Tumor suppressor genes <it>p53 </it>and <it>p16</it>^INK4aand the proto-oncogene <it>MDM2 </it>are considered to be essential G1 cell cycle regulatory genes whose loss of function is associated with ESCC carcinogenesis. We assessed the aberrant methylation of the <it>p16 </it>gene and its impact on <it>p16</it>^{<it>INK4a </it>}protein expression and correlations with <it>p53 </it>and <it>MDM2 </it>protein expressions in patients with ESCC in the Golestan province of northeastern Iran in which ESCC has the highest incidence of cancer, well above the world average.</p> <p>Methods</p> <p>Cancerous tissues and the adjacent normal tissue obtained from 50 ESCC patients were assessed with Methylation-Specific-PCR to examine the methylation status of <it>p16</it>. The expression of <it>p16</it>, <it>p53 </it>and <it>MDM2 </it>proteins was detected by immunohistochemical staining.</p> <p>Results</p> <p>Abnormal expression of <it>p16 </it>and <it>p53</it>, but not <it>MDM2</it>, was significantly higher in the tumoral tissue. <it>p53 </it>was concomitantly accumulated in ESCC tumor along with <it>MDM2 </it>overexpression and <it>p16 </it>negative expression. Aberrant methylation of the <it>p16</it>^{<it>INK4a </it>}gene was detected in 31/50 (62%) of esophageal tumor samples, while two of the adjacent normal mucosa were methylated (P < 0.001). <it>p16</it>^{<it>INK4a </it>}aberrant methylation was significantly associated with decreased <it>p16 </it>protein expression (P = 0.033), as well as the overexpression of <it>p53 </it>(P = 0.020).</p> <p>Conclusions</p> <p><it>p16 </it>hypermethylation is the principal mechanism of <it>p16 </it>protein underexpression and plays an important role in ESCC development. It is associated with p53 protein overexpression and may influence the accumulation of abnormally expressed proteins in <it>p53-MDM2 </it>and <it>p16-Rb </it>pathways, suggesting a possible cross-talk of the involved pathways in ESCC development.</p

Urinary Calcium Excretion in Healthy Children Living in Kashan/ Iran

Objective: Urinary calcium excretion is different in various geographical regions. Therefore, we decided to evaluate the urinary calcium excretion in pediatric inhabitants of residential districts in the Desert of Iran and to determine the frequency of hypercalciuria. Methods: This study was carried out from 2004 to 2005 on healthy children aged 7-12 years in Kashan (Central Desert of Iran). By proportional cluster sampling 95 rural and 305 urban cases were selected. The second non fasting morning urine sample was collected for measuring sodium, creatinine and calcium. Children whose urine calcium to creatinine ratio was more than 0.2 and urine sodium more than 200 meq/l were considered as hypercalciuric and hypernatriuric. Water samples were collected by health worker from 9 regions of the city and 9 villages for chemical analysis. The differences between frequencies were assessed by chi square test. P values less than 0.05 were considered significant. Findings: A total of 362 (175 females, 187 males) with a mean age of 9.5 (±1.4) years were studied. Mean urinary calcium/creatinine concentration ratio was 0.2 (±0.17). The 95th percentile value for urine calcium/creatinine concentration was 0.53 and prevalence of hypercalciuria was found as 37.8%. The contents of water were similar in Kashan city and the villages, only the mean of total water density was higher in water supply of the city (P<0.05). By regression analysis we found only direct but weak correlation between urine calcium and urine sodium excretion (r=0.37, P=0.0001). Conclusion: Urinary calcium excretion is high in desert of Kashan; thus it is important to conduct more studies to determine the risk factors and its untoward effect such as nephrolithiasis

Development and validation of the first iranian questionnaire to assess quality of life in patients with heart failure: IHF-QoL

Background: In its Constitution of 1948, WHO defined health as “a state of complete physical, mental, and social well-being, and not merely the absence of disease and infirmity” . In 1994, the Agency for Health Care Policy and Research published clinical practice guidelines recommending providers to routinely evaluate patients' HRQoL (Health Related Quality of Life) and use their assessment to modify and guide patient care. Objectives: to create a valid, sensitive, disease-specific Persian health status quality of life questionnaire for patients with chronic heart failure in Iran. Materials and Methods: Considering the existing relevant inventories and scientific literature, the authors designed the first draft of questionnaire which was modified and validated, using expert opinions and finalized in a session of expert panel. The questionnaire was processed among 130 patients with heart failure. Construct validity evaluated by principle component factor analysis, and promax method was used for factor rotation. MacNew quality of life questionnaire was selected to assess convergence validity, and the agreements were measured in 60 patients. Discriminant validity was also assessed. Thirty patients were followed for 3 months and responsiveness of questionnaire was measured. Cronbach's alpha, item analysis, and Intra-class correlation coefficients (ICCs) were used to investigate reliability of questionnaire. SPSS 15 for Windows was applied for statistical analysis. Results: Principle component factor analysis revealed 4 main components. Sub-group analysis suggested that IHF-QoL questionnaire demonstrated an acceptable discriminant validity. High conformity between this inventory and MacNew questionnaire revealed an appropriate convergence validity. Cronbach's alpha (α) for the overall questionnaire was equal to 0.922. Intra-class correlation coefficients (ICCs) for all components were significant (from. 708 to. 883; all P values < 0.001). Patients fallow-up revealed an acceptable responsiveness of our questionnaire. Conclusions: IHF-QoL questionnaire is a valid and reliable inventory. It can be applied in daily clinical practice and in the clinical research context

Insulin resistance in pulmonary arterial hypertension, is it a novel disease modifier?

Background: Recent studies have introduced glucose intolerance and insulin resistance (IR) as novel risk factors in patients with pulmonary arterial hypertension (PAH). Objectives: We aimed to investigate the prevalence of glucose intolerance and IR in patients with PAH and their correlation with functional capacity and prognostic factors. Patients and Methods: Sixty-nine patients with pulmonary arterial hypertension (class I Pulmonary hypertension in accordance with updated clinical classification of pulmonary hypertension) scheduled for right heart catheterization were enrolled. FBS, HbA1c, lipid profile, pro .BNP and hs-CRP were measured along with a 6-minute walk test (6-MWT) and obtaining demographic, functional and hemodynamic data. Fasting triglyceride to high-density lipoprotein cholesterol ratio (TG/HDL-C) was used as a surrogate of insulin sensitivity. Using published criteria, HbA1c ≤ 5.9% defined as normal, 6.0-6.4% as glucose intolerance, and ≥ 6.5% as diabetes. All patients were followed for a year regarding development of any cardiovascular event (mortality and/or hospitalization). Results: In total, 76.8% of patients were female: 61% of them had idiopathic PAH, 33% Eisenmenger syndrome, and 6% PAH secondary to a connective tissue disease. With respect to TG/HDL-C, 43.5% of patients had IR and 47.8% of patients had HbA1c > 6. There was no difference between IR and insulin sensitive (IS) group or glucose intolerance and sensitive group regarding NYHA class, 6MWT, Pro BNP, hs-CRP and hemodynamic data and there was no correlation between IR or glucose intolerance and any event. Conclusions: Unrecognized glucose intolerance and IR are common in PAH. However, further studies are needed to show whether glucose or insulin dysregulation plays any role in PAH pathogenesis or it is secondary to advanced PAH

The Incidence of Intravascular Needle Entrance during Inferior Alveolar Nerve Block Injection

&lt;p&gt;&lt;strong&gt;&lt;em&gt;Background and aims&lt;/em&gt;&lt;/strong&gt;&lt;strong&gt;&lt;em&gt;.&lt;/em&gt;&lt;/strong&gt; Dentists administer thousands of local anesthetic&lt;sup&gt; &lt;/sup&gt;injections every day. Injection to a highly vascular area such as pterygomandibular space during an inferior alveolar nerve block has a high risk of intravascular needle entrance. Accidental intravascular injection of local anesthetic agent with vasoconstrictor may result in cardiovascular and central nervous system toxicity, as well as tachycardia and hypertension. There are reports that indicate aspiration is not performed in every injection. The aim of the present study was to assess the incidence of intravascular needle entrance in inferior alveolar nerve block injections.&lt;/p&gt; &lt;p&gt;&lt;strong&gt;&lt;em&gt;Materials and methods. &lt;/em&gt;&lt;/strong&gt;Three experienced oral and maxillofacial surgeons performed 359 inferior alveolar nerve block injections using direct or indirect techniques, and reported the results of aspiration. Aspirable syringes and 27 gauge long needles were used, and the method of aspiration was similar in all cases. Data were analyzed using &lt;em&gt;t&lt;/em&gt;-test.&lt;/p&gt; &lt;p&gt;&lt;strong&gt;&lt;em&gt;Results&lt;/em&gt;&lt;/strong&gt;&lt;strong&gt;.&lt;/strong&gt; 15.3% of inferior alveolar nerve block injections were aspiration positive. Intravascular needle entrance was seen in 14.2% of cases using direct and 23.3% of cases using indirect block injection techniques. Of all injections, 15.8% were intravascular on the right side and 14.8% were intravascular on the left. There were no statistically significant differences between direct or indirect block injection techniques (P = 0.127) and between right and left injection sites (P = 0.778).&lt;/p&gt; &lt;p&gt;&lt;strong&gt;&lt;em&gt;Conclusion.&lt;/em&gt;&lt;/strong&gt; According to our findings, the incidence of intravascular needle entrance during inferior alveolar nerve block injection was relatively high. It seems that technique and maneuver of injection have no considerable effect in incidence of intravascular needle entrance. &lt;/p&gt

Central giant cell granuloma of the posterior maxilla: a case report

Central giant cell granuloma (CGCG), formerly called giant cell reparative granuloma, is a non-neoplastic proliferative lesion of unknown etiology. It occurs most commonly in the mandible. The case reported here resembled a wide variety of conditions that led to a misdiagnosis both on clinical and radiographic examinations but was histopathologically diagnosed as CGCG. We describe a case of CGCG arising from the posterior maxilla to highlight the importance of histopathology in the diagnosis of this enigmatic lesion

Hyper-prolactinemia in men with idiopathic dilated cardiomyopathy: Does it have any prognostic implications?

Background: Prolactin (PRL) has increasingly been recognized to play a stimulatory role in inflammatory response. Recently, studies have reported an increase in prolactin level among patients with chronic heart failure, however, there is conflicting data about its role as a prognostic factor in these patients. Objectives: We aimed to measure PRL level in male patients with idiopathic dilated cardiomyopathy (IDC) and its relationship with some prognostic factors. Patients and Methods: Serum prolactin level was assessed in 33 men with a diagnosis of IDC, left ventricle ejection fraction (LVEF) less than 35% on standard medical therapy for heart failure and New York Heart Association class II-III. Serum NT-Pro BNP (N terminal pro brain natriuretic peptide), hs-CRP (High sensitive C reactive protein) and six-minute walk test (6MWT) were also measured. Our secondary endpoints were mortality, transplantation and hospitalization due to acute heart failure and all patients were followed for one year. Results: The mean age was 33 ± 7 years (24-45 years) and the mean LVEF was 23% ± 6.5. The mean PRL level was 16 ± 7.7 ng/mL (95% confidence interval: 13.3-18.7 ng/mL), which was significantly higher than normal reference values (4.04-15 ng/mL) (P < 0.0001). There was no correlation between PRL levels and pro BNP, hs-CRP or 6MWT test, however, the serum PRL level was slightly higher among patients who died or were hospitalized or transplanted. Conclusions: Considering our study results, prognostic implication of PRL should be questioned. However, it seems that the significant increase in serum PRL in the study population needs more consideration and may have its own pathophysiologic importance. Further studies are recommended for better addressing the role of PRL in chronic heart failure patients