In this paper, a novel methodology of PV modeling is proposed to represent the instantaneous electrical characteristics of PV modules covered with snow. The attenuation of the transmitted solar radiation penetrating a layer of snow is rigorously estimated based on the Giddings and LaChapelle theory. This theory introduced the level of radiation that reaches the surface of PV module through snowpack, significantly affected by the snow properties and thickness. The proposed modeling approach is based on the single-diode-five-parameter equivalent circuit model. The parameters of the model are updated through instantaneous measurements of voltage and current that are optimized by the particle swarm optimization algorithm. The proposed approach for modeling snow-covered PV modules was successfully validated in outdoor tests using three different types of PV module technologies typically used in North America's PV farms under different cold weather conditions. In addition, the validity of the proposed model was investigated using real data obtained from the SCADA system of a 12-MW grid-connected PV farm. The proposed model can help improving PV performance under snow conditions and can be considered a powerful tool for the design and selection of PV modules subjected to snow accretion.

Background and Objectives: Romania faces one of the highest cervical cancer burdens in Europe though it is a preventable cancer through population screening by cytology and human papillomavirus (HPV) detection. Also, it has one of the highest incidences of human immunodeficiency virus (HIV) infection. HPV and HIV coinfection are frequently encountered. The aim of study was to establish the prevalence of HPV infection among HIV-positive women in Southeast Region of Romania, to genotype high risk HPV types -and to correlate the results with clinical data and cytological cervical lesions. Materials and Methods: 40 HIV-positive women were screened for HPV types and for cytological cervical lesions. The findings were evaluated in correlation with CD4 cell counts, HIV viral load, age at first sexual intercourse, number of sexual partners, vaginal candidiasis, and Gardnerella using statistical methods. Results: 19/40 (47.5%) women were positive for HPV types, 63.15%infected with single HPV type and 36.85%with multiple HPV types. The most frequent types were type: 31 (42.1%), 56 (31.57%), 53 (15.78%). On cytology, 34 (85%) women were found with NILM of which 38.23% were HPV-positive. Fifteen percent of women had abnormal cytology (three ASC-US, three LSIL), and all of them were HPV-positive. Through analyzing the value of CD4 count, women with CD4 count ≤200 cells/μL were found to be significantly more likely to be infected with HPV; meanwhile there was no correlation between the detection of HPV types and HIV viral load. Candida or Gardnerella were more often associated with HIV-positive women with HPV, than in women without HPV. Conclusions: Infection with HPV types is common among HIV-positive women in the Southeast Region of Romania and it is associated with age at the beginning of sexual life, number of sexual partners, CD4 value, vaginal candidiasis, and Gardnerella infection.

Adult low-grade gliomas are a rare and aggressive pathology of the central nervous system. Some of their characteristics contribute to the patient’s life expectancy and to their management. This study aimed to characterize and identify the main prognostic factors of low-grade gliomas. The six-year retrospective study statistically analyzed the demographic, imaging, and morphogenetic characteristics of the patient group through appropriate parameters. Immunohistochemical tests were performed: IDH1, Ki-67, p53, and Nestin, as well as FISH tests on the CDKN2A gene and 1p/19q codeletion. The pathology was prevalent in females, with patients having an average age of 56.31 years. The average tumor volume was 41.61 cm3, producing a midline shift with an average of 7.5 mm. Its displacement had a negative impact on survival. The presence of a residual tumor resulted in decreased survival and is an independent risk factor for mortality. Positivity for p53 identified a low survival rate. CDKN2A mutations were an independent risk factor for mortality. We identified that a negative prognosis is influenced by the association of epilepsy with headache, tumor volume, and immunoreactivity to IDH1 and p53. Independent factors associated with mortality were midline shift, presence of tumor residue, and CDKN2A gene deletions and amplifications.

Grade 4 adult gliomas are IDH-mutant astrocytomas and IDH-wildtype glioblastomas. They have a very high mortality rate, with survival at 5 years not exceeding 5%. We aimed to conduct a clinical imaging and morphogenetic characterization of them, as well as to identify the main negative prognostic factors that give them such aggressiveness. We conducted a ten-year retrospective study. We followed the clinical, imaging, and morphogenetic aspects of the cases. We analyzed immunohistochemical markers (IDH1, Ki-67, and nestin) and FISH tests based on the CDKN2A gene. The obtained results were analyzed using SPSS Statistics with the appropriate parameters. The clinical aspects representing negative prognostic factors were represented by patients’ comorbidities: hypertension (HR = 1.776) and diabetes mellitus/hyperglycemia (HR = 2.159). The lesions were mostly supratentorial, and the temporal lobe was the most affected. The mean volume was 88.05 cm3 and produced a midline shift with an average of 8.52 mm. Subtotal surgical resection was a negative prognostic factor (HR = 1.877). The proliferative index did not influence survival rate, whereas CDKN2A gene mutations were shown to have a major impact on survival. We identified the main negative prognostic factors that support the aggressiveness of grade 4 gliomas: patient comorbidities, type of surgical resection, degree of cell differentiation, and CDKN2A gene mutations.