THE IMPACT OF LHP POSITION TO REMOVE WASTE HEAT FROM THE POWER COMPONENTS

Given the rapid progress in the electronics industry, the thermal management of electronics components becomes an important and serious issue. Natural and forced cooling are often deficient. One possibility for heat dissipation for high heat flux is using loop heat pipe. A loop heat pipe (LHP) is a two-phase device with extremely high effective thermal conductivity that utilizes pressure difference in wick to circulate working fluid. It was invented in Russia in the early 1980’s. LHP is composed by an evaporator, a condenser, a compensation chamber (reservoir) and a vapor and liquid lines. Only the evaporator and part of the compensation chamber are equipped with a wick structure. The use of the wick structure in the evaporator provides a stable physical interface between the liquid and the vapor phases in the LHP. This work deals with the design of LHP for cooling of Insulated gate bipolar transistor and impact of tilt angle of LHP on temperature of transistor. The LHP position is changed from the vertical position (90°) to the horizontal position (0°) during the measurement. The LHP evaporator is made up with copper pipe and alumina saddle. Inside of the evaporator is wick structure and it is made from copper powder. The condenser is made as a tube heat exchanger. The water temperature for cooling is set at 20°C and it is regulated by a thermostat. The temperatures are measured with the thermocouples. As the working fluid was used distilled water. The maximum permissible temperature of transistor is 100°C

The G protein-coupled estrogen receptor 1 (GPER/GPR30) does not predict survival in patients with ovarian cancer

<p>Abstract</p> <p>Background</p> <p>Even though ovarian tumors are not generally considered estrogen-sensitive, estrogens may still have an impact on ovarian tumor progression. The recently identified trans-membrane estrogen receptor GPER is involved in rapid estrogen signaling. Furthermore, it binds selective estrogen receptor modulators with agonistic effect, which could explain tamoxifen controversies.</p> <p>Methods</p> <p>GPER mRNA was assayed with quantitative real-time PCR (qPCR) in 42 primary ovarian tumors and 7 ovarian cancer cell lines. ERα and ERβ mRNA were analyzed for comparison. GPER protein was semi-quantified with densitometric scanning of Western blots and its tissue distribution analyzed with immunohistochemistry (IHC) in 40 ovarian tumors. In addition, IHC was evaluated in a tissue microarray (TMA) of 150 primary malignant ovarian tumors.</p> <p>Results</p> <p>All tumor samples contained GPER mRNA. The content of mRNA was not different between benign and malignant tumors, but one third of malignant samples over-expressed GPER mRNA. The content of ERα mRNA was higher in malignant than in benign tumors, whereas ERβ mRNA was higher in benign than in malignant tumors. GPER mRNA was detected in all seven ovarian cancer cell lines with highest levels in TOV21G and TOV112D cells. Similar expression pattern was seen for ERβ mRNA. Western blot demonstrated GPER protein in all tumor samples. Semi-quantification showed no difference between benign and malignant tumors, but about one third of malignant samples over-expressed GPER protein. GPER staining was localized mainly in epithelial cells. In the TMA study we found no correlation between GPER staining and clinical stage, histological grade or patient survival.</p> <p>Conclusions</p> <p>GPER mRNA as well as GPER protein is present in both benign and malignant ovarian tumor tissue. About one third of malignant tumors over-expressed both GPER mRNA and protein. This, however, correlated neither with histological or clinical parameters nor with patient survival.</p

Normalizing to GADPH jeopardises correct quantification of gene expression in ovarian tumours – IPO8 and RPL4 are reliable reference genes

BACKGROUND: To ensure a correct interpretation of results obtained with quantitative real-time reverse transcription-polymerase chain reaction (RT-qPCR), it is critical to normalize to a reference gene with stable mRNA expression in the tissue of interest. GADPH is widely used as a reference gene in ovarian tumour studies, although lacking tissue-specific stability. The aim of this study was to identify alternative suitable reference genes for RT-qPCR studies on benign, borderline, and malignant ovarian tumours. METHODS: We assayed mRNA levels for 13 potential reference genes – ABL1, ACTB, CDKN1A, GADPH, GUSB, HPRT1, HSP90AB, IPO8, PPIA, RPL30, RPL4, RPLPO, and TBP –with RT-qPCR in 42 primary ovarian tumours, using commercially pre-designed RT-qPCR probes. Expression stability was subsequently analysed with four different statistical programs (GeNorm, NormFinder, BestKeeper, and the Equivalence test). RESULTS: Expression of IPO8, RPL4, TBP, RPLPO, and ACTB had the least variation in expression across the tumour samples according to GeNorm, NormFinder, and BestKeeper. The Equivalence test found variation in expression within a 3-fold expression change between tumour groups for: IPO8, RPL40, RPL30, GUSB, TBP, RPLPO, ACTB, ABL1, and CDKN1A. However, only IPO8 satisfied at a 2-fold change as a cut-off. Overall, IPO8 and RPL4 had the highest, whereas GADPH and HPRT1 the lowest expression stability. Employment of suitable reference genes (IPO8, RPL4) in comparison with unsuitable ones (GADPH, HPRT1), demonstrated divergent influence on the mRNA expression pattern of our target genes − GPER and uPAR. CONCLUSIONS: We found IPO8 and RPL4 to be suitable reference genes for normalization of target gene expression in benign, borderline, and malignant ovarian tumours. Moreover, IPO8 can be recommended as a single reference gene. Neither GADPH nor HPRT1 should be used as reference genes in studies on ovarian tumour tissue

Identification of a novel RPGR mutation associated with retinitis pigmentosa and primary ciliary dyskinesia in a Slovak family: a case report

BackgroundThe mutations in the RPGR (retinitis pigmentosa GTPase regulator) gene are the most common cause of X-linked retinitis pigmentosa (XLRP), a rare genetic disorder affecting the photoreceptor cells in the retina. Several reported cases identified this gene as a genetic link between retinitis pigmentosa (RP) and primary ciliary dyskinesia (PCD), characterised by impaired ciliary function predominantly in the respiratory tract. Since different mutations in the same gene can result in various clinical manifestations, it is important to describe a correlation between the gene variant and the observed phenotype.MethodsTwo young brothers from a non-consanguineous Slovak family with diagnosed retinal dystrophy and recurrent respiratory infections were examined. Suspected PCD was diagnosed based on a PICADAR questionnaire, nasal nitric oxide analysis, transmission electron microscopy, high-speed video microscopy analysis, and genetic testing.ResultsWe identified a novel frameshift RPGR mutation NM_001034853: c.309_310insA, p.Glu104Argfs*12, resulting in a complex X-linked phenotype combining PCD and RP. In our patients, this mutation was associated with normal ultrastructure of respiratory cilia, reduced ciliary epithelium, more aciliary respiratory epithelium, shorter cilia, and uncoordinated beating with a frequency at a lower limit of normal beating, explaining the clinical manifestation of PCD in our patients.ConclusionThe identified novel pathogenic mutation in the RPGR gene expands the spectrum of genetic variants associated with the X-linked PCD phenotype overlapping with RP, highlighting the diversity of mutations contributing to the disorder. The described genotype–phenotype correlation can be useful in clinical practice to recognise a broader spectrum of PCD phenotypes as well as for future research focused on the genetic basis of PCD, gene interactions, the pathways implicated in PCD pathogenesis, and the role of RPGR protein for the proper functioning of cilia in various tissues throughout the body

G protein-coupled estrogen receptor 1 (GPER) in the female reproductive tract: from physiology to cancer

Estrogen effects are mediated either through genomic action involving the classical estrogen receptors, estrogen receptor alpha (ERα) and beta (ERß), which function as transcription factors in the nucleus, or through rapid non-genomic action via receptors associated with plasma membrane. Recently, a member of the G protein-coupled receptor family was ascribed estrogen receptor properties and proposed as a candidate for mediating non-genomic estrogen signaling. G protein-coupled estrogen receptor, GPER, has a high affinity for estrogen and signals via various mitogenic pathways. The present studies have analyzed GPER mRNA and protein in estrogen sensitive tissues, such as normal endometrium from different phases of the menstrual cycle, early pregnancy decidua, endometrial hyperplasia, endometrial cancer, and ovarian tumors using real-time reverse transcription-polymerase chain reaction (RT-qPCR), in situ hybridization, Western blot, immunohistochemistry, and immune transmission electron microscopy. Endometrial GPER mRNA, mainly localized in glandular epithelial cells, was higher in the proliferative phase than in the secretory phase and early pregnancy decidua. In contrast, GPER protein had no cyclical variations. Compared to normal proliferative endometrium, atypical hyperplasia and endometrial cancer had reduced levels of GPER mRNA, whereas GPER protein was increased. The pattern of GPER gene expression in normal endometrium, hyperplasia, and cancer resembled that of ERα. GPER protein was detected in the plasma membrane, endoplasmic reticulum, mitochondria, filaments, and cytosolic vesicles of endometrial cells. A shift in the subcellular distribution from the endoplasmic reticulum to the plasma membrane was observed in the pathological endometrial cells. About one-third of malignant ovarian tumors had significant expression of GPER protein, but patient survival was not affected by GPER expression. GPER mRNA expression profile between ovarian tumor groups resembled that of ERα, but not that of ERß. IPO8 and RPL4 were identified as suitable reference genes for the normalization of target gene expression in RT-qPCR studies of ovarian tumors. We have described GPER expression in tissues, which have not been explored previously. GPER seems to be linked to proliferation in some conditions, possibly in collaboration with ERα. We have identified new subcellular localizations of GPER and differences in its distribution between normal and pathological cells, which open up for new insights into GPER function

Association of Circulating miRNA Expression with Preeclampsia, Its Onset, and Severity

MicroRNAs (miRNAs) are one of the important regulators of cellular functions fundamental for healthy pregnancy processes, including angiogenesis and differentiation of trophoblast cells, and their deregulation could be implicated in the pathogenesis of pregnancy complications, including preeclampsia (PE). The aim of this study was to assess the association of miRNA expression in plasma samples with PE, its onset, and severity. Our study enrolled 59 pregnant women, 27 in the preeclamptic study group and 32 in the control group with physiological pregnancy. Preeclamptic pregnancies were divided into subgroups based on the severity and onset of disease. Relative expression of miR-21-5p, miR-155-5p, miR-210-5p, miR-16-5p, and miR-650 isolated from plasma samples was analysed by quantitative real-time PCR and normalised to experimentally established reference genes. Our results revealed upregulation of miR-21-5p (1.16-fold change, p = 0.0015), miR-155-5p (1.62-fold change, p = 0.0005) in preeclamptic pregnancies, compared to controls. Overexpression of these two miRNAs was observed, especially in subgroups of severe and late-onset PE compared to healthy pregnancies. Although we hypothesised that the expression level of studied miRNAs could vary between PE subtypes (mild vs. severe, early onset vs. late-onset), no obvious differences were detected. In conclusion, our study could contribute to the large-scale studies for the identification of non-invasive biomarkers for PE detection to improve outcomes for women and their new-borns

G protein-coupled estrogen receptor 1 (GPER, GPR 30) in normal human endometrium and early pregnancy decidua.

The recently identified trans-membrane G protein-coupled estrogen receptor 1 (GPER, GPR30) has been implicated in rapid non-genomic effects of estrogens. This focusses on expression and localization of GPER mRNA and protein in normal cyclic endometrium and early pregnancy decidua. Real-time PCR, Western blotting, in situ hybridization, and immuno-histochemistry were used. Endometrial expression of GPER mRNA was lower in the secretory phase than in the proliferative phase , and even lower in the decidua. The expression pattern was similar to that of ERalpha mRNA, but different from that of ERss mRNA. Western blot detected GPER protein as a 54 kDa band in all endometrial and decidual samples. In contrast to the mRNA, GPER protein did not show cyclic variations. Apparently, a lower amount of mRNA is sufficient to maintain protein levels in the secretory phase. GPER mRNA was predominantly localized in the epithelium of mid and late proliferative phase endometrium, whereas expression in early proliferative and secretory glands could not be distinguished from the diffuse stromal signal, which was present throughout the cycle. Immuno-staining for GPER was stronger in glandular and luminal epithelium than in the stroma throughout the cycle. The cyclic variations of GPER mRNA obviously relate to strong epithelial expression in the proliferative phase, and the expression pattern suggests regulation by ovarian steroids. GPER protein is present in endometrial tissue throughout the cycle, and the epithelial localization suggests potential functions during sperm migration at midcycle as well as decidualization and blastocyst implantation in the mid-secretory phase

High-temperature reaction of sodium vapour with quartz glass

Heat pipes are one of the most efficient ways to transfer thermal energy hundred times more efficiently than copper. In this work, we present the investigation of sodium terminal velocity inside a glass pulsating heat pipe. Velocity measurements were conducted under operating conditions within the range of 500 – 1 100 °C. Since sodium is generally able to etch glass and ceramic materials, its presence resulted in glass reduction and sodium oxidation. From the XPS analysis of specimens extracted from a glass pipe after sodium explosion, it can be concluded that the reaction products are sodium oxide Na2O and a thin layer of carbon, which is localized on the SiO2 glass. The character of damage induced by chemical reactions is analysed in this manuscript

Is the Physiological Composition of the Vaginal Microbiome Altered in High-Risk HPV Infection of the Uterine Cervix?

Background: Cervical cancer is the fourth most common malignancy and fourth leading cause of cancer death in women worldwide. More than 99.7% of cases are caused by human papillomavirus (HPV), while HPV types 16 and 18 cause over 70% of all cervical cancer cases. In this preliminary study, we aimed to investigate the presence of HPV infection and diversity of bacteria associated with bacterial vaginosis. Methods: Cervical swabs (n = 21) taken from women aged 21–47 years, in seventeen cases, with different degrees of cervical abnormality, and from four healthy women, were tested for the presence of HPV DNA, as well as the bacterial strains associated with bacterial vaginosis, using the real-time PCR method. Results: HPV16 was the dominant genotype in 53% (9/17) of patients with confirmed precancerous lesions (ASCUS, LSIL, and HSIL). In specimens with confirmed cytological abnormalities and hrHPV infection, we detected a wide diversity of microbes, while the most common species were Gardnerella vaginalis, Atopobium vaginae, Prevotella bivia, Ureaplasma parvum, Ureaplasma urealyticum, Leptotrichia amnionii, Bacteroides ureolyticus, and Sneathia sanguinegens. The presence of pathogens did not differ, depending on the degree of precancerous lesions or HPV type. Conclusion: In our work, HPV16 dominated in patients with cervical precancerous lesions. We also suggest an increased bacterial diversity of the vaginal microbiome in patients with cervical lesions, for which the HPV virus is largely responsible