835 research outputs found
Investigation of the effects of constant darkness and light on blood serum cholesterol, insulin and glucose levels in healthy male rats
This study was designed to investigate the effects of constant darkness and light on changes of serum cholesterol, insulin and glucose levels in healthy male rats. In this study, healthy male rats (n = 30) were divided into 3 groups of tens and kept at various light/dark conditions: Control 12:12 light/dark (LD); constant darkness (DD), and constant light (LL) groups for 2 weeks. Blood samples were obtained from retro-orbital sinus before start of experiment and on the 7th and 14th days of the experimental period. The serum cholesterol and glucose levels were measured by the enzymatic method and insulin levels were measured using insulin kit by enzyme-linked immunosorbent assay (ELISA) method. The results of the study showed that the levels of serum cholesterol and glucose on the 7th and 14th days of the experimental period in DD group significantly decreased compared to the LD and LL groups (p < 0.05). On the 14th day of experiment, we observed significant decrease of serum insulin level in the constant darkness group compared with the two other groups (p < 0.05). The study showed that on the 7th and 14th days of experiment, constant light significantly increased serum glucose level without having any significant effects on serum cholesterol and insulin levels. Also, the long period of time (14 days) was found to be more effective in the serum of these metabolic parameters changes than the short period (7 days).Key words: Constant darkness, light, cholesterol, glucose, insulin, healthy male rats
Bifurcation in nonlinearizable eigenvalue problems for ordinary differential equations of fourth order with indefinite weight
Early experience with the ARTISENTIAL® articulated instruments in laparoscopic low anterior resection with TME
Background: The notion of articulation in surgery has been largely synonymous with robotics. The ARTISENTIAL® instruments aim at bringing advanced articulation to laparoscopy to overcome challenges in narrow anatomical spaces. In this paper, we present first single-center results of a series of low anterior resections, performed with ARTISENTIAL®. Methods: Between September 2020 and August 2021, at the Department of Surgery, St. Marienkrankenhaus Siegen, Siegen, Germany, patients with cancer of the mid- and low rectum were prospectively enrolled in a pilot feasibility study to evaluate the ARTISENTIAL® articulated instruments in performing a laparoscopic low anterior resection. Perioperative and short-term postoperative data were analyzed. Results: Seventeen patients (10 males/7 females) were enrolled in this study. The patients had a median age of 66 years (range 47–80 years) and a median body mass index of 28 kg/m2 (range 23–33 kg/m2). The median time to rectal transection was 155 min (range 118–280 min) and the median total operative time was 276 min (range 192–458 min). The median estimated blood loss was 30 ml (range 5–70 ml) and there were no conversions to laparotomy. The median number of harvested lymph nodes was 15 (range 12–28). Total mesorectal excision (TME) quality was ‘good’ in all patients with no cases of circumferential resection margin involvement (R0 = 100%). The median length of stay was 9 days (range 7–14 days). There were no anastomotic leaks and the overall complication rate was 17.6%. There was one unrelated readmission with no mortality. Conclusions: Low anterior resection with ARTISENTIAL® is feasible and safe. All patients had a successful TME procedure with a good oncological outcome. We will now seek to evaluate the benefits of ARTISENTIAL® in comparison with standard laparoscopic instruments through a larger study
Electron-phonon renormalization of the absorption edge of the cuprous halides
Compared to most tetrahedral semiconductors, the temperature dependence of
the absorption edges of the cuprous halides (CuCl, CuBr, CuI) is very small.
CuCl and CuBr show a small increase of the gap with increasing
temperature, with a change in the slope of vs. at around 150 K: above
this temperature, the variation of with becomes even smaller. This
unusual behavior has been clarified for CuCl by measurements of the low
temperature gap vs. the isotopic masses of both constituents, yielding an
anomalous negative shift with increasing copper mass. Here we report the
isotope effects of Cu and Br on the gap of CuBr, and that of Cu on the gap of
CuI. The measured isotope effects allow us to understand the corresponding
temperature dependences, which we also report, to our knowledge for the first
time, in the case of CuI. These results enable us to develop a more
quantitative understanding of the phenomena mentioned for the three halides,
and to interpret other anomalies reported for the temperature dependence of the
absorption gap in copper and silver chalcogenides; similarities to the behavior
observed for the copper chalcopyrites are also pointed out.Comment: 14 pages, 5 figures, submitted to Phys. Rev.
Prognostic resources of mineral deposits by geophysical methods
In the framework of non-equilibrium statistical thermodynamics a relation between the concentration of component of the ore to its physical properties.On the basis of this communication formulas for calculation of the differentiated and predicted stocks of deposits of minerals are received on the basis of the geophysical data. Methods of magnetic investigation, electric investigation, gravitational investigation and seismic prospecting, and also nuclear physical methods are considered. A comparison of the calculated expected resources with proven for a number of fields in Kazakhstan.
The proposed method allows to perform predictive assessment of stocks of deposits in the early stages of prospects with using the results of geophysical methods, while it has a rapidity and to be sufficiently accurate.
Non-equilibrium thermodynamics, geophysical methods, and estimated resources, deposits of minerals
Laparoscopic radical prostatectomy with sparing of the proximal prostatic urethra
Introduction. The most common treatment option for prostate cancer is radical prostatectomy, which involves the removal of the prostate itself and the prostatic urethra in a single block, followed by the formation of a vesicourethral anastomosis. This approach is fraught with postoperative complications, such as urinary incontinence and strictures of anastomosis. In this sense, the clinic's staff faced the question of the possibility of a urethral-sparing variant of operative benefit for a certain category of patients.Objective. To assess the possibility of performing radical prostatectomy with sparing of the proximal prostatic urethra in the laparoscopic version, its advantages, and disadvantages.Materials & methods. From 2021 to 2022, 18 successful laparoscopic operations were performed using this technique at the St. Luke Clinical Multidisciplinary Medical Centre. Patients were selected according to the above criteria. In the preoperative period, patients underwent a standard examination in accordance with guidelines, including a blood test for prostate-specific antigen (PSA), ultrasound, magnetic resonance imaging (MRI) with 3D-modelling, data from a multifocal prostate biopsy, the International Prostate Symptom Score (IPSS), the International Index of Erectile Function (IIEF), the Quality of Life (QoL) index due to urinary disorders, assessment by the Partin’s nomogram. Intraoperative ratios, early and late postoperative complications, length of hospital stay, day of catheter removal, and time to complete urethral recovery were evaluated to study the effectiveness of this surgery type. PSA testing, uroflowmetry with post-void residual urine measurement and IPSS questionnaire were carried out one month after surgery.Results. There was an improvement in all measurements one month after surgery: median values of the mean urine flow rate increased by 1.7 ml/s, median values of the max urine flow rate increased by 3.7 ml/s, the IPSS decreased by 12 points.Conclusion. Based on the results of the study, clinical observations, and statistical analysis of the data obtained, it can be concluded that laparoscopic radical prostatectomy with sparing of the proximal prostatic urethra is the preferred surgical option for this pathology, due to its organ-preserving nature
Study on the Structure and Morphology of Iron Nanopowders Obtained by the Method of Electric Explosion of Wires
This article presents the results of comprehensive study on the structure and morphology of iron nanopowders synthesized by electric explosive evaporation of metal wire. The results of scanning and transmission electron microscopy showed that nanoclusters have a spherical shape with an average diameter of 65 nm. It was revealed based on the analysis of the diffraction patterns that nanoparticles of nanopowders obtained in electric explosion have a crystal lattice with a parameter less than a standard cell. The results of computer experiments are in good agreement with the findings of X-ray analysis. However, the question about the reasons of distortion of the crystal lattice of nanoclusters remains controversial
Synthesis of Carbon Nanofibers on Copper Nanopowders by Low-Temperature CVD
The article presents the results of experiments on the synthesis of carbon nanofibers by thermal chemical vapor deposition using copper nanopowders obtained by electric explosion of wire as catalysts. Stable growth of carbon nanofibers was carried out at temperatures significantly lower than normally used. The process parameters that are optimal for low-temperature growth of carbon nanofibers have been identified during the performed experiments. The synthesized samples have different diameters and morphology (from spiral to direct). Copper clusters are both at the ends and inside the fibers. The results of IR spectroscopy indicate that the structure of the obtained carbon nanofibers is polymeric. X-ray analysis revealed the presence of a halo on the diffraction patterns at small values of the angle 2θ, which proves that the grown structures have an amorphous nature. There are no groups that are responsible for long-range order in all Raman spectra. Studies by transmission electron microscopy showed that nanostructures do not have an internal channel and nanofibers are solid
Investigation of SiC and C Nanostructures Obtained by MWCVD
The results of experiments on the synthesis of SiC and C nanostructures by chemical vapor deposition in microwave plasma are presented in this article. The single crystal silicon plates with orientations [100] and [111] which previously passed chemical purification were used as substrates. Also, the substrates of porous silicon were prepared in order to activate the surface during the synthesis. The synthesis temperature ranged from 700 to 900 °C in steps of 100 °C. The pressure in the chamber was changed depending on the power of the plasma. Studies by scanning electron microscopy (SEM) showed that formed nanostructures have a diameter of 200‒350 nm and a rough surface. The formation of nanostructures on the polished Si occurs on the SiC buffer layer. Analysis of SEM images of the samples shows that growth of NS on the surface of porous silicon is more widespread in contrast to the polished Si. The results of X-Ray spectral microanalysis showed that the carbon content in samples of nanostructures on polished Si varies from 10 to 20% and remains constant on porous silicon ~ 25%. The results of studies by Raman scattering confirmed that SiC film with structure of 3C-SiC is formed on the polished Si. Besides, the presence of main carbon peaks on both types of substrates in the range of 1338.2 and 1583 cm‒1 should be noted, which correspond to the carbon nanostructures
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