Search Results

1 - 9 of 9 items

  • Author: Ovidiu Vasile x
  • BY LANGUAGE: English x
Clear All Modify Search

Rezumat

Lucrarea abordează comportarea unui model de solid-rigid cu anumite simetrii structurale. Aceste simetrii permit simplificarea calculelor (ecuaţii de mişcare) şi, deci, a modelelor matematice. Dacă solidul rigid este conectat la structură prin patru legături elastice, modelul rămâne încă simplu şi uşor de rezolvat, vibraţiile putând fi decuplate în patru subsisteme de mişcare.

În final, se prezintă un studiu de caz pentru analiza modală a unui viaduct, modelat precum un corp solid-rigid, rezemat elastic, de pe autostrada Transilvania (km 29+602.75 m).

Abstract

The development and studies related to carbon nanotubes, due to their physical properties and small sizes, are revealing new applications in the medical field. The present paper is proposing a non-invasive method of patient glycemia measurement by mean of carbon nanotubes based sensor. Due to their small sizes and elastic properties, carbon nanotubes are able to oscillate under the weight of small molecules capable of fixing on their body structure. After piezoelectric activation, the carbon nanotubes sensor based, is able to detect the variation of oscillations produced in nanotubes due to acetone molecules diffused through a selectively permeable membrane from the exhaled air, and attached to the nanotubes. The mathematical model taken into accont shows a linear dependence between the concentration of acetone in blood and glycemia, and makes the carbon nanotube sensor suitable for indirect estimation of the glycemia by noninvasive measurements made on the exhaled air sample, providing zero risk for the patient and absence of stress during the measurements.

Abstract

Ovarian cancer is perhaps the most “worst” pathology in women’s genital area and represents the greatest diagnostic challenge and surgical treatment of genital cancers, and as much as the disease has a onset and asymptomatic evolution to the advanced stages or with a confused symptom.

The present study was performed due to the following factors characterizing ovarian cancer: increasing incidence, early diagnosis, lack of screening methods, difficult anatomopathological differentiation even for experienced anatomopathologists.

Abstract

Surgical integration in the overall ovarian cancer protocol is conditioned by the performance it has allowed in cytoreduction, the benefits obtained in the interest of the patients in terms of risk (postoperative mortality, severe sequelae, oncology survival criterion at 5 years).

Surgical treatment remains the fundamental technical means in the treatment of ovarian cancer. It is performed either in the “first intention” (the strand: High-Probability Clinical Diagnosis, Extemporaneous Histopathological Examination Surgery, Continued Intervention, Postoperative Adjuvant Treatments: Chemotherapy, Radiotherapy, Immunotherapy, Hormone Therapy, Second-look 6 Months), or in “second intent” (precise histopathological / pelviscopic or classic diagnosis, followed by chemotherapy, radiotherapy, immunotherapy and radical surgery).

Abstract

Objective: Tissue integration of vascular grafts partially depends on the host response to injury, which immediately begins after implantation and restoration of the circulation. In an infected environment, the inflammation changes the incorporation patterns. The aim of the study was to observe the tissue incorporation process, in a normal and an infected environment. Methods: We have created an experimental model by performing subfascial implantation of four types of vascular grafts, in rats (woven Dacron®, knitted Dacron®, silver coated Dacron® and expanded Polytetrafloroethylene - ePTFE) and by infecting some of them with three different bacterial strains. We have retrieved the noninfected grafts at two and four weeks after implantation, whilst the infected ones at one, two and three weeks. Results: Detailed microscopic appearences were analysed. The control and infected groups were compared. Statistical significance was calculated for various corelations. Conclusions: The morphopathological findings showed that the ePTFE graft’s structure was best preserved. Statistical significance existed between the bacterial strain and the degree of inflammation. The silver coated Dacron® was not shown to be superior to the knitted Dacron®. The poorest incorporation was the one of the woven Dacron®.

Abstract

Objective: Starting with the ‘Vinyon-N-revolution’ of the 50’s, there has been a constant interest in understanting tissue integration, or the so-called graft healing process, as well as its relationship with infection. In this study we present an experimental animal model designed to assess tissue integration of different graft materials, and their reaction to the presence of infection.

Methods: Synthetic grafts (knitted Dacron®, woven Dacron®, silver-impregnated Dacron® and Gore-Tex®) were implanted subfascially in the interscapular region of Wistar rats. Animals were divided into a control group and an infected group, with infection induced using bacterial suspensions of standard strains of Staphylococcus aureus, Staphylococcus epidermidis, and Escherichia coli. Implants were retrieved at 2 and 4 weeks postoperatively in the control group and at 1, 2 and 3 weeks postoperatively in theinfected group. Retrieved grafts were assessed bacteriologically and morpho-pathologically.

Results: All microorganisms produced clinically evident infections, with positive blood cultures in case of E. coli. Staphylococci produced more massive infections on Dacron® grafts, except for the silver-impregnated version, while E. coli produced more significant infections on Gore-Tex® grafts. Morpho-pathologically Dacron® grafts behaved poorly, with ocassional complete structural compromise, and no difference between the conventional and the silver-impregnated type. The Gore-Tex® graft showed a consistent structural resistance throughout the study period.

Conclusions: Although the silver-impregnated graft inhibited bacterial growth, it was poorly tolerated by the host tissue. In contrast, Gore-Tex® grafts showed more massive infection, especially with E. coli, but kept their structural integrity surprisingly well.

Abstract

Introduction: In physical and sports education, the effort dosing is essential for achieving the goals and is managed by altering the effort parameters and correlating these with a certain type of rest, respecting the physical norms of the body. According to a study, analyzing and comparison of “The Gauss curve” during a physical education and sport lesson, the expected rising of the effort curve was denied during its first 3 stages. Especially between stage 2 (Preparation of the body for effort) and stage 3 (Selective influence of the locomotive apparatus) there is a decrease of the heart rate. During the sports lessons, we recorded for 10 hours the heart rate of 10 children from 2 different classes of the same grade, 5-A and 5-B, creating one control group (of 5 boys) and one experimental group (5 boys). For the experimental group we recorded for 10 different classes, interchanging stages 2 with 3, more exactly, the stage “Selective influence of the locomotive apparatus” was done before the stage “Preparation of the body for effort”, and for the control group we also recorded for 10 different classes, but they performed the normal sports lesson, following the stages in chronological order.

Objective of the study: The objective of this research was to discover/identify if the effort curve follows an ascendant trajectory during the first 3 stages and a descendant curve during the last 3, by analyzing the heart rate for each stage during the physical education and sports lesson.

Material and methods: The data was collected using 5 - Polar M400 watches and 5 - H7 chest bands, during sport lessons inside the School “Aghiresu Fabricii” from Cluj-Napoca. After the recorded data of the heart rates were analyzed, we observed the differences between the classic sport lesson and the one with the stages 2 and 3 reversed, for the 5th grade subjects.

Results: By comparing the data obtained from the recordings, it was found that there are some differences between the classical physical education lesson and that in which interventions were made in the second and third stages, as a result of the change in heart rate values in the investigated subjects.

Conclusion: Analyzing the two groups in which we had different approaches in the physical education and sports lesson, it is denied that in the classical lesson we have a curve of ascending effort in the first stages. As a result of the reversal of the two-to-three stages, an ascending curve – the Gaussian Curve – is achieved through which an optimal adaptation to effort is made in the fundamental part of the physical education and sports lesson.

Abstract

While the exact relevance of the oxidative stress markers after the complex processes of alcohol withdrawal is still controversial, in the present report we were interested in studying the relevance of oxidative stress status in the alcohol withdrawal processes, by determining some oxidative stress markers after 3, 6 and 12 months of abstinence. 62 patients were selected, all of them males. Thus, 33 (baseline), 14 (3 months), 14 (6 months) and 15 (12 months) patients, while the control group (n=32) included healthy, sex and aged-matched subjects. Regarding superoxid dismutase, we observed a significant group difference (p<0.0001), together with an increase in all 3 cases of time-abstinence, as compared to baseline results: (p<0.0001-3 months), (p<0.0001-6 months) and (p<0.0001- 12 months). Also for glutathione peroxidase, we observed a significant overall effect of the abstinence in our groups (p=0.0003), plus an increase especially at 6 months (p=0.03) and 12 months (p=0.006). Regarding malondialdehyde, as a main marker for the lipid peroxidation processes, we found significant differences between our groups (p<0.0001), together with a decrease in all 3 cases, compared to the baseline group (p=0.003), (p=0.01) and (p=0.0002). In conclusion, this confirms the increased oxidative stress status in alcoholic patients and even more importantly, we showed that there is a significant and progressive decrease in the oxidative stress status at 3, 6 and 12 months after the withdrawal process, as demonstrated by the increased levels of antioxidant enzymes and decreased rate of lipid peroxidation, when compared to baseline values.

Abstract

Background: Although it is generally accepted that there is an increased oxidative stress status in alcoholics, the separate relevance of oxidative stress following alcohol withdrawal is still not understood to this date. There are reports stating that the increased oxidative stress status in alcoholics may persist independently of the constant presence of alcohol intake, while on the other side, it was demonstrated that the antioxidant defense mechanism could significantly increase after alcohol withdrawal.

Methods: In the present work, we were interested in studying the relevance of oxidative stress status in the alcohol withdrawal processes, by determining some oxidative stress markers (two antioxidant enzymes: superoxide dismutase - SOD and glutathione peroxidase - GPX and a lipid peroxidation maker - MDA) after one week and one month of abstinence, as compared to the baseline and a control group of subjects.

Results: Our data confirmed the increased oxidative stress status in alcoholic patients and, more importantly, we de m - onstrated here a significant decrease of the oxidative stress status one week and one month following the withdrawal, as showed by a significant increase in the specific activity of SOD (p<0.003), as well as by a decrease in MDA levels (p<0.019). Still, in the case of all three markers of oxidative stress status which we determined, the levels after one week or one month of abstinence were significantly altered when compared to controls.

Conclusions: This suggests that severe and prolonged deficiency in the oxidative stress marker levels needs longer than one month of abstinence to normalize.