226 research outputs found
Numerical and Rational Analysis of Shotcrete Lining for Rock Tunnels under Effect of Explosion Loads
Tunnels in rock media are considered one of the most important types of fortified structures that can be used to resist the progressive development of military destructive weapons. The geological formation of tunnel rock mass has a great influence on the degree of protection to human and weapons. This protection degree is based mainly on both the utilized system of tunnel lining and the type and quality of rock mass which reduces the effect of wave propagation generated by explosion. Shotcrete lining is one of the most commonly used support system used in tunnel lining. Understanding the dynamic response and damage characteristics of shotcrete lining for rock tunnels due to explosion loads is essential for safe design. The main aim of this paper is to investigate the stresses and displacements of shotcrete lining under blasting loads and the effect of different of rock mass qualities on the wave propagation associated with the explosion. In order to achieve this aim, numerical analysis technique, commercial software package, AUTODYN version 6.1 is used to perform 90 three-dimensional elasto-plastic dynamic models to analyze rock-shotcrete lining interaction. A parametric study was carried out taking into consideration the effect of Rock Mass Rating (RMR), tunnel radius, charge weight and detonation distance. The numerical simulation of explosion in rock mass is extremely demanding, requiring hydrodynamic computer codes, combined with non-linear dynamic codes based on finite elements which is a very complex approach. Therefore, regression analysis is used for statistics prediction of the behavior of shotcrete lining. A rational analysis is conducted to form non-linear equations to predict stresses and displacements of shotcrete lining at tunnel crown based on the results of the parametric study. The suggested equations were used to form design charts for different values of Rock Mass Rating. A comparison between the results of the numerical simulation and rational analysis for the different models showed a good matching
Articular eminence Inclination and its relationship with incisors mesiodistal inclination in skeletal class I occlusion adults with no clinical and radiographic symptoms of TMDs
Articular eminence participates in the functional formation of the posterior guidance of the mandibular movement, it's the anatomical point where functional stresses can result in alteration of the contours of the articular eminence, and its inclination respectively, Hence, orthodontists need to know the relationship between the articular eminence Inclination and the mesiodistal inclination of upper and lower incisors to achieve more stable results of orthodontics treatment. Aim The aim of this research is to investigate the relationship of upper and lower incisors mesiodistal inclination with the inclination of the articular eminence in class I skeletal occlusion in adult subjects with no clinical nor radiographic symptoms of TMDs. Materials and methods: In result of radiographic study and a multistage clinical examination protocol, 46 Caucasian patients with no prior orthodontics treatment were selected (19 males, 27 females) from 16 to 27 years of age with skeletal class I occlusion and no clinical or radiographic signs and symptoms of TMDs. Furthermore, cephalometric evaluating of the Inclination of the articular eminence and the mesiodistal inclination of the incisors was performed; Pearson's Correlation Coefficient was calculated to investigate the relationship of articular eminence Inclination with the mesiodistal inclination of the incisors. Results: no significant relationship between incisors mesiodistal inclination and the articular eminence inclination was found. Conclusions the steepness of the articular eminence appears not to vary with mesiodistal inclination of the incisors in skeletal class I occlusion adults with no clinical and radiographic symptoms of TMDs.
يشارك المنحدر المفصلي في التكوين الوظيفي للقيادة الخلفية لحركة الفك السفلي، إنه النقطة التشريحية حيث تستطيع الإجهادات الوظيفية أن تسبب تغيراً في حواف المنحدر المفصلي وبالتالي تغيراً في ميلانه أيضاً، ومن هنا تنبع أهمية التحقق من وجود علاقة بين ميلان المنحدر المفصلي من جهة وبين الميلان الأنسي الوحشي للقواطع العلوية والسفلية وذلك لتحقيق نتائج معالجة تقويمية أكثر استقراراً.
هدف البحث: دراسة العلاقة بين ميلان المنحدر المفصلي من جهة وبين الميلان الأنسي الوحشي للقواطع العلوية والسفلية وذلك لدى بالغين ذوي إطباق صنف أول هيكلي وبدون أعراض سريرية ولا شعاعية لإضطرابات المفصل الفكي الصدغي.
مواد وطرق البحث: من خلال الإستعانة بفحص الشعاعي وفحص سريري متعدد المراحل تم انتقاء 46 مريض من العرق قوقازي ممن لم يخضعوا لمعالجة تقويمية سابقة (19 ذكر و27 أنثى) تراوحت أعمارهم بين 16 و 27 سنة ذوي إطباق صنف أول هيكلي وبدون أعراض سريرية وشعاعية لإضطرابات المفصل الفكي الصدغي، حيث تم إجراء تقييم شعاعي سيفالومتري لميلان المنحدر المفصلي وللميلان الأنسي الوحشي لمحاور القواطع حيث تم لاحقاً إجراء تحليل معامل ارتباط بيرسون ما بين ميلان المنحدر المفصلي والميلان الأنسي الوحشي لمحاور القواطع.
النتائج: لم نجد إرتباطاً ذو دلالة إحصائية ما بين ميلان المنحدر المفصلي وبين الميلان الأنسي الوحشي لمحاور القواطع.
الخلاصة: لا يوجد إرتباط ما بين ميلان المنحدر المفصلي وبين الميلان الأنسي الوحشي لمحاور القواطع العلوية والسفلية لدى البالغين ذوي إطباق صنف أول هيكلي ليس لديهم أعراض سريرية وشعاعية لإضطرابات المفصل الفكي الصدغي
تقييم قابلية تطبيق مشعر بونت على عينة من جامعة تشرين
أولت العديد من المشعرات أهميّة لدراسة عرض القوس السنية وتحديد خصائصها ومنها مشعر بونت.
لكن أشارت الدراسات إلى وجود اختلافات عرقية بين الشعوب, الأمر الذي طرح العديد من التساؤلات حول مدى قابلية تطبيق هذه المشعرات كمشعر بونت.
هدف البحث: التحقق من قابلية تطبيق مشعر بونت كوسيلة موثوقة من وسائل التشخيص التقويمي.
المواد والطرق: تضمنت عينة الدراسة 100 مثال جبسي لمرضى في مرحلة الإطباق الدائم ذوي إطباق طبيعي.
النتائج: أظهرت النتائج وجود قيم معامل ارتباط منخفضة بين القيم المقاسة والمحسوبة حسب معادلة بونت في كل الحالات.
الاستنتاجات: لا يمكن اعتماد مشعر بونت كأداة موثوقة للتنبؤ بعرض القوس السنية المثالي في مجتمع الدراسة
تقييم قابلية تطبيق مشعر بونت على عينة من جامعة تشرين
أولت العديد من المشعرات أهميّة لدراسة عرض القوس السنية وتحديد خصائصها ومنها مشعر بونت.
لكن أشارت الدراسات إلى وجود اختلافات عرقية بين الشعوب, الأمر الذي طرح العديد من التساؤلات حول مدى قابلية تطبيق هذه المشعرات كمشعر بونت.
هدف البحث: التحقق من قابلية تطبيق مشعر بونت كوسيلة موثوقة من وسائل التشخيص التقويمي.
المواد والطرق: تضمنت عينة الدراسة 100 مثال جبسي لمرضى في مرحلة الإطباق الدائم ذوي إطباق طبيعي.
النتائج: أظهرت النتائج وجود قيم معامل ارتباط منخفضة بين القيم المقاسة والمحسوبة حسب معادلة بونت في كل الحالات.
الاستنتاجات: لا يمكن اعتماد مشعر بونت كأداة موثوقة للتنبؤ بعرض القوس السنية المثالي في مجتمع الدراسة
The Amazing Race Repeated Update Q-Learning VS. Q-Learning
In this paper, we will conduct an experiment that aims to compare the performance of two reinforcement learning algorithms, the Repeated Update Q-learning algorithm (RUQL) [1] and the Q-learning algorithm(QL) [5]. A simulated version of a robot crawler developed by [6] will be used in this experiment, it is shown in figure (1). An investigation study about the difference in performance between RUQL and Q-learning algorithm (QL) [5] is discussed in this paper. Several trials and tests were conducted to estimate the difference in the crawler’s movement using both algorithms. Additionally, a detailed description of the Markovian decision processes (MDPs) elements [2] is introduced, MDP model includes states, actions and rewards for the task in hand. The parameters that were used and tuned in this experiment will be mentioned and the reasons for choosing their values will be explained. Finally, the source code for the crawler robot was modified in order to implement RUQL and Q-Learning (QL) algorithms, Eclipse [3] and Java SE Development Kit 8 (JDK) [4] are used for this purpose. After running the crawler robot simulation, the results drawn from the experiment showed that RUQL significantly outperforms the traditional QL.  
Evaluation of Corneal High Order Aberrations in Post Laser-Assisted in Situ Keratomileusis versus Photorefractive Keratectomy in Myope
Background Aberrations of the eye are the difference between two surfaces: the ideal and the actual wave front. Higher order aberrations are a relatively small component, comprising about 10% of the eye’s total aberrations. High order aberrations increase with age and minor symmetry exists between the right and the left eyes. Aim and objectives To Compare corneal high order aberrations in post laser-assisted in situ keratomileusis with corneal high order aberrations in post Photorefractive keratectomy in myope. Subjects and methods this study was designed as a prospective randomized intervention study that conducted on 40 myopic eyes. The eyes divided into two randomized groups. Group A: 20 myopic eyes corrected with laser-assisted in situ keratomileusis and Group B: 20 myopic eyes corrected with Photorefractive keratectomy. Cases were collected for LASIK and PRK at operative theater in Beni-Suef University Hospital and clear vision laser center in Cairo, from May 2019 till January 2022. Result There was clinically significant difference between pre- and post-operative visual acuity, vertical trefoil and vertical coma of LASIK group and there was clinically significant between pre- and post-operative visual acuity, vertical trefoil and vertical coma of PRK group. But there was no significant difference between LASIK and PRK in visual acuity, spherical aberration, higher order 5 mm and 6 mm, vertical coma and Vertical trefoil. Conclusion There is non-significant increase in higher order aberration and spherical aberration post LASIK and post PRK with lesser amount in PRK
Role of Elastic Stable Intramedullary Nailing in Diaphyseal Fractures in Children
Background: All femoral or tibial fractures regardless of associated injuries, intramedullary nailing (IMN) has its more advantages in rapid rehabilitation, good effects on the child and his family and strong fixation.
Objective: To assess the role of elastic stable IMN in union of diaphyseal fractures of long bones in children.
Patients and Methods: A prospective and retrospective analytical study on ten children with isolated femoral or tibial fractures who were admitted to Orthopedic Department, Zagazig University Hospitals. They were divided equally into group I that included 5 patients with femoral shaft fracture managed with IMN and group II, which included 5 patients with tibial shaft fracture managed with IMN. Their mean age was 4.7 years old.
Results: When the groups compared, the spica cast group was found to have a shorter duration of hospital stay compared to elastic nail group. The knee range of motion of the spica cast group was found to be better compared to the elastic nailing group. The elastic nailing group was found to have started walking earlier both with and without support. Patients with intramedullary nailing started to walk with aid after one month and independently after 2 weeks. Patients with spica cast started to walk with aid after 2 months and independently after 12 weeks.
Conclusion: None of the available treatment tools to fix diaphyseal long bones fractures in preschool children is perfect because each method has its own set of complications. However, constitute the motive for developing new techniques or changing the design of currently available devices
Non-Invasive Panel for Prediction of Large Esophageal Varices in Patients with HCV-Related Cirrhosis after DAAS Therapy
To study sonographic and laboratory
parameters as diagnostic non-invasive Indices for
prediction and screening of large varices in liver
cirrhotic patients post hepatitis C virus after direct Actin
antiviral drugs (DAAS).
Introduction:
All cirrhotic patients should be screened for
esophageal varices (EV) via endoscopy, as recommended
by the guidelines. However, repeated endoscopy is not
well accepted by patients and is a costly procedure that
places a heavy burden on the endoscopic unit. Therefore,
noninvasive predictors of EVs and size discrimination
for EVs are of particular importance.After dividing
DAAS into three arms: arm 1 with Non-EV, arm
2grad1&2 EV (Small Vriceal arm), and arm 3 grade
3&4 EV (Large Variceal arm). medical history, physical
examination, standard laboratory tests, abdominal
ultrasound, and sonographic parameters such as portal
vein velocity (PVV). Splenic Index (SI) Splenoportal
Index (SPI), platelet count/spleen diameter ratio
(PCSDR) and upper gastrointestinal endoscopy were
performed for all participants.Results:
The Noninvasive sonographic and laboratory
parameters for prediction of the presence of EVs have
demonstrated that low platelet count/spleen diameter
ratio (PC/SD) at cut-off (CO) ≤ 1121.43 cu/mm, then
high SPI at CO >3.98 cm /sec then high FIB4 at CO >
2.68 then high APRI at CO > 0.6 then PVV at CO ≤ 22.2
cm/sec then high SI at CO > 89.7 and lastly Child’s –
Pugh’s score at CO > 6 respectively.. The Non Invasive
sonographic and laboratory parameters for
discrimination of the size of EVs showed that high SPI
was found to be the most accurate parameter at CO less
than >7.75 cm/sec Then low PC/SD at CO ≤ 514.08
cu/mm then high APRI at CO > 1.4 then high FIB4 at
CO > 7,6 then high SI with AUC 0.821 at CO > 122.4
then low PVV at CO < 15 and lastly Child’s –Pugh’s
score at CO> 6 respectively.Conclusions:
The sonographic and laboratory indices are non-
invasive parameters for the prediction of EV &
discrimination of its size. And to determine when Upper
Endoscopy is done for liver cirrhotic patients post-C
after DAA
Influence of immediate postpartum contraception counseling on the rate of unintended pregnancy in primigravida: a randomized controlled study
Background: The current study aims to assess the influence of immediate postpartum counselling about effective contraceptive methods to be used by primigravida on the rate of unintended pregnancy during first 6 months post-partum.Methods: The study was a prospective randomized controlled trial for assessment the influence of immediate postpartum counseling about effective contraceptive methods to be used by primigravida on the rate of unintended pregnancy during first 6 months post-partum who delivered at the period between the 1st of December 2016 and 31st of December 2017. The study patients were randomly assigned into two groups: Group (A) were received counseling about contraceptive methods using illustrations through postpartum interview with the study researcher. Group (B) were not received any counseling about contraceptive methods. The primary outcome was the difference in the rate of unintended pregnancy in both groups.Results: No significant difference between both groups in preventing unintended pregnancy. In group (A): After 3 months postpartum 140 women (93.3%) were used the contraceptive method correctly. 10 women used method incorrectly and 2 of them get pregnant. After 6 months postpartum 8 women did not use any method but 134 women (95.7%) were correctly used the contraceptive method. In group (B): After 3 months postpartum 127 women (84.7%) were used the contraceptive method correctly. 23 women used method incorrectly and 4 of them get pregnant. After 6 months postpartum 1 woman did not use any method but 30 women (20.7%) were incorrectly used the contraceptive method.Conclusions: Immediate post-partum counseling about contraceptive methods is good tool to educate women who intend to have optimal inter–pregnancy period about the effective methods that suit them and when to initiate
Analgesic Effect of Intra-Articular Dexamethasone versus Fentanyl added as an adjuvant to Bupivacaine for Postoperative Pain Relief in Knee Arthroscopic Surgery
Background: Knee arthroscopy is usually associated with a variable degree of pain ranging from moderate-to-severe pain in about 70% of patients.
Objective: This trial was designed to assess the efficacy of intra-articular administration of dexamethasone versus fentanyl as adjuncts to bupivacaine in patients undergoing arthroscopic knee surgery.
Patients and methods: Eighty-nine patients of either sex were enrolled in this study. The patients were randomly divided into three equal groups. Group F that received intra-articular (IA) injection of 1 μg/kg fentanyl (In 2 ml saline) added to 18 ml of 0.25% bupivacaine, group D, which received IA injection of 8 mg (2 ml) dexamethasone added to 18mL of 0.25% bupivacaine and group S that received IA injection of 2 ml normal saline added to 18 mL of 0.25% bupivacaine.
Results: The time required for the first request of analgesia in group F, group D, and group S was 5.7 ± 0.7 vs 4.5 ± 0.5 vs 3.3 ± 0.5 hours respectively. There were significant differences between both treatment groups and the control group (p < 0.001) and in between both treatment groups (p < 0.001) in favor of group F. There was a significantly lower median visual analogue score in group F when compared to group D and S at 6 hours (p = 0.006 & 0.01, respectively), 12 hours (p < 0.001 & < 0.001, respectively), and 18 hours (p = 0.003 & 0.007, respectively) postoperatively.
Conclusion: The addition of fentanyl or dexamethasone to IA bupivacaine in knee arthroscopic surgery provided a better quality of analgesia with less consumption of systemic analgesics without significant adverse effects
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