Continuum Modeling Methodology for Dynamic Behavior of Towers

A very common problem in Civil Engineering is the analysis and design of lattice structures. These types of structures generally consist of repetitive sections and have been utilized in the erection of transmission and communication towers, space roof trusses, solar energy collectors, and space platforms. Since lattice structures consist of a significantly large number of members and subsequently a large number of nodes, the classical discrete technique of analysis can be very expensive even on today\u27s modern computers. This study applies a rational approach which capitalizes on the repetitive nature of towers to develop the equivalent continuum model for the lattice structure. The continuum approach is based on equivalencing the strain and kinetic energies of the actual latticed tower with that of the equivalent continuum model. Introducing the kinematic assumption that the strain components of the lattice structure have linear variations in the plane of the tower cross section is the key step in obtaining correct expressions for the equivalent properties of the continuum model. Procedures for developing continuum models are presented along with the constitutive equations and strain expressions. The procedures are demonstrated by applying the continuum modeling approach to planar trusses, triangular towers with constant cross sections, triangular towers with variable cross sections, and towers with rectangular cross sections. Numerical results for static deflections and free vibration analysis of planar trusses and towers with triangular cross sections are presented, and they indicate the high accuracy of the continuum model solution. In addition, a numerical technique is developed to obtain member forces of the actual lattice structure from the continuum model results. Moreover, a comparison of computer times using the SAP IV finite element program to analyze the actual lattice structures versus the equivalent continuum model is presented. In general, the continuum approach when applied to the analysis of lattice structures demonstrates a significant savings in computer cost with a relatively insignificant loss in accuracy

L-Ornithine-L-Aspartate and Intermittent Renal Replacement Therapy in Fulminant Hepatitis A

Hepatitis A is a common viral infection worldwide that is transmitted via the fecal-oral route. Since the introduction of an efficient vaccine, the incidence of infection has decreased but the number of cases has risen due to widespread community outbreaks among unimmunized individuals. Classic symptoms include fever, malaise, dark urine, and jaundice, and are more common in older children and adults. People are often most infectious 14 days prior to and 7 days following the onset of jaundice. We will discuss the case of a young male patient, diagnosed with acute hepatitis A, leading to fulminant hepatitis refractory to conventional therapy and the development of subsequent kidney injury. The medical treatment through the course of hospitalization was challenging and included the use of L-ornithine-L-aspartate and prolonged intermittent hemodialysis, leading to a remarkable outcome. Hepatitis A is usually self-limited and vaccine-preventable; supportive care is often sufficient for treatment, and chronic infection or chronic liver disease rarely develops. However, fulminant hepatitis, although rare, can be very challenging to manage as in the case of our patient

In Vivo Investigation of the Ameliorating Effect of Copper Albumin Complex on chondroitin sulfate in Monosodium iodoacetate -Induced Knee Osteoarthritis

Osteoarthritis (OA) is a condition that manifests as cartilage deterioration and subchondral bone sclerosis in the joint tissues. The weight-bearing joint is most severely impacted by OA. According to some research, consuming foods high in copper albumin complex (cu-albumin complex) can help with OA-related joint degeneration and pain relief. The current study's objective to determine how oral administration of the cu-albumin complex as an anti-inflammatory medication affected the development of rat knee osteoarthritis (KOA). Fifty adult albino rats were divided into three groups: negative control untreated (n= 10, no KOA induction); positive untreated control (n= 20, KOA induction); and treated group (n= 20, KOA induction with administration of cu-albumin complex). According to the severity of the clinical symptoms, treated and untreated arthritic groups were equally divided into mild and severe groups (n=10). Monosodium iodoacetate (MIA) was used as intra-articular injection for osteoarthritis induction. Rats were euthanized after a month of the beginning of the experiment, and the joints were examined histopathologically and immunohistochemically. It was indicated that the treatment was effective in reducing KOA severity and in improvement of chondroitin sulfate of the affected cartilages. In conclusion, the structure of the chondroitin sulphate in the knee joint cartilages of KOA-affected rats was modified by the cu-albumin complex

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Late Neoproterozoic adakitic lavas in the Arabian-Nubian shield, Sinai Peninsula, Egypt

The Sahiya and Khashabi volcano-sedimentary successions are exposed near the southern tip of the Sinai Peninsula, the northernmost segment of the Arabian-Nubian Shield (ANS). These Neoproterozoic successions include a series of intermediate to acidic lavas and associated pyroclastic deposits. Field observations and geochemical data reveal two distinct eruptive phases. The lavas representing each phase are intercalated with volcaniclastic greywackes and siltstones. The first eruptive phase, well exposed at Wadi Sahiya, includes basaltic andesite, andesite and dacite with minor rhyolite. The rocks of this sequence are at most weakly deformed and slightly metamorphosed. The second eruptive phase, well exposed at Wadi Khashabi, includes only undeformed and unmetamorphosed dacite and rhyolite. The two volcano-sedimentary successions were separated and dismembered during intrusion of post-collisional calc-alkaline and alkaline granites. Geochemical compositions of the Sahiya and Khashabi volcanic rocks confirm the field data indicating discrete phases of magmatism, however all the compositions observed might plausibly be derived from a common source and be related to one another dominantly through fractional crystallization. The low and variable Mg# values (55–33) measured in the basaltic andesites and andesites preclude their equilibration with a mantle source. Rather, even the most primitive observed lavas are already the products of significant fractional crystallization, dominated by removal of amphibole and plagioclase. Continued fractionation eventually produced dacite and rhyolite marked by significant depletion in Y and HREE. The gradual appearance of negative Nb-Ta anomalies with increasing SiO_2 through both suites suggests at least some component of progressive crustal contamination. The medium- to high-K calc-alkaline character of the Sahiya and Khashabi volcanics could be explained either by their formation at an active continental margin or by a two-stage model that appeals to re-melting of arc material in a post-collisional setting. The Wadi Sahiya basaltic andesite and andesite samples exhibit the defining chemical characteristics of adakites: high Sr (>700 ppm), low Y (20) and low Yb (<1.8 ppm). Although this signature can be associated with slab melting, here we show that it reflects partial melting of lithospheric mantle beneath thickened continental arc crust. The early eruptive phase, exposed at Sahiya, was erupted on an active continental margin, whereas the later Khashabi succession marks the transition to a post-collisional stage

Late Neoproterozoic adakitic lavas in the Arabian-Nubian shield, Sinai Peninsula, Egypt

The Sahiya and Khashabi volcano-sedimentary successions are exposed near the southern tip of the Sinai Peninsula, the northernmost segment of the Arabian-Nubian Shield (ANS). These Neoproterozoic successions include a series of intermediate to acidic lavas and associated pyroclastic deposits. Field observations and geochemical data reveal two distinct eruptive phases. The lavas representing each phase are intercalated with volcaniclastic greywackes and siltstones. The first eruptive phase, well exposed at Wadi Sahiya, includes basaltic andesite, andesite and dacite with minor rhyolite. The rocks of this sequence are at most weakly deformed and slightly metamorphosed. The second eruptive phase, well exposed at Wadi Khashabi, includes only undeformed and unmetamorphosed dacite and rhyolite. The two volcano-sedimentary successions were separated and dismembered during intrusion of post-collisional calc-alkaline and alkaline granites. Geochemical compositions of the Sahiya and Khashabi volcanic rocks confirm the field data indicating discrete phases of magmatism, however all the compositions observed might plausibly be derived from a common source and be related to one another dominantly through fractional crystallization. The low and variable Mg# values (55–33) measured in the basaltic andesites and andesites preclude their equilibration with a mantle source. Rather, even the most primitive observed lavas are already the products of significant fractional crystallization, dominated by removal of amphibole and plagioclase. Continued fractionation eventually produced dacite and rhyolite marked by significant depletion in Y and HREE. The gradual appearance of negative Nb-Ta anomalies with increasing SiO_2 through both suites suggests at least some component of progressive crustal contamination. The medium- to high-K calc-alkaline character of the Sahiya and Khashabi volcanics could be explained either by their formation at an active continental margin or by a two-stage model that appeals to re-melting of arc material in a post-collisional setting. The Wadi Sahiya basaltic andesite and andesite samples exhibit the defining chemical characteristics of adakites: high Sr (>700 ppm), low Y (20) and low Yb (<1.8 ppm). Although this signature can be associated with slab melting, here we show that it reflects partial melting of lithospheric mantle beneath thickened continental arc crust. The early eruptive phase, exposed at Sahiya, was erupted on an active continental margin, whereas the later Khashabi succession marks the transition to a post-collisional stage

Lack of MERS Coronavirus Neutralizing Antibodies in Humans, Eastern Province, Saudi Arabia

We used a lentiviral vector bearing the viral spike protein to detect neutralizing antibodies against Middle East respiratory syndrome coronavirus (MERS-CoV) in persons from the Eastern Province of Saudi Arabia. None of the 268 samples tested displayed neutralizing activity, which suggests that MERS-CoV infections in humans are infrequent in this province

Locally advanced thymoma; does neoadjuvant chemotherapy make a difference?

Abstract Background Regardless of its rare occurrence, Thymoma remains the most frequently encountered primary tumor of the anterior mediastinum comprising about 50% of all masses in the region. Surgical resection, via thymectomy, remains the mainstay treatment modality. In locally advanced and borderline resectable tumors, neoadjuvant chemotherapy (NACT) may be utilized to increase the chance of R0 resection, raising the question of its efficacy and safety. Methods Demographic and clinical data from patients who presented to a tertiary cancer center between January 2015–October 2021 with a diagnosis of thymoma and underwent curative surgical resection was collected. Computed tomography scan was used to delineate clinical staging, tumor size and to detect post-therapeutic variations in tumor burden. The response evaluation criteria in solid tumors (RECIST) was used to classify the effect of NACT on tumor burden. The pathological response was determined by measuring the percentage of necrotic tissue. Results A total of 23 patients were diagnosed with thymoma. Most patients were male with a mean age 46 (± 15) years at diagnosis. The most common clinical stage was stage II with 5 patients (22%). A total of 12 patients had NACT as compared to 11 patients who had upfront surgery. The mean change in tumor volume was 165 cm3 (p = 0.079) and the change in and maximum diameter was 1.53 ± 1.49 cm (p < 0.01). The effect of NACT on tumor burden based on RECIST criteria was minimal as 8 patients had stable disease. Based on pathological findings, the average necrotic portion of the tumor was 39.5% (p = 0.152). The overall survival rate is 95.65%, mean survival was 115 months (4–125). Recurrence occurred in 5 patients. The NACT group had a higher risk for recurrence (4; 33.3%) with a mean survival of 43.8 months compared to 59.6 months in those who did not receive induction therapy. Conclusions The exact role of induction chemotherapy in locally advanced thymoma patients remains controversial. NACT effect after utilizing radiological and pathological assessment tools was not found to significantly improve oncological outcomes compared to upfront surgery in locally advanced disease, with minimal radiologic and pathologic effect. To further demonstrate the impact of induction chemotherapy, we recommend multicentric collaborative studies

After 9 Years of 3-Column Osteotomies, Are We Doing Better? Performance Curve Analysis of 573 Surgeries With 2-Year Follow-up.

BACKGROUND: In spinal deformity treatment, the increased utilization of 3-column (3CO) osteotomies reflects greater comfort and better training among surgeons. This study aims to evaluate the longitudinal performance and adverse events (complications or revisions) for a multicenter group following a decade of 3CO. OBJECTIVE: To investigate if performance of 3CO surgeries improves with years of practice. METHODS: Patients who underwent 3CO for spinal deformity with intra/postoperative and revision data collected up to 2 yr were included. Patients were chronologically divided into 4 even groups. Demographics, baseline deformity/correction, and surgical metrics were compared using Student t-test. Postoperative and revision rates were compared using Chi-square analysis. RESULTS: Five hundred seventy-three patients were stratified into: G1 (n = 143, 2004-2008), G2 (n = 142, 2008-2009), G3 (n = 144, 2009-2010), G4 (n = 144 2010-2013). The most recent patients were more disabled by Oswestry disability index (G4 = 49.2 vs G1 = 38.3, P = .001), and received a larger osteotomy resection (G4 = 26° vs G1 = 20°, P = .011) than the earliest group. There was a decrease in revision rate (45%, 35%, 33%, 30%, P = .039), notably in revisions for pseudarthrosis (16.7% G1 vs 6.9% G4, P = .007). Major complication rates also decreased (57%, 50%, 46%, 39%, P = .023) as did excessive blood loss (\u3e4 L, 27.2 vs 16.7%, P = .023) and bladder/bowel deficit (4.2% vs 0.7% P = .002). Successful outcomes (no complications or revision) significantly increased (P = .001). CONCLUSION: Over 9 yr, 3COs are being performed on an increasingly disabled population while gaining a greater correction at the osteotomy site. Revisions and complication rate decreased while success rate improved during the 2-yr follow-up period