Flexural Properties of Periodic Lattice Structured Lightweight Cantilever Beams Fabricated Using Additive Manufacturing: Experimental and Finite Element Methods.

Lattice structures are a type of lightweight structure that is more commonly being applied to engineering systems as a way to reduce mass and enhance mechanical properties. The cantilever beam case is one of the primary modes of loading in many engineering applications, where light-weighting is also crucial. However, lightweight lattice structured cantilever beams have not been investigated considerably due to design and manufacturing limitations. Therefore, the aim of this study was to investigate the response of four different lattice structured cantilever beams comprising of unit cells made from Schwarz-P, Schwarz-D, Gyroid, and Octet-truss structures fabricated using Multi Jet Fusion additive manufacturing technology. An investigation into the cross-sections of these structures leads to a conclusion that the beams made from such structures are non-prismatic in nature as a result of variation in cross-sections. This led to the development of equations for the moment of inertia of these structures, which helped in calculating symmetric and un-symmetric bending. These beams were subjected to cantilever loading until failure, which provided insights into flexural properties such as flexural stress, stiffness, and strain energy. Experimental results indicate that the surface-based structures, due to better surface-area-to-volume ratio, have better ability in transferring loads and hence perform better than the beam-based Octet-truss beam. The Schwarz-D beam had performed the best among all the beams, which is further supported in literature due to its stretch-dominated topology that results in higher values of modulus. The finite element analysis (FEA) findings also validate these findings in which the distribution of stresses can be seen to be better transmitted than the other structures. The FEA validation shows that the distribution of Von-Mises stress and their position in experimental tests and failure of these structures is also very close, which provides validation to the experimental setup and the testing of beams.

A Framework for Developing a Multidisciplinary Approach to Prone Positioning in Acute Respiratory Distress Syndrome.

Prone position ventilation (PPV) is one of the few interventions with a proven mortality benefit in the management of acute respiratory distress syndrome (ARDS), yet it is underutilized as demonstrated by multiple large observational studies. Significant barriers to its consistent application have been identified and studied. But the complex interplay of a multidisciplinary team makes its consistent application challenging. We present a framework of multidisciplinary collaboration that identifies the appropriate patients for this intervention and discuss our institutional experience applying a multidisciplinary team to implement prone position (PP) leading up to and through the current COVID-19 pandemic. We also highlight the role of such multidisciplinary teams in the effective implementation of prone positioning in ARDS throughout a large health care system. We emphasize the importance of proper selection of patients and provide guidance on how a protocolized approach can be utilized for proper patient selection.

Brief Review of Chylothorax Diagnosis and Management: Making the Case for Substance Over Appearance.

Chylothorax is the presence of a chylous effusion in the pleural space. Diagnosing chylothorax requires a high clinical suspicion, awareness of the different appearances of a chylothorax and the performance of tests on the pleural fluid, additional to those typically required to differentiate an exudate from a transudate based on Light's criteria. Chylothorax is a more common diagnosis in the trauma and post-surgical patients, but it is still important for practitioners of other disciplines to be aware of it. In this article we provide a concise summary of chylothorax diagnosis and management.

Inadvertent Nasogastric Tube Placement into the Left Bronchial Tree.

Nasogastric tube insertion is a routine procedure that is utilized on a daily basis in our hospitals and long-term care facilities. Blind insertion of these tubes is usually performed by nurses, residents and other health care providers. In this report, we present an incident of misplacement of the nasogastric tube into the bronchial tree causing parenchymal injury and pneumothorax. We also highlight the importance of nasogastric tube placement confirmation and possible pitfalls in interpreting confirmation radiographs.

A Review Article on 5-Oxoproline Induced High Anion Gap Metabolic Acidosis.

In 1989, an acquired high anion gap metabolic acidosis due to elevated 5-oxoproline (pyroglutamic acid) was first reported. This is related to chronic acetaminophen use in malnourished patients and women with chronic medical conditions, it could happen even using therapeutic or low doses. The mainstay of treatment is cessation of acetaminophen use along with the administration of intravenous fluids. N-acetyl cysteine might accelerate improvement. The best explanation of the disorder is glutathione depletion and activation of a key enzyme in the γ-glutamyl cycle. This review article aims to highlight the mechanism and management of acquired high anion gap metabolic acidosis caused by 5-oxoproline in the adult population.

Portosystemic Shunt Leading to Encephalopathy in a Non-Cirrhotic Patient.

While portal-systemic encephalopathy is a common entity in cirrhotic patients, it is less frequent in non-cirrhotic patients. We are reporting a case of a 68-year-old female who presented with unresponsiveness for the second time in six months. She underwent extensive evaluation for liver disease with ultrasonography and computerized tomography of the abdomen, testing for causes of liver disease including testing for viral hepatitis was negative. A liver biopsy was done clearing any doubt about the presence of significant liver disease or clinically significant portal hypertension. With absence of liver disease hence lower likelihood of portal-systemic encephalopathy (PSE) we evaluated for other causes of encephalopathy with unremarkable neuroimaging including brain MRI and head CT, unremarkable CSF analysis and EEG showing no seizure activity. Given the negative workup and the high ammonia level with the significant clinical response to ammonia lowering therapy we further evaluated the patient for other causes of PSE with Doppler ultrasonography of the liver and eventually angiography of the portal system with the high suspicion for a portosystemic shunt as a cause of her encephalopathy. A shunt from the inferior mesenteric vein to the left renal vein was diagnosed and successfully occluded utilizing coil embolization. The patient recovered normal mentation and was eventually discharged home. This case sheds light on the importance of diagnosing portosystemic shunts leading to encephalopathy, as occlusion of the shunt can correct the encephalopathy and help prevent further episodes.

Antiproliferative activity of stilbene derivatives and other constituents from the stem bark of Morus nigra L.

The antiproliferative activities of 2',3,4',5,5'-pentahydroxy-cis-stilbene 1, resveratrol 2, oxyresveratrol 3, norartocarpetin 4, kuwanon C 5, morusin 6, cudraflavone A7, kuwanon G 8, albafuran C 9, mulberrofuran G 10, 3-acetyl-O-α-amyrin 11, 3-acetyl-O-ß-amyrin 12, ursolic acid-3-O-acetate 13 and uvaol 14, previously identified from the barks of Morus nigra L., were investigated against HepG2 and MCF-7 cell lines. In addition, a series of methylated stilbenes 15-19 were prepared using compounds 1-3 and their antiproliferative effects were similarly investigated. The structure of a new 2',3,4'-trimethoxy-5-hydroxy-trans-stilbene 19 was elucidated using spectroscopic techniques. It showed remarkable activity against MCF-7 cells with IC50 12.5 µM. However, kuwanon C (5) showed the highest antiproliferative activity with IC50 3.92 and 9.54 µM against MCF-7 and HepG2, respectively.

Concurrent fusobacterial pyogenic liver abscess and empyema.

We present a very rare case of concurrent empyema and liver abscess caused by Fusobacterium. Our patient presented with 3-month history of subtle abdominal discomfort and cough leading to eventually presenting with marked chest pain, dyspnoea and septic shock. CT revealed a liver abscess and large right-sided pleural effusion. Drainage of the pleural effusion yielded gross pus with the growth of Fusobacterium varium, while drainage of the liver abscess yielded Fusobacterium nucleatum The patient responded to drainage and antibiotic therapy with resolution of symptoms and decrease in the size of empyema and abscess on follow-up imaging. We also include a review if literature of related fusobacterial infections.

Extensive Bilateral Nodular Lung: A Diagnostic Challenge.

An elderly female presented to the emergency department with a two-month history of dyspnea on exertion and productive cough. Imaging revealed miliary nodular pattern involving both lungs. She underwent extensive work up evaluating different possible pathological processes. The condition was ultimately lethal. In this educational case report, we review the common - and not-so-common - etiologies that might present with this constellation of signs and symptoms, along with the diagnostic strategies and thought processes used to identify the final diagnosis.

Pulmonary Hypertension: Brief Review Article.

Pulmonary hypertension (PH) is defined as mean pulmonary artery pressure (mPAP) 25 mmHg or greater at rest; this measurement is obtained during right heart catheterization. The exact prevalence of PH in the U.S. is unknown. Advances in hemodynamic studies of the right heart side and pulmonary circulations has helped improve our understanding of this condition. This better understanding aids the development of treatment agents aimed at improving quality of life, morbidity and mortality. Awareness of this condition and understanding the classification of PH and the available treatment modalities is crucial hence we aim to briefly review the classification, diagnosis and treatment of PH in this article.

CYP2C19 genotype, physician prescribing pattern, and risk for long QT on serotonin selective reuptake inhibitors.

Aim: To examine the impact of CYP2C19 genotype on selective serotonin reuptake inhibitor (SSRI) prescribing patterns. Patients & methods: Observational cohort containing 507 unique individuals receiving an SSRI prescription with CYP2C19 genotype already in their electronic medical record. Genotype was distributed as follows: n = 360 (71%) had no loss of function alleles, 136 (26.8%) had one loss of function allele and 11 (2.2%) had two loss of function alleles. Results & conclusion: For poor metabolizers exposed to sertraline, citalopram or escitalopram, providers changed prescribing patterns in response to alerts in the electronic medical record by either changing the drug, changing the dose or monitoring serial EKGs longitudinally. For intermediate metabolizers exposed to sertraline, citalopram or escitalopram, no alert was needed (mean QTc = 440.338 ms [SD = 31.1273] for CYP2C19*1/*1, mean QTc = 440.371 ms [SD = 29.2706] for CYP2C19*1/*2; p = 0.995).

A Brief Review of Left Ventricular Assist Devices and Their Management.

The number of people older than 65 will double by 2060, and with it, the number of people suffering from heart failure will also surge. In the United States, it is estimated that there are close to 250,000-500,000 endstage/ advanced heart failure cases. Mechanical circulatory support (MCS) is an evolving advanced therapy for end-stage heart failure. MCS can be an interim measure along with acute mechanical circulatory support measures including but not limited to the intra-aortic balloon pump, extracorporeal membrane oxygenation, or temporary ventricular assist devices such as Impella, or MCS can be a more prolonged and ambulatory measure in conjunction with an implantable, durable left ventricular assist device (LVAD). As the technology of LVADs advances, the complication rate is decreasing, and the living LVAD patient population is expanding. This indicates that the probability of a non-heart failure specialist encountering these patients is also on the rise. In this article, we aim to expand the familiarity and basic knowledge of non-heart failure specialists by detailing the concepts and complications of LVADs, enabling them to more comfortably manage these patients.

Chylothorax as a complication of extensive spontaneous left arm DVT.

We present a case of right sided chylothorax in the setting of cirrhosis believed to be secondary to extensive venous thromboembolism of the left upper extremity and exacerbated by chylous ascites. Our patient responded to conservative management with anticoagulation and a repeat thoracentesis revealed transformation of the fluid back to straw coloured transudate. We also include a brief discussion of the diagnosis and management of chylothorax.

Epidemiology and clinical outcomes of viral central nervous system infections.

BACKGROUND: Central nervous system (CNS) viral infections are an important cause of morbidity and mortality. No data are available regarding their epidemiology in Qatar. DESIGN: We retrospectively evaluated all cerebrospinal fluid findings from January 2011-March 2015 at Hamad Medical Corporation. Those with abnormal CSF finding were included in our study. We excluded those with missing medical records, no clinical evidence of viral CNS infection, or proven bacterial, fungal or tuberculosis CNS infection. CNS clinical findings were classified as meningitis, encephalitis or myelitis. RESULTS: Among 7690 patients with available CSF results, 550 cases met the inclusion criteria (meningitis 74.7%; encephalitis 25%; myelitis 0.4%). Two-thirds (65%) were male and 50% were between 16-60 years old. Viral etiology was confirmed in 38% (enterovirus, 44.3%; Epstein-Barr virus, 31%; varicella zoster virus, 12.4%). The estimated incidence was 6.4 per 100,000 population. Two persons died and the rest were discharged to home. Among those with confirmed viral etiology, 83.8% received ceftriaxone (mean duration 7.3±5.2 days), 38% received vancomycin (mean duration 2.7±5.4 days) and 38% received at least one other antibiotic. Intravenous acyclovir was continued for more than 48h in patients with confirmed negative viral etiology (mean duration 5±5.6 days). CONCLUSION: Viral etiology is not uncommon among those evaluated for CNS infection in Qatar. Clinical outcomes are excellent in this group of patients. Antibiotics and acyclovir are overly used even when a viral etiology is confirmed. There is a need for clinician education regarding etiology and treatment of viral CNS infections.

Viral infections of the central nervous system in Qatar: epidemiology, pathogenesis and clinical outcomes.

INTRODUCTION: Virus-induced diseases of the central nervous system (CNS) represent a significant burden to human health worldwide. They are common causes of morbidities and mortality. There are no previous epidiomologic studies about viral CNS infections done in Qatar or in the Gulf region. We conducted this study to determine the etiology, clinical and epidimiological characteristics, and outcome of viral central nerveous system infection in patients across a larger national healthcare system. METHODOLOGY: We retrospectively evaluated all cerebrospinal fluid findings from January 2011 - March 2015 at any of the 7 hospitals in the Hamad Medical Corporation healthcare system. We included those with an abnormal CSF finding in our study. We excluded those with missing medical records, those with no clinical evidence of CNS infection or proven bacterial CNS infection. Based on pre-defined clinical and CSF (lab, culture, PCR) criteria, persons with abnormal CSF and CNS clinical findings were classified as having meningitis, meningoencephalitis, encephalitis or myelitis. We reviewed the laboratory results to determine the proportion of persons with confirmed viral etiology. RESULTS: Among 7690 patients with available CSF results, 550 cases met the case definition criteria for viral CNS infection (meningitis 75%; meningoencephalitis 16%; encephalitis 9%; myelitis 0.4%). Two-thirds (65%) were male and 50% were between 16-60 years old. Persons from Southeast Asia (India, Pakistan, Bangladesh, Nepal, and Sri Lanka) accounted for 39.6 of all infections.  A definitive virologic etiologic agent was found in 38%, among whom enterovirus was the most common (44.3%) followed by Epstein-Barr virus (31%) and varicella zoster virus (12.4%). The clinical outcome was overall good, only 2 cases died and the rest discharged to home. Ninety-eight per cent were admitted to medical ward (mean stay 7.8±6.4 days) and 2 % to an intensive care unit. (mean stay 2.7±5.4 days). Among those with confirmed viral etiology, 83.8% received ceftriaxone, 38% received vancomycin and 38% received at least one other antibiotic. CONCLUSION: Viral etiology is not uncommon among those evaluated for CNS infection in Qatar, and is most commonly seen in Southeast Asian immigrants. Clinical outcomes are generally excellent in this group of patients. Antibiotics are overly used even when a viral etiology is confirmed. There is a need for clinician education regarding etiology and treatment of CNS infections.

Maternal and Fetal Outcomes in Pregnant Women with a Prosthetic Mechanical Heart Valve.

BACKGROUND: Pregnancy is associated with several cardiocirculatory changes that can significantly impact underlying cardiac disease. These changes include an increase in cardiac output, sodium, and water retention leading to blood volume expansion, and reductions in systemic vascular resistance and systemic blood pressure. In addition, pregnancy results in a hypercoagulable state that increases the risk of thromboembolic complications. OBJECTIVES: The aim of this study is to assess the maternal and fetal outcomes of pregnant women with mechanical prosthetic heart valves (PHVs). METHODS: This is a prospective observational study that included 100 pregnant patients with cardiac mechanical valve prostheses on anticoagulant therapy. The main maternal outcomes included thromboembolic or hemorrhagic complications, prosthetic valve thrombosis, and acute decompensated heart failure. Fetal outcomes included miscarriage, fetal death, live birth, small-for-gestational age, and warfarin embryopathy. The relationship between the following were observed: - Maternal and fetal complications and the site of the replaced valve (mitral, aortic, or double)- Maternal and fetal complications and warfarin dosage (≤5 mg, >5 mg)- Maternal and fetal complications and the type of anticoagulation administered during the first trimester. RESULTS: This study included 60 patients (60%) with mitral valve replacement (MVR), 22 patients (22%) with aortic valve replacement (AVR), and 18 patients (18%) with double valve replacement (DVR). A total of 65 patients (65%) received >5 mg of oral anticoagulant (warfarin), 33 patients (33%) received ≤5 mg of warfarin, and 2 patients (2%) received low-molecular-weight heparin (LMWH; enoxaparin sodium) throughout the pregnancy. A total of 17 patients (17%) received oral anticoagulant (warfarin) during the first trimester: 9 patients received a daily warfarin dose of >5 mg while the remaining 8 patients received a daily dose of ≤5 mg. Twenty-eight patients (28%) received subcutaneous (SC) heparin calcium and 53 patients (53%) received SC LMWH (enoxaparin sodium). Prosthetic valve thrombosis occurred more frequently in patients with MVR (P = 0.008). Postpartum hemorrhage was more common in patients with aortic valve prostheses than in patients with mitral valve prostheses (P = 0.005). The incidence of perinatal death was higher in patients with AVR (P = 0.014). The incidence of live birth was higher in patients with DVR (P = 0.012). The incidence of postpartum hemorrhage was higher in patients who received a daily dose of >5 mg of warfarin than in patients who received ≤5 mg of warfarin (P = 0.05). The incidence of spontaneous abortion was also higher in patients receiving >5 mg of warfarin (P ≤ 0.001), while the incidence of live births was higher in patients receiving ≤5 mg of warfarin (P = 0.008). There was a statistically significant difference between the anticoagulant received during the first trimester and cardiac outcomes. Specifically, patients on heparin developed more heart failure (P = 0.008), arrhythmias (P = 0.008), and endocarditis (P = 0.016). There was a statistically significant relationship between heparin shifts during the first trimester and spontaneous abortion (P = 0.003). CONCLUSION: Warfarin use during the first trimester is safer for the mother but is associated with more fetal loss, especially in doses that exceed 5 mg. The incidence of maternal complications is greater in women who receive LMWH or unfractionated heparin during the first trimester, especially prosthetic valve thrombosis, although the fetal outcome is better because heparin does not cross the placenta.

A new pregnane glycoside from Gomphocarpus fruticosus growing in Egypt.

Phytochemical investigation of Gomphocarpus fruticosus (L.) Ait. of Egyptian origin afforded the new pregnane glycoside lineolon-3-O-[ß-D-oleandropyranosyl-(1-4)-ß-D-cymaropyranosyl-(1-4)-ß-D-cymaropyranoside], along with six known compounds. The structures of the isolated compounds were elucidated on the basis of extensive spectroscopic evidences derived from 1D, 2D NMR experiments, mass spectrometry and by comparing their physical and spectroscopic data to literature. These included the triterpenoids 3ß-taraxerol, 3ß-taraxerol acetate and betulinic acid, which are identified for the first time in G. fruticosus and the cardenolides uzarigenin, gomphoside and calotropin.

Assessment of some Herbal Drugs for Prophylaxis of Peptic Ulcer.

Aqueous (hydrophilic) and chloroform (Lipophilic) extracts of nine medicinal plants currently used in Egyptian traditional medicine to treat some gastrointestinal tract (GIT) disorders were tested for their gastro-protective effect against the incidence of peptic ulcer. Indomethacin-induced ulcer in a rat model was used for this testing. Mentha microphylla, Brassica oleracea Capitata (Cabbage), B. oleracea Botrytis (cauliflower) aqueous fraction, Portolaca oleracea polysaccharide fraction, Oreganum marjoranum, Matricaria recutita, Solanum nigrum hydrophilic and lipophilic fractions, in addition to the chloroform fraction of Portolaca oleracea and Cicorium intybus afforded high protection against the incidence of gastric ulcer (~95%). O. syriacum hydrophilic and lipophilic fractions and gum arabic afforded moderate prophylactic effect. L. sicerarea, C. intybus hydrophilic fractions and M. microphylla lipophilic fraction were inactive. Herbs represent excellent resources for cost-effective and readily available gastro-protective remedies without side effects.