Search

A model that takes into consideration radial and axial changes in velocity in a tubular reactor for the thermal polymerization of styrene is used to simulate the effect of changes in inlet tube wall temperature and tube radius. The reactor performance is sensitive to the changes of these parameters. The method of orthogonal collocation is used to discretize the modeling equation in the radial direction and Gear method to solve the resulting stiff differential equations in the axial direction. It is found that reducing the wall temperature and the tube radius along the direction of the flow of the monomer reduces the variation in conversion between the tube center and tube wall and thus are advantageous., INTRODUCTION Polystyrene is usually produced by free radical bulk polymerization of styrene in a batch tank reactor (expandable polystyrene) or continuous stirred tank reactor (general purpose and high impact polystyrene). [...]

Objective: To examine the characteristics and outcomes of patients with inflammatory bowel disease (IBD) hospitalized with pulmonary embolism (PE)., Methods: This cross-sectional observational study analyzed data from the 2016 to 2019 National Inpatient Sample to investigate hospitalizations for PE in the USA, stratified by the presence or absence of IBD. Adult patients were selected using the International Classification of Diseases, Tenth Revision codes for PE, Crohn's disease, and ulcerative colitis. Data on patient demographics, comorbidities, and hospital characteristics were collected. Statistical analysis included univariable and multivariable logistic regression using Stata/BE 17.0, focusing on in-hospital mortality and complications in PE patients with and without IBD. Adjusted odds ratios (aOR) and their corresponding 95% confidence intervals (CI) were calculated when appropriate., Results: PE/IBD group was younger (mean age 58.3 vs. 62.7 years; P  < 0.001), had a higher proportion of white patients (81.2% vs. 70.9%; P  < 0.001), and had a greater prevalence of chronic liver disease (7.54% vs. 6.02%; P  = 0.002) when compared to PE/non-IBD patients. The PE/IBD group had lower prevalence rates of coronary artery disease, congestive heart failure, obesity, chronic obstructive pulmonary disease, hypertension, and diabetes. Regarding primary outcomes, there was no significant difference in in-hospital mortality between the two groups (aOR, 0.92; 95% CI, 0.77-1.09; P  = 0.355). However, the IBD/PE group had a higher risk of acute kidney injury, sepsis, septic shock, cardiac arrhythmias, and deep vein thrombosis. As for secondary outcomes, PE/IBD patients had more extended hospital stays and higher healthcare costs compared with PE/non-IBD patients., Conclusion: Hospitalized PE patients with IBD differ demographically and have a different comorbidity profile compared to those without IBD. PE/IBD patients demonstrate greater use of healthcare resources and elevated risk of hospitalization adverse events than PE/non-IBD patients, highlighting the necessity for individualized management approaches in this population., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: This study aimed to investigate the incidence and predictors of non-variceal upper gastrointestinal bleeding (NVUGIB) in hospitalized patients with coronavirus disease 2019 (COVID-19), as well as the inpatient outcomes associated with this complication., Methods: This was an analysis of the National Inpatient Sample Database from January to December 2020. Adult COVID-19 patients were categorized into two groups based on NVUGIB development during hospitalization. Multivariate logistic analysis was performed to identify predictors and outcomes associated with NVUGIB in hospitalized COVID-19 patients in the US, after adjusting for age, sex, race, and Charlson Comorbidity Index (CCI) score, using Stata/BE 17.0., Results: Among 1 050 045 hospitalized patients, 1.87% developed NVUGIB. Asian Americans had the highest risk, followed by Native Americans, Hispanics, and African Americans, with odds ratios (ORs) of 1.70, 1.59, 1.40, and 1.14, respectively. Patients with higher CCI scores were also at greater risk (with ORs of 1.47, 2.09, and 3.45 for CCI scores of 1, 2, and 3, respectively). COVID-19 patients with NVUGIB had a higher risk of inpatient mortality (OR=3.84), acute kidney injury (OR=3.12), hypovolemic shock (OR=13.7), blood transfusion (OR=7.02), and in-hospital cardiac arrest (OR=4.02)., Conclusion: NVUGIB occurred in 1.87% of hospitalized COVID-19 patients and was associated with a threefold increase in mortality. Further research is necessary to identify strategies for reducing its incidence in COVID-19 patients with multiple risk factors., Competing Interests: Conflict of Interest Statement. The authors declare that there are no competing interests associated with the content of this document. This includes financial, personal, professional, or any other interests that may influence or be perceived to influence the content presented., (© 2024. Huazhong University of Science and Technology.)

Avascular necrosis (AVN) of the femoral head is a rare complication that can be associated with prolonged use of glucocorticoids. On reviewing the literature, this is the first case of bilateral AVN secondary to the long use of topical steroids in an eosinophilic esophagitis (EoE) patient. A 28-year-old man presented to our gastroenterology clinic for worsening fibrostenotic (EoE) despite being on swallowed fluticasone administered through an inhaler for seven years. The latter was stopped, and the patient was commenced on dupilumab. The patient was referred to orthopedics to manage his limping and groin pain. Bilateral hip replacements were performed when bilateral AVN was confirmed on MRI of both hips. The patient's EoE symptoms resolved after endoscopic dilation and an ongoing course of dupilumab. Furthermore, dupilumab showed an excellent control of the disease activity based on esophageal biopsies. To our knowledge, this is the first case report of such an entity. Our case highlights the need to promote awareness of such serious side effects of prolonged use of topical corticosteroids among healthcare providers, even if administered through a metered inhaler., Competing Interests: Human subjects: Consent for treatment and open access publication was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Alakrad et al.)

Myeloid sarcoma (MS) is a proliferation of immature myeloid cells that occurs extramedullary, often accompanying acute myeloid leukemia (AML). It typically presents in areas such as lymph nodes, skin, and the head and neck regions. The emergence of MS within the temporal bone is rare, and it can manifest through nonspecific symptoms. In this paper, we reported a case of A 47-year-old female presented with right-sided otalgia, otorrhea, tinnitus, reduced hearing, and ear fullness, and developed facial asymmetry. She was initially diagnosed with necrotizing otitis externa and was treated accordingly. Further investigations were conducted, leading to the diagnosis of MS. She began treatment with induction chemotherapy followed by consolidation therapy. And we reviewed the literature and included 14 MS cases with the same anatomical localization, discussing the primary presentation, immunohistochemistry, and treatment approaches of these patients. In conclusion, temporal bone MS should be considered in patients with a history of AML presenting with nonspecific symptoms. Diagnostic modalities for MS include computed tomography and magnetic resonance imaging scans. Systemic chemotherapy remains the preferred treatment approach. The complexity and diversity of temporal bone MS presentations necessitate further comprehensive research to enhance understanding and improve management strategies for this rare condition., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Introduction: Malignant peripheral nerve sheath tumors (MPNSTs) are rare tumors that develop from peripheral nerve sheath cells and they account for approximately 5% to 10% of all soft-tissue sarcomas. MPNSTs in the head and neck region represent approximately 2% to 6% of all head and neck sarcomas and account for 12% to 19% of all MPNSTs, and the infratemporal fossa is a rare site for MPNSTs. MPNSTs originating from the trigeminal nerve are extremely rare. Case presentation: A 19-year-old female presented with a 6-month history of left-sided facial pain and paresthesia on the same side. On examination, there was left-sided facial paresthesia at the third trigeminal nerve (V3) areas; computed tomography scanning and magnetic resonance imaging showed an infratemporal lesion and surgical resection was done. Histological examination and the immunostaining finding showed high-grade MPNST. Conclusion: MPNSTs in the head and neck region may manifest with nonspecific symptoms. The diagnosis often requires a combination of clinical, pathological, and immunohistochemistry studies. Treatment involves total surgical resection with adjuvant radiotherapy., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.