1,465 research outputs found
Dynamics analysis of 3 axis gantry type multipurpose CNC machine
The determination of the natural frequency and the resonance is important before the machine can be use. If the natural frequency is occur and the resonance will be occur also and it will make the damage to the machine when the machine is using. From this paper, modal analysis is used to determine the natural frequency. Modal analysis is a process whereby describe a structure in terms of its natural characteristics which are the frequency, damping and mode shape of its dynamic properties. From the experiment that was carrying out, the natural frequency is occur at 24Hz. From the result, when the machine is running with the speed of 50Hz or 100Hz, it doesn’t meet with the natural frequency which is 24Hz. From the experiment that was carrying out, it was shows that the machine can be use as user to milling process. Most machines produce low levels of vibration when designed properly. During operation, all machines are subjected to fatigue, wear, deformation, and foundation settlement. These effect cause an increase in the clearances between mating part, misalignments in shafts, initiation of cracks in parts, and unbalances in rotors. All leading to an increase in the level of vibration, which cause additional dynamic loads on bearings. As time progresses, the vibration level continue to increase, leading ultimately to the failure or breakdown of the machine. So, the maintenance is needed for all the time the machine is use
University Students’ Antibiotic Use and Knowledge of Antimicrobial Resistance: What Are the Common Myths?
We aimed to assess antibiotic usage and knowledge regarding antibiotics and antimicrobial resistance (AMR) among undergraduate students of the Universiti Brunei Darussalam (UBD), public university located in Brunei Darussalam. A cross-sectional study was performed using a self-administered questionnaire. The questionnaire was adapted from the World Health Organization’s (WHO) “Antibiotic resistance: Multi-country public awareness” survey distributed online. Students at the UBD were invited to participate in the online survey through internal email. The questionnaire consisted of five sections: demographic information, antibiotic usage, knowledge on antibiotics, antibiotic resistance (AMR), and use of antibiotics in agriculture. The data were analyzed descriptively and appropriate inferential statistics were used accordingly. A total of 130 students returned a completed questionnaire. The result of the study found that 51% (n = 66) of the students had good level of knowledge of antibiotic and antimicrobial resistance with a mean total knowledge score of nine out of 14. Of note, 76% (n = 99) of the respondents mistakenly believed that antibiotic resistance is the result of the body becoming resistant to antibiotics. Only 14% (n = 18) of the respondents were found to have poor knowledge on antibiotics and antimicrobial resistance in the study. Misconceptions in regards to the use of antibiotics for conditions related to viral illnesses like cold and flu (41%, n = 53) were noticed among the respondents in our study. Thus, improving knowledge on antibiotics is crucial to address these beliefs
Lateral Nasal Wall Respiratory Epithelial Adenomatoid Hamartoma (REAH): A Diagnostic Conundrum
Introduction: This study aims to report a rare case of a respiratory epithelial adenomatoid hamartoma (REAH) of the lateral nasal wall that had initially presented as a fungating mass, similar to that of a sinonasal malignancy, and its complete removal from the lateral nasal wall. Case Report: We report the case of a 58-year-old woman who presented to us with a chief complaint of recurrent right-sided epistaxis and nasal blockage for the past 4 months, which was progressively worsening. Histopathological examination confirmed the presence of a REAH instead of a sinonasal malignancy. The tumor was surgically excised from the lateral nasal wall using electrocautery under endoscopic guidance. The patient was then carefully followed-up after surgery, and the wound was successfully healed 3 months after the initial surgery. There was no evidence of recurrence 6 months after the initial surgery Conclusion: This case demonstrates the rare presentation of a REAH, which had arisen from the lateral nasal wall. Clinically, it is difficult to distinguish a REAH from a more notorious mass such as a sinonasal malignancy. Therefore, biopsy is mandatory in all cases of lateral nasal mass in order to rule out malignancy before confirming nasal REAH. Fortunately, as seen in this case, a lateral nasal REAH, once diagnosed, can be safely and easily removed from the lateral nasal wall using electrocautery with good surgical outcomes and a low rate of recurrence
Gracilis pull-through flap for the repair of a recalcitrant recto-vaginal fistula
Recto-vaginal fistulas are difficult to treat due to their high recurrence rate. Currently, no single surgical intervention is universally regarded as the best treatment option for rectovaginal fistulas. We present a case of recurrent recto-vaginal fistula surgically treated with a gracilis pull-through flap. The surgical goals in this patient were complete excision of the recto-vaginal fistula and introduction of fresh, vascularized muscle to seal the fistula. A defunctioning colostomy was performed 1 month prior to the present procedure. The gracilis muscle and tendon were mobilized, pulled through the freshened recto-vaginal fistula, passed through the anus, and anchored externally. Excess muscle and tendon were trimmed 1 week after the procedure. Follow-up at 4 weeks demonstrated complete mucosal coverage over an intact gracilis muscle, and no leakage. At 8 weeks post-procedure, the patient resumed sexual intercourse with no dyspareunia. At 6 months post-procedure, her stoma was closed. The patient reported transient fecal staining of her vagina after stoma reversal, which resolved with conservative treatment. The fistula had not recurred at 20 months post-procedure. The gracilis pull-through flap is a reliable technique for a scarred vagina with an attenuated rectovaginal septum. It can function as a well-vascularized tissue plug to promote healing
Relations between Average Distance, Heterogeneity and Network Synchronizability
By using the random interchanging algorithm, we investigate the relations
between average distance, standard deviation of degree distribution and
synchronizability of complex networks. We find that both increasing the average
distance and magnifying the degree deviation will make the network synchronize
harder. Only the combination of short average distance and small standard
deviation of degree distribution that ensures strong synchronizability. Some
previous studies assert that the maximal betweenness is a right quantity to
estimate network synchronizability: the larger the maximal betweenness, the
poorer the network synchronizability. Here we address an interesting case,
which strongly suggests that the single quantity, maximal betweenness, may not
give a comprehensive description of network synchronizability.Comment: 14 pages, and 7 figures (to be published in Physica A
Natural products as novel anti-obesity agents: insights into mechanisms of action and potential for therapeutic management
Obesity affects more than 10% of the adult population globally. Despite the introduction of diverse medications aimed at combating fat accumulation and obesity, a significant number of these pharmaceutical interventions are linked to substantial occurrences of severe adverse events, occasionally leading to their withdrawal from the market. Natural products serve as attractive sources for anti-obesity agents as many of them can alter the host metabolic processes and maintain glucose homeostasis via metabolic and thermogenic stimulation, appetite regulation, pancreatic lipase and amylase inhibition, insulin sensitivity enhancing, adipogenesis inhibition and adipocyte apoptosis induction. In this review, we shed light on the biological processes that control energy balance and thermogenesis as well as metabolic pathways in white adipose tissue browning, we also highlight the anti-obesity potential of natural products with their mechanism of action. Based on previous findings, the crucial proteins and molecular pathways involved in adipose tissue browning and lipolysis induction are uncoupling protein-1, PR domain containing 16, and peroxisome proliferator-activated receptor-γ in addition to Sirtuin-1 and AMP-activated protein kinase pathway. Given that some phytochemicals can also lower proinflammatory substances like TNF-α, IL-6, and IL-1 secreted from adipose tissue and change the production of adipokines like leptin and adiponectin, which are important regulators of body weight, natural products represent a treasure trove for anti-obesity agents. In conclusion, conducting comprehensive research on natural products holds the potential to accelerate the development of an improved obesity management strategy characterized by heightened efficacy and reduced incidence of side effects
The role of head-up cardiopulmonary resuscitation in sudden cardiac arrest: a systematic review and meta-analysis
BACKGROUND: Head-up cardiopulmonary resuscitation (HU-CPR) is an experimental treatment for sudden cardiac arrest (SCA), where cardiopulmonary resuscitation (CPR) is performed in a ramped position. We evaluated whether HU-CPR improved survival and surrogate outcomes as compared to standard CPR (S-CPR). METHODS: Studies reporting on HU-CPR in SCA were searched for in PubMed, Embase and Cochrane Library from inception to May 1st 2021. Outcomes included neurologically-intact survival, 24-hour-survival, intracranial pressure (ICP), cerebral perfusion pressure (CerPP) and brain blood flow (BBF). Risk of bias was assessed using the GRADE assessment tool and Newcastle Ottawa Scale. Fixed- and random-effects models were used to estimate the pooled effects of HU-CPR at 30 degrees. RESULTS: Thirteen articles met the criteria for inclusion (11 animal-only studies, one before-and-after human-only study, one study that utilized human- and animal-cadavers). Among animal studies, the most common implementation of HU-CPR was a 30-degree upward tilt of the head and thorax (n=7), while four studies investigated controlled sequential elevation (CSE). Two animal studies reported improved cerebral performance category (CPC) scores at 24-hour. The pooled effect on 24-hour survival was not statistically significant (P=0.37). The lone human study reported doubled return of spontaneous circulation (ROSC) (17.9% versus 34.2%, P<0.0001). The pooled effect on ROSC in three porcine studies was OR =3.63 (95% CI: 0.72–18.39). Pooled effects for surrogate physiological outcomes of intracranial cranial pressure (MD −14.08, 95% CI: −23.21 to −4.95, P=0.003), CerPP (MD 14.39, 95% CI: 3.07–25.72, P=0.01) and BBF (MD 0.14, 95% CI: 0.02–0.27, P=0.03), showed statistically significant benefit. DISCUSSION: Overall, HU-CPR improved neurologically-intact survival at 24-hour, ROSC and physiological surrogate outcomes in animal models. Despite promising preclinical data, and one human observational study, clinical equipoise remains surrounding the role of HU-CPR in SCA, necessitating clarification with future randomized human trials
A Population-based and Clinical Cohort Validation of the Novel Consensus Definition of Metabolic Hyperferritinemia
Background: There is limited data on the clinical significance of metabolic hyperferritinemia (MHF) based on the most recent consensus. We aimed to validate the clinical outcomes of MHF in general population and biopsy-proven metabolic dysfunction-associated fatty liver disease (MAFLD) patients. Methods: NHANES database and PERSONS cohort were included. MHF was defined as elevated serum ferritin with metabolic dysfunction (MD) and stratified into different grades according to ferritin (grade 1: 200 [females]/300 [males] - 550 ng/ml; grade 2: 550 - 1000 ng/ml; grade 3: > 1000 ng/ml). The clinical outcomes, including all-cause death, comorbidities and liver histology were compared between non-MHF and MHF in adjusted models. Results: In NHANES, compared with non-MHF with MD, MHF was related to higher risks of advanced fibrosis (FIB-4, P = 0.036), elevated albumin-creatinine ratio (UACR, P = 0.001) and sarcopenia (P = 0.013). Although the association between all grades of MHF and mortality was insignificant (P = 0.122), grades 2/3 was associated with increased mortality (P = 0.029). While comparing with non-MHF without MD, the harmful effects of MHF were more significant in mortality (P < 0.001), elevated UACR (P < 0.001), cardiovascular disease (P = 0.028), and sarcopenia (P < 0.001). In PERSONS cohort, MHF was associated with more advanced grades of steatosis (P < 0.001), lobular inflammation (P < 0.001), advanced fibrosis (P = 0.017), and more severe hepatocellular iron deposition (P < 0.001). Conclusions: Both in general population and at-risk individuals with MAFLD, MHF was related with poorer clinical outcomes
Development of a novel direct compressible co-processed excipient and its application for formulation of Mirtazapine orally disintegrating tablets
Introduction: Orally disintegrating tablets (ODTs) are designed to dissolve in the oral cavity within 3 min, providing a convenient option for patients as they can be taken without water. Direct compression is the most common method used for ODTs formulations. However, the availability of single composite excipients with desirable characteristics such as good compressibility, fast disintegration, and a good mouth-feel suitable for direct compression is limited.
Objective: This research was proposed to develop a co-processed excipient composed of xylitol, mannitol, and microcrystalline cellulose for the formulation of ODTs.
Methods: A total of 11 formulations of co-processed excipients with different ratios of ingredients were prepared, which were then compressed into ODTs, and their characteristics were thoroughly examined. The primary focus was on evaluating the disintegration time and hardness of the tablets, as these factors
are important in ensuring the ODTs meet the desired criteria. The model drug, Mirtazapine was then incorporated into the chosen optimized formulation.
Results: The results showed that the formulation comprised of 10% xylitol, 10% mannitol and 80% micro-crystalline cellulose demonstrated the fastest disintegration time (1.77 ± 0.119 min) and sufficient hardness (3.521 ± 0.143 kg) compared to the other formulations. Furthermore, the drug was uniformly distributed within the tablets and fully released within 15 min.
Conclusion: Therefore, the developed co-processed excipients show great potential in enhancing the functionalities of ODTs, offering a promising solution to improve the overall performance and usability of ODTs in various therapeutic applications
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