Improving the throughput of plasticating extruders : manufacture of non-circular pellets, measurement of their interparticulate friction coefficient, and implications for screw design

This dissertation addresses the hypothesis that the interparticulate friction coefficient of a bed of polymeric particulates is a function of the cross-section of the pellets. Most pellets have a circular cross-section especially those that are strand cut. But when such pellets constitute a particulate bed there are few restrictions to adjacent pellets turning with respect to each other, or of the beds rupturing under shear load. This rupture can occur in plasticating extrusion, and it results in a poorly mixed melt with an inhomogeneous temperature distribution. The temperature fluctuations cause viscosity fluctuations which in turn cause pressure fluctuations. The pressure fluctuations cause throughput variations which lead to thickness variations in the product. That results in poor quality product. This sequence of events is termed surging. If the rupture of the solid bed can be prevented then surging can be curtailed. An increase in the interparticulate friction coefficient is expected to reduce solid bed rupturing. And the interparticulate friction coefficient can be increased if pellets with non-circular cross-section constitute it. Due to the fact that trilobal fibers are used to provide interlocking in the textile industry, the trilobal cross-section was first tested. This led to tests on bilobal and quadrilobal cross-sections as well. However, prior to testing the pellets required manufacture. Since bilobal, trilobal and quadrilobal cross-sections are different profile cross-sections, it was first necessary to design and build a series of profile extrusion dies. Each die was capable of producing a variety of pellet cross-sections if the material was changed, or if the throughput rate was varied. So many pellet geometries could be readily produced. Each variation of material and geometry was tested independently in a direct shear cell to measure the interparticulate friction coefficient. It was clearly found that the highest interparticulate friction coefficients occurred with pellets of bilobal cross-section, a 31% to 81% increase over pellets with circular cross-section. In addition pellets with trilobal and quadrilobal cross-section exhibited an improved interparticulate friction coefficient, a 20% to 34% increase compared to pellets with circular cross-sections. Consolidation pressure and time had minimal effects whereas agitation caused interparticulate friction coefficient increases from 51% to 89%. The effect of additives in the particulate continuum on the interparticulate friction coefficient was also studied. Since production runs could not be made to test if surging could in fact be reduced, due to the vast amounts of feedstock required, resort was made to numerical experimentation. An existing software package was modified to allow study of the transport of a portion of the solid bed. In this way rupture could be predicted based on the value of the interparticulate friction coefficient. Thus it could be inferred that surging would be reduced

Acute exacerbation of psychiatric symptoms during influenza treatment with oseltamivir in chronic schizophrenia

AbstractInfluenza treatment and prophylaxis with oseltamivir are critically important in reducing the morbidity and mortality of patients in chronic psychiatric facilities. Abnormal behavior, delusions, perceptual disturbances, mania, and depression have all been reported as oseltamivir-related psychiatric side effects. We hereby report two chronic schizophrenia patients in Taiwan manifesting psychiatric instability who were being treated with oseltamivir for suspected influenza infection, and further discuss other potential contributing factors. The possibility that oseltamivir can cause psychotic or affective symptoms suggests that additional caution is necessary for its use in patients with an established psychiatric diagnosis

How Does Time Synchronization Affect Innovation Quality? : Based on Information and Knowledge Acquirement

Peer reviewe

Credit Scoring Based on Hybrid Data Mining Classification

The credit scoring has been regarded as a critical topic. This study proposed four approaches combining with the NN (Neural Network) classifier for features selection that retains sufficient information for classification purpose. Two UCI data sets and different approaches combined with NN classifier were constructed by selecting features. NN classifier combines with conventional statistical LDA, Decision tree, Rough set and F-score approaches as features preprocessing step to optimize feature space by removing both irrelevant and redundant features. The procedure of the proposed algorithm is described first and then evaluated by their performances. The results are compared in combination with NN classifier and nonparametric Wilcoxon signed rank test will be held to show if there has any significant difference between these approaches. Our results suggest that hybrid credit scoring models are robust and effective in finding optimal subsets and the compound procedure is a promising method to the fields of data mining

Mortality of continuous infusion versus intermittent bolus of meropenem: a systematic review and meta-analysis of randomized controlled trials

BackgroundMeropenem belongs to the carbapenem class, which is categorized as beta-lactam antibiotics. These antibiotics are administered in intermittent bolus doses at specific time intervals. However, the continuous infusion approach ensures sustained drug exposure, maintaining the drug concentration above the minimum inhibitory concentration (MIC) throughout the entire treatment period. This study aimed to find out the association between continuous infusions of meropenem and mortality rates.Materials and methodsWe conducted a search of the PubMed/Medline, EMBASE, Cochrane Central, and ClinicalTrials.gov databases up to 14 August 2023. The six randomized controlled trials (RCTs) were identified and included in our analysis. The random-effects model was implemented using Comprehensive Meta-Analysis software to examine the outcomes.ResultsOur study included a total of 1,529 adult patients from six randomized controlled trials. The primary outcome indicated that continuous infusion of meropenem did not lead to reduction in the mortality rate (odds ratio = 0.844, 95% CI: 0.671–1.061, P =0.147). Secondary outcomes revealed no significant differences in ICU length of stay (LOS), ICU mortality, clinical cure, or adverse events between continuous infusion and traditional intermittent bolus strategies of meropenem. Notably, we observed significant improvements in bacterial eradication (odds ratio 19 = 2.207, 95% CI: 1.467–3.320, P < 0.001) with continuous infusion of meropenem. Our study also suggested that performing continuous infusion may lead to better bacterial eradication effects in resistant pathogens (coefficient: 2.5175, P = 0.0138*).ConclusionContinuous infusion of meropenem did not result in the reduction of mortality rates but showed potential in improving bacterial eradication. Furthermore, this strategy may be particularly beneficial for achieving better bacterial eradication, especially in cases involving resistant pathogens

2-(2H-Benzotriazol-2-yl)-6-[(diethyl­amino)meth­yl]-4-methyl­phenol

In the title compound, C18H22N4O, the dihedral angle between the planes of the benzotriazol unit and the phenyl ring of the phen­oxy group is 6.4 (2)°. There is an intra­molecular O—H⋯N hydrogen bond between the phenol and benzotriazol groups

Age-related changes in the neural gating of respiratory sensations in humans

Background: Neural gating of respiratory sensations (NGRS) characterises the brain\u27s ability to filter out repetitive respiratory sensory stimuli. This mechanism plays a crucial role in the neural processing of respiratory stimuli. However, whether ageing affects NGRS in healthy adults is still unclear. Therefore, we aimed to measure the effect of age on NGRS as well as the corresponding S1 and S2 components of the respiratory-related evoked potentials (RREPs). Methods: Three age groups of healthy adults participated in this study: a young group (YG; age 20-39 years), a middle-aged group (MG; age 40-59 years) and an old group (OG; age ≥60 years). NGRS was measured by the RREPs in the electroencephalogram in response to short-paired respiratory occlusion stimuli (S1 and S2). The S2/S1 ratio of the RREP N1 amplitude (the negative deflection of the RREP at ∼85-135 ms) was used to characterise NGRS. Results: The results showed a significantly smaller N1 S2/S1 ratio in the YG than in the MG (p=0.01) and OG (p=0.03). Further analysis showed that the S1 N1 amplitude was larger for the YG compared with the MG (p=0.03) and OG (p=0.007). Moreover, age was significantly correlated with the N1 S2/S1 ratio (r=0.43), with higher age relating to higher N1 S2/S1 ratios. Conclusions: The greater N1 S2/S1 ratios observed in older adults suggest that ageing has a negative impact on the NGRS. This might contribute to increased experiences of respiratory sensations such as dyspnoea in ageing adults

A rare, highly aggressive primitive neuroectodermal tumor of the kidney: Case report and literature review

AbstractWe report a case of a 14-year-old boy who initially suffered from a sudden onset of abdominal pain for 2 weeks with a protrusive soft mass over the left upper abdomen. No obvious symptomatic symptoms or body weight loss were observed. However, early lung metastasis was detected after an initial computed tomographic examination. Even after we performed salvage en bloc resection of the huge retroperitoneal tumor after primary neoadjuvant chemotherapy, the final outcome was still poor. A diagnosis according to radiologic findings was uncharacteristic. Finally, a pathologic diagnosis based on histologic and immunohistochemical results revealed a rare renal peripheral primitive neuroectodermal tumor

LrrA, a novel leucine-rich repeat protein involved in cytoskeleton remodeling, is required for multicellular morphogenesis in Dictyostelium discoideum

AbstractCell sorting by differential cell adhesion and movement is a fundamental process in multicellular morphogenesis. We have identified a Dictyostelium discoideum gene encoding a novel protein, LrrA, which composes almost entirely leucine-rich repeats (LRRs) including a putative leucine zipper motif. Transcription of lrrA appeared to be developmentally regulated with robust expression during vegetative growth and early development. lrrA null cells generated by homologous recombination aggregated to form loose mounds, but subsequent morphogenesis was blocked without formation of the apical tip. The cells adhered poorly to a substratum and did not form tight cell–cell agglomerates in suspension; in addition, they were unable to polarize and exhibit chemotactic movement in the submerged aggregation and Dunn chamber chemotaxis assays. Fluorescence-conjugated phalloidin staining revealed that both vegetative and aggregation competent lrrA− cells contained numerous F-actin-enriched microspikes around the periphery of cells. Quantitative analysis of the fluorescence-stained F-actin showed that lrrA− cells exhibited a dramatically increase in F-actin as compared to the wild-type cells. When developed together with wild-type cells, lrrA− cells were unable to move to the apical tip and sorted preferentially to the rear and lower cup regions. These results indicate that LrrA involves in cytoskeleton remodeling, which is needed for normal chemotactic aggregation and efficient cell sorting during multicellular morphogenesis, particularly in the formation of apical tip