3,063 research outputs found
Recommended from our members
Rational Development of Solid Lewis Acid Catalysts for Biomass Conversion
The need for sustainable production of everyday materials in addition to declining reserves of petroleum-based feedstocks has motivated research into the production of renewable aromatic chemicals from biomass. We have proposed a multistep pathway to produce renewable p-xylene from lignocellulosic biomass using heterogeneous catalysts. The pathway includes formation of glucose by saccharification of cellulose, isomerization of glucose into fructose, dehydration/hydrogenolysis for production of 2,5-dimethylfuran (DMF), and final step for producing p-xylene from reacting DMF with ethylene.
Lewis acid zeolite catalysts (e.g. Sn-BEA, a tin containing molecular sieve with zeolite BEA structure) exhibited critical roles in the pathway because of its excellent catalytic activity for the conversion of glucose into fructose by intramolecular hydride transfer reaction and the production of p-xylene from DMF by cycloaddition/dehydration reactions. However, the development of Sn-BEA is a grand challenge due to the lengthy crystallization time (up to 40 days) and unknown structure of acid site. In this work, a highly reproducible seeded growth approach was invented to significantly shorten the crystallization time. It is demonstrated that the seed crystals effectively reduce the induction time of crystallization and lower the energy barrier by bypassing the nucleation stage. Crystallization kinetic studies reveal the highly crystalline Sn-BEA catalyst can be obtained in 3 hours at 200 °C with similar catalytic activity in isomerization reaction of glucose compared to conventional Sn-BEA. The discovery is important for rational synthesis of heteroatom containing zeolites.
Zr-, Sn-, and Ti-BEA Lewis acid zeolite catalysts were employed in production of p-xylene from DMF and ethylene. It was found that these Lewis acid catalysts are able to catalyze the tandem reaction consisting of Diels-Alder cycloaddition and dehydration reactions to form p-xylene. Zr-BEA shows the best performance with improved recalcitrance to deactivation compared to Brønsted acid zeolite catalyst (Al-BEA), reaching 76 % yield to p-xylene at 99 % conversion of DMF. Zr-BEA also features high p-xylene production rate due to its catalytic activity for both cycloaddition and dehydration reactions. The results provide an approach to rational develop bi-functional (Lewis+Brønsted acids) catalysts for the tandem reaction pathway to efficiently produce p-xylene and many other aromatics
THE EFFECT OF INNOVATION STRATEGY ON POST-M&A INNOVATION PERFORMANCE: AN EVIDENCE FROM PHARMACEUTICAL INDUSTRY
M&A is a popular strategy for pharmaceutical industry due to high R&D risk and costs. Prior research related to post-M&A performance mainly focused on the financial and technology resource perspectives. This study aims to provide a new perspective of innovation strategy which is inspired by the research of March (1991), who noted the difference between exploration and exploitation. Moreover, we build the bridge between M&A and innovation strategy by applying the resource-based view theory. We argue that the acquirer’s exploration strategy will negatively influence the post-M&A innovation performance and the innovation strategy similarity between the acquirer and the target is beneficial for future innovation. Furthermore, we hypothesize that there is a negatively moderating effect caused by the acquirer’s exploration strategy on the effect of innovation strategy similarity. On the basis of 89 M&A deals in the pharmaceutical industry, our empirical results suggest two important findings. First, post- M&A innovation performance is influenced by acquirer’s innovation strategy, more specifically, acquirer’s exploration is harmful for post-M&A innovation. Second, the similarity effect is moderated by acquirer’s innovation strategy. Precisely, acquirer’s exploration will diminish the positive effect of similarity
Construction of Cell–Extracellular Matrix Microenvironments by Conjugating ECM Proteins on Supported Lipid Bilayers
The cell membrane is an organized and fluid structure that modulates cellular activities in response to specific extracellular signals, and maintains the critical communication, integration, and homeostasis between the cytosol and the extracellular matrix (ECM). In recent years, tissue engineering and cell biology research has been rapidly progressed by a remarkable understanding of cell and ECM interfaces. In this review, the design of new biomimetic platforms based on the conjugation of ECM proteins on solid supported lipid bilayers (SLBs) will be summarized. The platforms provide a better system to evaluate cellular responses to specific recognition events, gradient, mechanical property, nanostructures, and inter- and intra-molecular interactions of ECM proteins on a non-fouling and fluid membrane. Moreover, the findings from the molecular interactions and cellular activities will be highlighted to look into the cell-materials mechanisms
Applying a Heuristic Approach for a Minimum-cost Operating Strategy for Tap Water
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive
Out-of-hospital Cardiac Arrest in the Elderly
SummaryBackgroundTo investigate the characteristics of out-of-hospital cardiac arrest (OHCA) in the elderly, we retrospectively studied a 6-month series of cases in an emergency department (ED) of a medical center in northern Taiwan.MethodsThere were 145 OHCA cases sent to our ED from January 1, 2007 to June 30, 2007. Of these, 28 traumarelated and five pediatric cases were excluded, and 112 cases were eventually enrolled into our study. The 112 cases were divided into an elderly group (≥ 65 years) of 81 cases and a non-elderly group of 31 cases. There were 64 males and 48 females (male/female ratio, 1.33:1) aged 24–99 years. We collected the laboratory data and made comparisons between the elderly and non-elderly group in arterial blood gas, hemoglobin, potassium, glucose, and troponin I. We used the statistical software SPSS version 11.5.0 (SPSS Inc., Chicago, IL, USA) with t test analysis. The clinical significance was set at p < 0.05.ResultsReturn of spontaneous circulation (ROSC) occurred in 46 cases (41%) after standard resuscitation by advanced cardiac life support. The elderly group had a higher ROSC rate than the non-elderly group, but this was not significant (44% vs. 32%; p = 0.335). The elderly group had less acidosis, less hypercapnia, less hyperkalemia, less hyperglycemia and a higher rate of elevated troponin I than the non-elderly group, but the differences were not significant. The elderly group had significantly lower hemoglobin levels than the non-elderly group (10.52 ± 3.04 vs. 12.6 ± 3.32g/dL; p = 0.003). The glucose levels of the ROSC group were significantly higher than the non-ROSC group in the elderly (230.14 ± 130.4 vs. 195.1 ± 147.7mg/dL; p = 0.049). In the group of acute coronary syndrome (ACS)-related OHCA, the ROSC rate in the elderly group was significantly higher than that of the non-elderly (54.2% vs. 40%; p = 0.014). The elderly group had a slightly lower rate of survival than the non-elderly group (7.4% vs. 9.7%; p = 0.159).ConclusionThe elderly OHCA cases had an anemic status. The elderly had a higher ROSC rate in cases with relative hyperglycemia and ACS-related OHCA. This finding provides us with the theory of trialing administration of glucose water during resuscitation in OHCA cases
Identifying Essential Competency Areas for Occupational Therapy Education: A Scoping Review
This scoping review aims to explore the essential areas of competency in occupational therapy as the ability to acquire the necessary knowledge, skills, and values for the profession is not easily quantifiable. The objectives of this study were two-fold: (1) identify the key competency areas of occupational therapy and (2) identify assessments that measure the competency areas. The review was conducted by a team of a librarian and two independent reviewers to systematically search the peer-reviewed literature. The search yielded 296 articles and 52 articles that met the inclusion criteria. These articles were categorized under four overarching themes: (1) professional attitudes that include cultural competence and the ability to uphold ethical and legal responsibilities; (2) professional communication such as engaging in active participation with the client; (3) ability to work in collaboration with inter- and intra- professionals; and (4) provide quality service with a focus on evidence-based practices. Additional research is warranted to further build the evidence base of occupational therapy competence to improve outcomes for patients. The results of this study contribute to the ongoing collective work of researchers and practitioners who wish to continually improve a client-centered holistic approach through the recognition of these key themes. Identifying the relevant measures that assess these themes establishes the foundation needed to support the continuous effort to educate and support entry-level occupational therapists by paving the way for further development and refinement of measurement tools
Antimicrobial susceptibility and clinical outcomes of Candida parapsilosis bloodstream infections in a tertiary teaching hospital in Northern Taiwan
BackgroundCandida parapsilosis is an emerging non-albicans Candida that is associated with central line-associated infection. C. parapsilosis has higher minimal inhibitory concentration to echinocandin than Candida albicans, and the effects of echinocandin on C. parapsilosis are ambiguous. Therefore, in this study, we aimed to investigate the susceptibility and the correlation between incidence and drug consumption.MethodsThis retrospective study was conducted in a tertiary teaching hospital in northern Taiwan between 2008 and 2012. The Candida species distribution, the correlation between the use of antifungal agents and the incidence of C. parapsilosis bloodstream infection, demographic information, clinical characteristics, mortality rate, and in vitro susceptibility of C. parapsilosis were analyzed.ResultsA total of 77 episodes from 77 patients were included for analysis. The overall 90-day mortality rate was 41.6%. The incidence of C. parapsilosis bloodstream infection showed a moderate positive correlation with the increased defined daily dose of echinocandin. The risk factors associated with mortality included malignancy or a metastatic tumor. Multivariate logistical regression analysis showed that patients with malignancy had higher odds ratios in terms of mortality. The rate of C. parapsilosis resistance to fluconazole was 3%, whereas the susceptibility rate was 95.5%.ConclusionUnderlying comorbidity and malignancy were factors leading to death in patients with C. parapsilosis bloodstream infection. Catheter removal did not influence the mortality rate. The survival rate of patients receiving echinocandin was lower than the group receiving fluconazole. Fluconazole remains the drug of choice to treat C. parapsilosis bloodstream infections
- …