13 research outputs found
Failure of early mycological clearance in HIV-negative cryptococcal meningitis
BACKGROUND: Negative cerebrospinal fluid (CSF) cultures at 2 weeks after antifungal treatment (early mycological clearance [EMC]) should be a treatment goal of cryptococcal meningitis (CM). However, EMC in human immunodeficiency virus (HIV)-negative patients with CM is poorly understood.
METHODS: We conducted a retrospective review of medical records and 1-year follow-up of 141 HIV-negative patients with CM with an initial positive CSF culture for
RESULTS: Of 141 patients, 28 (19.9%) had EMC failure. The 1-year mortality rate was 5.7% (8/141). Multivariate analysis showed that non-amphotericin B (AmB)-based regimens, baseline log
CONCLUSIONS: EMC failure in HIV-negative CM is attributed to non-AmB-based therapy and is associated with lo
Arylboronic Acids Catalyzed Upgrade of Glucosamines for Deoxyfructosazine and Insights on Reaction Mechanism
Chitin is the most abundant N-containing polysaccharides in nature and D-glucosamine is one of most successful commercial monomer products in current market. Here we reported an arylboronic acids catalyzed upgrade of glucosamines in aqueous solution for deoxyfructosazine which is an important high-value compound in pharmaceutical and food industries, as well as a promising bio-based platform molecule for speciality chemicals and sustainable functional materials. Such direct integration of deoxyfructosazine into development of renewable chemicals/functional materials might be a practical way for utilization of chitin as a renewable nitrogen source. A mechanism focusing on catalytic cycle of arylboronic acid via a boron transfer was also proposed
Imidazole Promoted Efficient Anomerization of β-D-Glucose Pentaacetate in Solid State and Reaction Mechanism
Anomerization of glycosides was rarely performed under basic condition. Here an imidazole promoted anomerization of β-D-glucose pentaacetate in solid state at room temperature was discovered. This unprecedent anomerization in solid state occurred after simple mixing and reaction proceeded continuously to full conversion without stirring or mechanomixing. Current understanding of reaction mechanism involved with inter/intramolecular acyl transfer promoted by two imidazole in concerted manner may promote discovery of more new transformations of glucosides in solid state
Tunable Boc Modification of Lignin and Its Impact on Microbial Degradation Rate
A new type of modified lignin, lignin-p-Boc, was obtained through
reaction with di-tert-butyl
dicarbonate (Boc2O) in aqueous media catalyzed by 4-dimethylaminopyridine
(DMAP). Boc modification occurred regardless
of type of lignin, was tunable, and proceeded well in recovering
lignin at high purity from sodium lignosulfonate (a common byproduct from pulping industry; lignin content: 60%). Lignin-p-BOC was demonstrated as a potential reactive filler in green plastic and as a
potential crosslinker in design of bioresorbable composite polymeric implants.
Furthermore, the effects of the modification on the breakdown rate of alkali
lignin by microbes was investigated, and the results showed that the
modification substantially decreases the breakdown rate. The tunable Boc
modification process was designed via a system thinking, including availability
of raw lignin, economical/green modification, potentiality of drop-in-change to
current thermoplastic processing, modification impact on microbial degradability/disposed
environment at the end of use life; hence the holistic consideration makes this alternative method for upgrade
of technical lignins very practical for future industrial application. Via “in-situ” forming “easily breakable covalent bonds” with existing
thermopolymers inside, Lignin-p-BOCs are also promising to play an important
role as both excellent binders via “random match” and reductants in
transforming linear plastic waste into circular plastics.<br /