12 research outputs found
Acute cholangitis: a state-of-the-art review
Acute cholangitis is a potentially life-threatening bacterial infection of the intra and/or extrahepatic bile ducts. It remains the second and third cause of community-acquired and hospital-acquired bacteremia, respectively, and is associated with mortality rates of up to 15%, despite advances in broad-spectrum antimicrobial therapy and improved access to emergency biliary tract decompression procedures. Even though not much has changed in recent years in terms of diagnosis or treatment, new data have emerged regarding multidrug-resistant bacteria that serve as etiologic agents of cholangitis. Moreover, different approaches in antibiotic regimes depending on severity grading and bile sample cultures as well as novel minimally invasive endoscopic procedures that can help when consecrated treatments such as endoscopic retrograde cholangiopancreatography (ERCP) fail, cannot be performed, or are unavailable have been proposed. This state-of-the-art review aims to offer a complete and updated assessment of the epidemiology, novel diagnostic and therapeutic methods, complications, and prognostic variables of acute cholangitis. The authors will review the prognostic implications of unusual complications, the relevance of regular bile samples and antibiograms, and their new role in guiding antibiotic therapy and limiting antibiotic resistance to present an organized and comprehensive approach to the care of acute cholangitis
How Effective Are Sub-Bandgap States in AgInS<sub>2</sub> Quantum Dots for Electron Transfer?
Ternary IāIIIāVI2 semiconductors,
such
as CuInS2 and AgInS2 (compliant with RoHS, restriction
of hazardous substances), are useful as light-harvesting materials.
However, the presence of sub-bandgap states (donorāacceptor
pair or DAP) introduces complexity during their activation through
photoexcitation. When photoirradiated, the photogenerated charge carriers
in AgInS2 quantum dots undergo rapid relaxation to populate
intrinsic DAP states while competing with charge carrier recombination.
Interestingly, these defect-related DAP states can be activated through
sub-bandgap excitation and, thus, extend the absorption range to the
near-infrared region. We have now employed time-resolved absorption
and emission techniques to glean mechanistic insights into the photophysical
properties of intragap states of AgInS2 quantum dots (QDs)
and their participation in interfacial electron transfer. When the
AgInS2 QDs are excited with above bandgap excitation (400
nm), we observe a prompt formation (<1 ps) of the bleach at wavelengths
closer to the bandgap, indicating the formation of a charge-separated
pair. This transient bleach shifts to lower energies with time (ā¼5
ps), indicating population of sub-bandgap states via relaxation of
electrons and holes from the conduction and valence bands, respectively.
These sub-bandgap states which can also be populated via direct excitation
using low energy (Ī» Eg) excitation
exhibit prompt bleach (<1 ps) in contrast to bandgap excitation.
The excited DAP states are long-lived (ā¼1 Ī¼s) and can
participate in the electron transfer process. We have elucidated the
electron transfer dynamics from these midgap states of AgInS2 by employing ethyl viologen (EV2+) as a probe molecule.
The role of surface-anchored viologen as an electron shuttle was further
exploited by using free-floating benzoquinone (BQ) as a secondary
electron acceptor. The sub-bandgap response of AgInS2 to
promote electron transfer paves the way to extend the photoresponse
of ternary IāIIIāVI2 semiconductor-based
photocatalytic systems
Photocatalytic Membrane for Hydrogen Evolution: Directed Electron and Hole Transfer across PtāAgInS<sub>2</sub>āNafion
A photocatalytically active membrane, designed by embedding
AgInS2 semiconductor nanoparticles and a Pt cocatalyst,
facilitates
a āvectorialā flow of photogenerated electrons and holes
in opposite directions. The fabricated PtāAgInS2āNafion membrane, when inserted in an H-cell containing 50%
ethanol (AgInS2 side) and water (pH = 4, Pt side), produced
H2 under visible light irradiation. Photogenerated electrons
reduced H+ at the Pt surface to produce H2,
while oxidation of ethanol with holes at AgInS2 also produced
H2. Back electron transfer at the Pt surface and surface
defects within AgInS2 were responsible for the lower H2 yield in the reduction compartment. Remediation of the AgInS2 film with mercaptopropionic acid increased the yield 5ā10
times by overcoming the loss of charge carriers at the defect sites.
The feasibility of carrying out selective reduction and oxidation
processes by directing the flow of charge carriers highlights the
usefulness of photocatalytic membranes in solar fuel generation
Anatomical variations of the pyramidalis muscle: a systematic review and meta-analysis
Purpose: To provide a comprehensive evidence-based assessment of the anatomical characteristics of the pyramidalis muscle (PM). Materials and methods: A thorough systematic search of the literature through August 31st 2020 was conducted on major electronic databases PubMed, Scopus and Web of Science (WOS) to identify studies eligible for inclusion. Data were extracted and pooled into a meta-analysis using MetaFor package in R and MetaXL. A random-effects model was applied. The primary outcome of interest was the prevalence of PM. The secondary outcomes were the dimensions (length and width) of the PM. Results: A total of 11 studies (n = 787 patients; 1548 sides) were included in the meta-analysis. The multinomial pooled prevalence estimate (PPE) for a bilateral absence of the PM was 11.3% (95% CI [7.2%, 16.2%], 82.3% (95% CI [76.2%, 87.6%]) for a bilateral presence, and 6.3% (95% CI [3.3%, 10.2%]) for a unilateral presence. Of four studies (n = 37 patients) that reported the side of a unilateral presence, the PPE of a unilateral right-side presence was 42.2% (95% CI [23.0%, 62.3%]) compared to 57.8% for a unilateral left-side presence (95% CI [37.7%, 77.0%]). The mean length of the PM displayed high levels of heterogeneity, ranging from 3.12 to 12.50 cm. Conclusion: The pyramidalis muscle is a rather constant anatomical structure being present in approximately 90% of individuals
The status of flora and fauna in the Nzoia River drainage basin in western Kenya
The species richness of flora and fauna in the Nzoia River drainage basin is documented through a study of museum specimens, catalogues and databases. The catchment area and basin covers 2.2% (12900/580367 km2) of Kenyaās total land area with an altitudinal range of 1140 to 4300 m and varied ecosystem and land uses. We recorded approximately 9.3% (3239/34677) of Kenyaās current known species of vascular plants, invertebrates (insects and spiders), fish, amphibians, reptiles, birds and mammals. Bird species made up the highest proportion 58.3% (650/1114) of the national total followed by amphibians 37.3% (41/110), reptiles 45.0% (86/191), mammals 31.3% (122/390), vascular plants 17.9% (1251/7000), fish 6.7% (58/872) (32.2% (58/180) for freshwater fish only) and invertebrates (insects and spiders) 4.1% (1031/25000). Ninety-five species recorded in this area are endemic to Kenya and 42 globally threatened. The species recorded contribute to several ecosystem services including pest control, pollination, bio-indicators, medicine and cosmetics, building materials, ecotourism, research and education. Data available differed substantially across counties and taxon groups with gaps apparent in five counties (Bungoma, Busia, Elgeyo Marakwet, Siaya and Usain Gishu) and four taxa plants, invertebrates, fungi and bacteria where a dearth of information exists. To fill these gaps we recommend prioritisng future survey effort on taxa and counties with fewer than 10% of the total numbers of records