716 research outputs found
Spherical Tin Oxide, SnO2 Particles Fabricated via Facile Hydrothermal Method for Detection of Mercury (II) Ions.
Smooth-surface spherical tin oxide particles were fabricated via hydrothermal processing route. X-ray
diffraction (XRD) revealed that the particles consisted of
the rutile phase of SnO2 with tetragonal structure.
The spherical morphology was realized with the aid of ammonia. The aggregation of SnO2 particles could be avoided by adjusting the concentration of tin (II) chloride. Bare
glassy carbon electrode (GCE) was modified with the hydrothermally prepared SnO2 particles to detect the presence of mercury (II) ions (Hg2+), in the presence of
potassium chloride (KCl) as a supporting electrolyte.
GCE modified with the spherical SnO2 particles that possessed small crystallite size and smooth surface exhibited significantly enhanced oxidative and reductive current of Hg2+ during cyclic voltammetry compared with its bare counterpart. The reductive current was observed to increase by two fold and the detection limit of 75 nM for Hg
2+ was achieved. This suggests that SnO2 particles are
a promising chemical sensor for the detection of Hg2+
in natural waters
Comparative genome analysis of Fusobacterium nucleatum
Fusobacterium nucleatum is considered to be a key oral bacterium in recruiting periodontal pathogens into subgingival dental plaque. Currently F. Nucleatum can be subdivided into five subspecies. Our previous genome analysis of F. Nucleatum W1481 (referred to hereafter asW1481), isolated from an 8-mmperiodontal pocket in a patient with chronic periodontitis, suggested the possibility of a new subspecies. To further investigate the biology and relationships of this possible subspecies with other known subspecies, we performed comparative analysis between W1481 and 35 genome sequences represented by the five known Fusobacterium subspecies.Our analyses suggest thatW1481ismost likely anew F. Nucleatum subspecies, supported by evidence fromphylogenetic analysesandmaximaluniquematchindices(MUMi). Interestingly,wefoundahorizontally transferredW1481-specificgenomicisland harboring the tripartite ATP-independent (TRAP)-like transporter genes, suggesting this bacterium might have a high-Affinity transport system for the C4-dicarboxylates malate, succinate, and fumarate.Moreover, we found virulence genes in theW1481 genome that may provide a strong defense mechanism which might enable it to colonize and survive within the host by evading immune surveillance. This comparative study provides better understanding of F. Nucleatum and the basis for future functional work on this important pathogen
Survival outcomes of salvage surgery in the watch-and-wait approach for rectal cancer with clinical complete response after neoadjuvant chemoradiotherapy: a systematic review and meta-analysis
Purpose This systematic review and meta-analysis compared the outcomes of the watch-and-wait (WW) approach versus radical surgery (RS) in rectal cancers with clinical complete response (cCR) after neoadjuvant chemoradiotherapy. Methods This study followed the PRISMA guidelines. Major databases were searched to identify relevant articles. WW and RS were compared through meta-analyses of pooled proportions. Primary outcomes included overall survival (OS), disease-free survival (DFS), local recurrence, and distant metastasis rates. Pooled salvage surgery rates and outcomes were also collected. The Newcastle-Ottawa scale was employed to assess the risk of bias. Results Eleven studies including 1,112 rectal cancer patients showing cCR after neoadjuvant chemoradiation were included. Of these patients, 378 were treated nonoperatively with WW, 663 underwent RS, and 71 underwent local excision. The 2-year OS (risk ratio [RR], 0.95; P=0.94), 5-year OS (RR, 2.59; P=0.25), and distant metastasis rates (RR, 1.05; P=0.80) showed no significant differences between WW and RS. Local recurrence was more frequent in the WW group (RR, 6.93; P<0.001), and 78.4% of patients later underwent salvage surgery (R0 resection rate, 97.5%). The 2-year DFS (RR, 1.58; P=0.05) and 5-year DFS (RR, 2.07; P=0.02) were higher among RS cases. However, after adjustment for R0 salvage surgery, DFS showed no significant between-group difference (RR, 0.82; P=0.41). Conclusion Local recurrence rates are higher for WW than RS, but complete salvage surgery is often possible with similar long-term outcomes. WW is a viable strategy for rectal cancer with cCR after neoadjuvant chemoradiation, but further research is required to improve patient selection
Adaptive Introgression across Semipermeable Species Boundaries between Local Helicoverpa zea and Invasive Helicoverpa armigera Moths.
Hybridization between invasive and native species has raised global concern, given the dramatic increase in species range shifts and pest outbreaks due to anthropogenic dispersal. Nevertheless, secondary contact between sister lineages of local and invasive species provides a natural laboratory to understand the factors that determine introgression and the maintenance or loss of species barriers. Here, we characterize the early evolutionary outcomes following secondary contact between invasive Helicoverpa armigera and native H. zea in Brazil. We carried out whole-genome resequencing of Helicoverpa moths from Brazil in two temporal samples: during the outbreak of H. armigera in 2013 and 2017. There is evidence for a burst of hybridization and widespread introgression from local H. zea into invasive H. armigera coinciding with H. armigera expansion in 2013. However, in H. armigera, the admixture proportion and the length of introgressed blocks were significantly reduced between 2013 and 2017, suggesting selection against admixture. In contrast to the genome-wide pattern, there was striking evidence for adaptive introgression of a single region from the invasive H. armigera into local H. zea, including an insecticide resistance allele that increased in frequency over time. In summary, despite extensive gene flow after secondary contact, the species boundaries are largely maintained except for the single introgressed region containing the insecticide-resistant locus. We document the worst-case scenario for an invasive species, in which there are now two pest species instead of one, and the native species has acquired resistance to pyrethroid insecticides through introgression
Laser hemorrhoidoplasty versus conventional hemorrhoidectomy for grade II/III hemorrhoids: a systematic review and meta-analysis
Purpose This study compared the short- and long-term clinical outcomes of laser hemorrhoidoplasty (LH) vs. conventional hemorrhoidectomy (CH) in patients with grade II/III hemorrhoids. Methods PubMed/Medline and the Cochrane Library were searched for randomized and nonrandomized studies comparing LH against CH in grade II/III hemorrhoids. The primary outcomes included postoperative use of analgesia, postoperative morbidity (bleeding, urinary retention, pain, thrombosis), and time of return to work/daily activities. Results Nine studies totaling 661 patients (LH, 336 and CH, 325) were included. The LH group had shorter operative time (P0.999) and prolapse (P=0.240), and the likelihood of complete resolution at 12 months, were similar (P=0.240). Conclusion LH offers more favorable short-term clinical outcomes than CH, with reduced morbidity and pain and earlier return to work or daily activities. Medium-term symptom recurrence at 12 months was similar. Our results should be verified in future well-designed trials with larger samples
Preparation and characterization of tin oxide, SnO2 nanoparticles decorated graphene
SnO2 nanoparticles/graphene (SnO2/GP) nanocomposite was synthesized by a facile microwave method. The X-ray diffraction (XRD) pattern of the nanocomposite corresponded to the diffraction peak typical of graphene and the rutile phase of SnO2 with tetragonal structure. The field emission scanning electron microscope (FESEM) images revealed that the graphene sheets were dotted with SnO2 nanoparticles with an average size of 10 nm. The X-ray photoelectron spectroscopy (XPS) analysis indicated that the development of SnO2/GP resulted from the removal of the oxygenous groups on graphene oxide (GO) by Sn2+ ions. The nanocomposite modified glassy carbon electrode (GCE) showed excellent enhancement of electrochemical performance when interacting with mercury(II) ions in potassium chloride supporting electrolyte. The current was increased by more than tenfold, suggesting its potential to be used as a mercury(II) sensor
Postoperative outcomes after prehabilitation for colorectal cancer patients undergoing surgery: a systematic review and meta-analysis of randomized and nonrandomized studies
Purpose Prehabilitation (PH) is purported to improve patients’ preoperative functional status. This systematic review and meta-analysis sought to compare short-term postoperative outcomes between patients who underwent a protocolized PH program and the existing standard of care among colorectal cancer patients awaiting surgery. Methods A search in MEDLINE/PubMed, the Cochrane Library, Embase, Scopus, and CINAHL was conducted to identify relevant articles. Repetitive and exhaustive combinations of MeSH search terms (“prehabilitation,” “colorectal cancer,” “colon cancer,” and “rectal cancer”) were used to identify randomized and nonrandomized studies comparing PH versus standard of care for colorectal cancer patients awaiting surgery. The primary outcomes included postoperative morbidity, length of hospital stay, and readmission rates. Results Seven studies including 1,042 colorectal cancer patients (PH, 382) were included. No significant differences were found in intraoperative outcomes. The postoperative complication rates were comparable between groups (Clavien-Dindo grades I and II: risk ratio, 0.82; 95% confidence interval, 0.62–1.07; P=0.15; Clavien-Dindo grades ≥III: risk ratio, 1.02; 95% confidence interval, 0.72–1.44; P=0.92). There were also no significant differences in length of hospital stay (P=0.21) or the risk of 30-day readmission (P=0.68). Conclusion Although PH does not appear to improve short-term postoperative outcomes following colorectal cancer surgery, the quality of evidence is impaired by the limited trials and heterogeneity. Thus, further large-scale trials are warranted to draw definitive conclusions and establish the long-term effects of PH
Ascorbic acid and tetrahydrobiopterin potentiate the EDHF phenomenon by generating hydrogen peroxide
Aims Our objective was to investigate whether pro-oxidant properties of ascorbic acid (AA) and tetrahydrobiopterin
(BH4) modulate endothelium-dependent, electrotonically mediated arterial relaxation.
Methods and results In studies with rabbit iliac artery (RIA) rings, NO-independent, endotheliumderived
hyperpolarizing factor (EDHF)-type relaxations evoked by the sarcoplasmic endoplasmic reticulum
Ca2þ-ATPase inhibitor cyclopiazonic acid and the G protein-coupled agonist acetylcholine (ACh)
were enhanced by AA (1 mM) and BH4 (200 mM), which generated buffer concentrations of H2O2 in
the range of 40–80 mM. Exogenous H2O2 potentiated cyclopiazonic acid (CPA)- and ACh-evoked relaxations
with a threshold of 10–30 mM, and potentiation by AA and BH4 was abolished by catalase,
which destroyed H2O2 generated by oxidation of these agents in the organ chamber. Adventitial application
of H2O2 also enhanced EDHF-type dilator responses evoked by CPA and ACh in RIA segments perfused
intraluminally with H2O2-free buffer, albeit with reduced efficacy. In RIA rings, both control
relaxations and their potentiation by H2O2 were overcome by blockade of gap junctions by connexinmimetic
peptides (YDKSFPISHVR and SRPTEK) targeted to the first and second extracellular loops of
the dominant vascular connexins expressed in the RIA. Superoxide dismutase attenuated the potentiation
of EDHF-type relaxations by BH4, but not AA, consistent with findings demonstrating a differential
role for superoxide anions in the generation of H2O2 by the two agents.
Conclusion Pro-oxidant effects of AA and BH4 can enhance the EDHF phenomenon by generating H2O2,
which has previously been shown to amplify electrotonic hyperpolarization-mediated relaxation by
facilitating Ca2þ release from endothelial stores
A Divergent Synthetic Approach to Diverse Molecular Scaffolds: Assessment of Lead-Likeness using LLAMA, an Open-Access Computational Tool
Complementary cyclisation reactions of hex-2-ene-1,6-diamine derivatives were exploited in the synthesis of alternative molecular scaffolds. The value of the synthetic approach was analysed using LLAMA, an open-access computational tool for assessing the lead-likeness and novelty of molecular scaffolds
Pneumonia in adults - Quality standard QS110
IntroductionThis quality standard covers adults (18 years and older) with a suspected or confirmed diagnosis of community acquired pneumonia. For more information see the pneumonia topic overview.Why this quality standard is neededPneumonia is an infection of the lung tissue. When a person has pneumonia the air sacs in their lungs become filled with microorganisms, fluid and inflammatory cells and their lungs are not able to work properly. Diagnosis of pneumonia is based on symptoms and signs of an acute lower respiratory tract infection, and can be confirmed by a chest X-ray showing new shadowing that is not due to any other cause (such as pulmonary oedema or infarction). The NICE guideline on pneumonia classifies pneumonia depending on the source of the infection as community acquired or hospital-acquired, which need different management strategies. Every year between 0.5% and 1% of adults in the UK will have community-acquired pneumonia. It is diagnosed in 5–12% of adults who present to GPs with symptoms of lower respiratory tract infection, and 22–42% of these are admitted to hospital, where the mortality rate is between 5% and 14%. Between 1.2% and 10% of adults admitted to hospital with community acquired pneumonia are managed in an intensive care unit, and for these patients the risk of dying is over 30%. More than half of pneumonia-related deaths occur in people older than 84 years.At any time, 1.5% of hospital patients in England have a hospital-acquired respiratory infection, more than half of which are hospital-acquired pneumonia and are not associated with intubation. Hospital-acquired pneumonia is estimated to increase a hospital stay by about 8 days and has a reported mortality rate ranging from 30–70%. There are variations in clinical management and outcomes across the UK
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