[Determination of metal elements in PM2. 5 by ICP-OES with microwave digestion].

In the present work, a method was developed for determining lead, zinc, copper, cadmium, znd chromium in PM2. 5 by inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis with microwave digestion and glass fibre filter collection of samples. The microwave digestion systems were investigated and the experimental conditions were optimized. The results show that (1) HNO3-H2O02 digestion system is more stable and complete than HNO3-HCl and HNO3-H2 SO4 digestion systems; (2) The most sensitive emission wave length of lead, zinc, copper, cadmium, and chromium are 220.353, 213.857, 327.393, 228.802, and 267.716 nm, respectively; (3) The highest signal-to-noise ratios were observed under the conditions: RF power of 1 300 W, peristaltic pump flow rate of 1.5 mL x min(-1), cooling gas flow rate of 15 L x min(-1), and carrier gas flow rate of 0.8 L x min(-1). In addition, the detection limit for these elements ranged between 2.02 x 10(-3) and 8.20 x 10(-3(µg x mL(-1), the relative standard deviations (RSD, n = 6) for the samples were in the range of 1.86%-2.82%, and the recovery for the elements determined was from 91.6% to 103.7%. The proposed method was used for determination of the above five elements in atmospheric fine particulate matter at Wanzhou Monitoring Site of Chongqing Institute of Green and Intelligent Technology. The results revealed that the atmospheric fine particulate matter at this monitoring site was not polluted by cadmium and chromium, lead was at the level of potential contamination, while zinc and copper were at the level of slight pollution.

Effects of the interaction between Na2Wo4-6-benzylaminopurine anionic chelate and rhodamine 6G on the resonance Rayleigh scattering and fluorescence spectra and their analytical applications.

In pH 4.99-6.06 Britton-Robinson (BR) buffer medium, 6-benzylaminopurine (6-BA) reacted with Na2WO4 to form 1:1 anionic chelate (6-BA·WO4)(2-), which further reacted with rhodamine 6G to form ternary ion complexes at room temperature. This resulted in a significant enhancement of resonance Rayleigh scattering (RRS) with a maximum RRS wavelength of 316 nm. Meanwhile, the fluorescence of the solution was quenched and excitation (λ ex) and emission (λ em) wavelengths of the fluorescence were 290 and 559 nm, respectively. Intensities of RRS enhancing (ΔIRRS ) and fluorescence quenching (ΔIF) were directly proportional to concentrations of 6-BA. As a result, RRS and fluorescence quenching for determination of trace amounts of 6-BA were developed. Under optimal conditions, linear ranges and detection limits of the two methods were 0.05-15.00 µg/mL and 8.2 ng/mL (RRS), 0.50-15.00 µg/mL and 17.0 ng/mL, respectively. It was found that the RRS method was superior to fluorescence quenching. The influence of these methods were investigated and results showed that RRS had good selectivity. RRS was applied to determine 6-BA in vegetable samples with satisfactory results. Furthermore, the reaction mechanisms of the ternary ion-association system are discussed. In addition, the polarization experiment revealed that the resonance light scattering (RLS) peak of Na2WO4-6-BA-R6G consisted mainly of depolarized resonance fluorescence and resonance scattering. It was speculated that light emission fluorescence energy (EL) transformed into resonance light scattering energy (ERLS), which was a key reason for enhancement of RRS.

[Manipulative reduction and plaster external fixation for the treatment of the scaphoid fracture and perilunate dislocation].

OBJECTIVE: To investigate the efficacy and complications of manual reduction and external fixation for the treatment of scaphoid fractures and perilunate dislocations. METHODS: From January 2009 to January 2013, 43 patients suffered from scaphoid fractures and perilunate dislocations were retrospective analyzed. Among them, 17 cases were treated with manipulative reduction and plaster external fixation as conservation group including 10 males and 7 females, the other 26 cases were treated with application of surgical as operation group including 15 males and 11 females. The clinical effects were assessed by Cooney function score, radiological analysis and observation of complications. RESULTS: All patients were followed up for(45.00±8.72) months ranging from 36 to 60 months. At the final follow-up, the Cooney score of wrist function was 88.53±4.24 in conservation group and 89.58±4.59in operation group(t=0.455, P>0.05). During the follow-up, 4 patients were found scaphoid avascular necrosis in the imaging performance in the conservation group(χ²=4.32, P<0.05). The difference of other complications between two groups was not statistically significant(P>0.05). CONCLUSIONS: For patients suffered from the scaphoid fractures and perilunate dislocation, the early manipulative reduction and plaster external fixation after injury as soon as possible is necessary. Maintaining a satisfactory reduction and reliable fixation at the same time can lead to good treatment effect and there's no weakness compared to surgical treatment. But there was an increase in danger of complications. The key of conservative treatment lies in early diagnosis and maintenance of reduction, reliable fixation, and timely and appropriate functional exercise.

Photoinduced and N-bromosuccinimide-mediated cyclization of 2-azido-N-phenylacetamides.

An efficient synthesis of quinoxalin-2(1H)-ones or spiro[cyclohexene-1,2'-imidazol]-4'-ones has been achieved in moderate to high yields by the visible light-induced and N-bromosuccinimide-mediated cyclization reaction of 2-azido-N-phenylacetamides at ambient temperature. Both the regioselectivity and the speed of cyclization are affected by the substituents attached to the phenyl ring. For example, quinoxalin-2-ones are produced as the main products when the substrates bear electron-withdrawing groups at the para-position of the phenyl ring; in contrast, spiro[cyclohexene-1,2'-imidazol]-4'-ones are obtained as the main products when the substrates bear electron-donating groups at the para-position.

Usefulness of heart-type fatty acid-binding protein in patients with severe sepsis.

PURPOSE: The purpose of the study was to evaluate the value of heart-type fatty acid-binding protein (hFABP) as a novel clinical biomarker in patients with severe sepsis. METHODS: Serum concentrations of hFABP and traditional cardiac biomarkers including cardiac troponin I, creatine kinase-MB, and B-type natriuretic peptides levels were measured within 6 hours after admission in 93 severe septic patients. The value of hFABP for the diagnosis of sepsis-related myocardial dysfunction (SRMD) and for the prediction of 28-day mortality was evaluated by receiver operating characteristics curve analysis. The prognostic value of elevated hFABP was subsequently confirmed by multivariate Cox proportional hazards analysis and Kaplan-Meier survival analysis. RESULTS: Heart-type fatty acid-binding protein was elevated (≥ 4.5 ng/mL) in 58 (62.4%) patients; patients with elevated hFABP appeared more likely to have SRMD (84.5% vs 31.4%, P < .001) and have higher prevalence of 28-day death (37.9% vs 8.6%, P = .002). Heart-type fatty acid-binding protein offered superior value over conventional biomarkers in both diagnosis of SRMD (area under the curve, 0.767; P < .001) and prediction of 28-day death (area under the curve, 0.805; P < .001). CONCLUSIONS: Serum hFABP is frequently elevated among patients with severe sepsis and appears to be associated with SRMD. Elevated hFABP independently predicts 28-day mortality in severe sepsis.

Fluorescence quenching of serum albumin by rifamycin antibiotics and their analytical application.

In neutral medium, rifamycin antibiotics such as rifapentin (RFPT), rifampicin (RFP), rifandin (RFD) and rifamycin SV (RFSV) can bind with human serum albumin (HSA) and bovine serum albumin (BSA) to form complexes, resulting in the quenching of the intrinsic fluorescence (lambda(ex)/lambda(em) = 285/355 nm) of the BSA and HSA. The quenching intensity (DeltaF) is directly proportional to the concentration of the rifamycin antibiotics. Therefore, a new analytical method was established to determine trace rifamycin antibiotics. The method had fairly high sensitivity and the detecting limits (3sigma) for RFPT, RFP, RFD and RFSV were 0.85, 0.98, 1.83, 1.89 ng/mL, respectively, for the HSA system and 0.76, 0.89, 1.55, 1.77 ng/mL, respectively, for the BSA system. All relative standard deviations (RSDs) were <3.8%. In this work, the characteristics of the fluorescence spectra were studied and the optimum reaction conditions and influencing factors were investigated. The influence of coexisting substances was tested and the results showed that the method had good selectivity and could be applied to determine trace rifamycin antibiotics in medicine capsules and urine samples. Taking the RFSV-serum albumin system as an example, the reaction mechanisms, such as binding constants, binding sites, binding distance and the type of fluorescence quenching, were investigated.