Re(i)-nitroxide complexes

Spin-labeled cyrhetrenes [(NNCp)Re(CO)₃] and [(INCp)Re(CO)₃], where NNCp is nitronyl nitroxide 2-(η⁵-cyclopentadienyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl and INCp is the corresponding imino nitroxide, were synthesized and characterized by EPR, CV, XRD, magnetochemistry and quantum chemistry methods. The correlations between different arrangements of paramagnetic centers and the magnetic exchange interactions for three polymorphs of [(NNCp)Re(CO)₃] were studied. It was concluded that high kinetic stability of nitroxide-substituted cyrhetrenes is a promising feature of compounds for the creation of multifunctional contrast agents.

Stable nitroxide-substituted cyrhetrenes were synthesized and characterized by EPR, CV, XRD, magnetochemistry and quantum chemistry methods.     

The Diagnostic Accuracy Of Procalcitonin for Urinary Tract Infection in Hospitalized Older Adults: a Prospective Study

BackgroundThe diagnosis of urinary tract infection (UTI) is challenging among hospitalized older adults, particularly among those with altered mental status.ObjectiveTo determine the diagnostic accuracy of procalcitonin (PCT) for UTI in hospitalized older adults.DesignWe performed a prospective cohort study of older adults (≥65 years old) admitted to a single hospital with evidence of pyuria on urinalysis. PCT was tested on initial blood samples. The reference standard was a clinical definition that included the presence of a positive urine culture and any symptom or sign of infection referable to the genitourinary tract. We also surveyed the treating physicians for their clinical judgment and performed expert adjudication of cases for the determination of UTI.ParticipantsTwo hundred twenty-nine study participants at a major academic medical center.Main MeasuresWe calculated the area under the receiver operating characteristic curve (AUC) of PCT for the diagnosis of UTI.Key ResultsIn this study cohort, 61 (27%) participants met clinical criteria for UTI. The median age of the overall cohort was 82.6 (IQR 74.9–89.7) years. The AUC of PCT for the diagnosis of UTI was 0.56 (95% CI, 0.46–0.65). A series of sensitivity analyses on UTI definition, which included using a decreased threshold for bacteriuria, the treating physicians’ clinical judgment, and independent infectious disease specialist adjudication, confirmed the negative result.ConclusionsOur findings demonstrate that PCT has limited value in the diagnosis of UTI among hospitalized older adults. Clinicians should be cautious using PCT for the diagnosis of UTI in hospitalized older adults.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11606-021-07265-8.KEY WORDS: procalcitonin, diagnostic accuracy, urinary tract infection, older adults     

Microstructural Features in Multicore Cu–Nb Composites

The study is devoted to heavily drawn multicore Cu–18Nb composites of cylindrical and rectangular shapes. The composites were fabricated by the melt-and-deform method, namely, 600 in situ rods of Cu–18%Nb alloy were assembled in a copper shell and cold-drawn to a diameter of 15.4 mm (e = 10.2) and then rolled into a rectangular shape the size of 3 × 5.8 mm (e = 12.5). The specimens were analyzed from the viewpoints of their microstructure, microhardness, and thermal stability. The methods of SEM, TEM, X-ray analysis, and microhardness measurements were applied. It is demonstrated that, at higher strain, the fiber texture 110Nb∥111Cu∥DD(drawing direction), characteristic of this material, becomes sharper. The distortions of niobium lattice can be observed, namely, the 110Nb interplanar distance is broadened in longitudinal direction of specimens and compacted in transverse sections. The copper matrix lattice is distorted as well, though its distortions are much less pronounced due to its recrystallization. Evolution of microstructure under annealing consists mainly in the coagulation of ribbon-like Nb filaments and in the vanishing of lattice distortions. The structural changes in Nb filaments start at 300–400 °C, then develop actively at 600 °C and cause considerable decrease of strength at 700–800 °C.     

Is Lone Hypertension a Risk Factor for More Severe COVID-19 Outcomes?

Background:Based on current evidence, it is not clear whether lone hypertension increases the risk for severe illness from COVID-19, or if increased risk is mainly associated with age, obesity and diabetes. The objective of the study was to evaluate whether lone hypertension is associated with increase mortality or a more severe course of COVID-19, and if treatment and control of hypertension mitigates this risk.Methods:This is a prospective multi-center observational cohort study with 30-day outcomes of 9,531 consecutive SARS-CoV-2 PCR-positive patients ≥ 18 years old (41.9 ± 9.7 years, 49.2% male), Uzbekistan, June 1-September 30, 2020. Patients were subclassified according to JNC8 criteria into six blood pressure stages. Univariable and multiple logistic regression was conducted to examine how variables predict outcomes.Results:The 30-days all-cause mortality was 1.18% (n = 112) in the whole cohort. After adjusting for age, sex, history of myocardial infarction (MI), type-2 diabetes, and obesity, none of six JNC8 groups showed any significant difference in all-cause mortality. However, age was associated with an increased risk of 30-days all-cause mortality (OR = 1.09, 95%CI [1.07–1.12], p < 0.001), obesity (OR = 7.18, 95% CI [4.18–12.44], p < 0.001), diabetes (OR 4.18, 95% CI [2.58–6.76], p < 0.001), and history of MI (OR = 2.68, 95% CI [1.67–4.31], p < 0.001). In the sensitivity test, being ≥ 65 years old increased mortality 10.56-fold (95% CI [5.89–18.92], p < 0.001). Hospital admission was 12.4% (n = 1,183), ICU admission 1.38% (n = 132). The odds of hospitalization increased having stage-2 untreated hypertension (OR = 4.51, 95%CI [3.21–6.32], p < 0.001), stage-1 untreated hypertension (OR = 1.97, 95%CI [1.52–2.56], p < 0.001), and elevated blood pressure (OR = 1.82, 95% CI [1.42–2.34], p < 0.001). Neither stage-1 nor stage-2 treated hypertension patients were at statistically significant increased risk for hospitalization after adjusting for confounders. Presenting with stage-2 untreated hypertension increased the odds of ICU admission (OR = 3.05, 95 %CI [1.57–5.93], p = 0.001).Conclusions:Lone hypertension did not increase COVID-19 mortality or in treated patients risk of hospitalization.     

Comparative evaluation of interpolyelectrolyte complexes of chitosan with Eudragit L100 and Eudragit L100-55 as potential carriers for oral controlled drug delivery

With a view to the application in oral controlled drug delivery systems, the formation of interpolyelectrolyte complexes (IPEC) between chitosan (CS) and Eudragit L100 (L100) or Eudragit L100-55 (L100-55) was investigated at pH 6.0, using elementary analysis. The interaction or binding ratio of a unit molecule of CS with Eudragit L copolymers depends on the molecular weight of CS, and changes from 1:0.85 to 1:1.22 (1.17相似文献   

Selection of cultivation medium for production of late stationary phase serine proteinases from Bacillus intermedius

B. intermedius have been shown previously to secrete two serine proteinases: glutamyl endopeptidase 2 and subtilisin 2 during the late stationary phase, with maximal levels of the enzymes activities recorded at the 40th and 44th hours of growth, respectively. In the current study, we analyzed the impact of various culture medium components on biosynthesis of these proteinases. Yeast extract and gelatin did not stimulate the enzymes biosynthesis. However, on the medium containing 0.1% casein subtilisin 2 production increased to reach 140%. Biosynthesis of both serine proteinases, produced by B. intermedius at the late stationary phase, were found to be inhibited by individual amino acids, and to be insensitive to catabolite repression. In order to maximise enzyme production, the presence of Ca(2+) and Mg(2+) at concentration of 5 mM was shown to be necessary. Based on the results of this work, the composition of a complex culture media for the effective production of late stationary phase proteinases by B. intermedius was developed.