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1.
Biotechnol Bioeng ; 2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34612520

RESUMO

Compatible solutes are key for the ability of halophilic bacteria to resist high osmotic stress. They have received wide attention from researchers for their excellent osmotic protection properties. Hydroxyectoine is a particularly important compatible solute, but its production by microbes faces several challenges, including low titer/yield, the presence of the byproduct ectoine, and the requirement of high salinity. Here, we aimed to metabolically engineer Escherichia coli to efficiently produce hydroxyectoine in the absence of osmotic stress without accumulating the byproduct ectoine. First, combinatorial optimization of the expression strength of key genes in the ectoine synthesis module and hydroxyectoine synthesis module was conducted. After optimization of the expression of these genes, 12.12 g/L hydroxyectoine and 0.24 g/L ectoine were obtained at 36 h in shake-flask fermentation with the addition of the co-substrate α-ketoglutarate. Further optimization of the addition of α-ketoglutarate achieved the sole production of hydroxyectoine (i.e., no ectoine accumulation), indicating that the supply of α-ketoglutarate is critically important for sole hydroxyectoine production. Finally, quorum sensing-based auto-regulation of intracellular α-ketoglutarate pool was implemented as an alternative to α-ketoglutarate addition by coupling the expression of sucA with the esaI/esaR circuit, which led to 14.93 g/L hydroxyectoine with a unit cell yield of 1.678 g/g and no ectoine accumulation in the absence of osmotic stress. This is the highest reported titer of sole hydroxyectoine production under salinity-free fermentation to date.

2.
Sci Total Environ ; : 150831, 2021 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-34627884

RESUMO

Peatlands in northeast China are experiencing severe climate warming. Most studies on peatlands focus on the responses of CH4 dynamics to temperature. However, they rarely consider the synchronous changes in the composition of plant communities caused by the expansion of vascular plants. In this study, an experiment combined warming with the manipulation of plants to examine the concentrations of CH4 porewater and its fluxes in the mesocosm. We found that warming increased the concentration of CH4 and its fluxes relative to the control treatments, and it was strongly modulated by plant richness and functional types. The average CH4 fluxes in the warming and non-warming mesocosms varied from 72.10 to 119.44 and 97.95 to 194.43 mg m-2 h-1, respectively. Plant species richness significantly increased CH4 flux at the warming level of 3.2 °C (P < 0.01). The presence of vascular plants, such as Carex globularis and Vaccinium uliginosum, significantly increased the CH4 fluxes after warming had occurred. Our results suggest that the distinct response of CH4 to richness and species primarily stemmed from the direct or indirect effects of plant biomass and functional characteristics. Therefore, more consideration should be given to the diversity changes caused by vascular plant expansion when estimating CH4 flux in boreal peatland, especially in the context of future climate warming.

3.
Org Biomol Chem ; 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34607335

RESUMO

Excellent and unique diastereoselectivity is observed in the iridium-catalyzed deoxygenation of tertiary cyclohexanols and cyclopentanols. The substituent effect on the diastereoselectivity and detailed control models are analyzed case by case, using tertiary monocyclic and polycyclic cyclohexanols, bicyclic bridged cycloalkanols, and cyclopentanols as the model substrates. The selectivity is decided by the steric environment of the carbocation intermediates and is independent of the catalyst loading. Stereoelectronically, the iridium hydride approaches the carbocation in directions perpendicular to the carbocation plane. The sterically large iridium hydride delivers its hydride in the sterically least hindered direction to the carbocation. The deoxygenation has found important applications in the stereospecific arylations of sterically complex compounds. Our deoxygenation is stereochemically very different from the coupling reactions and can be used to specifically synthesize stereoisomers that are not available via cross-couplings.

4.
Environ Sci Technol ; 2021 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-34623154

RESUMO

Iron (Fe) phases are tightly linked to the preservation rather than the loss of organic carbon (OC) in soil; however, during redox fluctuations, OC may be lost due to Fe phase-mediated abiotic processes. This study examined the role of Fe phases in driving hydroxyl radical (•OH) formation and OC transformation during redox cycles in paddy soils. Chemical probes, sequential extraction, and Mössbauer analyses showed that the active Fe species, such as exchangeable and surface-bound Fe and Fe in low-crystalline minerals (e.g., green rust-like Fe phases), predominantly regulated •OH formation during redox cycles. The •OH oxidation strongly induced the oxidative transformation of OC, which accounted for 15.1-30.8% of CO2 production during oxygenation. Microbial processes contributed 7.3-12.1% of CO2 production, as estimated by chemical quenching and γ-irradiation experiments. After five redox cycles, 30.1-71.9% of the OC associated with active Fe species was released, whereas 5.2-7.1% was stabilized by high-crystalline Fe phases due to the irreversible transformation of these active Fe species during redox cycles. Collectively, our findings might unveil the under-appreciated role of active Fe phases in driving more loss than conservation of OC in soil redox fluctuation events.

5.
Bipolar Disord ; 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34606159

RESUMO

BACKGROUND: Recently, functional homotopy (FH) architecture, defined as robust functional connectivity (FC) between homotopic regions, has been frequently reported to be altered in MDD patients (MDDs) but with divergent locations. METHODS: In this study, we obtained resting-state functional magnetic resonance imaging (R-fMRI) data from 1004 MDDs (mean age, 33.88 years; age range, 18-60 years) and 898 matched healthy controls (HCs) from an aggregated dataset from 20 centers in China. We focused on interhemispheric function integration in MDDs and its correlation with clinical characteristics using voxel-mirrored homotopic connectivity (VMHC) devised to inquire about FH patterns. RESULTS: As compared with HCs, MDDs showed decreased VMHC in visual, motor, somatosensory, limbic, angular gyrus, and cerebellum, particularly in posterior cingulate gyrus/precuneus (PCC/PCu) (false discovery rate [FDR] q < .002, z =-7.07). Further analysis observed that the reduction in SMG and insula was more prominent with age, of which SMG reflected such age-related change in males instead of females. Besides, the reduction of MTG was found to be a male-special abnormal pattern in MDDs. VMHC alterations were markedly related to episode type and illness severity. The higher Hamilton Depression Rating Scale score, the more apparent VMHC reduction in the primary visual cortex. First-episode MDDs revealed stronger VMHC reduction in PCu relative to recurrent MDDs. CONCLUSIONS: We confirmed a significant VMHC reduction in MDDs in broad areas, especially in PCC/PCu. This reduction was affected by gender, age, episode type, and illness severity. These findings suggest that the depressive brain tends to disconnect information exchange across hemispheres.

6.
J Am Chem Soc ; 143(37): 15309-15318, 2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34516733

RESUMO

Endohedral mono-metallofullerenes are the prototypes to understand the fundamental nature and the unique interactions between the encapsulated metals and the fullerene cages. Herein, we report the crystallographic characterizations of four new U-based mono-metallofullerenes, namely, U@Cs(6)-C82, U@C2(8)-C84, U@Cs(15)-C84, and U@C1(12)-C86, among which the chiral cages C2(8)-C84 and C1(12)-C86 have never been previously reported for either endohedral or empty fullerenes. Symmetrical patterns, such as indacene, sumanene, and phenalene, and charge transfer are found to determine the metal positions inside the fullerene cages. In addition, a new finding concerning the metal positions inside the cages reveals that the encapsulated metal ions are always located on symmetry planes of the fullerene cages, as long as the fullerene cages possess mirror planes. DFT calculations show that the metal-fullerene motif interaction determines the stability of the metal position. In fullerenes containing symmetry planes, the metal prefers to occupy a symmetrical arrangement with respect to the interacting motifs, which share one of their symmetry planes with the fullerene. In all computationally analyzed fullerenes containing at least one symmetry plane, the actinide was found to be located on the mirror plane. This finding provides new insights into the nature of metal-cage interactions and gives new guidelines for structural determinations using crystallographic and theoretical methods.

7.
J Am Chem Soc ; 2021 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-34553913

RESUMO

Understanding the chemical behavior of actinide elements is essential for the effective management and use of actinide materials. In this study, we report an unprecedented η2 (side-on) coordination of U by a cyanide in a UCN cluster, which was stabilized inside a C82 fullerene cage. UCN@Cs(6)-C82 was successfully synthesized and fully characterized by mass spectrometry, single crystal X-ray crystallography, cyclic voltammetry, spectroscopy, and theoretical calculations. The bonding analysis demonstrates significant donation bonding between CN- and uranium, and covalent interactions between uranium and the carbon cage. These effects correlate with an observed elongated cyanide C-N bond, resulting in a rare case where the oxidation state of uranium shows ambiguity between U(III) and U(I). The discovery of this unprecedented triangular configuration of the uranium cyanide cluster provides a new insight in coordination chemistry and highlights the large variety of bonding situations that uranium can have.

8.
J Genet Genomics ; 2021 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-34537414

RESUMO

Multi-factors have been reported to affect the gut microbiome, including genotype, age, diet, and nutrition. However, few reports have investigated the relative capacity of different factors to shape the gut microbiome in a single study. Our design used a genetic Vitamin A deficient mouse model, the Rbp4-/- mouse, feeding with the low Vitamin A diets at different ages of initiation (4 or 7 weeks) for 28 days. Fecal samples were collected for bacterial profiling at seven time points after diet controlling. With RBP4 depletion, Akkermansia decreased and Bacteroides increased, while Desulfovibrio, Barnesiella, Clostridium_XlVa, and Lactobacillus fluctuated. The bacterial community swiftly adjusted with the Vitamin A-deficient diet administration and gradually changed (e.g., decrease of Barnesiella and increase of Desulfovibrio). Age exerted a relatively weaker but long-last influence. At an earlier age to feed a Vitamin-A deficient diet, a higher microbial dysbiosis index (MDI) will be valued. Of note, the shaping effects of diet and age on the bacterial community varied with the difference of genotype, which might indicate a greater role of genotype than diet and age in shaping the gut microbiome.

9.
Curr Neurovasc Res ; 2021 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-34561979

RESUMO

BACKGROUND: The relationship between serum lipids and migraine remains controversial. OBJECTIVE: This study aimed to analyze the association between serum lipids and severe headache or migraine in the general population. METHOD: Data were collected from a nationally representative sample of participants in the National Health and Nutrition Examination Survey from 1999 to 2004. Interviewers recorded self-reported severe headaches or migraines and whether pain lasted for more than 24 h in three months. A weighted general linear model was used to estimate the association between serum lipids and severe headache or migraine. Regression analyses were performed after adjusting for age, sex, race, energy intake, sodium intake, etc. Subgroup analyses were performed using the same regression model. RESULTS: We included 5,937 individuals in the study, with a weighted mean age of 45.8 years. Males accounted for 47.6% of the participants. After adjusting for covariates, a non-significant association was found between migraine and total cholesterol (odds ratio=0.96, 95% confidence interval=0.85, 1.05; P=0.32), low-density lipoprotein cholesterol (odds ratio=0.96; 95% confidence interval= 0.75, 1.17, P=0.55), and high-density lipoprotein cholesterol (odds ratio=0.99; 95% confidence interval=0.49, 1.59, P=0.58) in the continuous form. In subgroup analyses, no significant association was found between total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and self-reported severe headache or migraine. CONCLUSION: Total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol were not significantly associated with severe headache or migraine in the general American population after adjusting for covariates. The supporting information for measuring common serum lipids in general headaches and migraines is insufficient.

10.
Pediatr Investig ; : e12282, 2021 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-34540320

RESUMO

Importance: The Coronavirus disease 2019 (COVID-19) global pandemic poses a considerable challenge for pediatricians. Objective: This study aimed to identify the epidemiological characteristics and clinical features of pediatric patients with COVID-19 in China. Methods: This multicenter retrospective study included pediatric patients from 46 hospitals in China, covering 12 provinces and two municipalities. Epidemiological, demographic, clinical, laboratory, treatment, and outcome data were analyzed. Results: In total, 211 pediatric patients with COVID-19 were included in this study. The median age was 7.0 years (range: 22 days to 18 years). Approximately 16.3% of the patients exhibited asymptomatic infections, 23.0% had upper respiratory tract infections, and 60.7% had pneumonia, including two with severe pneumonia and one with critical illness. Approximately 78.7% of the pediatric patients occurred in familial clusters. The most three common symptoms or signs at onset in children with COVID-19 were fever (54.5%), cough (49.3%), and pharyngeal congestion (20.8%). Only 17.6% of the patients presented with decreased lymphocyte count, whereas 13.6% had increased lymphocyte count. Among the patients with pneumonia who exhibited abnormal chest computed tomography findings, 18.2% (23/127) of the patients had no other symptoms. Generally, the chest radiographs showed abnormalities that affected both lungs (49.6%); ground-glass opacity (47.2%) was the most common manifestation. The cure and improvement rates were 86.7% (183/211) and 13.3% (28/211), respectively. Only one patient with an underlying condition received invasive mechanical ventilation; none of the patients died. Interpretation: Similar to adults, children of all age groups are susceptible to COVID-19. Fortunately, most pediatric patients have mild symptoms or remain asymptomatic, despite the high incidence of pneumonia. Decreased proportions of white blood cells and lymphocytes are less frequent in children than in adults.

11.
Artigo em Inglês | MEDLINE | ID: mdl-34574528

RESUMO

Older age, obesity, and obstructive sleep apnea syndrome (OSAS) are known to increase the risk of hypertension in adults. However, data for children are scarce. This study aimed to investigate the relationships between hypertension, age, weight status, and disease severity in 396 children with OSAS. The prevalence rates of hypertension, obesity, and severe OSAS (apnea-hypopnea index ≥10) were 27.0%, 28.0%, and 42.9%, respectively. Weight z-score and apnea-hypopnea index were independently correlated with systolic blood pressure z-score, and minimal blood oxygen saturation (SpO2) was independently associated with diastolic blood pressure z-score. Overall, late childhood/adolescence (odds ratio (OR) = 1.72, 95% CI = 1.05-2.81), obesity (OR, 2.58, 95% CI = 1.58-4.22), and severe OSAS (OR = 2.38, 95% CI = 1.48-3.81) were independent predictors of pediatric hypertension. Furthermore, late childhood/adolescence (OR = 2.50, 95% CI = 1.10-5.71) and abnormal SpO2 (mean SpO2 < 95%; OR = 4.91, 95% CI = 1.81-13.27) independently predicted hypertension in obese children, and severe OSAS (OR = 2.28, 95% CI = 1.27-4.10) independently predicted hypertension in non-obese children. In conclusion, obesity, OSAS severity, and abnormal SpO2 are potentially modifiable targets to improve hypertension while treating children with OSAS.

12.
Medicina (Kaunas) ; 57(9)2021 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-34577838

RESUMO

Backgroundand Objectives: Obstructive sleep apnea (OSA) patients may remove their mask unconsciously during automatic continuous positive airway pressure (Auto-CPAP) therapy and therefore cannot receive good treatment. The discomfort from the airflow of Auto-CPAP may be one reason for interrupted sleep. Sens Awake (SA) can detect the arousal and lower the pressure to prevent patients from fully awakening from sleep. Materials and Methods: To evaluate the effect of SA, we designed a prospective, randomized, crossover trial comparing Auto-CPAP with and without SA on Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), Nasal Obstruction Symptom Evaluation (NOSE) Scale and recorded data from the auto-CPAP machine. Results: In the 25 patients who completed the study, the gender, age, body mass index, neck circumference, polysomnography data, and previous CPAP use were not significantly different between the two arms. The average and 90th percentile pressures were significantly lower during SA on (SA on vs. off: 6.9 ± 2.7 vs. 7.3 ± 2.6 [p = 0.032] and 8.6 ± 3.0 vs. 9.2 ± 2.9 [p = 0.002], respectively). The time used, days used, compliance, average and 90th percentile leaks, and the residual Apnea-Hypopnea Index (AHI) were not significantly changed between the SA on-and-off. Based on the subjective evaluation, PSQI, ESS, and NOSE were not significantly different between the SA on-and-off; however, based on additional analyses which were compared with baseline data, the ESS was significantly lower when the SA was on (SA on vs. baseline: 11.1 ± 6.1 vs. 13.2 ± 6.0 [p = 0.023]). Conclusions: CPAP therapy with or without two weeks of the SA had a similar effect on CPAP use, sleep quality, daytime sleepiness, and nasal obstruction. The SA may have a tendency to improve daytime sleepiness, but needs further study with a longer duration of treatment.


Assuntos
Pressão Positiva Contínua nas Vias Aéreas , Apneia Obstrutiva do Sono , Estudos Cross-Over , Humanos , Polissonografia , Estudos Prospectivos , Apneia Obstrutiva do Sono/terapia
13.
Chemistry ; 2021 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-34549465

RESUMO

Surface cracks could improve the optical and photoelectronic properties of crystalline materials as they increase specific surface area, but the controlled self-assembly of fullerene (C60 ) molecules into micro-/nanostructures with surface cracks is still challenging. Herein, we report the morphology engineering of novel C60 microstructures bearing surface cracks for the first time, selecting phenetole and propan-1-ol (NPA) as good and poor solvents, respectively. Our systematic investigations reveal that phenetole molecules initially participate in the formation of the ends of the C60 microstructures, and then NPA molecules are involved in the gradual growth of the sidewalls of the microstructures. Therefore, the surface cracks of C60 microstructures can be finely regulated by adjusting the addition of NPA and the crystallization time. Interestingly, the cracked C60 microstructures show superior photoluminescence properties relative to the smooth microstructures due to the increased specific surface area. In addition, C60 microstructures with wide cracks show preferential recognition of silica particles over C60 particles owing to electrostatic interactions between the negatively charged C60 microstructures and the positively charged silica microparticles. These C60 crystals with surface cracks have potential applications from optoelectronics to biology.

14.
Theranostics ; 11(17): 8197-8217, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34373737

RESUMO

Ischemic stroke is an acute and severe neurological disease, which leads to disability and death. Immunomodulatory therapies exert multiple remarkable protective effects during ischemic stroke. However, patients suffering from ischemic stroke do not benefit from immunomodulatory therapies due to the presence of the blood-brain barrier (BBB) and their off-target effects. Methods: We presented a delivery strategy to optimize immunomodulatory therapies by facilitating BBB penetration and selectively delivering intravenous immunoglobulin (IVIg) to ischemic regions using 2-methacryloyloxyethyl phosphorylcholine (MPC)-nanocapsules, MPC-n(IVIg), synthesized using MPC monomers and ethylene glycol dimethyl acrylate (EGDMA) crosslinker via in situ polymerization. In vitro and in vivo experiments verify the effect and safety of MPC-n(IVIg). Results: MPC-n(IVIg) efficiently crosses the BBB and IVIg selectively accumulates in ischemic areas in a high-affinity choline transporter 1 (ChT1)-overexpression dependent manner via endothelial cells in ischemic areas. Moreover, earlier administration of MPC-n(IVIg) more efficiently deliver IVIg to ischemic areas. Furthermore, the early administration of low-dosage MPC-n(IVIg) decreases neurological deficits and mortality by suppressing stroke-induced inflammation in the middle cerebral artery occlusion model. Conclusion: Our findings indicate a promising strategy to efficiently deliver the therapeutics to the ischemic target brain tissue and lower the effective dose of therapeutic drugs for treating ischemic strokes.

15.
Artigo em Inglês | MEDLINE | ID: mdl-34431292

RESUMO

Piezoelectric energy harvesters have received widespread attention in recent decades due to their inimitable electrical energy conversion methods. However, traditional polymer/piezoceramic materials and 2D thin-film structures have limited output performance, making them difficult to be efficiently applied in the collection of discrete mechanical energy. Here, new ternary composite powders were successfully developed by the ultrasonic coating method, and array structural devices with the construction of micropores were prepared using selective laser sintering (SLS) and supercritical carbon dioxide foaming (Sc-CO2) technologies. Coating carbon nanotubes improved the polarization efficiency of poly(vinylidene fluoride)/barium titanate (PVDF/BaTiO3) composites, which made it easy to perfectly combine the BaTiO3 piezoelectric constant and the flexibility of PVDF, promoting d33 from 0.7 to 2.6 pc/N. In addition, simulations and experiments simultaneously proved that SLS parts with high array densities amplified piezoelectric outputs because of a greater compression deformation in the vertical direction. Meanwhile, under the synergistic effect of SLS and Sc-CO2, 3D bionic balsa wood structure foams were successfully fabricated, which took advantage of the normal space, expanded the stress-strain effect, and improved the piezoelectric output capability. Excitingly, the prepared foam could directly produce 19.3 V and 415 nA piezoelectric output to charge a 1 µF commercial capacitor to 5.03 V within 180 s, which surpassed most of the PVDF piezoelectric energy harvesters reported thus far. This work has an excellent innovative and practical value in enriching the types of piezoelectric materials for SLS 3D printing and the design of 3D piezoelectric structures.

16.
Mol Psychiatry ; 2021 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-34385597

RESUMO

Aberrant topological organization of whole-brain networks has been inconsistently reported in studies of patients with major depressive disorder (MDD), reflecting limited sample sizes. To address this issue, we utilized a big data sample of MDD patients from the REST-meta-MDD Project, including 821 MDD patients and 765 normal controls (NCs) from 16 sites. Using the Dosenbach 160 node atlas, we examined whole-brain functional networks and extracted topological features (e.g., global and local efficiency, nodal efficiency, and degree) using graph theory-based methods. Linear mixed-effect models were used for group comparisons to control for site variability; robustness of results was confirmed (e.g., multiple topological parameters, different node definitions, and several head motion control strategies were applied). We found decreased global and local efficiency in patients with MDD compared to NCs. At the nodal level, patients with MDD were characterized by decreased nodal degrees in the somatomotor network (SMN), dorsal attention network (DAN) and visual network (VN) and decreased nodal efficiency in the default mode network (DMN), SMN, DAN, and VN. These topological differences were mostly driven by recurrent MDD patients, rather than first-episode drug naive (FEDN) patients with MDD. In this highly powered multisite study, we observed disrupted topological architecture of functional brain networks in MDD, suggesting both locally and globally decreased efficiency in brain networks.

17.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 29(4): 1280-1288, 2021 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-34362517

RESUMO

OBJECTIVE: To study the hematologic and molecular features of 14 patients with hemoglobin (Hb) variants, so as to provide reference data for its laboratory screening. METHODS: A total of 1 029 samples were screened by high performance liquid chromatography (HPLC) on the Bio-Rad VariantⅡHPLC system. GAP-PCR and reverse dot blot (RDB) were used to detect common mutation of α and ß globin gene in Chinese. DNA sequencing for α and ß globin gene was simultaneously performed in samples with abnormal spectrum peak and negative thalassemia gene. RESULTS: In 1 029 samples, 10 types of structural Hb variants were detected in14 cases (1.36%), including 1 case of Hb E / ß- thalassemia, 1 case of Hb E /α- thalassemia (HbH disease), 2 cases of HbG-Taipei, 2 cases of Hb Q-Thailand, 2 cases of Hb Youngstown, 1 case of Hb Guangzhou-Hangzhou, 1 case of Hb M-Boston, 1 case of Hb G-Siriraj, 1 case of Hb J-Baltimore, 1 case of Hb J-Sicilia and 1 case of Hb Tamano. CONCLUSION: The occurrence of abnormal structural Hb variants with many genotypes in Shanghai is unique. Except for Hb E, Hb Youngstown, and Hb M-Boston, other types of heterozygous are normal in phenotypes, and symptoms such as hemolysis and anemia often occur when other diseases are combined.


Assuntos
Hemoglobinas Anormais , Talassemia alfa , China , Genótipo , Hemoglobinas Anormais/genética , Humanos , Fenótipo , Globinas beta/genética
18.
Talanta ; 234: 122652, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34364461

RESUMO

Although triple-quadrupole inductively coupled plasma-mass spectrometry (ICP-MS/MS) has become an attractive technique for the measurement of long-lived radionuclides, the abundance sensitivity, isobaric and polyatomic ions interferences seriously restrict the application. The spectral peak tailing and uranium hydrides (UH+, UH2+) from 238U have a serious influence on the accurate measurement of 239Pu and 240Pu, especially for the ultra-trace level plutonium isotopes in the higher uranium sample. A new method was developed using ICP-MS/MS measurement in mass-shift mode with collision-reaction gas combined with a chemical separation procedure. As O2 readily converted Pu+ ion to PuO2+, while disassociated the interfering diatomic ions of interfering elements (U, Pb, Hg, Tl, etc.), the interferences from these elements were completely eliminated if plutonium was detected as PuO2+ at the m/z more than 270. By the mass filter in MS/MS mode combined with O2 as reaction gas the lower peak tailing of 238U+ (<5 × 10-12) was significantly suppressed. By this way, the 238UO2H+/238UO2+ atomic ratio was reduced to 4.82 × 10-9, which is significantly lower than that of other collision-reaction gas modes. Interferences from Pb, Hg and Tl polyatomic ions were also completely eliminated. Thus, accurate measurement of ultra-trace level 239Pu in high uranium sample solutions with the 239Pu/238U concentration ratio of 10-10 was achieved by the mass-shift mode with 0.15 mL/min O2/He + 12.0 mL/min He as collision-reaction gas, and high elimination efficiency of uranium interferences up to 1014 can be obtained by combination with the chemical separation using a single UTEVA resin column. The developed method can be applied to accurately determine the fg level 239Pu in high uranium samples, such as large-size deep seawater, deep soil and sediment, uranium debris of nuclear fuel.


Assuntos
Plutônio , Urânio , Plutônio/análise , Solo , Análise Espectral , Espectrometria de Massas em Tandem , Urânio/análise
19.
Heart Lung Circ ; 2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34364800

RESUMO

BACKGROUND: The association of female sex with quality of care and short-term mortality rates in patients with chronic heart failure (CHF) remains controversial. METHOD: We performed a retrospective study using data from 2,663 patients with CHF from nine hospitals in Beijing between January 2014 and December 2015. Multivariable logistic regression analyses were performed to investigate whether female sex was independently associated with quality of care and short-term mortality rates in Chinese patients with CHF. RESULTS: Compared to male patients, female patients (48%) were older and had a higher prevalence of comorbidities. Performance measures, including angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, aldosterone receptor antagonists, and beta blocker use in patients with heart failure with reduced ejection fraction. warfarin therapy in those with atrial fibrillation, documentation of B-type natriuretic peptide/N-terminal pro-B-type natriuretic peptide, and left ventricular ejection fraction, showed no sex difference in multivariable analysis. Adjusted in-hospital mortality (1.7% vs 2.1%; adjusted odds ratio, 0.908; 95% confidence interval [CI], 0.448-1.842; p=0.789) and 30-day mortality (4.2% vs. 4.4%; adjusted hazard ratio, 0.908; 95% CI, 0.567-1.454; p=0.689) were comparable between the sexes. CONCLUSION: Chinese female patients with CHF receive a similar quality of care and have similar short-term mortality rates as male patients.

20.
Water Res ; 203: 117484, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34388500

RESUMO

The frequently occurring redox fluctuations in paddy soil are critical to the cycling of redox-sensitive elements (e.g., iron (Fe) and carbon) due to the driving of microbial processes. However, the associated abiotic process, such as hydroxyl radical (•OH) formation, was rarely investigated. Hence, we examined the under-appreciated role of •OH formation in driving polycyclic aromatic hydrocarbons (PAHs) degradation upon oxygenation of anoxic paddy slurries. Results showed that •OH production largely differed in different paddy slurries, in the range of 271.5-581.2 µmol kg-1 soil after 12 h reaction. The •OH production was highly hinged on the contents of active Fe species, i.e., exchangeable, surface-bound Fe and Fe in low-crystalline phases rather than Fe in high-crystalline minerals or silicates. Besides, •OH production significantly decreased with increasing soil depth due to the declined active Fe species and abundance of functional microbes. Oxygenation also induced the transformation of these active Fe species into the low- and high-crystalline phases, which might affect the following redox process. The produced •OH can efficiently degrade PAHs with degradation extents depending on their physiochemical properties. Our findings highlight the key roles of active Fe species in driving •OH formation and organic contaminants degradation during redox fluctuations of paddy soils.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Poluentes do Solo , Radical Hidroxila , Ferro , Oxirredução , Solo , Poluentes do Solo/análise
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