Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 66
Filtrar
1.
Opt Express ; 29(24): 40668-40676, 2021 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-34809401

RESUMO

Coherence and steerability are two essential characteristics of quantum systems. For a two-qubit state, the first-order coherence and the maximal violation of linear steering inequality are used to operationally measure the degree of coherence and steerability, respectively. Recently, a complementary relation between first-order coherence and linear steerability has been proposed. In this paper, we report an experimental verification of the complementary relation by preparing biphoton polarization entangled states in an all-optical setup. We propose an operable method for experimental measurement of the first-order coherence and linear steerability and calculate the purity of the initial states by reconstructing the density matrices of them. The experimental results coincide with the theoretical predictions very well, which provides a valuable reference for the application of optical quantum technology.

2.
J Phys Chem Lett ; 12(43): 10465-10471, 2021 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-34672593

RESUMO

A time-reversal invariant two-dimensional (2D) topological insulator (TI) is characterized by the gapless helical edge states propagating along the perimeter of the system. However, the small band gap in the 2D TIs discovered so far hinders their applications. Recently, we predicted that single-layer Bi4Br4 is a 2D TI with a remarkable band gap and that α-Bi4Br4 crystals can host topological edge states at the step edges. Here we report the growth of α-Bi4Br4 nanowires with (102)-oriented top surfaces on the TiSe2 substrates and the direct observation of the predicted topological edge states at the step edges of the nanowires using scanning tunneling microscopy. The coupling between the edge states leads to the formation of surface states at the (102) top surfaces of the nanowires. Our work demonstrates the existence of topological edge states in α-Bi4Br4 and paves the way for developing α-Bi4Br4-based devices for a high-temperature quantum spin Hall effect.

3.
Chin Med J (Engl) ; 134(11): 1335-1344, 2021 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-34039863

RESUMO

BACKGROUND: Fecal immunochemical tests (FITs) are the most widely used non-invasive tests in colorectal cancer (CRC) screening. However, evidence about the direct comparison of the test performance of the self-administered qualitative a laboratory-based quantitative FITs in a CRC screening setting is sparse. METHODS: Based on a CRC screening trial (TARGET-C), we included 3144 pre-colonoscopy fecal samples, including 24 CRCs, 230 advanced adenomas, 622 non-advanced adenomas, and 2268 participants without significant findings at colonoscopy. Three self-administered qualitative FITs (Pupu tube) with positivity thresholds of 8.0, 14.4, or 20.8 µg hemoglobin (Hb)/g preset by the manufacturer and one laboratory-based quantitative FIT (OC-Sensor) with a positivity threshold of 20 µg Hb/g recommended by the manufacturer were tested by trained staff in the central laboratory. The diagnostic performance of the FITs for detecting colorectal neoplasms was compared in the different scenarios using the preset and adjusted thresholds (for the quantitative FIT). RESULTS: At the thresholds preset by the manufacturers, apart from the qualitative FIT-3, significantly higher sensitivities for detecting advanced adenoma were observed for the qualitative FIT-1 (33.9% [95% CI: 28.7-39.4%]) and qualitative FIT-2 (22.2% [95% CI: 17.7-27.2%]) compared to the quantitative FIT (11.7% [95% CI: 8.4-15.8%]), while at a cost of significantly lower specificities. However, such difference was not observed for detecting CRC. For scenarios of adjusting the positivity thresholds of the quantitative FIT to yield comparable specificity or comparable positivity rate to the three qualitative FITs accordingly, there were no significant differences in terms of sensitivity, specificity, positive/negative predictive values and positive/negative likelihood ratios for detecting CRC or advanced adenoma between the two types of FITs, which was further evidenced in ROC analysis. CONCLUSIONS: Although the self-administered qualitative and the laboratory-based quantitative FITs had varied test performance at the positivity thresholds preset by the manufacturer, such heterogeneity could be overcome by adjusting thresholds to yield comparable specificities or positivity rates. Future CRC screening programs should select appropriate types of FITs and define the thresholds based on the targeted specificities and manageable positivity rates.


Assuntos
Neoplasias Colorretais , Laboratórios , Colonoscopia , Neoplasias Colorretais/diagnóstico , Detecção Precoce de Câncer , Fezes , Hemoglobinas/análise , Humanos , Sangue Oculto , Sensibilidade e Especificidade
4.
Cancer ; 127(11): 1880-1893, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33784413

RESUMO

BACKGROUND: Colorectal cancer (CRC) is the third most common cancer in China, however, publicly available, descriptive information on the clinical epidemiology of CRC is limited. METHODS: Patients diagnosed with primary CRC during 2005 through 2014 were sampled from 13 tertiary hospitals in 9 provinces across China. Data related to sociodemographic characteristics, the use of diagnostic technology, treatment adoption, and expenditure were extracted from individual medical records. RESULTS: In the full cohort of 8465 patients, the mean ± SD age at diagnosis was 59.3 ± 12.8 years, 57.2% were men, and 58.7% had rectal cancer. On average, 14.4% of patients were diagnosed with stage IV disease, and this proportion increased from 13.5% in 2005 to 20.5% in 2014 (P value for trend < .05). For diagnostic techniques, along with less use of x-rays (average, 81.6%; decreased from 90.0% to 65.7%), there were increases in the use of computed tomography (average, 70.4%; increased from 4.5% to 90.5%) and magnetic resonance imaging (average, 8.8%; increased from 0.1% to 20.4%) over the study period from 2005 to 2014. With regard to treatment, surgery alone was the most common (average, 50.1%), but its use decreased from 51.3% to 39.8% during 2005 through 2014; and the use of other treatments increased simultaneously, such as chemotherapy alone (average, 4.1%; increased from 4.1% to 11.9%). The average medical expenditure per patient was 66,291 Chinese Yuan (2014 value) and increased from 47,259 to 86,709 Chinese Yuan. CONCLUSIONS: The increasing proportion of late-stage diagnoses presents a challenge for CRC control in China. Changes in diagnostic and treatment options and increased expenditures are clearly illustrated in this study. Coupled with the recent introduction of screening initiatives, these data provide an understanding of changes over time and may form a benchmark for future related evaluations of CRC interventions in China.

5.
J Colloid Interface Sci ; 593: 323-334, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33744541

RESUMO

In recent years, chemodynamic therapy (CDT) has gained increasing interest in cancer treatment. In contrast to photodynamic therapy and sonodynamic therapy, extrinsic excitations such as laser or ultrasound are not required in CDT. As a result, the CDT performance is not limited by the penetration depth of the external irritation. However, CDT relies heavily on hydrogen peroxide (H2O2) in the tumour microenvironment (TME). Insufficient H2O2 in the TME limits the CDT performance, and the most reported methods to produce H2O2 in the TME are dependent on oxygen supply, which is restricted by the hypoxic TME. In this study, H2O2 self-providing copper nanodots were proposed, and the drug doxorubicin (DOX) was successfully loaded to construct DOX-nanodots. Our results showed that the nanodots produced H2O2 in the weakly acidic TME due to the peroxo group and further generated the most active hydroxyl radical (OH) through the Fenton-like reaction. This process was pH-dependent and did not occur in a neutral environment. In addition to OH, the nanodots also produced singlet oxygen (1O2) and superoxide anions (O2-) in the cancer cells. The copper nanodots performed promising CDT against breast cancer in vitro and in vivo, with enhanced cell apoptosis and decreased cell proliferation. The combination of chemotherapy and CDT using DOX-nanodots further improved the therapeutic effects. The treatments showed good biocompatibility with no obvious toxicity in major tissues, possibly due to the specific OH generation in the weakly acidic TME. In summary, the H2O2 self-providing copper nanodots in combination with DOX showed promising cancer-curing effects due to the oxygen-independent and tumour-specific production of reactive oxygen species and the cooperation of chemotherapy.


Assuntos
Neoplasias da Mama , Peróxido de Hidrogênio , Neoplasias da Mama/tratamento farmacológico , Linhagem Celular Tumoral , Cobre , Doxorrubicina/farmacologia , Feminino , Humanos , Microambiente Tumoral
7.
Proc Natl Acad Sci U S A ; 118(9)2021 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-33619099

RESUMO

Natural aerosols in pristine regions form the baseline used to evaluate the impact of anthropogenic aerosols on climate. Sea spray aerosol (SSA) is a major component of natural aerosols. Despite its importance, the abundance of SSA is poorly constrained. It is generally accepted that wind-driven wave breaking is the principle governing SSA production. This mechanism alone, however, is insufficient to explain the variability of SSA concentration at given wind speed. The role of other parameters, such as sea surface temperature (SST), remains controversial. Here, we show that higher SST promotes SSA mass generation at a wide range of wind speed levels over the remote Pacific and Atlantic Oceans, in addition to demonstrating the wind-driven SSA production mechanism. The results are from a global scale dataset of airborne SSA measurements at 150 to 200 m above the ocean surface during the NASA Atmospheric Tomography Mission. Statistical analysis suggests that accounting for SST greatly enhances the predictability of the observed SSA concentration compared to using wind speed alone. Our results support implementing SST into SSA source functions in global models to better understand the atmospheric burdens of SSA.

8.
Qual Life Res ; 30(3): 841-854, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32930993

RESUMO

PURPOSE: To compare the performance of three-level EuroQol five-dimensions (EQ-5D-3L) and five-level EuroQol five-dimensions (EQ-5D-5L) among common cancer patients in urban China. METHODS: A hospital-based cross-sectional survey was conducted in three provinces from 2016 to 2018 in urban China. Patients with breast cancer, colorectal cancer, or lung cancer were recruited to complete the EQ-5D-3L and EQ-5D-5L questionnaires. Response distribution, discriminatory power (indicator: Shannon index [H'] and Shannon evenness index [J']), ceiling effect (the proportion of full health state), convergent validity, and health-related quality of life (HRQoL) were compared between the two instruments. RESULTS: A total of 1802 cancer patients (breast cancer: 601, colorectal cancer: 601, lung cancer: 600) were included, with the mean age of 55.6 years. The average inconsistency rate was 4.4%. Compared with EQ-5D-3L (average: H' = 1.100, J' = 0.696), an improved discriminatory power was observed in EQ-5D-5L (H' = 1.473, J' = 0.932), especially contributing to anxiety/depression dimensions. The ceiling effect was diminished in EQ-5D-5L (26.5%) in comparison with EQ-5D-3L (34.5%) (p < 0.001), mainly reflected in the pain/discomfort and anxiety/depression dimensions. The overall utility score was 0.790 (95% CI 0.778-0.801) for EQ-5D-3L and 0.803 (0.790-0.816) for EQ-5D-5L (p < 0.001). A similar pattern was also observed in the detailed cancer-specific analysis. CONCLUSIONS: With greater discriminatory power, convergent validity and lower ceiling, EQ-5D-5L may be preferable to EQ-5D-3L for the assessment of HRQoL among cancer patients. However, higher utility scores derived form EQ-5D-5L may also lead to lower QALY gains than those of 3L potentially in cost-utility studies and underestimation in the burden of disease.


Assuntos
Neoplasias/epidemiologia , Psicometria/métodos , Qualidade de Vida/psicologia , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes
9.
J Gastroenterol Hepatol ; 36(5): 1197-1207, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-32875595

RESUMO

BACKGROUND AND AIM: This study aimed to clarify health-related quality of life (HRQoL) of patients with colorectal precancer and colorectal cancer (CRC) in China and to better understand related utility scores. METHODS: A hospital-based cross-sectional survey was conducted in precancer and CRC patients from 2012 to 2014, covering 12 provinces in China. HRQoL was assessed with EuroQol 5-Dimensions 3-Levels. Utility scores were derived using Chinese value set. A multivariate regression model was established to explore potential predictors of utility scores. RESULTS: A total of 376 precancer (mean age 58.7 years, 61.2% men) and 2470 CRC patients (mean age 58.6 years, 57.6% men) were included. In five dimensions, there was a certain percentage of problem reported among precancer (range: 12.0% to 36.7%) and CRC (range: 32.4% to 50.3%) patients, with pain/discomfort being the most serious dimension. Utility scores of precancer and CRC patients were 0.870 (95% confidence interval [CI], 0.855-0.886) and 0.751 (95% CI, 0.742-0.759), both of which were lower than those of general Chinese population (0.960 [95% CI, 0.960-0.960]). Utilities for patients at stage I to stage IV were 0.742 (95% CI, 0.715-0.769), 0.722 (95% CI, 0.705-0.740), 0.756 (95% CI, 0.741-0.772), and 0.745 (95% CI, 0.742-0.767), respectively. Multivariate analysis showed that therapeutic regimen, time point of the interview, education, occupation, annual household income, and geographic region were associated with utilities of CRC patients. CONCLUSION: Health-related quality of life of both precancer and CRC patients in China declined considerably. Utility scores differed by sociodemographic and clinical characteristics, and findings of these utilities may facilitate implementation of further cost-utility evaluations.


Assuntos
Neoplasias Colorretais , Qualidade de Vida , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , China , Neoplasias Colorretais/patologia , Neoplasias Colorretais/psicologia , Neoplasias Colorretais/terapia , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Estadiamento de Neoplasias , Análise de Regressão , Adulto Jovem
10.
Math Biosci Eng ; 17(5): 4443-4456, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-33120512

RESUMO

With the continuous development of the earth observation technology, the spatial resolution of remote sensing images is also continuously improved. As one of the key problems in remote sensing images interpretation, the classification of high-resolution remote sensing images has been widely concerned by scholars at home and abroad. With the improvement of science and technology, deep learning has provided new ideas for the development of image classification, but it has not been widely used in remote sensing images processing. In the background of remote sensing huge data, the remote sensing images classification based on deep learning proposed in the study has more research significance and application value. The study proposes a high-resolution remote sensing images classification method based on an improved convolutional neural network. The traditional convolutional neural network framework is optimized and the initial structure is added. The actual classification results of radial basis functions and support vector machine are compared horizontally. The classification results of hyperspectral images were presented that the improved method can perform better in overall accuracy and Kappa coefficient. The commission errors of support vector machine classification method are more than 6 times of that of the improved convolutional neural network classification method and the overall accuracy of the improved convolutional neural network classification method has reached 97% above.

11.
ACS Nano ; 14(10): 13081-13090, 2020 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-33052664

RESUMO

In the magic-angle twisted bilayer graphene (MA-TBG), strong electron-electron (e-e) correlations caused by the band-flattening lead to many exotic quantum phases such as superconductivity, correlated insulator, ferromagnetism, and quantum anomalous Hall effects, when its low-energy van Hove singularities (VHSs) are partially filled. Here our high-resolution scanning tunneling microscope and spectroscopy measurements demonstrate that the e-e correlation in a nonmagic-angle TBG with a twist angle θ = 1.49° still plays an important role in determining its electronic properties. Our most interesting observation on that sample is when one of its VHSs is partially filled, the one associated peak in the spectrum splits into four peaks. Simultaneously, the spatial symmetry of electronic states around the split VHSs is broken by the e-e correlation. Our analysis based on the continuum model suggests that such a one-to-four split of the VHS originates from the formation of an interaction-driven spin-valley-polarized metallic state near the VHS, which is a symmetry-breaking phase that has not been identified in the MA-TBG or in other systems.

12.
Huan Jing Ke Xue ; 41(6): 2869-2877, 2020 Jun 08.
Artigo em Chinês | MEDLINE | ID: mdl-32608804

RESUMO

In recent years, heavy metal pollution in farmlands has become increasingly serious because of human activities such as metal smelting, sewage irrigation, and road traffic in China. A field survey was conducted to investigate characteristics of Cd, As, and Pb in soil and wheat grains and assess the health risk of grain-Cd/As/Pb to humans on the fields scale. The farmland was influenced by smelter and sewage irrigation in the attitude and by road traffic in the horizon. The results showed that in farmland soil with moderate pollution levels, Cd, As, and Pb concentrations in soil samples all exceeded the risk screening values of farmland soil (GB 15618-2018), and the exceeding rates were 100%, 100%, and 36.7% respectively; the exceeding rates of Cd and Pb concentrations in wheat grains were 76.7% and 13.3%, respectively (GB 2762-2017). Distance from smelter, river of sewage irrigation, and road had no significant effect on Cd, As, and Pb concentrations in soil but had a significant effect on Cd and As concentrations in wheat grains, with the median Cd and As concentrations of the closest group being 14.9% and 41.8%, respectively, higher than the highest group (P<0.05). The Pb concentrations in soil and wheat grains were influenced by road traffic; the median Pb concentrations of the closest group were 78.9% and 471%, respectively, higher than the highest group (P<0.05). Cd and As in wheat grains have carcinogenic risks (Ri>1×10-4), RCd > RAs, Rchildren > Radult, while Pb poses no health risks in this farmland.


Assuntos
Metais Pesados/análise , Poluentes do Solo/análise , Adulto , Cádmio , Criança , China , Monitoramento Ambiental , Humanos , Chumbo , Medição de Risco , Solo , Triticum
13.
Phys Rev Lett ; 125(1): 017002, 2020 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-32678627

RESUMO

The Kohn-Luttinger mechanism for unconventional superconductivity (SC) driven by weak repulsive electron-electron interactions on a periodic lattice is generalized to the quasicrystal (QC) via a real-space perturbative approach. The repulsive Hubbard model on the Penrose lattice is studied as an example, on which a classification of the pairing symmetries is performed and a pairing phase diagram is obtained. Two remarkable properties of these pairing states are revealed, due to the combination of the presence of the point-group symmetry and the lack of translation symmetry on this lattice. First, the spin and spacial angular momenta of a Cooper pair is decorrelated: for each pairing symmetry, both spin-singlet and spin-triplet pairings are possible even in the weak-pairing limit. Second, the pairing states belonging to the 2D irreducible representations of the D_{5} point group can be time-reversal-symmetry-breaking topological SCs carrying spontaneous bulk super current and spontaneous vortices. These two remarkable properties are general for the SCs on all QCs, and are rare on periodic lattices. Our work starts the new area of unconventional SCs driven by repulsive interactions on the QC.

14.
Phys Rev Lett ; 124(1): 016402, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31976722

RESUMO

Spin-gapless semimetals (SGSMs), which generate 100% spin polarization, are viewed as promising semi-half-metals in spintronics with high speed and low consumption. We propose and characterize a new Z_{2} class of topological nodal line (TNL) in SGSMs. The proposed TNLSGSMs are protected by space-time inversion symmetry or glide mirror symmetry with two-dimensional (2D) fully spin-polarized nearly flat surface states. Based on first-principles calculations and effective model analysis, a series of high-quality materials with R3[over ¯]c and R3c space groups are predicted to realize such TNLSGSMs (chainlike). The 2D fully spin-polarized nearly flat surface states may provide a route to achieving equal spin pairing topological superconductivity as well as topological catalysts.

15.
Tob Control ; 29(2): 191-199, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31073096

RESUMO

BACKGROUND: Lung cancer is substantially attributable to smoking, but detailed related estimates on smoking-attributable expenditure (SAE) in China are not available yet, which could inform tobacco control and cancer prevention initiatives. METHODS: A prevalence-based approach was adopted to estimate the total SAE, including direct expenditure (medical and non-medical) and indirect cost (disability and premature death). Detailed per-patient data on direct expenditure and work-loss days were acquired from a unique multicentre survey in China. Other parameters were from literatures and official reports. RESULTS: The total estimated SAE of lung cancer was US$5249 million in China in 2015 (0.05 % of gross domestic product for China). The estimated direct SAE was US$1937 million (36.9 % of the total SAE), accounting for 0.29 % of total healthcare expenditure for China. The medical and non-medical direct expenditures were US$1749 million and US$188 million, respectively. The estimated indirect cost was US$3312 million (63.1 % of the total SAE), including US$377 million due to disability and US$2935 million due to premature death. The SAE increased with age, peaking at 60-64 years (US$1004 million), and was higher among men, in urban areas and in eastern China. If smoking prevalence was reduced to 20%, as is the goal of Healthy China 2030, the total SAE would be decreased by 4.9 %. CONCLUSIONS: Smoking-attributable economic burden caused by lung cancer was substantial in China in 2015, and will continue increasing given current trends in lung cancer. However, future economic burden can be prevented with implementation of effective tobacco control and other interventions.


Assuntos
Efeitos Psicossociais da Doença , Neoplasias Pulmonares/epidemiologia , Fumar Tabaco/efeitos adversos , Adulto , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , China/epidemiologia , Feminino , Custos de Cuidados de Saúde/estatística & dados numéricos , Gastos em Saúde/estatística & dados numéricos , Humanos , Neoplasias Pulmonares/economia , Neoplasias Pulmonares/etiologia , Masculino , Pessoa de Meia-Idade , Mortalidade Prematura , Prevalência , Distribuição por Sexo , Inquéritos e Questionários , Fumar Tabaco/economia , Fumar Tabaco/epidemiologia
16.
Front Pharmacol ; 11: 572569, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33536905

RESUMO

Background and Purpose: The availability of oncology biosimilars is deemed as a fundamental strategy to achieve sustainable health care. However, there is scarce systematic evidence on economic effectiveness of cancer biosimilars. We aimed to synthesize evidence from pharmacoeconomic evaluation of oncology biosimilars globally, provide essential data and methodological reference for involved stakeholders. Materials and Methods: This systematic review was conducted in PubMed, embase, the Cochrane library, CRD, ISPOR and NICE utill December 31, 2019. Information on basic characteristics, evaluation methodology and results were extracted. Quality of included studies was assessed using the Consolidated Health Economic Evaluation Reporting Standards Checklist. Results: For 17 studies identified (13 from Europe and four from United States), the overall quality was generally acceptable. A total of seven biological molecules involved with filgrastim, EPOETIN α, and trastuzumab leading the three. The mostly common evaluation perspective was payer, but the time horizon varied greatly. There were ten studies which adopted cost minimization analysis to evaluate efficiency while seven studies adopted budget impact analysis to address affordability, with cost ratio and cost saving being its corresponding primary endpoint. Although the comparability of included studies was limited and specific results were largely affected by uptake and price discount rates of the oncology biosimilar, the comprehensive results consistently favored its promotion. Conclusion: Globally, the economic evaluation of cancer biosimilars is in its initial phase. However, limited evidence from developed countries consistently supported both cost-effectiveness of efficiency and affordability of oncology biosimilars, while they were largely affected by uptake and price discount rate.

17.
Huan Jing Ke Xue ; 40(9): 4152-4159, 2019 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854880

RESUMO

For the rapid cultivation of anaerobic ammonium oxidation (ANAMMOX) granular sludge (AGS), a small amount of flocculent ANAMMOX sludge (FAS) was taken as the research object, and a bio-flow separate ball was used as the filler in an up-flow anaerobic sludge bed (UASB) to rapidly begin ANAMMOX and to cultivate granular sludge. In addition, the substrate inhibition kinetic characteristics of the AGS were investigated by using the Haldane model. The results showed that start-up of the ANAMMOX was successfully achieved. The total nitrogen removal rate was more than 85%, and the volume load of total nitrogen was 0.72 kg·(m3·d)-1. AGS with diameters of 1.0-3.0 mm were cultured within 127 days using the Bio-flow Separate Ball. The kinetic studies showed that the maximum reaction rates for ammonia and nitrite of granular sludge were 1.46 kg·(kg·d)-1 and 1.76 kg·(kg·d)-1, with half inhibition constants of ammonia and nitrite at 852.2 mmol·L-1 and 108.2 mmol·L-1, respectively. Compared with FAS, AGS can withstand higher concentrations of ammonia and nitrite and can maintain a higher reaction rate. The placement of the filler has positive significance for starting ANAMMOX and rapidly culturing AGS.

19.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 37(4): 422-427, 2019 Aug 01.
Artigo em Chinês | MEDLINE | ID: mdl-31512838

RESUMO

Periodontitis is a chronic inflammatory disease of periodontal tissues initiated by oral biofilm. Cellular autophagy is an effective weapon against bacterial infection. Recent studies have shown that autophagy not only promotes the removal of bacteria and toxins from infected cells, but also helps to suppress the inflammatory response to maintain the homeostasis of intracellular environment, which is closely related to the development of periodontitis. Here, we reviewed the relationship between autophagy and periodontitis from three aspects: the interactions between autophagy and periodontal pathogen infection, the regulation of autophagy and immune inflammatory responses, and the relationship between autophagy and alveolar bone metabolism. We aim to provide ideas for further study on the mechanisms of autophagy and periodontitis, and ultimately contribute to a better prevention and treatment of periodontitis.


Assuntos
Autofagia , Periodontite , Bactérias , Biofilmes , Humanos , Periodonto
20.
Proc Natl Acad Sci U S A ; 116(36): 17696-17700, 2019 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-31420513

RESUMO

Great progress has been achieved in the research field of topological states of matter during the past decade. Recently, a quasi-1-dimensional bismuth bromide, Bi4Br4, has been predicted to be a rotational symmetry-protected topological crystalline insulator; it would also exhibit more exotic topological properties under pressure. Here, we report a thorough study of phase transitions and superconductivity in a quasihydrostatically pressurized α-Bi4Br4 crystal by performing detailed measurements of electrical resistance, alternating current magnetic susceptibility, and in situ high-pressure single-crystal X-ray diffraction together with first principles calculations. We find a pressure-induced insulator-metal transition between ∼3.0 and 3.8 GPa where valence and conduction bands cross the Fermi level to form a set of small pockets of holes and electrons. With further increase of pressure, 2 superconductive transitions emerge. One shows a sharp resistance drop to 0 near 6.8 K at 3.8 GPa; the transition temperature gradually lowers with increasing pressure and completely vanishes above 12.0 GPa. Another transition sets in around 9.0 K at 5.5 GPa and persists up to the highest pressure of 45.0 GPa studied in this work. Intriguingly, we find that the first superconducting phase might coexist with a nontrivial rotational symmetry-protected topology in the pressure range of ∼3.8 to 4.3 GPa; the second one is associated with a structural phase transition from monoclinic C2/m to triclinic P-1 symmetry.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...