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We systematically studied the relation between the conditional auto-correlation function (CACF) and cross-correlation function (CCF) of biphotons or pairs of single photons. The biphotons were generated from a heated atomic vapor via the spontaneous four-wave mixing (SFWM) process. In practical usage, one single photon of a pair is utilized as the heralding photon, and another is employed as the heralded photon. Motivated by the data of CACF of the heralded photons versus CCF, we proposed a universal formula to predict the CACF. The derived formula was based on general theory and is also valid for the biphoton generation process of spontaneous parametric down-conversion (SPDC). With the formula, we utilized the experimentally determined parameters to predict CACFs, which can well agree with the measured CACFs. The proposed formula enables one to quantitatively know the CACF of heralded single photons without the measurement of Hanbury-Brown-Twiss-type three-fold coincidence count. This study provides a better understanding of biphoton generation using the SFWM or SPDC process. Our work demonstrates a valuable tool for analyzing a vital property of how the heralded photons are close to Fock-state single photons.
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Two novel vanadoborate compounds, [Cu(en)2]3[Li(H2O)]4[Li(H2O)3]2[V12B18O50(OH)10(H2O)]2·33.5H2O (1) and (H2en)4[Li(H2O)]4[V12B18O55(OH)5(H2O)]·14H2O (2), were synthesized via hydrothermal synthesis under identical conditions except for temperature. Structural analysis revealed that although both contain [V12B18O60]n- cluster anion, the different countercations potentially lead to variations in the [V12B18O60]n- cluster anion skeletons. In compound 1, the V4+/V5+ ratio was 10:2; while in compound 2 the ratio was 11:1. It is speculated that different countercations may influence the valence states of cluster anions. In this study, quantum chemical calculations revealed that the aromaticity and activity of the two compounds were different, and two-dimensional correlation infrared spectroscopy (2D-COS-IR) under magnetic perturbation confirmed that distinct response peaks of functional group vibrations to the magnetic field due to the different V4+/V5+ ratios and aromaticity of the two compounds. An electrochemical analysis revealed that compound 2 exhibits higher electrocatalytic activity. The results of quantum chemical calculations are aligned not only with the changes in the 2D-COS-IR spectra but also with the conclusions obtained from experiments on electrochemical properties. Overall, this work proposes a novel strategy for interpreting the alteration of vanadoborate anionic skeleton due to the introduction of different countercations by combining 2D-COS-IR with quantum chemical calculations.
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BACKGROUND: Neutrophil-lymphocyte ratio (NLR), fibrosis index based on four factors (Fib4), aspartate aminotransferase-to-platelet ratio index (APRI) can be used for prognostic evaluation of hepatocellular carcinoma. However, no study has established an individualized prediction model for the prognosis of hepatocellular carcinoma based on these factors. AIM: To screen the factors that affect the prognosis of hepatocellular carcinoma and establish a nomogram model that predicts postoperative liver failure after hepatic resection in patients with hepatocellular carcinoma. METHODS: In total, 220 patients with hepatocellular carcinoma treated in our hospital from January 2022 to January 2023 were selected. They were divided into 154 participants in the modeling cohort, and 66 in the validation cohort. Comparative analysis of the changes in NLR, Fib4, and APRI levels in 154 patients with hepatocellular carcinoma before liver resection and at 3 mo, 6 mo, and 12 mo postoperatively was conducted. Binary logistic regression to analyze the influencing factors on the occurrence of liver failure in hepatocellular carcinoma patients, roadmap prediction modeling, and validation, patient work characteristic curves (ROCs) to evaluate the predictive efficacy of the model, calibration curves to assess the consistency, and decision curve analysis (DCA) to evaluate the model's validity were also conducted. RESULTS: Binary logistic regression showed that Child-Pugh grading, Surgical site, NLR, Fib4, and APRI were all risk factors for liver failure after hepatic resection in patients with hepatocellular carcinoma. The modeling cohort built a column-line graph model, and the area under the ROC curve was 0.986 [95% confidence interval (CI): 0.963-1.000]. The patients in the validation cohort utilized the column-line graph to predict the probability of survival in the validation cohort and plotted the ROC curve with an area under the curve of the model of 0.692 (95%CI: 0.548-0.837). The deviation of the actual outcome curves from the calibration curves of the column-line plots generated by the modeling and validation cohorts was small, and the DCA confirmed the validity. CONCLUSION: NLR, Fib4, and APRI independently influence posthepatectomy liver failure in patients with hepatocellular carcinoma. The column-line graph prediction model exhibited strong prognostic capability, with substantial concordance between predicted and actual events.
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Objective To investigate the application value of spectral computed tomography venography(CTV)in the display and staging of deep venous thrombosis(DVT)in the lower extremity.Methods Eighty-two patients with CTV were selected and ran-domly divided into group A(42 patients)and group B(40 patients).Group A:tube voltage 120 kVp.Group B:gemstone spectral ima-ging(GSI)mode,reconstruction of 50 keV and iodine(water)maps.The CT and standard deviation(SD)values of the veins were measured,signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)were calculated in 120 kVp images of group A and in 50 keV images of group B.Two observers scored the image quality of the 2 groups subjectively,and Kappa test was used to examine the con-sistency.Based on the duration from the occurrence of clinical symptoms,the DVTs were classified.The CT values and iodine con-centration(IC)of DVT were measured in the 120 kVp images of group A and in the iodine(water)maps of group B,respectively.The receiver operating characteristic(ROC)curve was drawn to compare the effectiveness of CT values and IC in diagnosing DVT staging.Results CT values,SNR,and CNR of veins in group B were higher than those in group A(P<0.05).The subjective scores of the two groups were consistent(Kappa=0.926-0.955,P<0.05).The score for the display of veins and thrombus clarity in group B was 5(4,5),which was better than the score of 4(3,4)in group A(P<0.05).The efficiency of IC in diagnosing DVT staging[area under the curve(AUC)=0.973]was better than that of CT values(AUC=0.891).Conclusion The spectral CTV can improve the contrast of lower extremity deep veins and the clarity of thrombus,and can provide more objective indicators for the diagnosis of thrombus staging,which is conducive to accurate clinical diagnosis and treatment.
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Objective:To compare the efficiency and purity of exosomes extracted from synovial fibroblasts of patients with rheumatoid arthritis by ultracentrifugation, size exclusion chromatography and modified polymer precipitation.Methods:The exosomes were extracted from human synovial fibroblasts by ultracentrifugation, size exclusion chromatography and modified polymer precipitation. Transmission electron microscopy, particle size detection and western Blot were used to identify the morphological characteristics, particle size distribution, concentration, and expression of marker proteins. One-way analysis of variance (ANOVA) was used for comparison among the three groups, and LSD- t test was used for pairwise comparison. P<0.05 was considered statistically significant. Results:Exosomes could be successfully obtained with all three extraction methods. The typical "saucer-like" structure could be observed under transmission electron microscope. The marker proteins of exosomes TSG101, Syntenin-1 and CD63 were all detectable by western blot. The peaks of main particle size were located within 30~150 nm. As for purity, the exosomes obtained by ultracentrifugation showed the highest purity, while modified polymer precipitation was the worst, with a large number of polymer particles and impurities protein. The purity of exosomes obtained by size exclusion chromatography was the moderate. For extraction efficiency, concentrations of exosomes particles obtained by the three methods were different ( F=9.61, P=0.049), and modified polymer precipitation was significantly higher than ultracentrifugation in terms of concentration of exosomes particles [(98.0±17.0)×10 10 particles/ml vs (11.6±7.7)×10 10 particles/ml, t=-4.34, P=0.023]. Conclusion:Human synovial fibroblasts derived exosomes canbe obtained by three methods. Ultracentrifugation is time-consuming, but can produce high-purity exosomes, which may be considered in the situation when high purity requirement with large volume samples are needed. Size exclusion chromatography is a good choice with high yield and purity exosomes, and suitable for small volume samples. Modified polymer precipitation is not recommended due to production of lowest purity exosomes.
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The Bower's Berylmys (Berylmys bowersi) is one of the largest rodent species with a wide distribution range in southern China and the Indochinese Peninsula. The taxonomy and evolutionary history of the B. bowersi is still controversial and confusing. In this study, we used two mitochondrial (Cyt b and COI) and three nuclear (GHR, IRBP, and RAG1) genes to estimate the phylogeny, divergence times, and biogeographic history of B. bowersi. We also explored morphological variations among the specimens collected across China. Our phylogenetic analyses indicated that the traditional B. bowersi contains at least two species: B. bowersi and B. latouchei. Berylmys latouchei was considered a junior synonym of B. bowersi distributed in eastern China, which is confirmed to be distinguishable at specific level because of its larger size, relatively larger and whiter hind feet, and several cranial traits. The estimated split of B. bowersi and B. latouchei was at the early Pleistocene (ca. 2.00 Mya), which might be the outcome of the combined effects of climate change in the early Pleistocene and isolation by the Minjiang River. Our results highlight the Wuyi Mountains in northern Fujian, China, as a glacial refugia during the Pleistocene and call for more intensive surveys and systematic revisions of small mammals in eastern China.
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Thorium oxide has many important applications in industry. In this article, theoretical calculations have been carried out to explore the hydrolysis reactions of the ThOn (n=1-3) clusters. The reaction mechanisms of the O-deficient ThO and the O-rich ThO3 are compared with the stoichiometric ThO2 . The theoretical results show good agreement with the prior experiments. It is shown that the hydrolysis mainly occurred on the singlet potential surface. The overall reactions consist of two hydrolysis steps which are all favourable in energy. The effects of oxygen content on the hydrolysis are elucidated. Interestingly, among them, the peroxo group O2 2- in ThO3 is converted to the HOO- ligand, behaving like the terminal O2- in the hydrolysis which is transformed into the HO- groups. In addition, natural bond orbital (NBO) analyses were employed to further understand the bonding of the pertinent species and to interpret the differences in hydrolysis.
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BACKGROUND: Although exposure to ambient air pollution has been associated with mental disorder, little is known about its potential effects on children and adolescents, especially in Chinese population. We aimed to reveal the relationship of air pollutants with hospital outpatient visits for child and adolescence psychiatry (HOVCAP) in Shenzhen. METHODS: A case-crossover study based on time-series data was applied, and a distributed lag non-linear model (DLNM) was used to evaluate the non-linear and delayed effects of 4 major air pollutants (NO2, PM2.5, SO2 and O3) on HOVCAP. Least absolute shrinkage and selection operator (LASSO) regression was used to control the multicollinearity between covariates and to filter variables. RESULT: A total of 94,660 cases aged 3-18 were collected from 2014 to 2019 in the Mental Health Center of Shenzhen. Results of pollutants at mode value (M0) showed that in the single lag effect result, when the average daily concentration of NO2 at 24 µg/m3, there was a significant effect on HOVCAP over lag 1, lag 4 and lag 5, respectively. The cumulative RR of NO2 M0 value to the outpatient visits were 1.438 (1.137-1.818) over lag 0-2, 1.454 (1.120-1.887) over lag 0-3, 1.466 (1.084-1.982) over lag 0-4, 1.680 (1.199-2.354) over lag 0-5, 1.993 (1.369-2.903) over lag 0-6, and 2.069 (1.372-3.119) over lag 0-7. However, PM2.5, SO2, O3 were not associated with HOVCAP over neither single lag effects nor cumulative effects. The RR values both shown an increase either when NO2 increases by 10 units or when the maximum concentration of NO2 is reached. CONCLUSION: Our study suggests that exposure to the normal air quality of NO2 in Shenzhen may associated with the risk of HOVCAP. However, PM2.5, SO2, O3 were not associated with HOVCAP.
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Contaminantes Atmosféricos , Contaminación del Aire , Psiquiatría , Niño , Adolescente , Humanos , Contaminantes Atmosféricos/análisis , Estudios Cruzados , Pacientes Ambulatorios , Dióxido de Nitrógeno , Contaminación del Aire/análisis , China/epidemiología , Hospitales , Material Particulado/análisisRESUMEN
BACKGROUND@#Vaccination has been shown effective in controlling the global coronavirus disease 2019 (COVID-19) pandemic and reducing severe cases. This study was to assess the flare and change in disease activity after COVID-19 vaccination in patients with stable rheumatoid arthritis (RA).@*METHODS@#A prospective cohort of RA patients in remission or with low disease activity was divided into a vaccination group and a non-vaccination group based on their COVID-19 vaccination status. Each of them was examined every 3 to 6 months. In the vaccination group, disease activity was compared before and after vaccination. The rates of flare defined as disease activity scores based on 28-joint count (DAS28) >3.2 with ΔDAS28 ≥0.6 were compared between vaccination and non-vaccination groups.@*RESULTS@#A total of 202 eligible RA patients were enrolled. Of these, 98 patients received no vaccine shot (non-vaccination group), and 104 patients received two doses of vaccine (vaccination group). The median time interval from pre-vaccination visit to the first immunization and from the second dose of vaccine to post-vaccination visit was 67 days and 83 days, respectively. The disease activity scores at pre-vaccination and post-vaccination visits in the vaccination group patients were similar. At enrollment, gender, RA disease course, seropositivity, and disease activity were comparable across the two groups. Flare was observed in five (4.8%) of the vaccination group patients and nine (9.2%) of the non-vaccination group patients at post-vaccination assessment ( P = 0.221). In terms of safety, 29 (27.9%) patients experienced adverse events (AEs) after vaccination. No serious AEs occurred.@*CONCLUSIONS@#COVID-19 vaccinations had no significant effect on disease activity or risk of flare in RA patients in remission or with low disease activity. Patients with stable RA should be encouraged to receive the COVID-19 vaccination.
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Humanos , Artritis Reumatoide , Estudios de Cohortes , COVID-19/prevención & control , Vacunas contra la COVID-19/efectos adversos , Pueblos del Este de Asia , Estudios Prospectivos , Vacunación/efectos adversosRESUMEN
Wearable monitoring, which has the advantages of continuous monitoring for a long time with low physiological and psychological load, represents a future development direction of monitoring technology. Based on wearable physiological monitoring technology, combined with Internet of Things (IoT) and artificial intelligence technology, this paper has developed an intelligent monitoring system, including wearable hardware, ward Internet of Things platform, continuous physiological data analysis algorithm and software. We explored the clinical value of continuous physiological data using this system through a lot of clinical practices. And four value points were given, namely, real-time monitoring, disease assessment, prediction and early warning, and rehabilitation training. Depending on the real clinical environment, we explored the mode of applying wearable technology in general ward monitoring, cardiopulmonary rehabilitation, and integrated monitoring inside and outside the hospital. The research results show that this monitoring system can be effectively used for monitoring of patients in hospital, evaluation and training of patients' cardiopulmonary function, and management of patients outside hospital.
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Humanos , Inteligencia Artificial , Internet de las Cosas , Dispositivos Electrónicos Vestibles , Monitoreo Fisiológico/métodos , Electrocardiografía , InternetRESUMEN
Internet of Things (IoT) technology plays an important role in smart healthcare. This paper discusses IoT solution for emergency medical devices in hospitals. Based on the cloud-edge-device architecture, different medical devices were connected; Streaming data were parsed, distributed, and computed at the edge nodes; Data were stored, analyzed and visualized in the cloud nodes. The IoT system has been working steadily for nearly 20 months since it run in the emergency department in January 2021. Through preliminary analysis with collected data, IoT performance testing and development of early warning model, the feasibility and reliability of the in-hospital emergency medical devices IoT was verified, which can collect data for a long time on a large scale and support the development and deployment of machine learning models. The paper ends with an outlook on medical device data exchange and wireless transmission in the IoT of emergency medical devices, the connection of emergency equipment inside and outside the hospital, and the next step of analyzing IoT data to develop emergency intelligent IoT applications.
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Internet de las Cosas , Reproducibilidad de los Resultados , Internet , Aprendizaje Automático , TecnologíaRESUMEN
OBJECTIVES: Salidroside is used for treating inflammation-based diseases; however, its molecular mechanism is unclear. In this study, we determined the protective role of salidroside on the endotoxin-induced damage caused to the mouse alveolar epithelial type II (MLE-12) cells and its underlying mechanism. METHODS: An in vitro model for acute lung injury was constructed by inducing the MLE-12 cells using lipopolysaccharide (lipopolysaccharides, 1 mg/L). Then, The MTT assay was conducted to assess the survival rate of the MLE-12 cells in the different groups. After the treatment, apoptosis of MLE-12 cells was determined, and the mRNA and protein expression of miR-199a-5p, HMGB1, NF-kB65, TNFAIP8L2, p-IkB-α, and TLR4 was estimated by Western Blotting and RT-PCR. ELISA was also used to measure the concentration of inflammatory cytokine molecules IL-1ß, IL-6, TNF-α, and IL-18 in the cell-free supernatant. Lastly, cell morphology was examined using the AO/EB technique. RESULTS: We showed that salidroside reduced the protein and gene expression of HMGB1, NF-kB65, miR-199a-5p, p-IkB-α, and TLR4, whereas it increased the gene and protein expression of TNFAIP8L2. Furthermore, it decreased the concentrations of cytokine molecules like IL-1ß, IL-6, TNF-α, and IL-18 in the cell-free supernatant. MLE-12 also showed a lower apoptosis rate, higher survival rate, and better cell morphology. CONCLUSION: Salidroside significantly inhibited the LPS-induced MLE-12 cell damage. Our results suggest that this could be by reducing miR-199a-5p and enhancing TNFAIP8L2 expression.
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Proteína HMGB1 , MicroARNs , Animales , Citocinas/metabolismo , Glucósidos , Interleucina-18 , Interleucina-6/metabolismo , Lipopolisacáridos/farmacología , Ratones , MicroARNs/genética , MicroARNs/metabolismo , Fenoles , ARN Mensajero , Receptor Toll-Like 4 , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
Asiatic shrews of the genus Chodsigoa (Soricidae, Eulipotyphla) currently comprise nine species, mostly occurring in southwest China. From May 2017 to August 2020, 11 specimens of Chodsigoa were collected from the Dabie Mountains in Anhui Province, eastern China. Their morphology was compared with other species within the genus and one mitochondrial (cytochrome b) and two nuclear (apolipoprotein B and breast cancer 1) genes were sequenced to estimate the phylogenetic relationships of these specimens. Based on morphological and molecular evidence, these specimens are recognized as a distinct species, Chodsigoadabieshanensis sp. nov., which is formally described here. Morphologically, the new species is most similar to Chodsigoahypsibia, but it is distinguishable from all known congeners by the combination of dark brownish pelage, small size, and relatively short tail. Phylogenetic analyses revealed that C.dabieshanensis sp. nov. forms a phylogenetic lineage sister to the clade containing C.parva + C.hypsibia. The-Kimura 2-parameter genetic distances of the cytochrome b (CYT B) gene between the new species and other nominal Chodsigoa species ranged between 8.6 and 17.6%. The new species is distributed at elevations from 750 to 1250 m in the Dabie Mountains and is geographically distant from other species in the genus.
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We present a full quantum model to study the fidelity of single photons with different quantum states propagating in a medium exhibiting electromagnetically induced transparency (EIT). By using the general reservoir theory, we can calculate the quantum state of the transmitted probe photons that reveal the EIT phenomenon predicted by semiclassical theory while reflecting the influence of the quantum fluctuations of the strong coupling field. Our study shows that the coupling field fluctuations not only change the quantum state of the probe photons, but also slightly affect its transmittance. Moreover, we demonstrate that the squeezed coupling field can enhance the influence of its fluctuations on the quantum state of the probe photons, which means that the EIT effect can be manipulated by controlling the quantum state properties of the coupling field. The full quantum theory in this paper is suitable for studying quantum systems related to the EIT mechanism that would allow us to examine various quantum effects in EIT-based systems from a full quantum perspective.
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Two new chemically stable metalloporphyrin-bridged metal-catechol frameworks, InTCP-Co and FeTCP-Co, were constructed to achieve artificial photosynthesis without additional sacrificial agents and photosensitizers. The CO2 photoreduction rate over FeTCP-Co considerably exceeds that obtained over InTCP-Co, and the incorporation of uncoordinated hydroxyl groups, associated with catechol, into the network further promotes the photocatalytic activity. The iron-oxo coordination chain assists energy band alignment and provides a redox-active site, and the uncoordinated hydroxyl group contributes to the visible-light absorptance, charge-carrier transfer, and CO2 -scaffold affinity. With a formic acid selectivity of 97.8 %, FeTCP-OH-Co affords CO2 photoconversion with a reaction rate 4.3 and 15.7 times higher than those of FeTCP- Co and InTCP-Co, respectively. These findings are also consistent with the spectroscopic study and DFT calculation.
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Objective:To investigate the effect of the combination of Auto-prescription and ODM full on image quality and radiation dose of chest enhanced CT inorder to explore the feasibility of individualized low radiation dose chest enhanced CT. Methods:The phantoms PH-75 in two sizes were scanned with four scanning modes: group A, 120 kVp + Smart-mA; group B, 120 kVp + Smart-mA+ ODM full; group C, Auto-prescription + Smart-mA; group D, Auto-prescription + Smart-mA+ ODM full. The images of each group were reconstructed with 40%-80% ASIR-V (interval 20%), recorded as A 1-3-D 1-3. Image quality and radiation dose were evaluated in order to obtain optimal scanning modes. Totally 35 cases(from the First Hospital of Dalian Medical University during November 2021 to July 2022) of chest enhancement CT were collected prospectively in the clinical study using the parameters of D 2 group recorded as D patients. Patients in this group received chest enhancement CT scanning for the second time within three months. The CT parameters in first enhanced scanning recorded as A patient were as same as those in group A 1, and the parameters in second scanning recorded as D patient were as same as those in group D 2. The SNRs, CNRs, subjective grading and imaging findings of the lesion in two groups were compared. Results:In phantom study, the radiation dose of each group was statistically significant, and that in D group was the lowest. For two sizes of phantoms, A 1 was uesd as the control group in pairwise comparison. The SDs of B 1, C 1, and D 2 images had no statistical difference with that of A 1 ( P > 0.05), and SD of D 1was higher than that of A 1, and SDs of other groups were lower than that of A 1( F=10.77, 122.50, P<0.05). CNR of B 1 had no statistical difference with that of A 1, and the CNRs of other groups were higher( F=136.20, 30.21, P<0.05). Subjective scores of A 2, C 2, D 2 had no statistical difference with that of A 1 and those of other groups were lower than that of A 1( H=52.89, 43.95, P<0.05). In clinical study, 80 kVp was uesd for 22 cases and 100 kVp was used for 13 cases in D patients group. SNRs and CNRs in the D patients group were all higher than those in the A patients group ( P > 0.05). The consistency of image quality scores for two observers was good ( kappa = 0.754, P < 0.05). The median scores of the two groups were (4, 4). Conclusion:Auto-prescription combined with ODM full in chest enhanced CT imaging can achieve individualized low radiation dose with meeting the requirements of image quality and clinical diagnosis.
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Objective: To investigate the efficacy and safety of a new cervical artificial disc prosthesis in the treatment of cervical degenerative diseases. Methods: The clinical data of 18 patients with single-level cervical degenerative diseases who underwent three dimensional printed anatomical bionic cervical disc replacement at Department of Spinal Surgery,Honghui Hospital,Xi'an Jiaotong University from May 2019 to July 2020 were analyzed retrospectively. There were 7 males and 11 females,aged (45±8) years old(range:28 to 58 years).The surgical segment was located at C3-4 level in 2 cases, C4-5 level in 5 cases, C5-6 level in 9 cases, and C6-7 level in 2 cases.The clinical and radiographic outcomes were recorded and compared at preoperative,postoperative times of one month and twelve months.The clinical assessments contained Japanese orthopedic association (JOA) score,neck disability index (NDI) and visual analogue scale (VAS).Imaging assessments included range of motion (ROM) of cervical spine, prosthesis subsidence and prosthesis anteroposterior migration.Repeated measurement variance analysis was used for comparison between groups,and paired t test was used for pairwise comparison. Results: All patients underwent the operation successfully and were followed up for more than 12 months.Compared with preoperative score,the JOA score,NDI and VAS were significantly improved after surgery (all P<0.01).There was no significant difference in postoperative ROM compared with 1-and 12-month preoperative ROM (t=1.570,P=0.135;t=1.744,P=0.099). The prosthesis subsidence was (0.29±0.13) mm (range: 0.18 to 0.50 mm) at 12-month postoperatively.The migration of prosthesis at 12-months postoperatively were (0.71±0.20) mm (range: 0.44 to 1.08 mm).There was no prosthesis subsidence or migration>2 mm at 12-month postoperatively. Conclusion: Three dimensional printed anatomical biomimetic cervical artificial disc replacement has a good early clinical effect in the treatment of cervical degenerative diseases, good mobility can be obtained while maintaining stability.
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Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Biomimética , Vértebras Cervicales/cirugía , Estudios de Seguimiento , Disco Intervertebral/cirugía , Degeneración del Disco Intervertebral/cirugía , Rango del Movimiento Articular , Estudios Retrospectivos , Reeemplazo Total de Disco/métodos , Resultado del TratamientoRESUMEN
Ni-rich layered oxides, like LiNi0.8Co0.1Mn0.1O2 (NCM811), have been widely investigated as cathodes due to their high energy density. However, gradual structural transformation during cycling can lead to capacity degradation and potential decay of cathode materials. Herein, we doped high-valence transition metal (TM) ions (V5+, Nb5+, and Zr4+) at the Ni site of NCM811 by first principles simulations and explored the mechanism of doping TMs in NCMs for enhancing the electrochemical performance. Analysis of the calculations shows that doping V, Nb and Zr has an efficient influence on alleviating the Ni oxidation, reducing the loss of oxygen, and facilitating Li+ migration. Moreover, V doping can further suppress the lattice distortion due to the radius of V5+ being close to the radius of Mn4+. In particular, compared with the barrier of the pristine NCM in Li divacancy, the barrier of V-doped NCM reaches the lowest. In conclusion, V is the most favorable dopant for NCM811 to improve the electrochemical properties and achieve both high capacity and cycling stability.
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We utilized the all-copropagating scheme, which maintains the phase-match condition, in the spontaneous four-wave mixing (SFWM) process to generate biphotons from a hot atomic vapor. The linewidth and spectral brightness of our biphotons surpass those of the biphotons produced with the hot-atom SFWM in the previous works. Moreover, the generation rate of the sub-MHz biphoton source in this work can also compete with those of the sub-MHz biphoton sources of the cold-atom SFWM or cavity-assisted spontaneous parametric down conversion. Here, the biphoton linewidth is tunable for an order of magnitude. As we tuned the linewidth to 610 kHz, the generation rate per linewidth is 1,500 pairs/(s·MHz) and the maximum two-photon correlation function, gs,as(2), of the biphotons is 42. This gs,as(2) violates the Cauchy-Schwarz inequality for classical light by 440 folds, and demonstrates that the biphotons have a high purity. By increasing the pump power by 16 folds, we further enhanced the generation rate per linewidth to 2.3×104 pairs/(s·MHz), while the maximum gs,as(2) became 6.7. In addition, we are able to tune the linewidth down to 290±20 kHz. This is the narrowest linewidth to date among all single-mode biphoton sources of room-temperature and hot media.
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Efficient frequency conversion of photons has important applications in optical quantum technology because the frequency range suitable for photon manipulation and communication usually varies widely. Recently, an efficient frequency conversion system using a double-Λ four-wave mixing (FWM) process based on electromagnetically induced transparency (EIT) has attracted considerable attention because of its potential to achieve a nearly 100% conversion efficiency (CE). To obtain such a high CE, the spontaneous emission loss in this resonant-type FWM system must be suppressed considerably. A simple solution is to arrange the applied laser fields in a backward configuration. However, the phase mismatch due to this configuration can cause a significant decrease in CE. Here, we demonstrate that the phase mismatch can be effectively compensated by introducing the phase shift obtained by two-photon detuning. Under optimal conditions, we observe a wavelength conversion from 780 to 795 nm with a maximum CE of 91.2%±0.6% by using this backward FWM system at an optical depth of 130 in cold 87Rb atoms. The current work represents an important step toward achieving low-loss, high-fidelity quantum frequency conversion based on EIT.