Optical bistability in a heterodimer composed of a quantum dot and a metallic nanoshell.

We theoretically explore the conditions for generating optical bistability (OB) in a heterodimer comprised of a semiconductor quantum dot (SQD) and a metallic nanoshell (MNS). The MNS is made of a metallic nanosphere as a core and a dielectric material as a shell. For the specific hybrid system considered, the bistable effect appears only if the frequency of the pump field is equal to (or slightly less than) the exciton frequency for a proper shell thickness. Bistability phase diagrams, when plotted, show that the dipole-induced bistable region can be greatly broadened by changing the shell thickness of the MNS in a strong exciton-plasmon coupling regime. In particular, we demonstrate that the multipole polarization not only narrows the bistable zone but also enlarges the corresponding thresholds for a given intermediate scaled pumping intensity. On the other hand, when the SQD couples strongly with the MNS, the multipole polarization can also significantly broaden the bistable region and induce a great suppression of the FWM (four-wave mixing) signal for a fixed shell thickness. These interesting findings offer a fresh understanding of the bistability conditions in an SQD/MNS heterodimer, and may be useful in the fabrication of high-performance and low-threshold optical bistable nanodevices.

Ultra-strong optical four-wave mixing signal induced by strong exciton-phonon and exciton-plasmon couplings.

We propose a scheme to generate ultra-strong four-wave mixing (FWM) signal based on a suspended monolayer graphene nanoribbon nanomechanical resonator (NR) coupled to an Au nanoparticle (NP). It is shown that, the FWM spectrum can switch among two-peaked, three-peaked, four-peaked or five-peaked via the modulation of exciton-phonon and exciton-plasmon couplings. This is mainly attributed to the vibrational properties of NR related to the exciton-phonon coupling, and the energy-level splitting of the localized exciton correlated to three classes of resonances consisting of three-photon resonance, Rayleigh Resonance, and AC-Stark atomic resonance. Especially, in a dual-strong coupling regime, the gains for these peaks can be as high as nine orders of magnitude (∼ 109) around the lower bistable threshold due to a combined effect of two couplings. Our findings not only offer an efficient way to measure the vibrational frequency of NR and the exciton-phonon coupling strength but also provide a possibility to fabricate high-performance optoelectronic nanodevices.

[Social Determinants Affecting Changes in Mental Health of Rural-Urban Migrant Population in Chengdu: An Oaxaca-Blinder Decomposition Analysis].

Objective: To investigate the social determinants that influenced the changes in the mental health of the rural-urban migrant population in Chengdu. Methods: Using data from two cross-sectional surveys, one conducted in 2009 and another, in 2018, of the rural-urban migrant population in Chengdu, we analyzed the social determinants of mental health affecting the rural-urban migrant population in Chengdu by multiple linear regression, and analyzed the contribution of changes in social determinants to the disparity in mental health over a decade using the Oaxaca-Blinder decomposition analysis. Results: This study included 3091 cases of rural-urban migrants in Chengdu, with 965 (31.22%) covered in the survey year of 2009 and 2126 (68.78%) covered in 2018. Multiple linear regression models were established with mental component summary (MCS) as the dependent variable, the social determinants of health as the independent variables, and gender, age, and survey year as covariates. The findings showed that being married ( ß=2.33, P<0.001), drinking 1-2 times per week ( ß=-1.42, P<0.05), illness within four weeks ( ß=-2.57, P<0.001), and hospitalization in the past year ( ß=-1.82, P<0.05), wage arrears ( ß=-1.67, P<0.05), job satisfaction ( ß=1.25, P<0.001), monthly housing costs (housing costs below monthly income: ß=-1.55, P=0.001; housing costs above monthly income: ß=-4.59, P=0.001) and housing condition ( ß=0.23, P<0.05) had significant impact on the MCS of the rural-urban migrant population. The results of the Oaxaca-Blinder decomposition method showed that the MCS disparity between the two surveys was -4.7660 points. With 2018 as the base year, the explainable parts accounted for 15.80%. Being married, decrease in the prevalence of illnesses within four weeks, and increased job satisfaction formed positive contribution to the improvement of the mental health, and increase in the proportion of monthly housing expenses formed negative contribution. Conclusion: Between 2009 and 2018, the mental health of the rural-urban migrant population in Chengdu showed improvement, and changes in marital status, illness within four weeks, job satisfaction, and monthly housing costs contributed to improvements in mental health during the period. Future intervention measures to promote the mental health of the floating population can be developed with the perspective of improving the social determinants of health in mind.

[Impact of mild hypothermia therapy on hemodynamics during the induction stage in neonates with moderate to severe hypoxic-ischemic encephalopathy].

OBJECTIVE: To study the changes in hemodynamics during the induction stage of systemic mild hypothermia therapy in neonates with moderate to severe hypoxic-ischemic encephalopathy (HIE). METHODS: A total of 21 neonates with HIE who underwent systemic mild hypothermia therapy in the Department of Neonatology, Dongguan Children's Hospital Affiliated to Guangdong Medical University, from July 2017 to April 2020 were enrolled. The rectal temperature of the neonates was lowered to 34℃ after 1-2 hours of induction and maintained at this level for 72 hours using a hypothermia blanket. The impedance method was used for noninvasive hemodynamic monitoring, and the changes in heart rate (HR), mean arterial pressure (MAP), stroke volume (SV), cardiac output (CO), cardiac index (CI), and total peripheral resistance (TPR) from the start of hypothermia induction to the achievement of target rectal temperature (34℃). Blood lactic acid (LAC) and resistance index (RI) of the middle cerebral artery were recorded simultaneously. RESULTS: The 21 neonates with HIE had a mean gestational age of (39.6±1.1) weeks, a mean birth weight of (3 439±517) g, and a mean 5-minute Apgar score of 6.8±2.0. From the start of hypothermia induction to the achievement of target rectal temperature (34℃), there were significant reductions in HR, CO, and CI (P < 0.05), while there was no significant change in SV and MAP (P > 0.05). There was a significant increase in TPR (P < 0.05) and a significant reduction in LAC (P < 0.05), while there was no significant change in RI (P > 0.05). CONCLUSIONS: The systemic mild hypothermia therapy may have a significant impact on hemodynamics in neonates with moderate to severe HIE, and continuous hemodynamic monitoring is required during the treatment.

Dual-channel bistable switch based on a monolayer graphene nanoribbon nanoresonator coupled to a metal nanoparticle.

We theoretically propose a dual-channel bistable switch based on a monolayer Z-shaped graphene nanoribbon nanoresonator (NR) coupled to a metal nanoparticle (MNP). We show that the bistable nonlinear absorption response can be realized due to a competition and combination of the exciton-plasmon and exciton-phonon interactions. We map out two-dimensional and three-dimensional bistability phase diagrams, which reveal clearly the dynamical evolution of the roles played by these two interactions in managing optical bistability (OB) at all stages. Specifically, the bistable switch proposed can be controlled via a single channel or dual channels by only adjusting the intensity or frequency of the pump field. In/outside these channels, the switch will be turned on/off. The results obtained here not only can be employed to measure precisely the distance between the MNP and the NR but also provide promising applications in optical switching and optical storage.

Elevated Osteoprotegerin Concentration Predicts Increased Risk of Cardiovascular Mortality in Patients with Chronic Kidney Disease: A Systematic Review and Meta-Analysis.

INTRODUCTION: Studies have shown inconsistent results regarding the association between osteoprotegerin (OPG) concentration and cardiovascular mortality in patients with chronic kidney disease (CKD). This systematic review and meta-analysis aims to investigate the association between OPG concentration and cardiovascular mortality in patients with CKD. METHODS: Between January 1970 and February 2020, the PubMed, EMBASE, and Cochrane Library databases were searched for eligible studies investigating the association between OPG concentration and cardiovascular mortality in patients with CKD. Pooled hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs) were calculated using random effects models. RESULTS: In total, 10 studies comprising 2,120 patients (including 1,723 receiving dialysis) with CKD were included. The included studies were considered to be of fair to high quality. Patients in the highest OPG concentration group had a significantly higher risk of cardiovascular mortality (4 studies; adjusted HR, 2.05; 95% CI, 1.39-3.00) than patients in the low OPG concentration group. An increase of 1 pmol/L in OPG concentration was associated with a 4% increased risk of cardiovascular mortality (6 studies; adjusted HR, 1.04; 95% CI, 1.02-1.07). CONCLUSION: Elevated OPG concentrations are associated with an increased risk of cardiovascular death in patients with CKD.

[Correlation of gr/gr and b2/b3 deletions in the AZFc region of the Y-chromosome with recurrent spontaneous abortion].

OBJECTIVE: To investigate the association of gr/gr, b2/b3 and gr/gr with b1-2/b3-4 deletions (repetitions) in the AZFc region of the Y chromosome with recurrent spontaneous abortion (RSA). METHODS: Using the next-generation sequencing technology, we examined the men with indications of Y chromosome microdeletion at our center from June 2017 to March 2018 and excluded the common causes of RSA through inquiry and other related examinations. Totally, 170 cases of AZFc deletion (80 cases of gr/gr deletion, 75 cases of b2/b3 deletion, and 15 cases of gr/gr with b1-2/b3-4 deletion) were detected and included in the case group, and another 328 normal males enlisted as controls. We analyzed the correlation of Y chromosome microdeletions with the incidence rate of RSA. RESULTS: The incidence rate of RSA was significantly higher in the case group than in the normal controls (28.8% ï¼»49/170ï¼½ vs 13.1% ï¼»43/328ï¼½, P < 0.01), 22.5% (18/80) in the gr/gr deletion cases (P < 0.05), 30.7% (23/75) in the b2/b3 deletion cases (P < 0.01), and 53.3% (8/15) in the gr/gr with b1-2/b3-4 deletion cases (P < 0.01), remarkably lower in the gr/gr than in the gr/gr with b1-2/b3-4 deletion subgroup (P < 0.05), but with no statistically significant difference between the other subgroups. CONCLUSIONS: The gr/gr, b2/b3, and gr/gr with b1-2/b3-4 deletions (repetitions) in the AZFc region of the Y chromosome may cause recurrent spontaneous abortion.

Circulating Osteoprotegerin Levels Independently Predict All-cause Mortality in Patients with Chronic Kidney Disease: a Meta-analysis.

Background: Studies have shown inconsistent results regarding the association between circulating osteoprotegerin (OPG) levels and all-cause mortality in patients with chronic kidney disease (CKD). The aim of this meta-analysis is to investigate the association between circulating OPG levels and all-cause mortality in patients with CKD. Methods: The PubMed, EMBASE and Cochrane Library databases were searched for eligible studies investigating the association between circulating OPG levels and all-cause mortality in patients with CKD. Pooled hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs) were calculated using a random effects model. Results: In all, 13 studies that included 2,895 patients with CKD were included in this analysis. According to the meta-analysis, patients with the highest circulating OPG level had a significantly higher risk of all-cause mortality (7 studies; the adjusted HR, 1.88; 95% CI, 1.45 - 2.44) compared with patients with the lower circulating OPG level. An increase of 1 pmol/L in the circulating OPG level was associated with a 6% increased risk of all-cause mortality (7 studies; the adjusted HR, 1.06; 95% CI, 1.03-1.10). A subgroup analysis by dialysis methods suggested that an elevated circulating OPG level was independently associated with all-cause mortality in the HD only population. Conclusion: Elevated circulating OPG levels independently predict an increased risk of all-cause mortality in patients with CKD, especially in the HD only population.

Plasmon-modulated bistable four-wave mixing signals from a metal nanoparticle-monolayer MoS2 nanoresonator hybrid system.

We present a study for the impact of exciton-phonon and exciton-plasmon interactions on bistable four-wave mixing (FWM) signals in a metal nanoparticle (MNP)-monolayer MoS2 nanoresonator hybrid system. Via tracing the FWM response we predict that, depending on the excitation conditions and the system parameters, such a system exhibits 'U-shaped' bistable FWM signals. We also map out bistability phase diagrams within the system's parameter space. Especially, we show that compared with the exciton-phonon interaction, a strong exciton-plasmon interaction plays a dominant role in the generation of optical bistability, and the bistable region will be greatly broadened by shortening the distance between the MNP and the monolayer MoS2 nanoresonator. In the weak exciton-plasmon coupling regime, the impact of exciton-phonon interaction on optical bistability will become obvious. The scheme proposed may be used for building optical switches and logic-gate devices for optical computing and quantum information processing.

Bistable four-wave mixing response in a semiconductor quantum dot coupled to a photonic crystal nanocavity.

We perform a theoretical study of the bistable four-wave mixing (FWM) response in a coupled system comprised of a semiconductor quantum dot (SQD) and a photonic crystal (PC) nanocavity in which the SQD is embedded. It is shown that the shape of the FWM spectrum can switch among single-peaked, double-peaked, triple-peaked, and four-peaked arising from the vacuum Rabi splitting and the exciton-nanocavity coupling. Especially, we map out bistability phase diagrams within a parameter subspace of the system, and find that it is easy to turn on or off the bistable FWM response by only adjusting the excitation frequency or the pumping intensity. Our results offer a feasible means for measuring the SQD-PC nanocavity coupling strength and open a new avenue to design optical switches and memories.

Switching freely between superluminal and subluminal light propagation in a monolayer MoS2 nanoresonator.

We theoretically propose a feasible scheme to advance or slow the propagation of light in a monolayer MoS2 nanoresonator (NR). The scheme allows one to easily turn on or off the fast (superluminal) and slow (subluminal) light effects and switch freely between fast and slow light propagation by only adjusting the frequency or intensity of the pump field. As the exciton interacts strongly with the phonons in MoS2, the slow light effect will appear along with a large dispersion with a very steep negative slope and a sharp absorption peak. Especially, the maximal group velocity index of the slow light in the monolayer MoS2 NR can reach two orders of magnitude larger than that in a carbon nanotube resonator. These results provide a new way to measure the exciton-phonon coupling strength and may prove useful in device applications such as optical switching and optical signal processing.

Serum atrial natriuretic peptide (ANP) as an objective indicator for the diagnosis of neurogenic shock: animal experiment and human case report.

In forensic medicine, the diagnosis of death due to neurogenic shock is considered to be an aporia, as lacking objective indicators and presenting atypical symptoms in autopsy. Medico-legal disputes and complaints occasionally result from this ambiguity. To explore potential objective indicators of neurogenic shock, we set up a model of neurogenic shock by applying an external mechanical force on the carotid sinus baroreceptor in rabbits. The serum atrial natriuretic peptide (ANP) level was measured by radioimmunoassay in the control group (n = 8), survival group (n = 15) and death group (n = 5) both before and after the insult. The serum ANP level showed a significant increase after the insult in the death group compared with the serum obtained before the insult (P = 0.006), while the serum ANP level after the insult in the survival group and control group was not statistically significant compared with the serum obtained before the insult (P = 0.332 and P = 0.492, respectively). To verify the repeatability of the model and the postmortem behavior of serum ANP, five healthy adult rabbits underwent the same procedure as the experimental group. The mortality rate was consistent with the former experiment (20 %). There were no significant changes in serum ANP level in vitro and in vivo (within 48 and 24 h, respectively). But there was a significant decrease in serum ANP level at 48 h postmortem in vivo (P = 0.001). A female patient who expired due to neurogenic shock during a hysteroscopy was reported. Neither fatal primary disease nor evidence for mechanical injuries or intoxication was found according to the autopsy. The serum ANP level was assayed as a supplementary indicator and was found to be three-fold higher than the normal maximum limit. Combined with the animal experiment, this case highlights that serum ANP has the potential to be an objective indicator for the diagnosis of death due to neurogenic shock.

Four-wave mixing signal enhancement and optical bistability of a hybrid metal nanoparticle-quantum dot molecule in a nanomechanical resonator.

We investigate theoretically four-wave mixing (FWM) response and optical bistability (OB) in a hybrid nanosystem composed of a metal nanoparticle (MNP) and a semiconductor quantum dot (SQD) coupled to a nanomechanical resonator (NR). It is shown that the FWM signal is enhanced by more than three orders of magnitude as compared to that of the system without exciton-phonon interaction, and the FWM signal can also be suppressed significantly and broadened due to the exciton-plasmon interaction. As the MNP couples strongly with the SQD, the bistable FWM response can be achieved by adjusting the SQD-MNP distance and the pumping intensity. For a given pumping constant and a fixed SQD-MNP distance, the enhanced exciton-phonon interaction can promote the occurrence of bistability. Our findings not only present a feasible way to detect the spacing between two nanoparticles, but also hold promise for developing quantum switches and nanoscale rulers.

Transport properties of a single plasmon interacting with a hybrid exciton of a metal nanoparticle-semiconductor quantum dot system coupled to a plasmonic waveguide.

The transport properties of a single plasmon interacting with a hybrid system composed of a semiconductor quantum dot (SQD) and a metal nanoparticle (MNP) coupled to a one-dimensional surface plasmonic waveguide are investigated theoretically via the real-space approach. We considered that the MNP-SQD interaction leads to the formation of a hybrid exciton and the transmission and reflection of a single incident plasmon could be controlled by adjusting the frequency of the classical control field applied to the MNP-SQD hybrid nanosystem, the kinds of MNPs and the background media. The transport properties of a single plasmon interacting with such a hybrid nanosystem discussed here could find applications in the design of next-generation quantum devices, such as single-photon switching and nanomirrors, and in quantum information processing.

Four-wave parametric amplification in semiconductor quantum dot-metallic nanoparticle hybrid molecules.

We study theoretically four-wave parametric amplification arising from the nonlinear optical response of hybrid molecules composed of semiconductor quantum dots and metallic nanoparticles. It is shown that highly efficient four-wave parametric amplification can be achieved by adjusting the frequency and intensity of the pump field and the distance between the quantum dot and the metallic nanoparticle. Specifically, the induced probe-wave gain is tunable in a large range from 1 to 1.43 × 105. This gain reaches its maximum at the position of three-photon resonance. Our findings hold great promise for developing four-wave parametric oscillators.

Plasmon resonances in a stacked pair of graphene ribbon arrays with a lateral displacement.

We find that a stacked pair of graphene ribbon arrays with a lateral displacement can excite plasmon waveguide mode in the gap between ribbons, as well as surface plasmon mode on graphene ribbon surface. When the resonance wavelengthes of plasmon waveguide mode and surface plasmon mode are close to each other, there is a strong electromagnetic interaction between the two modes, and then they contribute together to transmission dip. The plasmon waveguide mode resonance can be manipulated by the lateral displacement and longitudinal interval between arrays due to their influence on the manner and strength of electromagnetic coupling between two arrays. The findings expand our understanding of electromagnetic resonances in graphene-ribbon array structure and may affect further engineering of nanoplasmonic devices and metamaterials.

A human-specific insertion promotes cell proliferation and migration by enhancing TBC1D8B expression.

Human-specific insertions play important roles in human phenotypes and diseases. Here we reported a 446-bp insertion (Insert-446) in intron 11 of the TBC1D8B gene, located on chromosome X, and traced its origin to a portion of intron 6 of the EBF1 gene on chromosome 5. Interestingly, Insert-446 was present in the human Neanderthal and Denisovans genomes, and was fixed in humans after human-chimpanzee divergence. We have demonstrated that Insert-446 acts as an enhancer through binding transcript factors that promotes a higher expression of human TBC1D8B gene as compared with orthologs in macaques. In addition, over-expression TBC1D8B promoted cell proliferation and migration through "a dual finger" catalytic mechanism (Arg538 and Gln573) in the TBC domain in vitro and knockdown of TBC1D8B attenuated tumorigenesis in vivo. Knockout of Insert-446 prevented cell proliferation and migration in cancer and normal cells. Our results reveal that the human-specific Insert-446 promotes cell proliferation and migration by upregulating the expression of TBC1D8B gene. These findings provide a significant insight into the effects of human-specific insertions on evolution.

Double-bundle reconstruction results in superior clinical outcome than single-bundle reconstruction.

PURPOSE: To compare the short- and long-term clinical outcomes of the double-bundle (DB) anterior cruciate ligament (ACL) reconstruction with those of single-bundle (SB) ACL reconstruction. METHODS: An electronic search of the database PubMed (1966-September 2011), EMBASE (1984-September 2011), and Cochrane Controlled Trials Register (CENTRAL; 3rd Quarter, 2011) was undertaken to identify relevant studies. Main clinical outcomes were knee stability measurements including KT-1000 arthrometer measurement, Pivot shift test, and Lachman test, and clinical outcome measurements including International Knee Documentation Committee (IKDC), Lysholm knee score, Tegner activity score, and complications. RESULTS: Eighteen studies were finally included in this meta-analysis, which were all classified as high risk of bias according to the Collaboration's recommended tool. It is seen that compared to SB ACL reconstruction, DB ACL reconstruction results in a KT-1000 arthrometer outcome 0.63 and 1.00 mm closer to the normal knee in a short- and long-term follow-up, respectively. Our results also reveal that DB-treated patients have a significantly higher negative rate of the pivot shift test (p < 0.00001 and = 0.006 in a short- and long-term follow-up, respectively) and Lachman test (n.s. and p < 0.0001 in a short- and long-term follow-up, respectively) compared to SB-treated patients. As for the clinical outcome measurements, a significant difference is found between SB versus DB ACL reconstruction regarding the IKDC (p = 0.006 and < 0.0001 in a short- and long-term follow-up, respectively) and complications (p = 0.03), while there is no significant difference between the two groups regarding Lysholm knee score (n.s.) and Tegner activity score (n.s.). CONCLUSION: Overall, double-bundle ACL reconstruction yields better clinical outcomes when compared to single-bundle ACL reconstruction. LEVELS OF EVIDENCE: II.

[ICSI causes abnormal H3K9 methylation in the male pronuclei and growth retardation of mouse embryos].

OBJECTIVE: To evaluate the safety of intracytoplasmic sperm injection (ICSI) in the mouse model. METHODS: We simulated clinical ICSI technology and comprehensively evaluated it by parthenogenetic activation, immunofluorescence, embryo transplantation, examination of early implantation, and measurement of the crown-rump length (CRL). RESULTS: ICSI significantly reduced the ability of preimplantation embryo development of the mouse, especially after the 8-cell stage (P < 0.01). The fluorescence of H3K9 dimethylation was abnormal at the male pronuclei of the embryos derived from ICSI. Further examination of the development of the transferred ICSI embryos indicated no significant difference in the rate of early implantation at E5. 5 days as compared with normal fertilization (P = 0.6), but the percentage of "normal embryos" was decreased significantly at E9.5 days (P < 0.01). Obvious growth retardation phenotype was observed even in the normal ICSI embryos at E9.5 days. CONCLUSION: ICSI might result in growth retardation of embryos by affecting H3K9 dimethylation in the male pronuclei.

[Correlation of DNA methylation status of imprinted gene H19 ICR with oligozoospermia and asthenozoospermia].

OBJECTIVE: To study the correlation of the DNA methylation status of the imprinted gene H19 imprinting control region (ICR) with oligozoospermia and asthenozoospermia. METHODS: We eliminated chromosomal abnormality as the cause of male infertility in the subjects by karyotype analysis and detection of Y-chromosome microdeletions, and identified 18 cases of single factor-induced oligozoospermia (sperm concentration < 15 x 10(6)/ml) and 20 cases of single factor-induced asthenozoospermia (progressively motile sperm <32%) by computer-aided sperm analysis (CASA). Then we extracted genome-wide sperm DNA, treated it with bisul- fite, subjected the target gene fragments to PCR amplification and sequencing. Lastly, we analyzed the DNA methylation status of the target genes with BIQ Analyzer and processed the data using SPSS17.0. RESULTS: The DNA methylation level of the H19 ICR was increased significantly in the oligozoospermia patients ([9.19 +/- 2.45]%, P < 0.05), especially in the severe oligozoospermia males with sperm concentration < 3 x 10(6)/ml (P < 0.01), as compared with that of the 20 fertile control men ([0.30 +/- 0.06]%). However, no significant differences were found in the level ([0.30 +/- 0.07]%) and pattern of the DNA methylation of the H19 ICR (P = 0.62). Further analysis of the DNA methylation status of the CTCF-6 binding sites indicated that the DNA methylation degree was significant higher in the oligozoospermia men ([2.67 +/- 0.75]%) than in the fertile control ([0.05 +/- 0.03]%) or the asthenozoospermia group ([0.03 +/- 0.02]%), with no significant differences between the latter two (P = 0.35). CONCLUSION: The reduced DNA methylation of the H19 ICR is negatively correlated with sperm concentration but not associated with sperm motility.