We report the first experimental demonstration of quantum entanglement among ten spatially separated single photons. A near-optimal entangled photon-pair source was developed with simultaneously a ...source brightness of ∼12 MHz/W, a collection efficiency of ∼70%, and an indistinguishability of ∼91% between independent photons, which was used for a step-by-step engineering of multiphoton entanglement. Under a pump power of 0.57 W, the ten-photon count rate was increased by about 2 orders of magnitude compared to previous experiments, while maintaining a state fidelity sufficiently high for proving the genuine ten-particle entanglement. Our work created a state-of-the-art platform for multiphoton experiments, and enabled technologies for challenging optical quantum information tasks, such as the realization of Shor's error correction code and high-efficiency scattershot boson sampling.
Summary
Periosteal expansion and bone loss have opposite effects on femur strength. Their combined effect has not been fully understood. Our investigation using a recently developed beam model ...suggested that periosteal expansion may maintain femur bending stiffness among elderly women, but not help preserve femoral strength and reduce hip fracture risk.
Introduction
Periosteal expansion and bone loss are two accompanying biological phenomena in old population. Their combined effect on bone stiffness, strength, and fracture risk is still not clear, because previous studies have reported contradictory results.
Methods
A recently developed DXA (dual-energy X-ray absorptiometry)-based beam model was applied to study the effect at the femoral neck. We first made a theoretical analysis. Then, a clinical cohort consisting of 961 women (316 hip fractures and 645 controls, age of 75.9 ± 7.1) was used to investigate the associations quantitatively. We investigated (1) correlations of femoral-neck width and bone mineral density with femoral stiffness and strength; (2) correlations of femoral stiffness, strength, and hip fracture risk index with age; (3) associations of femoral stiffness, strength and fracture risk index with actual fracture status, measured by the area under the curve (AUC) and odds ratio (OR).
Results
The investigation results showed that (i) femoral-neck width had stronger correlation with femoral bending stiffness (
r
= 0.61–0.82,
p
< 0.001) than with the other stiffness components, while bone mineral density had stronger correlation with axial/shearing stiffness (
r
= 0.84–0.97,
p
< 0.001), strength (
r
= 0.85–0.92,
p
< 0.001), and fracture risk index (
r
= −0.61–0.62,
p
< 0.001) than with bending stiffness. (ii) The association between femoral bending stiffness and age was insignificant (
r
= − 0.06–0.05,
r
> 0.05); The associations of axial/shearing stiffness (
r
= − 0.27–−0.20,
p
< 0.001), strength (
r
= − 0.28,
p
< 0.001), and fracture risk index (
r
= 0.38,
p
< 0.001) with age were significant. (iii) Fracture risk index had the strongest association with actual fracture status (AUC = 0.75, OR = 3.19), followed by strength (AUC = 0.74, OR = 2.84) and axial/shearing stiffness (AUC = 0.56–0.65, OR = 2.39–2.49). Femoral bending stiffness had the weakest association (AUC = 0.48–0.69, OR = 1.42–2.09).
Conclusion
We concluded that periosteal expansion may be adequate to maintain femoral bending stiffness among elderly women, but it may not help preserve strength and reduce hip fracture risk.
Background
To investigate the role of adjuvant radiotherapy in patients with pancreatic cancer.
Methods and patients
The patients with pancreatic cancer from 18 registered institutions in the ...Surveillance Epidemiology and End Results (SEER) database were retrospectively analyzed. The characteristics of patients who would benefit from adjuvant radiotherapy were screened, as well as whether neoadjuvant or adjuvant radiotherapy conferred to a better clinical outcome. Propensity score matching was used to control for confounding features.
Results
Thirty thousand two hundred and forty-nine patients were included in this study (21,295 vs 8954 in surgery and adjuvant radiotherapy group); 1150 patients were matched in two groups. The median survivals in the surgery (S) group and adjuvant radiotherapy (S + R) group were 24 and 21 months, respectively. The 1-, 3-, and 5-year overall survival (OS) rates in the S group and S + R group were 68%, 40%, 31%, and 75%, 30%, 20%, respectively (
p
< 0.001), and the median OS was 22 and 25 months in S and S + R group after PSM, the former 1-, 2-, 3-, and 5-year OS were 73%, 45%, 30%, and 19%, and the later were 81%, 52%, 37%, and 24% (
p
= 0.0015), respectively; stratified analysis showed patients whose carcinoma located at pancreatic head with II stage infiltrating duct carcinoma (22 vs 25,
p
= 0.0276), T4 adenocarcinoma (28 vs 33,
p
= 0.0022), N1 stage adenocarcinoma (20 vs 23,
p
= 0.0203), and patients with infiltrating duct carcinoma received regional resection (23 vs 25,
p
= 0.028) and number of resected lymph node were ≥ 4 (22 vs 25,
p
= 0.009) had better OS after additional radiotherapy than surgery alone. Patients with pancreatic body/tail carcinoma III stage adenocarcinoma (13 vs,
p
= 0.0503) and T4 adenocarcinoma (14 vs,
p
= 0.0869) had survival advantage within 24 months for additional radiotherapy. However, patients with T2 stage adenocarcinoma located in pancreatic body/tail had better OS in surgery group than that in R + S group.
Conclusions
Additional radiotherapy may contribute to improved prognosis for patients with pancreatic head II stage infiltrating duct carcinoma, III stage adenocarcinoma, T4 stage carcinoma, N1 stage adenocarcinoma, regional resection, or number of lymphadenectomy ≥ 4 in infiltrating duct carcinoma. A specific subgroup of patients with specific stage and histological type pancreatic cancer should be considered for additional radiotherapy.
Summary
Femur expansion occurs during normal aging in both men and women. Average bone mineral density (BMD) over a region of interest (ROI) on the femur may considerably decrease with age even in ...healthy people, and therefore, it is inaccurate if used to monitor treatment-induced bone change.
Introduction
Areal bone mineral density (BMD), averaged over a region of interest (ROI) on the femur, is widely used in the diagnosis of osteoporosis, assessment of fracture risk, and monitoring of treatment effectiveness. We studied the effect of age-related change in femur geometry on average BMD.
Methods
The effect of age-related bone geometric change on averaged BMD was investigated by a cross-sectional study. Total 83 healthy subjects were selected for this study. For each subject, QCT of left femur was scanned using clinical scanner. For each standard volume of interest (VOI), integral/cortical/trabecular bone volume, volumetric BMD (vBMD), and bone mass were measured using QCT Pro; the corresponding areal BMD (aBMD) was projected using CTXA-Hip. Both QCT Pro and CTXA-Hip are commercial software. Correlations between bone volume/density/mass and age were studied.
Results
In the studied population, there was no association between body weight/BMI (body mass index) and age, correlation between normalized femoral neck width and age was 0.24 (
p
< 0.05). Both aBMD and integral vBMD decreased with age (after adjusted by BMI, for aBMD,
r
= − 0.21 to − 0.24,
p
≤ 0.05 except at trochanter; for vBMD,
r
= − 0.20 to − 0.31,
p
< 0.05); cortical vBMD had no significant change; trabecular vBMD decreased at all VOIs except at trochanter (after adjusted by BMI,
r
= − 0.22 to 0.32,
p
≤ 0.05). Integral volume showed slight increase but only significant at the trochanter after adjusted by body size, cortical volume showed insignificant decrease, and trabecular volume considerably increased with age in all VOIs (after adjusted by body size,
r
= 0.27–0.40,
p
< 0.05). Integral, cortical, and trabecular mass had no significant change in all VOIs, except that at the trochanter trabecular mass slightly increased with age (
r
= 0.31,
p
< 0.05).
Conclusions
Even though there is no change in bone mass, average BMD may considerably decrease with age due to bone expansion. Comparatively, aBMD is less affected than vBMD.
Twisted bilayer graphene (TBLG) is one of the simplest van der Waals heterostructures, yet it yields a complex electronic system with intricate interplay between moiré physics and interlayer ...hybridization effects. We report on electronic transport measurements of high mobility small angle TBLG devices showing clear evidence for insulating states at the superlattice band edges, with thermal activation gaps several times larger than theoretically predicted. Moreover, Shubnikov-de Haas oscillations and tight binding calculations reveal that the band structure consists of two intersecting Fermi contours whose crossing points are effectively unhybridized. We attribute this to exponentially suppressed interlayer hopping amplitudes for momentum transfers larger than the moiré wave vector.
Short chain fatty acids (SCFAs) are the main products of indigestible carbohydrates that are fermented by microbiota in the hindgut. This study was designed to investigate the effects of oral SCFAs ...administration on the lipid metabolism of weaned pigs. A total of 21 barrows were randomly allocated into three groups, including control group (orally infused with 200 mL physiological saline per day), low dose SCFAs group (orally infused with 200 mL SCFAs containing acetic acid 20.04 mM, propionic acid 7.71 mM and butyric acid 4.89 mM per day), and high dose SCFAs group (orally infused with 200 mL SCFAs containing acetic acid 40.08 mM, propionic acid 15.42 mM and butyric acid 9.78 mM per day). The results showed that the average daily feed intake of SCFAs groups were lower than that of control group (P<0.05). Oral administration of SCFAs decreased the concentrations of triglyceride (TG), total cholesterol (TC), high density lipoprotein-cholesterol and insulin (P<0.05), and increased the leptin concentration in serum (P<0.05). The total fat, as well as TC and TG levels in liver, was decreased by oral SCFAs administration (P<0.05). In addition, SCFAs down-regulated the mRNA expressions of fatty acid synthase (FAS) and sterol regulatory element binding protein 1c (P<0.05), and enhanced the mRNA expression of carnitine palmitoyltransferase-1α (CPT-1α) in liver (P<0.05). SCFAs also decreased FAS, acetyl-CoA carboxylase (ACC) and peroxisome proliferator activated receptor σ mRNA expressions in longissimus dorsi (P<0.05). And in abdominal fat, SCFAs reduced FAS and ACC mRNA expressions (P<0.05), and increased CPT-1α mRNA expression (P<0.05). These results suggested that oral administration of SCFAs could attenuate fat deposition in weaned pigs via reducing lipogenesis and enhancing lipolysis of different tissues.
This paper reviews progress on understanding biological carbon sequestration in the ocean with special reference to the microbial formation and transformation of recalcitrant dissolved organic carbon ...(RDOC), the microbial carbon pump (MCP). We propose that RDOC is a concept with a wide continuum of recalcitrance. Most RDOC compounds maintain their levels of recalcitrance only in a specific environmental context (RDOCt). The ocean RDOC pool also contains compounds that may be inaccessible to microbes due to their extremely low concentration (RDOCc). This differentiation allows us to appreciate the linkage between microbial source and RDOC composition on a range of temporal and spatial scales. Analyses of biomarkers and isotopic records show intensive MCP processes in the Proterozoic oceans when the MCP could have played a significant role in regulating climate. Understanding the dynamics of the MCP in conjunction with the better constrained biological pump (BP) over geological timescales could help to predict future climate trends. Integration of the MCP and the BP will require new research approaches and opportunities. Major goals include understanding the interactions between particulate organic carbon (POC) and RDOC that contribute to sequestration efficiency, and the concurrent determination of the chemical composition of organic carbon, microbial community composition and enzymatic activity. Molecular biomarkers and isotopic tracers should be employed to link water column processes to sediment records, as well as to link present-day observations to paleo-evolution. Ecosystem models need to be developed based on empirical relationships derived from bioassay experiments and field investigations in order to predict the dynamics of carbon cycling along the stability continuum of POC and RDOC under potential global change scenarios. We propose that inorganic nutrient input to coastal waters may reduce the capacity for carbon sequestration as RDOC. The nutrient regime enabling maximum carbon storage from combined POC flux and RDOC formation should therefore be sought.
Asymptomatic patients, together with those with mild symptoms of coronavirus disease 2019 (COVID-19), may play an important role in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ...transmission. However, the dynamics of virus shedding during the various phases of the clinical course of COVID-19 remains unclear at this stage.
A total of 18 patients found to be positive for SARS-CoV-2 infection by real-time reverse transcription PCR (RT-PCR) assay and admitted to Chongqing University Central Hospital between 29 January and 5 February 2020 were enrolled into this study. Medical data, pulmonary computed tomographic (CT) scan images and RT-PCR results were periodically collected during the patients' hospital stay. All participants were actively followed up for 2 weeks after discharge.
A total of nine (50%) asymptomatic patients and nine (50%) patients with mild symptoms of COVID-19 were identified at admission. Six patients (66.7%) who were asymptomatic at admission developed subjective symptoms during hospitalization and were recategorized as being presymptomatic. The median duration of virus shedding was 11.5, 28 and 31 days for presymptomatic, asymptomatic and mildly symptomatic patients, separately. Seven patients (38.9%) continued to shed virus after hospital discharge. During the convalescent phase, detectable antibodies to SARS-CoV-2 and RNA were simultaneously observed in five patients (27.8%).
Long-term virus shedding was documented in patients with mild symptoms and in asymptomatic patients. Specific antibody production to SARS-CoV-2 may not guarantee virus clearance after discharge. These observations should be considered when making decisions regarding clinical and public health, and when considering strategies for the prevention and control of SARS-CoV-2 infection.
Osteoporotic fracture has been found associated with many clinical risk factors, and the associations have been explored dominantly by evidence-based and case-control approaches. The major challenges ...emerging from the studies are the large number of the risk factors, the difficulty in quantification, the incomplete list, and the interdependence of the risk factors. A biomechanical sorting of the risk factors may shed lights on resolving the above issues. Based on the definition of load-strength ratio (LSR), we first identified the four biomechanical variables determining fracture risk, i.e., the risk of fall, impact force, bone quality, and bone geometry. Then, we explored the links between the FRAX clinical risk factors and the biomechanical variables by looking for evidences in the literature. To accurately assess fracture risk, none of the four biomechanical variables can be ignored and their values must be subject-specific. A clinical risk factor contributes to osteoporotic fracture by affecting one or more of the biomechanical variables. A biomechanical variable represents the integral effect from all the clinical risk factors linked to the variable. The clinical risk factors in FRAX mostly stand for bone quality. The other three biomechanical variables are not adequately represented by the clinical risk factors. From the biomechanical viewpoint, most clinical risk factors are interdependent to each other as they affect the same biomechanical variable(s). As biomechanical variables must be expressed in numbers before their use in calculating LSR, the numerical value of a biomechanical variable can be used as a gauge of the linked clinical risk factors to measure their integral effect on fracture risk, which may be more efficient than to study each individual risk factor.
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