Induction of Changes Over time in the Rat Proximal Femur Following Ovariectomy: A Model with Clinical Implications

The menopause-related expansion of the proximal femoral marrow cavity is thought to have implications  for the long-term cohesion of hip prostheses. This theory would be further strengthened if there was evidence  to show that the expansion of the proximal femur marrow cavity takes place after the occurrence of  a femoral neck fracture, which, it is often recommended, should be fixed with a hip prosthesis. But till now,  the temporal relationship between those two osteoporotic-related changes has not been checked carefully.  The objective of the current study was to examine the temporal relationship between the marrow cavity  expansion of the proximal femur and the biomechanical deterioration of the femoral neck in a rat model.  To do so, a cross-sectional study with multiple time points was carried out on 6-month old Sprague-Dawley  rats, which were ovariectomized or sham-operated (as controls). The biomechanical properties of the femur  neck and geometrical parameters of the femur shaft were evaluated at 0, 3, 6, 9, 12, 15, 18, and 21 weeks  postoperatively, with special reference to the timescale of the observed changes. We found that the maximum  load of the femoral neck in ovariectomized rats could bear decreased significantly compared, to that  of controls, at 9 weeks postoperatively (p=0.03), while the marrow cavity of the proximal femur in ovariectomized  rats turned out to be significantly enlarged at 15 weeks postoperatively (p=0.04). Conclusion: Our  result demonstrated that the osteoporosis-related marrow-enlarged posterior led to the collapse of femoral  neck strength. If the change in postmenopausal women is analogous to that in ovariectomized rats, the  menopause-related marrow cavity expansion would be a risk factor for the longevity of hip prostheses.

Entanglement Swapping with Semiconductor-Generated Photons Violates Bell’s Inequality

Transferring entangled states between photon pairs is essential in quantum communication. Semiconductor quantum dots are the leading candidate for generating polarization-entangled photons deterministically. Here we show for the first time swapping of entangled states between two pairs of photons emitted by a single dot. A joint Bell measurement heralds the successful generation of the Bell state Ψ+, yielding a fidelity of 0.81±0.04 and violating the CHSH and Bell inequalities. Our photon source matches atomic quantum memory frequencies, facilitating implementation of hybrid quantum repeaters.BMBF/Q.comERC/QD-NOMSIFW Excellence Progra

Gene selection for optimal prediction of cell position in tissues from single-cell transcriptomics data.

Single-cell RNA-sequencing (scRNAseq) technologies are rapidly evolving. Although very informative, in standard scRNAseq experiments, the spatial organization of the cells in the tissue of origin is lost. Conversely, spatial RNA-seq technologies designed to maintain cell localization have limited throughput and gene coverage. Mapping scRNAseq to genes with spatial information increases coverage while providing spatial location. However, methods to perform such mapping have not yet been benchmarked. To fill this gap, we organized the DREAM Single-Cell Transcriptomics challenge focused on the spatial reconstruction of cells from the Drosophila embryo from scRNAseq data, leveraging as silver standard, genes with in situ hybridization data from the Berkeley Drosophila Transcription Network Project reference atlas. The 34 participating teams used diverse algorithms for gene selection and location prediction, while being able to correctly localize clusters of cells. Selection of predictor genes was essential for this task. Predictor genes showed a relatively high expression entropy, high spatial clustering and included prominent developmental genes such as gap and pair-rule genes and tissue markers. Application of the top 10 methods to a zebra fish embryo dataset yielded similar performance and statistical properties of the selected genes than in the Drosophila data. This suggests that methods developed in this challenge are able to extract generalizable properties of genes that are useful to accurately reconstruct the spatial arrangement of cells in tissues

Spatio-Temporal Change Characteristics of Spatial-Interaction Networks: Case Study within the Sixth Ring Road of Beijing, China

Spatial-interaction networks are an important factor in geography that could help in the exploration of both human spatial-temporal behavior and the structure of urban areas. This paper analyzes changes in the spatio-temporal characteristics of the Spatial-Interaction Networks of Beijing (SINB) in three consecutive steps. To begin with, we constructed 24 sequential snapshots of spatial population interactions on the basis of points of interest (POIs) collected from Dianping.com and various taxi GPS data in Beijing. Then, we used Jensen–Shannon distance and hierarchical clustering to integrate the 24 sequential network snapshots into four clusters. Finally, we improved the weighted k-core decomposition method by combining the complex network method and weighted distance in a geographic space. The results showed: (1) There are three layers in the SINB: a core layer, a bridge layer, and a periphery layer. The number of places greatly varies, and the SINB show an obvious hierarchical structure at different periods. The core layer contains fewer places that are between the Second and Fifth Ring Road in Beijing. Moreover, spatial distribution of places in the bridge layer is always in the same location as that of the core layer, and the quantity in the bridge layer is always superior to that in the core layer. The distributions of places in the periphery layer, however, are much greater and wider than the other two layers. (2) The SINB connected compactly over time, bearing much resemblance to a small-world network. (3) Two patterns of connection, each with different connecting ratios between layers, appear on weekdays and weekends, respectively. Our research plays a vital role in understanding urban spatial heterogeneity, and helps to support decisions in urban planning and traffic management

A Brief Analysis of Traditional Chinese Medical Elongated Needle Therapy on Acute Spinal Cord Injury and Its Mechanism

Acute spinal cord injury is one of the most common and complicated diseases among human spinal injury. We aimed to explore the effect of point-through-point acupuncture therapy with elongated needles on acute spinal cord injury in rabbits and its possible mechanism. Adult rabbits were randomly divided into a model group, elongated needle therapy group, and blank group. Immunohistochemical staining showed that the protein levels of Fas and caspase-3 in the model group were significantly higher than those in the blank group at each time point (P<0.05) and significantly lower than those in the elongated needle therapy group on the 3rd and 5th days after operation (P<0.05). RT-PCR showed that Fas and caspase-3 mRNA levels in the model group and elongated needle therapy group were significantly higher than those in the blank group (P<0.05, 0.01). The mRNA levels of Fas and caspase-3 in the elongated needle therapy group were significantly lower than those in model group on the 3rd day (P<0.05, 0.01). Therefore, we confirmed that elongated needle therapy has an obvious effect on acute spinal cord injury in rabbits. Its mechanism is made possible by inhibiting the expression of the Fas→caspase-3 cascade, thereby inhibiting cell apoptosis after spinal cord injury

Spatiotemporal Change Characteristics of Nodes’ Heterogeneity in the Directed and Weighted Spatial Interaction Networks: Case Study within the Sixth Ring Road of Beijing, China

Spatial heterogeneity patterns in cities are an essential topic in geographic research and urban planning. This paper analyzes the spatial heterogeneity of places and reflects on the urban structure in cites based on spatial interaction networks. To begin with, we constructed 24 sequentially directed and weighted spatial interaction networks (DWNs) on the basis of points of interest (POIs) and taxi GPS data in Beijing. Then, we merged 24 sequential networks into four clusters: early morning, morning, afternoon, and evening. Next, we introduced the weighted D-core decomposition method in view of the complex network method and weighted distance in a geographic space in order to obtain the in-coreness/out-coreness of places. Finally, three indices (the entropy index, the node symmetry index, and the t-test) were used to measure the heterogeneity of places from both the strength dimension and the direction dimension. The results showed: (1) For the strength dimension, the spatiotemporal strength characteristics of the nodes in the DWN are uneven on weekdays or on the weekends, and the strength heterogeneity on weekdays is more obvious than on weekends; (2) for the direction dimension, out-flows and in-flows are different in the early morning and evening on weekends. In addition, the direction of the DWN is not obvious. The city networks present flat characteristics. This study used the weighted D-core method to identify the heterogeneity of nodes in the DWN, which has certain theoretical and practical value for the planning of urban and urban systems and the coordinated development of cities

Inorganic p-type semiconductors and carbon materials based hole transport materials for perovskite solar cells

Organic-inorganic lead halide based perovskite solar cells (PSCs) have presented a promising prospective in photovoltaic field with current record power conversion efficiency of 22.7%, which is comparable to commercial crystalline silicon cells and even higher than traditional thin film solar cells of CIGS. However, the pressure to enhance device stability under operational condition has driven researches towards development of stable hole transport materials (HTMs) for PSCs. Compared to traditional expensive organic HTMs such as spiro-OMeTAD, there is no doubt that inorganic p-type semiconductors and carbon materials are attractive alternatives that not only possess better stability but also are much cheaper. This review summarized the most recent progress of inorganic hole-transporting materials and carbon materials that have been developed for PSCs. The most recent advancement of device performance using these HTMs was demonstrated. In addition, the research of using various types of carbon materials as additives in HTMs to enhance device performance and stability or as electrical contact in HTM-free PSC was also demonstrated. The effectiveness of each type of materials on mitigating ion migration and degradation of PSC induced by humidity, illumination light intensity and high temperature is discussed. This timely review sheds light on the approaches to tackle the stability issue of PSCs to push the technology towards commercialization through material engineering of HTM

Self-charging flexible solar capacitors based on integrated perovskite solar cells and quasi-solid-state supercapacitors fabricated at low temperature

Self-charging perovskite solar capacitors (SPSCs) that harvest and store solar energy simultaneously can offer sustainable, off-grid power supply for electrical devices. In particular, flexible and lightweight SPSCs are highly desirable in practical applications but are currently restricted by the high annealing temperature needed to make the electron transport layer (ETL) in the devices. Herein, we demonstrate a novel SPSC by integrating a perovskite solar cell (PSC) using amorphous WOx film deposited at room temperature as ETL and a quasi-solid-state supercapacitor (SC). The WOx film with 26 nm thickness yielded a champion power conversion efficiency of 14.14% and 10.80% with the FTO/glass rigid and the ITO/PEN flexible PSCs, respectively. Investigation of the performance of the SPSCs based on the rigid substrate (r-SPSC) and the flexible substrate (f- SPSC) exhibited that the r-SPSC could be photo-charged to 0.68 V within 20 s while the f-SPSC required 25 s to be charged to 0.65 V. Consequently, an overall conversion efficiencies of 2.13% and 1.27% were obtained with the r-SPSCs and the f-SPSC, respectively. This work paves a new way towards making SPSCs that may serve as off-grid electrical power supply in the future