Curved Space-Time at the Planck Scale

This paper presents a physically plausible and somewhat illuminating first step in extending the fundamental principles of mechanical stress and strain to space-time. Here the geometry of space-time, encoded in the metric tensor, is considered to be made up of a dynamic lattice of extremely small, localized fields that form a perfectly elastic Lorentz symmetric space-time at the global (macroscopic) scale. This theoretical model of space-time at the Planck scale leads to a somewhat surprising result in which matter waves in curved space-time radiate thermal gravitational energy, as well as an equally intriguing relationship for the anomalous dispersion of light in a gravitational field.

Active-passive radial-additive friction stir repairing of mechanical hole out of dimension tolerance of AZ31 magnesium alloy

In order to avoid the depth increasing of repaired hole and eliminate the super-fine grain band in stir zone by radial-additive friction stir repairing(R-AFSR), a solid-state repairing technique of active-passive radial-additive friction stir repairing(AP-RAFSR) assisted by the truncated cone-shaped filling material was proposed in this study. The mechanical hole out of dimension tolerance of AZ31 magnesium alloy was chosen as the repaired object. The results indicated that the AP-RAFSR process rather than the R-AFSR process avoided the kissing bond in the bottom of the repairing interface under the condition of the tool pin length equal to the height of the standard mechanical hole.The continuously-distributed and large-length super-fine grain bands were eliminated in the stir zone by AP-RAFSR. The maximum tensile and compressive-shear strengths of repaired hole by AP-RAFSR reached 190.6 MPa and 138.9 MPa at 1200 rpm respectively, which were equivalent to 97.7% and 89.6% of those of the standard mechanical hole. This AP-RAFSR process assisted by the truncated cone-shaped filling material provides a new technique to obtain a no-depth-increasing, defect-free and high-strength repaired mechanical hole.

Repair mechanism of astrocytes and non-astrocytes in spinal cord injury

BACKGROUND Spinal cord injury(SCI)is a destructive disease that incurs huge personal and social costs,and there is no effective treatment.Although the pathogenesis and treatment mechanism of SCI has always been a strong scientific focus,the pathogenesis of SCI is still under investigation.AIM To determine the key genes based on the modularization of in-depth analysis,in order to identify the repair mechanism of astrocytes and non-astrocytes in SCI.METHODS Firstly,the differences between injured and non-injured spinal cord of astrocyte(HA),injured and non-injured spinal cord of non-astrocyte(FLOW),injured spinal cord of non-injured astrocyte(HA)and non-injured spinal cord of nonastrocyte(FLOW),and non-injured spinal cord of astrocyte(HA)and nonastrocyte(FLOW)were analyzed.The total number of differentially expressed genes was obtained by merging the four groups of differential results.Secondly,the genes were co-expressed and clustered.Then,the enrichment of GO function and KEGG pathway of module genes was analyzed.Finally,non-coding RNA,transcription factors and drugs that regulate module genes were predicted using hypergeometric tests.RESULTS In summary,we obtained 19 expression modules involving 5216 differentially expressed genes.Among them,miR-494,XIST and other genes were differentially expressed in SCI patients,and played an active regulatory role in dysfunction module,and these genes were recognized as the driving genes of SCI.Enrichment results showed that module genes were significantly involved in the biological processes of inflammation,oxidation and apoptosis.Signal pathways such as NF-kappa B/A20,AMPK and MAPK were significantly regulated.In addition,non-coding RNA pivot(including miR-136-5p and let-7d-5p,etc.)and transcription factor pivot(including NFKB1,MYC,etc.)were identified as significant regulatory dysfunction modules.CONCLUSION Overall,this study uncovered a co-expression network of key genes involved in astrocyte and non-astrocyte regulation in SCI.These findings helped to reveal the core dysfunction modules,potential regulatory factors and driving genes of the disease,and to improve our understanding of its pathogenesis.

Associative Space-Time Sedenions and Their Application in Relativistic Quantum Mechanics and Field Theory

We present an alternative sixteen-component hypercomplex scalar-vector values named “space-time sedenions”, generating associative noncommutative space-time Clifford algebra. The generalization of relativistic quantum mechanics and field theory equations based on sedenionic wave function and space-time operators is discussed.

Infinite Freedom of Space-Time for Zero-Energy-Entity in Quantum Mechanics

Zero-energy state is investigated by taking infinitesimal energy and observing its uncertainty in space-time, adopting quantum mechanics. In this paper, the uncertainty in conventional quantum mechanics is found to be interpreted as freedom in space-time, which results in possibility of time travel and space transition of the zero-energy state, which could be information or mind. The wave function of a physical system composed of multiple particles or wave-packets is examined and found that it can be arbitrarily changed by grouping by observers. It leads to an idea that even infinitesimal energy or wave-packets in a heavy physical system may separately exist and it has the infinite freedom of space-time.

Activin-Directed Differentiation of Human Embryonic Stem Cells Differentially Modulates Alveolar Epithelial Wound Repair via Paracrine Mechanism

Differentiated embryonic stem cells (ESC) can ameliorate lung inflammation and fibrosis in animal lung injury models;therefore, ESC, or their products, could be candidates for regenerative therapy for incurable lung diseases, such as idiopathic pulmonary fibrosis (IPF). In this study, we have investigated the paracrine effect of differentiated and undifferentiated human ESC on alveolar epithelial cell (AEC) wound repair. hESC line, SHEF-2 cells were differentiated with Activin treatment for 22 days in an embryoid body (EB) suspension culture. Conditioned media (CM) which contain cell secretory factors were collected at different time points of differentiation. CM were then tested onin vitro?wound repair model with human type II AEC line, A549 cells (AEC). Our study demonstrated that CM originated from undifferentiated hESC significantly inhibited AEC wound repair when compared to the control. Whereas, CM originated from Activin-directed hESC differentiated cell population demonstrated a differential reparative effect on AEC wound repair model. CM obtained from Day-11 of differentiation significantly enhanced AEC wound repair in comparison to CM collected from pre- and post-Day-11 of differentiation. Day-11 CM enhanced AEC wound repair through significant stimulation of cell migration and cell proliferation. RT-PCR and immunocytochemistry confirmed that Day-11 CM was originated form a mixed population of endodermal/mesodermal differentiated hESC. This report suggests a putative paracrine-mediated epithelial injury healing mechanism by hESC secreted products, which is valuable in the development of novel stem cell-based therapeutic strategies.

A study on mechanism of repair of pancreas following acute pancreatitis

To study the mechanism of repair of pancreas following acute pancreatitis (AP).Methods NIH Swiss mice were randomized into the saline control group and AP group.AP was induced by intraperitoneal injection of 50 ug/kg body weight cearulein for 4 times,once per hour.The cellular proliferation was detected using flow cytometry.Collagen Ⅰ was detected with immunohistochemistry.Protein zymography was used to evaluate the expression of matrix metalloproteinase-3 (MMP-3).Results In the AP group,the pancreatic lesions were the severest in 8 h and then recovered on the 7th d after induction of AP.Flow cytometry showed that there were three stages of cell proliferation after AP:the active proliferation in early stage,inhibition of proliferation in middle stage and high proliferation in the late stage.The expression level of collage Ⅰ and MMP-3 was markedly higher in the AP group than in the saline control group.Conclusion The pancreas can be repaired after AP.The regeneration mechanism includes intersitial fibrosis and acinar cell replication.7 refs,4 figs.

Effect of Boundary Condition on Impact Response and Damage Meso-mechanism for Scarf Bonded Repair of Load-bearing Composite Structures

Composite scarf repair is applied in airplane load-bearing structures. But the repairs would have different boundary supports in real situation, such as simply support, clamped support and flexible support. With different boundary supports, the bonded scarf repair of composite structures could have diverse damage mechanisms and responses. This work intends to study the impact performance of different boundaries. For this purpose, experimental tests were carried out on the specimens with two sides support and four sides support. The impact load and deflection was monitored during the tests. After impact being finished, the meso-mechanism was studied by means of micro-cracks of the side section for two sides support condition and cross section for the four sides support condition. It was possible to conclude that the four sides boundary possess higher impact resistance maximum loads, lower displacements and lower extent load dropping. In terms of damage modes, as the impact energy relative low 12 J and 16 J, the central position of scarf bonding zone for two sides support appears adhesive cohesive failure and adhesive-composite interface failure. When the energy increases to 20 J, the dominated damage of two sides support moves down to the feathered tip. For four sides support, the critical energy level is 25 J, under which the scarf adhesive begins to be damaged.

Restorative effect and mechanism of mecobalamin on sciatic nerve crush injury in mice

Mecobalamin, a form of vitamin B12 containing a central metal element （cobalt）, is one of the most important mediators of nervous system function. In the clinic, it is often used to accelerate recovery of peripheral nerves, but its molecular mechanism remains unclear. In the present study, we performed sciatic nerve crush injury in mice, followed by daily intraperitoneal administra-tion of mecobalamin （65 μg/kg or 130 μg/kg） or saline （negative control）. Walking track analysis, histomorphological examination, and quantitative real-time PCR showed that mecobalamin signiifcantly improved functional recovery of the sciatic nerve, thickened the myelin sheath in myelinated nerve ifbers, and increased the cross-sectional area of target muscle cells. Further-more, mecobalamin upregulated mRNA expression of growth associated protein 43 in nerve tissue ipsilateral to the injury, and of neurotrophic factors （nerve growth factor, brain-derived nerve growth factor and ciliary neurotrophic factor） in the L4–6 dorsal root ganglia. Our ifndings indicate that the molecular mechanism underlying the therapeutic effect of mecobalamin after sciatic nerve injury involves the upregulation of multiple neurotrophic factor genes.

Molecular signaling mechanisms of apoptosis in hereditary non-polyposis colorectal cancer

Colorectal cancer is the second most leading cause of cancer related deaths in the western countries. One of the forms of colorectal cancer is hereditary non-polyposis colorectal cancer (HNPCC), also known as "Lynch syndrome". It is the most common hereditary form of cancer accounting for 5%-10% of all colon cancers. HNPCC is a dominant autosomal genetic disorder caused by germ line mutations in mismatch repair genes. Human mismatch repair genes play a crucial role in genetic stability of DNA, the inactivation of which results in an increased rate of mutation and often a loss of mismatch repair function. Recent studies have shown that certain mismatch repair genes are involved in the regulation of key cellular processes including apoptosis. Thus, differential expression of mismatch repair genes particularly the contributions of MLH1 and MSH2 play important roles in therapeutic resistance to certain cytotoxic drugs such as cisplatin that is used normally as chemoprevention. An understanding of the role of mismatch repair genes in molecular signaling mechanism of apoptosis and its involvement in HNPCC needs attention for further work into this important area of cancer research, and this review article is intended to accomplish that goal of linkage of apoptosis with HNPCC. The current review was not intended to provide a comprehensive enumeration of the entire body of literature in the area of HNPCC or mismatch repair system or apoptosis; it is rather intended to focus primarily on the current state of knowledge of the role of mismatch repair proteins in molecular signaling mechanism of apoptosis as it relates to understanding of HNPCC.

Ewings sarcoma of patella:A rare entity treated with a novel technique of extensor mechanism reconstruction using tendoachilles auto graft

We report a case of Ewings sarcoma(ES) involving the patella in a young female. ES of patella is a rare entity. The patient was presented with anterior knee pain and swelling arising from the patella. She was treated with neoadjuvant chemotherapy followed by wide excision of the patella and reconstruction of the extensor mechanism using split tendoachilles auto graft. The patella is an uncommon site for primary or metastatic tumors of the bone. ES, though rare, should be included in the differential diagnosis of swellings arising from the patella. Auto graft from the tendoachilles is a good alternative for reconstructing the extensor mechanism of the knee.

Mechanotransduction of stem cells for tendon repair

Tendon is a mechanosensitive tissue that transmits force from muscle to bone.Physiological loading contributes to maintaining the homeostasis and adaptation of tendon,but aberrant loading may lead to injury or failed repair.It is shown that stem cells respond to mechanical loading and play an essential role in both acute and chronic injuries,as well as in tendon repair.In the process of mechanotransduction,mechanical loading is detected by mechanosensors that regulate cell differentiation and proliferation via several signaling pathways.In order to better understand the stem-cell response to mechanical stimulation and the potential mechanism of the tendon repair process,in this review,we summarize the source and role of endogenous and exogenous stem cells active in tendon repair,describe the mechanical response of stem cells,and finally,highlight the mechanotransduction process and underlying signaling pathways.

Erosion Mechanism of Al_(2)O_(3)-SiC Castables for Lining Maintenance in Blast Furnace Hearths

Al_(2)O_(3)-SiC castables,for the relining of BF hearths in mid-campaign repair,were sampled and investigated after two years’service.The chemical and mineralogical characteristics of the residual castables were analyzed by X-ray diffraction,scanning electron microscopy,and energy dispersive X-ray spectrometry to study the erosion mechanism.The results show that as gaseous K diffuses in the castables,leucite(KAlSi_(2)O_(8))and multiple cracks are formed.Molten iron and slag penetrate through the cracks to form anorthite([Ca,Na][Al,Si]_(4)O_(8))and iron,which will not form an embrittlement layer similar to carbon bricks.The entire repair of the hearth with Al_(2)O_(3)-SiC castables combined with the design of thin-wall lining hearth eliminates“elephant foot shaped”erosion,greatly prolonging the service life of the hearth lining.

STABC-IR:An air target intention recognition method based on bidirectional gated recurrent unit and conditional random field with space-time attention mechanism

The battlefield environment is changing rapidly,and fast and accurate identification of the tactical intention of enemy targets is an important condition for gaining a decision-making advantage.The current Intention Recognition(IR)method for air targets has shortcomings in temporality,interpretability and back-and-forth dependency of intentions.To address these problems,this paper designs a novel air target intention recognition method named STABC-IR,which is based on Bidirectional Gated Recurrent Unit(Bi GRU)and Conditional Random Field(CRF)with Space-Time Attention mechanism(STA).First,the problem of intention recognition of air targets is described and analyzed in detail.Then,a temporal network based on Bi GRU is constructed to achieve the temporal requirement.Subsequently,STA is proposed to focus on the key parts of the features and timing information to meet certain interpretability requirements while strengthening the timing requirements.Finally,an intention transformation network based on CRF is proposed to solve the back-and-forth dependency and transformation problem by jointly modeling the tactical intention of the target at each moment.The experimental results show that the recognition accuracy of the jointly trained STABC-IR model can reach 95.7%,which is higher than other latest intention recognition methods.STABC-IR solves the problem of intention transformation for the first time and considers both temporality and interpretability,which is important for improving the tactical intention recognition capability and has reference value for the construction of command and control auxiliary decision-making system.

RESISTANT MECHANISMS OF CISPLATIN IN HUMAN LUNG ADENOCARCINOMA CELL LINE A_(549)DDP

To study the resistant mechanisms of cisplatin in human lung adenocarcinoma cell line A 549 DDP. A 549 DDP cells was established by stepwise increasing concentration of cisplatin (CDDP) in medium. Interstrand cross linked DNA (ICL) was measured by ethidium bromide fluorescence assay. The intracellular and intranuclear accumulation of cisplatin was measured by atomic absorption spectrometry. The removal of GS X was determined by FCM and fluorescence microscopy. Results: The A 549 DDP cell line was 8.9 fold resistance relative to the parental A 549 cell line. The formation of ICL in A 549 was 6.28 times higher than that in A 549 DDP cells. The intracellular and intranuclear accumulation of cisplatin in A 549 cells was 5.9 times and 4.1 times higher than that in A 549 DDP cells, respectively. The ability of GS X pump pumped GS X complex (GS Pt) in A 549 DDP cells was higher than that in A 549 . The repair rate in A 549 DDP cells was 2 times higher than that in A 549 . Conclusions: Decreased accumulation and increased export of cisplatin might be the main mechanism of cisplatin resistant A 549 DDP cells while the enhanced repair capacity of DNA may play a role in CDDP resistance.

From Space-Time Quantization to Dark Matter

We generalize relativistic quantum mechanics and the Standard Model of elementary particle physics by considering a finite limit for the smallest measurable length. The resulting theory of Space-Time Quantization is logically consistent and accounts for all possible particle states by means of four new quantum numbers. They specify possible variations of wave functions at the smallest possible scale in space and time, while states of motion are defined by their large-scale variations. This theory also provides insight into the nature and properties of dark matter particles. It can facilitate their detection and identification because of a very strict conservation law.

Repairing of exit-hole in friction-stir-spot welded joints for 2024-T4 aluminum alloy by resistance welding

The exit-hole in friction stir spot welded(FSSWed) 2024-T4 aluminum alloy joints was successfully repaired by using a three-phase secondary rectification resistance spot welding machine, which is termed as filling exit-hole based on resistance welding(FEBRW). The filling dynamic behavior of force was recorded by a device monitoring. Optical microscope(OM), electron backscatter diffraction(EBSD), and tensile shear tests and finite element modelling were conducted to investigate the repairing stages and bonding mechanisms of the repaired joints in detail. Results showed that exit-hole was completely filled and repaired experiencing three stages. Metallurgical bonding was achieved between plug and exit-hole wall in two forms, including melting bonding in the middle of the joints and partial diffusion bonding on both the upper and bottom of the joints. The highest tensile shear strength of the repaired joints was 7.43 kN, which was 36.3% higher than that of the as welded joints. Resistance welding paves an efficient way to repair the exit-hole in FSSWed joints.

古建筑木构件开裂机制、评估与加固研究进展

开裂作为古建筑木构件最常见的残损类型之一,影响木构件的长期服役性能,是古建筑稳定性与安全性评估的重要考查内容。本文从古建筑木构件开裂情况、原因、影响,评估方法及修复加固等方面,系统梳理古建筑木构件开裂残损相关研究成果。分析发现我国古建筑木构件开裂的主要原因为木材干缩与受力破坏,主要类型为纵向开裂,开裂可降低木构件力学性能,也可为其他不利因素作用于木构件提供条件。目前主要通过实际试验与数值模拟评估开裂对木构件性能的影响,利用金属材料、纤维增强复合材料(fiber reinforced polymer,FRP)与高分子树脂材料对开裂木构件进行修复加固。然而,由于古建筑的特殊性与木材变异性,仍需进一步探索木构件的不同尺度开裂机制,开发适用于古建筑开裂木构件的检测、评估与加固方法,建立科学系统性的古建筑保护体系。

信用修复机制及在市场监管领域的实践研究

随着社会信用体系建设的深入推进,信用修复制度在理论研究和实践应用中逐渐成为关注焦点,发挥着维护信用主体合法权益、鼓励重塑信用、激发市场活力的积极作用。通过系统梳理信用修复的概念和信用修复的制度探索,厘清了当前社会信用体系建设中的信用修复规范,并从信用修复的方式、主体、客体和程序方面对信用修复机理进行了阐述;以市场监管领域信用修复实践作为切入点,对当前信用修复的实施现状和存在问题进行系统分析,并给出了加强信用修复机制建设的措施建议。

基于自注意力机制神经机器翻译的软件缺陷自动修复方法

循环神经网络对于代码序列数据有着良好的处理能力,软件缺陷修复的补丁生成模型大多采用循环神经网络实现.然而,基于循环神经网络的补丁生成模型在处理代码序列中长距离依赖问题时仍然具有局限性,其修复成功率和修复效率较低.针对此问题,提出一种基于自注意力神经机器翻译的软件缺陷自动修复方法(Self-attention Neural machine translation based automatic software Repair,SNRepair).首先,为有效缓解源码中的未登录词问题,对数据集引入子词切分技术进行预处理;其次,为解决源代码中棘手的长距离依赖问题并更充分地利用局部信息,构建融合局部建模的Transformer程序补丁生成模型;然后,采用缺陷自动定位技术定位缺陷语句位置,利用参数优化后的Transformer补丁生成模型生成候选补丁;最后,运行测试用例验证候选补丁.在具有395个真实Java软件缺陷的Defects4J缺陷库上实验评估,结果表明SNRepair方法与对比方法比较,修复成功率和修复效率更高.