Auscultation transformed:the ingenious invention of the stethoscope by René Théophile Hyacinthe Laennec

This study delves into the life and significant contributions of René Théophile Hyacinthe Laennec,a prominent French physician of the 19^(th) century,and thoroughly examines his revolutionary creation,the stethoscope.Laennec’s innovative spirit not only revolutionized medical diagnosis during his time but also left a lasting imprint on the broader field of medicine,influencing healthcare for generations.This extensive inquiry covers various aspects,including his historical context,the development of the stethoscope,its profound implications for medical diagnosis,and its enduring impact on the history of medicine.

MMP-1 Over-expression Promotes Malignancy and Stem-Like Properties of Human Osteosarcoma MG-63 Cells In Vitro

Osteosarcoma is the most common primary malignant bone tumor in childhood,and it maintains a high level of recurrence.Matrix metalloproteinase-1(MMP-1)was found to contribute to cancer progression.The present study was to investigate the in vitro effects of MMP-1 over-expression on the proliferation,invasion,metastasis and stem-like properties of osteosarcoma MG-63 cells.The MG-63 cells were cultured and had a full length MMP-1 cDNA inserted by the tentiviral vector (MG-63^MMP-1+).MG-63 negative control and MG-63 blank control groups were established as well.MMP-1 expression was detected in MG-63^MMP-1+,MG-63 negative control and MG-63 blank control cells using qPCR,Western blotting and immunofluorescence after 24h of culture. The cell proliferation assay was performed with a camera attached to a bioreactor,which was programmed to photograph five regions of each well every 10 min over a period of 48 h.The cell invasion assay was conducted with Matrigel to assess the invasive potential,of MG-63 cells over 24h,the qPCR analysis to measure stem cell markers,including Oct4, Sox-2,Nanog,and Pax-7,and Western blot analysis to detect invasive and metastatic potential markers TIMP-1,VEGF and BMP2/4,after 24h of culture.Immunofluorescence was used to investigate the presence of the stem cell marker Pax-7 after 24-h culture. The results showed that over-expression of MMP-1 after transfection could significantly increase minor cell proliferation and invasion (P<0.05,MG-63^MMP-1+ versus controls).Pax-7 was highly expressed in MG-63^MMP-1+ cells,with no significant changes of Oct-4,Sox-2, and Nanog observed (P<0.05).MG-63^MMP-1+ cells showed higher expression of VEGF and BMP 2/4 proteins and lower expression of TIMP-1 protein than controls (P<0.05).It was concluded that MMP-1 over-expression in MG-63 cells contributed to the proliferation, invasion,metastasis and stem-like properties of osteosarcoma cells.Future studies should focus on in vivo effects of MMP-1 over-expression and the application of MMP-1 and Pax-7 inhibition in vivo to osteosarcoma theraoies.

Seismic performance of an existing bridge with scoured caisson foundation

This paper presents in-situ seismic performance tests of a bridge before its demolition due to accumulated scouring problem. The tests were conducted on three single columns and one caisson-type foundation. The three single columns were 1.8 m in diameter,reinforced by 30-D32 longitudinal reinforcements and laterally hooped by D16 reinforcements with spacing of 20 cm. The column height is 9.54 m,10.59 m and 10.37 m for Column P2,P3,and P4,respectively. Column P2 had no exposed foundation and was subjected to pseudo-dynamic tests with peak ground acceleration of 0.32 g first,followed by one cyclic loading test. Column P3 was the benchmark specimen with exposed length of 1.2 m on its foundation. The exposed length for Column P4 was excavated to 4 m,approximately 1/3 of the foundation length,to study the effect of the scouring problem to the column performance. Both Column P3 and Column P4 were subjected to cyclic loading tests. Based on the test results,due to the large dimension of the caisson foundation and the well graded gravel soil type that provided large lateral resistance,the seismic performance among the three columns had only minor differences. Lateral push tests were also conducted on the caisson foundation at Column P5. The caisson was 12 m long and had circular cross-sections whose diameters were 5 m in the upper portion and 4 m in the lower portion. An analytical model to simulate the test results was developed in the OpenSees platform. The analytical model comprised nonlinear flexural elements as well as nonlinear soil springs. The analytical results closely followed the experimental test results. A parametric study to predict the behavior of the bridge column with different ground motions and different levels of scouring on the foundation are also discussed.

Hierarchical Interconnected NiMoN with Large Specific Surface Area and High Mechanical Strength for Efficient and Stable Alkaline Water/Seawater Hydrogen Evolution

NiMo-based nanostructures are among the most active hydrogen evolution reaction(HER)catalysts under an alkaline environment due to their strong water dissociation ability.However,these nanostructures are vulnerable to the destructive effects of H_(2) production,especially at industry-standard current densities.Therefore,developing a strategy to improve their mechanical strength while maintaining or even further increasing the activity of these nanocatalysts is of great interest to both the research and industrial communities.Here,a hierarchical interconnected NiMoN(HW-NiMoN-2h)with a nanorod-nanowire morphology was synthesized based on a rational combination of hydrothermal and water bath processes.HW-NiMoN-2h is found to exhibit excellent HER activity due to the accomodation of abundant active sites on its hierarchical morphology,in which nanowires con-nect free-standing nanorods,concurrently strengthening its structural stability to withstand H_(2) production at 1 A cm^(−2).Seawater is an attractive feedstock for water electrolysis since H_(2) generation and water desalination can be addressed simultaneously in a single process.The HER performance of HW-NiMoN-2h in alkaline seawater suggests that the presence of Na+ions interferes with the reation kinetics,thus lowering its activity slightly.However,benefiting from its hierarchical and interconnected characteristics,HW-NiMoN-2h is found to deliver outstanding HER activity of 1 A cm^(−2) at 130 mV overpotential and to exhibit excellent stability at 1 A cm^(−2) over 70 h in 1 M KOH seawater.

基于格林理论的鬼波压制方法及其应用

海洋地震资料存在受海水面虚反射(鬼波)引起的陷波效应,为此,从散射理论出发,提出了基于格林理论的空间-频率(x-ω)域任意震源鬼波压制方法,并详细论述了其物理意义。在一维理论数据分析的基础上,形成了格林理论鬼波压制处理流程。利用模拟数据和实际数据进行了测试,实现了基于上下缆和双检采集地震资料的鬼波压制。处理结果表明,此方法完全基于地震数据驱动,无需任何地下介质信息,适用于各种复杂的海洋地形和地质情况。鬼波压制后地震资料的频带得到有效拓宽、地震资料的分辨率得到提高,有利于地震资料的后续处理和解释。

Effect of electrolyte anions on the cycle life of a polymer electrode in aqueous batteries

Redox polymers are a class of high-capacity, low-cost electrode materials for electrochemical energy storage, butthe mechanisms governing their cycling stability are not well understood. Here we investigate the effect of anionson the longevity of a p-dopable polymer through comparing two aqueous zinc-based electrolytes. Galvanostaticcycling studies reveal the polymer has better capacity retention in the presence of triflate anions than that withsulfate anions. Based on electrode microstructural analysis and evolution profiles of the cell stacking pressure, theorigin of capacity decay is ascribed to mechanical fractures induced by volume change of the polymer activematerials during repeated cycling. The volume change of the polymer with the triflate anion is 61% less than thatwith the sulfate anion, resulting in fewer cracks in the electrodes. The difference is related to the different anionsolvation structures—the triflate anion has fewer solvated water molecules compared with the sulfate anion,leading to smaller volume expansion. This work highlights that anions with low solvation degree are preferablefor long-term cycling.

Morphologic features of the cerebellum of the Atlantic stingray, and their possible evolutionary significance

The morphology of the cerebellar corpus in cartilaginous fishes varies from a smooth,relatively simple structure to a complex,multilobed structure.Atlantic stingrays possess a trilobed corpus that includes an anterior lobe,divided into rostral and caudal lobules,and a posterior lobe.The corpus in this stingray is assymetrical.This asymmetry was examined in the stingray population of Galveston Bay.In 49%of the animals the axis of the caudal lobule was right of the midline,in 27%it was across the midline,and in 24%it was to the left.This variation is not related to size,sex,or an asymmetry in the cranial volume,but might reflect a variation in the cerebellar developmental program.To gain insight into the factors that have driven cerebellar hypertrophy in cartilaginous fishes,the neural connections of the lobules of the cerebellum of the Atlantic stingray were examined using biotinylated dextrans.It was found that,for the most part,the stingray cerebellum receives inputs from the same diencephalic and brainstem nuclei as in cartilaginous fishes with a bilobed cerebellum.However,in stingrays there is greater segregation of inputs.The anterior lobe rostral lobule receives inputs from the accessory optic nuclei,the caudal lobule receives inputs from trigeminal and octavolateral nuclei,and the posterior lobe receives inputs from the spinal cord.The rostral lobule and posterior lobe also receive input from midbrain nuclei that do not appear to be present in carti-laginous fishes with a morphologically simple corpus.Therefore,it is proposed that the complex hypertrophy of the corpus in stingrays might result from a combination of functional specialization of the lobes,and the acquisition of new inputs.

Impact of fabrication methods on binder distribution and charge transport in composite cathodes of all-solid-state batteries

The manufacturing process of all-solid-state batteries necessitates the use of polymer binders.However,these binders,being ionic insulators by nature,can adversely affect charge transport within composite cathodes,thereby impacting the rate performance of the batteries.In this work,we aim to investigate the impact of fabrication methods,specifically the solvent-free dry process versus the slurry-cast wet process,on binder distribution and charge transport in composite cathodes of solid-state batteries.In the dry process,the binder forms a fibrous network,while the wet process results in binder coverage on the surface of cathode active materials.The difference in microstructure leads to a notable 20-fold increase in ionic conductivity in the dry-processed cathode.Consequently,the cells processed via the dry method exhibit higher capacity retention of 89%and 83%at C/3 and C/2 rates,respectively,in comparison to 68%and 58%for the wet-processed cells at the same rate.These findings provide valuable insights into the influence of fabrication methods on binder distribution and charge transport,contributing to a better understanding of the binder’s role in manufacturing of all-solid-state batteries.

N-Type Mg_(3)Sb_(2-x)Bi_(x) Alloys as Promising Thermoelectric Materials

N-type Mg_(3)Sb_(2-x)Bi_(x) alloys have been extensively studied in recent years due to their significantly enhanced thermoelectric figure of merit(zT),thus promoting them as potential candidates for waste heat recovery and cooling applications.In this review,the effects resulting from alloying Mg_(3)Bi_(2) with Mg_(3)Sb_(2),including narrowed bandgap,decreased effective mass,and increased carrier mobility,are summarized.Subsequently,defect-controlled electrical properties in n-type Mg_(3)Sb_(2-x)Bi_(x) are revealed.On one hand,manipulation of intrinsic and extrinsic defects can achieve optimal carrier concentration.On the other hand,Mg vacancies dominate carrier-scattering mechanisms(ionized impurity scattering and grain boundary scattering).Both aspects are discussed for Mg_(3)Sb_(2-x)Bi_(x) thermoelectric materials.Finally,we review the present status of,and future outlook for,these materials in power generation and cooling applications.

Moisture-driven phase transition for improved perovskite solar cells with reduced trap-state density

We report a mechanistic understanding of a moisture-driven intermediate-phase transition that improves the quality of perovskite thin films based on a lead-acetate precursor, improving the power-conversion effidency. We clarify the composition of the intermediate phase and attribute the transition of this phase to the hygroscopic nature of the organic product, i.e., methylammonium acetate. Thermal annealing aids in the coarsening of the grains. These decoupled processes result in better crystal formation with a lower spatial and energetic distribution of traps. Thermal annealing of the films without exposure to air results in a faster intermediate-phase transition and grain coarsening, which occur simultaneously, leading to disorder in the films and a higher deep trap-state density. Our results indicate the need for a humid environment for the growth of high-quality perovskite films and provide insight into intermediate-phase dissociation and conversion kinetics. Thus, they are useful for the large-scale production of effident solution-processed perovskite solar cells.

FLIGHT:Federated Learning with IRS for Grouped Heterogeneous Training

In recent years,federated learning(FL)has played an important role in private data-sensitive scenarios to perform learning tasks collectively without data exchange.However,due to the centralized model aggregation for heterogeneous devices in FL,the last updated model after local training delays the convergence,which increases the economic cost and dampens clients’motivations for participating in FL.In addition,with the rapid development and application of intelligent reflecting surface(IRS)in the next-generation wireless communication,IRS has proven to be one effective way to enhance the communication quality.In this paper,we propose a framework of federated learning with IRS for grouped heterogeneous training(FLIGHT)to reduce the latency caused by the heterogeneous communication and computation of the clients.Specifically,we formulate a cost function and a greedy-based grouping strategy,which divides the clients into several groups to accelerate the convergence of the FL model.The simulation results verify the effectiveness of FLIGHT for accelerating the convergence of FL with heterogeneous clients.Besides the exemplified linear regression(LR)model and convolutional neural network(CNN),FLIGHT is also applicable to other learning models.

Insurance Plan for Service Assurance in Cloud Computing Market with Incomplete Information

Nowadays,cloud computing has been identified as new opportunities for migrating to the expected agility,reuse,and adaptive capabilities that can support the ever changing IT trends and requirements.Unfortunately,the rapid evolution of those technologies also comes with open issues such as security,privacy,integrity,quality of services,and their possible detrimental consequences.In this work,the concept of insurance is introduced to compensate the cloud computing customers when encountering those failures if service providers(SPs)have insurance purchased.Particularly,we consider the situation when the insurer is unable to see the system failure risk levels of the SPs,which is usually seen as an incomplete information market,in contrast with the optimal situation in a complete information market.First,an insurance-based cloud computing architecture is proposed to build a monetary credit system in which the cloud computing SP pays a premium for a certain coverage to the insurer.Subsequently,problem is formulated to solve the optimal insurance plan in complete and incomplete information markets,together with detail analysis of insurance policies in both cases are provided.Furthermore,simulation results show the properties of the two insurance plans and parameters that affect the design of the insurance plan.