Study on the clogging mechanism of punching screen in sand control by the punching structure parameters

As an independent sand control unit or a common protective shell of a high-quality screen,the punching screen is the outermost sand retaining unit of the sand control pipe which is used in geothermal well or oil and gas well.However,most screens only consider the influence of the internal sand retaining medium parameters in the sand control performance design while ignoring the influence of the plugging of the punching screen on the overall sand retaining performance of the screen.To explore the clogging mechanism of the punching screen,this paper established the clogging mechanism calculation model of a single punching screen sand control unit by using the computational fluid mechanics-discrete element method(CFD-DEM)combined method.According to the combined motion of particles and fluids,the influence of the internal flow state on particle motion and accumulation was analyzed.The results showed that(1)the clogging process of the punching sand control unit is divided into three stages:initial clogging,aggravation of clogging and stability of clogging.In the initial stage of blockage,coarse particles form a loose bridge structure,and blockage often occurs preferentially at the streamline gathering place below chamfering inside the sand control unit.In the stage of blockage intensification,the particle mass develops into a relatively complete sand bridge,which develops from both ends of the opening to the center of the opening.In the stable plugging stage,the sand deposits show a“fan shape”and form a“V-shaped”gully inside the punching slot element.(2)Under a certain reservoir particle-size distribution,The slit length and opening height have a large influence on the permeability and blockage rate,while the slit width size has little influence on the permeability and blockage rate.The microscopic clogging mechanism and its law of the punching screen prevention unit are proposed in this study,which has some field guidance significance for the design of punching screen and sand prevention selection.

Internal electric field modulation by copper vacancy concentration of cuprous sulfide nanosheets for enhanced selective CO_(2) photoreduction

Although the internal electric field(IEF)of photocatalysts is acknowledged as a potent driving force for photocharge separation,modulating the IEF intensity to achieve enhanced photocatalytic performances remains a challenge.Herein,cuprous sulfide nanosheets with different Cu vacancy concentration were employed to study IEF modulation and corresponding direct charge transfer.Among the samples,Cu_(1.8)S nanosheets possessed intensified IEF intensity compared with those of Cu_(2)S and Cu_(1.95)S nanosheets,suggesting that an enhanced IEF intensity could be achieved by introducing more Cu vacancies.This intensified IEF of Cu_(1.8)S nanosheets induced numerous photogenerated electrons to migrate to its surface,and the dissociative electrons were then captured by Cu vacancies,resulting in efficient charge separation spatially.In addition,the Cu vacancies on Cu_(1.8)S nanosheets accumulated electrons as active sites to lower the energy barrier of rate-determining step of CO_(2)photoreduction,leading to the selective conversion of CO_(2)to CO.Herein,the manipulation of IEF intensity through Cu vacancy concentration regulation of cuprous sulfide photocatalysts for efficient charge separation has been discussed,providing a scientific strategy to rationally improve photocata lytic performances for solar energy conversion.

Structure optimization of the organ-pipe cavitating nozzle and its erosion ability test on hydrate-bearing sediments

Cavitating jet is a promising drilling rate improvement technology in both the marine natural gas hydrate (NGH) fluidization exploitation method and the integrated radial jet drilling and completion method. In present study, we aim to improve the efficiency of jet erosion and extracting NGH. With a computational fluid dynamics (CFD) method, the pressure, velocity and cavitation field characteristics of organ-pipe cavitating jet (OPCJ) are analysed. The divergent angle, throat length, and divergent length of OPCJ nozzle are preferred to obtain stronger jet cavitation erosion effect. Laboratory experiments of gas hydrate-bearing sediments (GHBS) erosion by OPCJ and conical jet (CJ) are conducted to compare and validate the jet erosion performance. The impinging models of OPCJ and CJ are constructed to study the impact characteristics. Results show that the preferred values of divergent angle, throat length, and divergent length are 15°, 1d, and 3d, respectively, in present simulation conditions. For GHBS, the OPCJ possesses the advantages of high efficiency and low energy consumption. Moreover, the OPCJ has higher penetration efficiency, while showing equivalent penetration ability compared to CJ. During the impinging process, the OPCJ can induce stronger impact pressure and turbulence effect, and also shows stronger chambering effect and bottom cleaning ability compared to CJ. This study presents the erosion performance of OPCJ and CJ on GHBS, and provides preliminary insights on the potential field applications in NGH exploitation.

UROTENSIN II RECEPTOR IN THE RAT AIRWAY SMOOTH MUSCLE AND ITS EFFECT ON THE RAT AIRWAY SMOOTH MUSCLE CELLS PROLIFERATION

Objective. To investigate the characteristics of urotensin II (U II) receptor in the rat airway smooth muscle and the effect and signal transduction pathway of U II on the proliferation of airway smooth muscle cells. Methods. Using 125I UII binding assay to measure the Bmax and Kd of U II receptor. Using the 3H TdR incorporation to determine the effect of U II on the proliferation of airway smooth muscle cells and its signal transduction pathway. Using Fura 2/AM to measure the effect of U II on the cytosolic free calcium concentration. Results. 1. 125I UII binding increased with the time and reached saturation at 45min. The Bmax was (11.36±0.37)fmol/mg pr and Kd was (4.46±0.61)nmol/L. 2. U II increased 3H TdR incorporation of the airway smooth muscle cells in a dose dependent manner. 3. H7, PD98059 and nicardipine, inhibitors of PKC, MAPK, calcium channel, respectively, significantly inhibited U II stimulated 3H TdR incorporation of airway smooth muscle cells. W7, inhibitor of CaM PK, had no effect. 4. Cyclosporin A, inhibitor of CaN, inhibited 3H TdR incorporation of the airway smooth muscle cells induced by U II in a dose dependent manner. 5. U II promoted cytosolic free calcium concentration increase by 18%. Conclusions. 1. There was U II receptor in the rat airway smooth muscle. 2. The effect of U II stimulated 3H TdR incorporation of airway smooth muscle cells was mediated by such signal transduction pathway as Ca2+, PKC, MAPK and CaN, etc.

种植前胚胎内空泡的形成与发展结局

Objective: Since little is known about the actual incidence and fate of vacuoles at different stages of development this preliminary study was set up to accurately measure vacuoles and track them to day 5. Design: Prospective study. Setting: Women’s General Hospital in Austria. Patient(s): A total of 223 consecutive IVF and intracytoplasmic sperm injection (ICSI) cycles (206 patients). Intervention(s): Accurate measurement of vacuoles. Affected gametes and embryos were cultured individually and tracked until day 5. Main Outcome Measure(s): Size and number of vacuoles, fertilization rate, blastocyst formation rate, blastocyst quality. Result(s): There was a significant relationship between size of the vacuole (cutoff value 14 μ m) and fertilization (P< .05). At zygote stage the incidence of vacuoles was higher (P< .01) in ICSI (11.6% ) than in IVF (5.3% ). Only 32.2% of affected ICSI- embryos reached blastocyst stage on day 5 compared with 53.0% of the normal ones (P< .001). In terms of blastocyst formation vacuolization on day 4 (P< .001) turned out to be the most severe one. At blastocyst stage inner cell mass was affected less frequently than the trophectoderm (P< .05). Conclusion(s): Three types of vacuoles could be identified: (1) those already present at oocyte collection, which develop during maturation (day 0); (2) those artificially created by ICSI (day 1); and (3) those accompanied with developmental arrest (day 4). The later that vacuoles arose, the more detrimental their effect on blastocyst formation.

A mathematical diffusion model of carbon isotopic reversals inside ultra-tight Longmaxi shale matrixes

Developing mathematical models for high Knudsen number(Kn)flow for isotopic gas fractionation in tight sedimentary rocks is still challenging.In this study,carbon isotopic reversals(δ^(13)C_(1)>δ^(13)C_(2))were found for four Longmaxi shale samples based on gas degassing experiments.Gas in shale with higher gas content exhibits larger reversal.Then,a mathematical model was developed to simulate the carbon isotopic reversals of methane and ethane.This model is based on these hypotheses:(i)diffusion flow is dominating during gas transport process;(ii)diffusion coefficients are nonlinear depending on concentration gradient.Our model not only shows a good agreement with isotopic reversals,but also well predicts gas production rates by selecting appropriate exponents m and m^(*) of gas pressure gradient,where m is for ^(12)C and m^(*)is for ^(13)C.Moreover,the(m−m^(*))value has a positive correlation with fractionation level.(m1−m1^(*))of methane are much higher than that of ethane.Finally,the predicted carbon isotopic reversal magnitude(δ^(13)C_(1)−δ^(13)C_(2))exhibits a positive relationship with total gas content since gas in shale with higher gas content experiences a more extensive high Kn number diffusion flow.As a result,our model demonstrates an impressive agreement with the experimental carbon isotopic reversal data.

Fibrinogen-thrombin collagen patch reinforcement of highrisk colonic anastomoses in rats

AIM To evaluate the effectiveness of human fibrinogenthrombin collagen patch (TachoSil?) in the reinforcement of high-risk colon anastomoses. METHODS A quasi-experimental study was conducted in Wistar rats (n = 56) that all underwent high-risk anastomoses (anastomosis with only two sutures) after colectomies.The rats were divided into two randomized groups:Control group (24 rats) and treatment group (24 rats).In the treatment group, high-risk anastomosis was reinforced with TachoSil? (a piece of TachoSil? was applied over this high-risk anastomosis, covering the gap). Leak incidence, overall survival, intra-abdominal adhesions, and histologic healing of anastomoses were analyzed. Survivors were divided into two subgroups and euthanized at 15 and 30 d after intervention in order to analyze the adhesions and histologic changes.RESULTS Overall survival was 71.4% and 57.14% in the TachoSil? group and control group, respectively (P = 0.29); four rats died from other causes and six rats in the treatment group and 10 in the control group experienced colonic leakage (P > 0.05). The intra-abdominal adhesion score was similar in both groups, with no differences between subgroups. We found non-significant differences in the healing process according to the histologic score used in both groups (P = 0.066). CONCLUSION In our study, the use of TachoSil? was associated with a non-statistically significant reduction in the rate of leakage in high-risk anastomoses. TachoSil? has been shown to be a safe product because it does not affect the histologic healing process or increase intra-abdominal adhesions.

Platelet-rich plasma vs bone marrow aspirate concentrate:An overview of mechanisms of action and orthobiologic synergistic effects

The use of orthobiologics as a novel therapy for the treatment of numerous musculoskeletal disorders has increased considerably over the past decade.Currently,there are multiple alternatives available as suitable treatments;however,the use of autologous blood-derived products such as platelet-rich plasma(PRP),bone marrow aspirate(BMA)and BMA concentrate(BMAC),specifically,is expanding.Although many investigations attempted to demonstrate the effectiveness of these therapies,even with positive results,the literature lacks standardized protocols and overall accuracy in study designs,which leads to variance and difficulty in reproducibility of protocols.The efficacy of PRP for the treatment of cartilage,bone and muscle tissues is well known.Although BMAC has generated optimistic results for the same purposes,its applicability in clinical trials is still relatively recent when compared to PRP.Both products demonstrate the potential to set forth reparative processes,each in their own distinct mechanism.The combination of these biological products has been previously proposed,yet little is known about their synergism.Evidence indicates that growth factor,cytokine,and chemokine profiles seen in both PRP and BMAC vary but are likely to work synergistically to enhance musculoskeletal healing.BMAC products seem to work well without PRP;however,the addition of PRP to BMAC has been shown to act as a rich and natural source of culture medium for stem cells located either peripherally or in the bone marrow itself.Nevertheless,additional variables associated with the use of BMAC and PRP in orthopedics must be further evaluated in order to consolidate the efficacy of this therapeutic strategy.

Single cell analysis reveals inhibition of angiogenesis attenuates the progression of heterotopic ossification in Mkx^(−/−)mice

Tendon heterotopic ossification(HO)is characterized by bone formation inside tendon tissue,which severely debilitates people in their daily life.Current therapies fail to promote functional tissue repair largely due to our limited understanding of HO pathogenesis.Here,we investigate the pathological mechanism and propose a potential treatment method for HO.Immunofluorescence assays showed that the Mohawk(MKX)expression level was decreased in human tendon HO tissue,coinciding with spontaneous HO and the upregulated expression of osteochondrogenic and angiogenic genes in the tendons of Mkx^(−/−)mice.Single-cell RNA sequencing analyses of wild-type and Mkx^(−/−)tendons identified three cell types and revealed the excessive activation of osteochondrogenic genes during the tenogenesis of Mkx^(−/−)tendon cells.Single-cell analysis revealed that the gene expression program of angiogenesis,which is strongly associated with bone formation,was activated in all cell types during HO.Moreover,inhibition of angiogenesis by the small-molecule inhibitor BIBF1120 attenuated bone formation and angiogenesis in the Achilles tendons of both Mkx mutant mice and a rat traumatic model of HO.These findings provide new insights into the cellular mechanisms of tendon HO and highlight the inhibition of angiogenesis with BIBF1120 as a potential treatment strategy for HO.

Preparation and Characterization of Polyimide Attached with Azo-dye Chromophore Side Chain

In order to improve the nonlinear optical property and stability of azo-dye chromophore, the nonlinear optical polyimide (NLOPI) attached with azo chromophore side chain is synthesized by diazo coupling reaction of 4-nitrobenzenediazonium tetrafloroborate. The designed chemical structure of production can be proved in the infrared spectrum and ultraviolet-visible absorption spectrum. The NLOPI exhibited UV-Vis absorption of the azobenzene chromophore in the vicinity of the wavelengths of 330 and 490 nm. The broad amorphous peak proved that the NLOPI was amorphous with a little periodical structure along the side chain. According to transmission electron microscope, the NLOPI film was homogeneous. NLOPI only displayed a decrease in mass of about 5% at the temperature of 400 ℃ through thermogravimetric analysis.

Propagation Characteristics of Partial Discharge Pulses in the Cable

In order to determine the type and location of partial discharge in cable, the effect of partial discharge (PD) pulse propagation in the cable is studied. Firstly, pulses are injected to cables of different lengths so that input and output signal can be measured at both ends of each cable. Then the transfer function of pulse propagation path can be defined. Secondly, high-voltage test is done in the cable joint with man-made defects, and typical PD waveforms are gotten. Seven parameters of waveform characteristics are calculated, including edge times, waveform shape and statistical characteristics. They are used to distinguish different types of PD or distances of the pulse propagation. Thus the efficiency of PD recognition in cable can be improved.

First-row transition metal compounds for aqueous metal ion batteries

In recent years,a series of aqueous metal ion batteries(AMIBs)has been developed to improve the safety and cost-efficiency of portable electronics and electric vehicles.However,the significant gaps in energy density,power density,and cycle stability of AMIBs directly hinder them from replacing the currently widely used non-aqueous metal ion batteries,which stems from the lack of reasonable configuration and performance optimization of electrode materials.First-row transition metal compounds(FRTMCs),with the advantages of optional voltage ranges(from low to high),adjustable crystal structures(layered and tunnel types with large spacing),and designable morphology(multi-dimensional nanostructures),are widely used to construct high-performance AMIBs.However,no comprehensive review papers were generated to highlight their specific and significant roles in AMIBs.In this review,we first summarize the superiority and characteristics of FRTMCs in AMIBs.Then,we put forward control strategies of FRTMCs from subsurface engineering to inner construction to promote capacitance control and diffusion control energy storage.After that,the electrochemical performance of the FRTMCs regulation strategies in AMIBs is reviewed.Finally,we present potential directions and challenges for further enhancements of FRTMCs in AMIBs.The review aims to provide an in-depth understanding of regulation strategies for enhancing energy storage to build high-performance AMIBs that meet practical applications.

Fibulin5基因错义变异和年龄相关性黄斑变性

BACKGROUND:Age-related macular degeneration(AM-D)is the most common cause of irreversible vision loss in the developed world.The study of a ra re mendelian form of macular degeneration implicated fibulin genes in the pathogenesis of more common forms of this disease.We evaluated five fibulin genes in a large series of patients with AMD.METHODS:We studied 402patients with AMD and 429control subjects from the same clinic pop-ulation.Patients were examined by m eans of indirect ophthalmoscopy,slit-lamp microsc opy,and fundus pho-tography to establish the presence a nd phenotypic pattern of AMD.DNA samples were screened for sequence vari-ations in five members of the fibulin gene family.RE-SULTS:Amino acid-altering sequence variations were found in all five fibulin genes,many of which were ob-served only in patients with AMD.Sev eral of the altered residues have been conserved during evolution.Seven of the 402patients with AMD had amino ac idaltering se-quence variations in the fibulin 5ge ne,whereas none were observed among 429control subjects(P<0.01).In addition,these seven patients all h ad small,circular drusen,which are commonly referred to as basal laminar or cuticular drusen.CONCLUSIONS:Missense mutations in the fibulin 5gene were found in 1.7percent of patients with AMD.Many variationsin other fibulin genes were also found in these patients,and the evolutionary con-servation of the affected residues s uggests that several of these variations may also be involved in AMD.

TRANSFORMING-GROWTH FACTOR-PI PREFERENTIALLY INHIBITS THE INDUCTION OF CYTOTOXICITY IN HUMAN T CELLS STIMULATED VIA CD28

Generally, TGF-βs are held to down- regulate the growth of immune cells and to inhibit the development of certain differentiated functions, such as the induction of LAK activity by IL-2. In the present study, the effects of TGF-β1 on the proliferation and cytotoxicity of human PBMC activated by anti-CD3 or and-CD3 plus anti-CD28 was investigated. The results demonstrated that TGF- β1 clearly inhibits the induction of cytotoxic ability in human PBMC stimulated via CD3 or CD3 and CD28 ( P<0. 01) , without significantly altering the proliferative response to these stimuli, at the tested doses of TGF-β1. Co-stimulation with IL-2 was hardly altered, suggesting that TGF-β1 action is affected by the nature of the costimulatory signals.

Study of the blocking mechanism in gravel packing based on CFD-DEM

Gravel packing sand control(GPSC),as the optimization of mechanical sand control technology,is widely used in the deep water completion and sand control of loose sandstone heavy oil reservoirs and highly argillaceous.To explore the blocking mechanism of GPSC,the influence of its structural parameters on the blocking of GPSC is investigated.This paper establishes a particle element model based on computational fluid dynamics-discrete element method coupling using the discrete element method and establishes a fluid flow model combined with computational fluid dynamics to realize their full coupling solution.And sand control experiments were carried out using a micro visual sand control simulation device to verify the blocking model.The blocking mechanism is analyzed from the microscopic point of view,and then,the influence of sand control structure parameters on the blocking in GPSC design is evaluated.The results show the following:(1)the blocking process of GPSC can be divided into three stages:an initial stage,sand accumulation stage,and equilibrium stage.(2)There are two main types of gravel packing blockage.The first type of blocking is blocking on the surface of the gravel layer.Sand particles on the surface of gravel layer mainly exist in the form of large particle size blocking gravel pores and sand particles bridging each other.The second type of blockage is the blockage inside the gravel layer.Sand particles mainly exist in the form of internal mud cakes and adsorption on gravels inside the gravel layer.(3)To ensure the sand control performance of the gravel layer,the gravel layer thickness is designed between 23 and 28 mm.The displacement or pressure of the on-site packing pump should be increased to ensure that the gravel layer packing solidity ranges between 59%and 62%.In the design of GPSC,it should be ensured that the median particle size of gravel is 5–6 times the median particle size of sand.This study provides an effective technical reference for the design of gravel structural parameters in on-site gravel packing completion sand control.

Catalytic conversion of mixed polyolefins under mild atmospheric pressure

The chemical recycling of polyolefin presents a considerable challenge,especially as upcycling methods struggle with the reality that plastic wastes typically consist of mixtures of polyethylene(PE),polystyrene(PS),and polypropylene(PP).We report a catalytic aerobic oxidative approach for polyolefins upcycling with the corresponding carboxylic acids as the product.This method encompasses three key innovations.First,it operates under atmospheric pressure and mild conditions,using O_(2) or air as the oxidant.Second,it is compatible with high-density polyethylene,low-density polyethylene,PS,PP,and their blends.Third,it uses an economical and recoverable metal catalyst.It has been demonstrated that this approach can efficiently degrade mixed wastes of plastic bags,bottles,masks,and foam boxes.

SEI/dead Li-turning capacity loss for high-performance anode-free solid-state lithium batteries

Anode-free solid-state lithium metal batteries(AF-SSLBs)have the potential to deliver higher energy density and improved safety beyond lithium-metal batteries.However,the unclear mechanism for the fast capacity decay in AF-SSLBs,either determined by dead Li or solid electrolyte interface(SEI),limits the proposal of effective strategies to prolong cycling life.To clarify the underlying mechanism,herein,the evolution of SEI and dead Li is quantitatively analyzed by a solid-state nuclear magnetic resonance(ss-NMR)technology in a typical LiPF6-based polymer electrolyte.The results show that the initial capacity loss is attributed to the formation of SEI,while the dead Li dominates the following capacity loss and the growth rate is 0.141 mA h cm^(−2)cycle−1.To reduce the active Li loss,the combination of inorganic-rich SEI and self-healing electrostatic shield effect is proposed to improve the reversibility of Li deposition/dissolution behavior,which reduces the capacity loss rate for the initial SEI and following dead Li generation by 2.3 and 20.1 folds,respectively.As a result,the initial Coulombic efficiency(ICE)and stable CE increase by 15.1%and 15.3%in Li-Cu cells,which guides the rational design of high-performance AF-SSLBs.

Engineering SIRPα cellular membrane-based nanovesicles for combination immunotherapy

Immune checkpoint inhibitors(ICIs)have revolutionized cancer treatment for their unprecedented clinical efficacy.Signal regulatory proteinα(SIRPα)is a phagocytic checkpoint expressed on macrophages,dendritic cells,other myeloid cells.Cancer cells inhibit macrophage phagocytosis through the interaction of the CD47-SIRPαaxis.Disrupting the CD47-SIRPαaxis has therefore been a promising strategy in restoring the immune attack against cancer.Herein,we engineered cellular membrane nanovesicles(NVs)presenting SIRPαreceptors for phagocytosis checkpoint blockade to augment the antitumor immune response.Furthermore,zebularine(Zeb),an inhibitor of DNA methyltransferase,was encapsulated into SIRPαNVs to reprogram the immunosuppressive tumor microenvironment together with blockade of phagocytosis checkpoint.It is demonstrated that SIRPα@Zeb can improve tumor immunogenicity,the polarization of tumor-associated macrophages to the M1 phenotype,increase the infiltration of CD8^(+)T lymphocytes in tumors.The robust antitumor immune response induced by SIRPα@Zeb significantly suppressed tumor growth and extended mice-bearing melanoma xenograft survival.

Deciphering the placental abnormalities associated with somatic cell nuclear transfer at single-nucleus resolution

Dear Editor,The placenta connecting the fetus to the matermal uterus provides material exchange and an immune-tolerant environment for the embryo in all eutherian mammals(Shao et al.,2022).The representative mouse placenta displays a multilayered structure with distinct characteristics and functions,including the matermal decidua,junctional zone,and labyrinth layer(Marsh and Blelloch,2020).The decidua,which is thought to be derived from the matermal endometrium(and further undergoes decidualization),provides an anchor for fetal trophoblast invasion.The junctional zone predominantly contains spongiotrophoblasts(SpT),glycogen trophoblasts(GlyT),and trophoblast giant cells(TGCs).The labyrinth is the innermost two-layer structure,which mainly consists of syncytiotrophoblast cells(SynTI and SynTII),sinusoidal TGCs(S-TGCs),and fetal endothelial cells(Simmons and Cross,2005).

A new era for hepatocellular carcinoma

Hepatocellular carcinoma(HCC)is one of the most frequent cancers worldwide among patients with cirrhosis,and its management and treatment is in continuous evolution due to the introductions of new therapeutic option.It represents most common primary malignancy of the liver,developing in 90%of cases of un underlying liver disease(1)[chronic HBV and HCV hepatitis,dysmetabolic liver disease].