Dissolvable temporary barrier:a novel paradigm for flexible hydrogel patterning in organ-on-a-chip models

A combination of hydrogels and microfluidics allows the construction of biomimetic three-dimensional(3D)tissue models in vitro,which are also known as organ-on-a-chipmodels.The hydrogel patterningwith awell-controlled spatial distribution is typically achieved by embedding sophisticated microstructures to act as a boundary.However,these physical barriers inevitably expose cells/tissues to a less physiologically relevant microenvironment than in vivo conditions.Herein,we present a novel dissolvable temporary barrier(DTB)strategy that allows robust and flexible hydrogel patterning with great freedom of design and desirable flow stimuli for cellular hydrogels.The key aspect of this approach is the patterning of a water-soluble rigid barrier as a guiding path for the hydrogel using stencil printing technology,followed by a barrier-free medium perfusion after the dissolution of the DTB.Single and multiple tissue compartments with different geometries can be established using either straight or curved DTB structures.The effectiveness of this strategy is further validated by generating a 3D vascular network through vasculogenesis and angiogenesis using a vascularized microtumor model.As a new proof-of-concept in vasculature-on-a-chip,DTB enables seamless contact between the hydrogel and the culture medium in closed microdevices,which is an improved protocol for the fabrication ofmultiorgan chips.Therefore,we expect it to serve as a promising paradigm for organ-on-a-chip devices for the development of tumor vascularization and drug evaluation in the future preclinical studies.

Fracture propagation law of temporary plugging and diversion fracturing in shale reservoirs under completion experiments of horizontal well with multi-cluster sand jetting perforation

This study conducted temporary plugging and diversion fracturing(TPDF)experiments using a true triaxial fracturing simulation system within a laboratory setting that replicated a lab-based horizontal well completion with multi-cluster sand jetting perforation.The effects of temporary plugging agent(TPA)particle size,TPA concentration,single-cluster perforation number and cluster number on plugging pressure,multi-fracture diversion pattern and distribution of TPAs were investigated.A combination of TPAs with small particle sizes within the fracture and large particle sizes within the segment is conducive to increasing the plugging pressure and promoting the diversion of multi-fractures.The addition of fibers can quickly achieve ultra-high pressure,but it may lead to longitudinal fractures extending along the wellbore.The temporary plugging peak pressure increases with an increase in the concentration of the TPA,reaching a peak at a certain concentration,and further increases do not significantly improve the temporary plugging peak pressure.The breaking pressure and temporary plugging peak pressure show a decreasing trend with an increase in single-cluster perforation number.A lower number of single-cluster perforations is beneficial for increasing the breaking pressure and temporary plugging peak pressure,and it has a more significant control on the propagation of multi-cluster fractures.A lower number of clusters is not conducive to increasing the total number and complexity of artificial fractures,while a higher number of clusters makes it difficult to achieve effective plugging.The TPAs within the fracture is mainly concentrated in the complex fracture areas,especially at the intersections of fractures.Meanwhile,the TPAs within the segment are primarily distributed near the perforation cluster apertures which initiated complex fractures.

HVOF-sprayed HAp/S53P4 BG composite coatings on an AZ31 alloy for potential applications in temporary implants

Bioactive thermal spray coatings produced via high-velocity oxygen fuel spray(HVOF)from hydroxyapatite(HAp)and bioactive glasses(BG)have the potential to be employed on temporary implants due to the ability of both HAp and BG to dissolve and promote osseointegration,considering that both phases have different reaction and dissolution rates under in-vitro conditions.In the present work,75%wt.HAp-25%wt.S53P4 bioactive glass powders were HVOF-sprayed to obtain HAp/S53P4 BG composite coatings on a bioresorbable AZ31 alloy.The study is focused on exploring the effect of the stand-off distance and fuel/oxygen ratio variation as HVOF parameters to obtain stable structural coatings and to establish their effect on the phases and microstructure produced in those coatings.Different characterization techniques,such as scanning electron microscopy,X-ray diffraction,and Fourier transform infrared spectroscopy,were employed to characterize relevant structural and microstructural properties of the composite coatings.The results showed that thermal gradients during coating deposition must be managed to avoid delamination due to the high temperature achieved(max 550℃)and the differences in coefficients of thermal expansion.It was also found that both spraying distance and oxygen/fuel ratio allowed to keep the hydroxyapatite as the main phase in the coatings.In addition,in-vitro electrochemical studies were performed on the obtained HAp/S53P4 BG composite coatings and compared against the uncoated AZ31 alloy.The results showed a significant decrease in hydrogen evolution(at least 98%)when the bioactive coating was applied on the Mg alloy during evaluation in simulated body fluid(SBF).

Qualitative exploration of home life experiences and care needs among elderly patients with temporary intestinal stomas

BACKGROUND This study employed a phenomenological research approach within qualitative research to explore the challenges encountered by elderly individuals with temporary colostomies in managing their daily lives and care needs.Protecting the anus surgery combined with temporary colostomy has emerged as a prevalent treatment modality for low rectal cancer.However,the ileostomy is susceptible to peri-stoma skin complications,as well as fluid,electrolyte,and nutritional imbalances,posing challenges to effective management.The successful selfmanagement of patients is intricately linked to their adjustment to temporary colostomy;nonetheless,there remains a dearth of research examining the factors influencing self-care among temporary colostomy patients and the obstacles they confront.AIM To investigate the lived experiences,perceptions,and care requirements of temporary colostomy patients within their home environment,with the ultimate goal of formulating a standardized management protocol.METHODS Over the period of June to August 2023,a purposive sampling technique was utilized to select 12 patients with temporary intestinal stomas from a tertiary hospital in Shanghai,China.Employing a phenomenological research approach,a semi-structured interview guide was developed,and qualitative interviews were conducted using in-depth interview techniques.The acquired data underwent coding,analysis,organization,and summarization following Colaizzi’s seven-step method.RESULTS The findings of this study revealed that the experiences and needs of patients with temporary intestinal stomas can be delineated into four principal themes:Firstly,Temporary colostomy patients bear various burdens and concerns about the uncertainty of disease progression;secondly,patients exhibit limited self-care capabilities and face information deficits,resulting in heightened reliance on healthcare professionals;thirdly,patients demonstrate the potential for internal motivation through proactive self-adjustment;and finally,patients express a significant need for emotional and social support.CONCLUSION Home-living patients with temporary intestinal stomas confront multifaceted challenges encompassing burdens,inadequate self-care abilities,informational deficits,and emotional needs.Identifying factors influencing patients’self-care at home and proposing strategies to mitigate barriers can serve as a foundational framework for developing and implementing nursing interventions tailored to the needs of patients with temporary intestinal stomas.

Laser speckle contrast imaging to predict the effect of temporary spinal cord stimulation in postherpetic neuralgia patients: A prospective observational study

Temporary spinal cord stimulation(tSCS)can effectively reduce the pain and severity of postherpetic neuralgia(PHN).However,there are no effective and objective methods for predicting the effects of tSCS on PHN.Laser speckle contrast imaging(LSCI)is frequently used in neurology to evaluate the effectiveness of treatment.To assess the accuracy of LSCI in predicting the impact of tSCS on PHN,14 adult patients receiving tSCS treatments for spinal nerve-innervated(C6-T2)PHN participated in this observational study.Visual analog scale(VAS)assessments and LSCI bloodflow images of the-ngers were recorded after the tSCS procedure.The results showed that the VAS scores of all patients decreased signi-cantly.Moreover,the bloodflow index(BFI)values were signi-cantly higher than they were before the procedure.Increased bloodflow and pain alleviation were positively correlated.The-ndings indicated that spinal nerve PHN(C6-T2)was signi-cantly reduced by tSCS.Pain alleviation by tSCS was positively correlated with increased bloodflow in the hand.The effect of tSCS on PHN may thus be predicted using an independent and consistent indicator such as LSCI.

Clinical Efficacy of GBR Technique Combined with Temporary Bridgework-Guided Gingival Contouring in Treating Upper Anterior Tooth Loss with Labial Bone Defects

Objective:To investigate the clinical effect of the guided bone regeneration(GBR)technique combined with temporary bridgework-guided gingival contouring in treating upper anterior tooth loss with labial bone defects.Methods:From July 2023 to April 2024,80 patients with upper anterior tooth loss and labial bone defects were admitted to the hospital and selected as evaluation samples.They were divided into an observation group(n=40)and a control group(n=40)using a numerical table lottery scheme.The control group received treatment with the GBR technique,while the observation group received treatment with the GBR technique combined with temporary bridges to guide gingival contouring.The two groups were compared in terms of clinical red aesthetic scores(PES),labial alveolar bone density,labial bone wall thickness,gingival papillae,gingival margin levels,and patient satisfaction.Results:The PES scores of patients in the observation group were higher than those in the control group after surgery(P<0.05).The bone density of the labial alveolar bone and the thickness of the labial bone wall in the observation group were higher than those in the control group.The levels of gingival papillae and gingival margins were lower in the observation group after surgery(P<0.05).Additionally,patient satisfaction in the observation group was higher than in the control group(P<0.05).Conclusion:The GBR technique combined with temporary bridge-guided gingival contouring for treating upper anterior tooth loss with labial bone defects can improve the aesthetic effect of gingival soft tissue,increase alveolar bone density and the thickness of the labial bone wall,and enhance patient satisfaction.This approach is suitable for widespread application in healthcare institutions.

Temporary pacemaker protected transjugular intrahepatic portosystemic shunt in a patient with acute variceal bleeding and bradyarrhythmia:A case report

BACKGROUND Esophagogastric varices are a common complication of cirrhosis with portal hypertension and endoscopic treatment has been recognized as a primary preventive and therapeutic option for such patients;however,it should be noted that bradyarrhythmia is regarded as one of the contraindications to endoscopic examination.Meanwhile,acute variceal bleeding may result in a high mortality rate in cirrhotic patients with portal hypertension accompanied by bradyarrhythmia.At present,there is an absence of reports concerning the treatment of such group of patients who underwent transjugular intrahepatic portosystemic shunt(TIPS).The present report details the case of a cirrhotic patient with acute variceal bleeding accompanied by bradyarrhythmia who underwent TIPS under temporary pacemaker protection.CASE SUMMARY We report the case of a 64-year-old male patient who was confirmed with bradyarrhythmia by ambulatory electrocardiogram 24 h before the operation.The patient was successfully treated by TIPS under temporary pacemaker protection.CONCLUSION In terms of cirrhotic patients with abnormal cardiac electrophysiological conduction,TIPS may be effective in reducing the complications of portal hypertension following the exclusion of severe pulmonary hypertension and heart failure,showing moderate feasibility in clinical applications.

Design and Construction of a Pneumatic Temporary Immersion Bioreactor System for the Multiplication of <i>Ananas comosus</i>var. Trujillana Red

The present work initially identified the design parameters of a temporary immersion bioreactor to later scale it to a complete system for the in vitro multiplication of Ananas comosus var. Trujillana Red. Thus, a low-cost pneumatic temporary immersion bioreactor system was designed and built with 24 tanks of 2 L each. The automation of the system was designed and implemented by means of a timer circuit whose design parameters were: duration of the propagation process, which depends on the multiplication period of the crop and is an open variable, which means that the operator decides when to turn off the system;the duration of each dive, which for reasons of complexity of the algorithm was standardized as one minute;immersion frequency, which was programmed for intervals of 1, 2, 3, 4, 5, 6, 7, 8 hours respectively and duration of aeration, which from a test run times of 0.20 were chosen, 30, 40, 50, 60, 70, and 80 seconds that correspond to the time of delivery of compressed air;additionally, the multiplication rate of Ananas comosus var. Trujillana Red in the immersion system which was 6.5 times per propagative unit inoculated in thirty days.

High Efficiency of Propagation for Sagittaria sagittifolia Using a Temporary Immersion Bioreactor System

Although several studies have reported on the propagation of the Sagittaria sagittifolia to date, none of these methods have efficiently achieved the mass production of these plants. The present study aimed to investigate the propagation and growth of S. sagittifolia using a temporary immersion bioreactor system （TIBS） compared with conventional semi-solid and liquid culture. The effect of different immersion frequencies and immersion times together with supplementation of various plant growth regulators to the Murashige and Skoog （MS） medium was evaluated on shoot proliferation and plant growth. The results showed that the higher immersion frequency （every 6 h） and shorter immersion time （3 min and 10 rain） in medium containing 4 mg/L BA and 0.1 mg/L NAA produced the highest multiplication rate （23）, which are significantly higher than conventional semi-solid （3.6） and liquid （4.5） method, and the best plant growth parameter. While, the lower immersion frequency and longer immersion time （30 rain every 12 h and 60 min every 24 h） induced vitrification and pollution rate in shoot tips 16.6% and 19%, 42% and 37%, respectively. There is distinct decrease in pollution rate （8.3%） in TIBS （10 min every 6 h） compared with the conventional semi-solid and liquid cultures. Medium containing 4 mg/L BA and 0.5 mg/L NAA using 10 min immersion every 6 h showed satisfaction at the rooting stage, with high shoot proliferation rate （21.6）, 100% rooting and 94% plant survival. Therefore, applying TIBS in S. sagittifolia is an efficient method for scaling up the production of plantlets with high quality seedlings.

Rapid Propagation of Virus-free Sugarcane Plantlets via Temporary Immersion Bioreactor System

By employing temporary immersion bioreactor system(TIBs),we studied virus-free culture of seedlings from sugarcane varieties ROC16 and ROC22,from medium recipe,inoculation amount,sucrose concentration,and variety difference. The results showed,using this method,that proliferation rate of ROC16 improved by 40 times,per flask generated about 800 plantlets; of ROC22 improved by 30 times,per flask generated about 400-600 plantlets. The results provided basis for using TIBs in rapid propagation of plantlets via tissue culture.

Plugging behaviors of temporary plugging particles in hydraulic fractures

Using the visualized experimental device of temporary plugging in hydraulic fractures, the plugging behaviors of temporary plugging particles with different sizes and concentrations in hydraulic fractures were experimentally analyzed under the conditions of different carrier fluid displacements and viscosities. The results show that the greater the carrier fluid viscosity and displacement, the more difficult it is to form a plugging layer, and that the larger the size and concentration of the temporary plugging particle, the less difficult it is to form a plugging layer. When the ratio of particle size to fracture width is 0.45, the formation of the plugging layer is mainly controlled by the mass concentration of the temporary plugging particle and the viscosity of the carrier fluid, and a stable plugging layer cannot form if the mass concentration of the temporary plugging particle is less than 20 kg/m^(3)or the viscosity of the carrier fluid is greater than 3 mPa·s. When the ratio of particle size to fracture width is 0.60, the formation of the plugging layer is mainly controlled by the mass concentration of the temporary plugging particle, and a stable plugging layer cannot form if the mass concentration of the temporary plugging particle is less than 10 kg/m^(3). When the ratio of particle size to fracture width is 0.75, the formation of the plugging layer is basically not affected by other parameters, and a stable plugging layer can form within the experimental conditions. The formation process of plugging layer includes two stages and four modes. The main controlling factors affecting the formation mode are the ratio of particle size to fracture width, carrier fluid displacement and carrier fluid viscosity.

Complex fracture propagation model and plugging timing optimization for temporary plugging fracturing in naturally fractured shale

In this paper,a viscoelasticity-plastic damage constitutive equation for naturally fractured shale is deduced,coupling nonlinear tensile-shear mixed fracture mode.Dynamic perforation-erosion on fluid re-distribution among multi-clusters are considered as well.DFN-FEM(discrete fracture network combined with finite element method)was developed to simulate the multi-cluster complex fractures propagation within temporary plugging fracturing(TPF).Numerical results are matched with field injection and micro-seismic monitoring data.Based on geomechanical characteristics of Weiyuan deep shale gas reservoir in Sichuan Basin,SW China,a multi-cluster complex fractures propagation model is built for TPF.To study complex fractures propagation and the permeability-enhanced region evolution,intersecting and competition mechanisms between the fractures before and after TPF treatment are revealed.Simulation results show that:fracture from middle cluster is restricted by the fractures from side-clusters,and side-clusters plugging is benefit for multi fractures propagation in uniformity;optimized TPF timing should be delayed within a higher density or strike of natural fractures;Within a reservoir-featured natural fractures distribution,optimized TPF timing for most clustered method is 2/3 of total fluid injection time as the optimal plugging time under different clustering modes.

Research and application of non-clay low damage temporary bridging drilling/completion fluids system

Following the basic theory of protecting gas-reservoirs from damage with the temporary bridging technology,inert calcium carbonate (CaCO3) particles,whose diameter is consistent with the size of pores or apertures in the reservoir,were selected as the bridging agent,and modified resolvable starch was selected as filtration loss reducing particles to form the non-clay low damage temporary bridging drilling/completion fluids system (NLTDFS). Under the simulated condition of the well bottom during real drilling,NLTDFS was used to conduct dynamic and static damage experiments of cores for 48 hours,respectively,and then the experimented cores were permeated with pure nitrogen from the undamaged end to the damaged one to measure their recovery of permeability. The results showed that the permeability recovery rate of the core reached 90% or so,and the damaged depth was less than 1 cm,which demonstrates that NLTDFS has higher temporary bridging effectiveness and lower damage to the gas-reservoir than other drilling fluids system. NLTDFS has been used to drill many horizontal wells,and four of them have obtained high yield of natural gas. The yield of natural gas of LP1 well reached 85×104 m3/day after completion with the rump pipe. The formation of the stable well wall and smooth drilling led to an API loss less than 4 mL and an HTHP loss less than 15 mL.

Emergency internal iliac artery temporary occlusion after massive hemorrhage during surgery of cesarean scar pregnancy:A case report

BACKGROUND Cesarean scar pregnancy(CSP)is rare but may result in uterine rupture during pregnancy or massive hemorrhage during abortion procedures.Awareness of this condition is increasing,and most patients with CSP are now diagnosed early and can be managed safely.However,some atypical patients are misdiagnosed,and their surgical risks are underestimated,increasing the risk of fatal hemorrhage.CASE SUMMARY A 27-year-old Asian woman visited our institution because of abnormal pregnancy,and she was diagnosed with a hydatidiform mole through transvaginal ultrasound(TVS).Under hysteroscopy,a large amount of placental tissue was found in the scar of the lower uterine segment,and a sudden massive hemorrhage occurred during the removal process.The bilateral internal iliac arteries were temporarily blocked under laparoscopy,and scar resection and repair were rapidly performed.She was discharged in good condition 5 d after the operation.CONCLUSION Although TVS is widely used in the diagnosis of CSP,delays in the diagnosis of atypical CSP remain.Surgical treatment following internal iliac artery temporary occlusion may be an appropriate management method for unanticipated massive hemorrhage during CSP surgery.

A Study for the Influence of the Location of PCMs Assembly System on Improving Thermal Environment inside Disaster-Relief Temporary Houses

Currently,people pay more and more attention to the transitional resettlement of victims after various natural disasters.There is an urgent need for a large number of temporary houses to resettle the victims after natural disasters.Disaster-relief temporary houses(DTHs)played an important role in the post-disaster resettlement in the past,which can not only be produced on a large scale,but also can be quickly and conveniently erected,which were the main means to solve the problem of transitional resettlement.However,due to their temporary nature,there was no extra energy consuming system installed in the DTHs generally.Hence the indoor thermal environment inside the DTHs was severe in summer.In this study,combined with the field experimental tests of the DTHs in Wenchuan Earthquake and Lushan Earthquake and the experimental study of the full-size DTH,it found that the thermal environment inside the DTH was intolerably high in summer.It had negative impact on victims.In order to improve the thermal environment inside DTHs during post-disaster period which lacked of extra energy resources,this study used the method of combining phase change materials(PCMs)with walls of the DTH to explore its feasibility and effectiveness.The results showed that PCMs could effectively improve the thermal environment inside the DTH in summer.Furthermore,the difference of the composite positions between PCMs and the wall affected the improvement effect.The energy release rate of the PCMs assembly system(PAS)varied according to the positions of the PCMs.

Rapid Propagation of Three Herbal Species in a Newly Developed Temporary Immersion System

[ Objeelive] This study aimed to develop a rapid propagation method in a novel temporary immersion bioreactor system （TIS） for herbal plantlets com- pared with solid culture method. [ Method ] Three herbal species, including Dendrobium candidum Wall. Ex IJndl （D. candidum）, Anoectochilus roxburghii （Wall.）Lindl. （A. roxburghii） and Lilium davidii var. unicolor （L. davidii）, were used and tested by TIS against solid culture method. [Result] When the two culture methods were compared, the multiplication rate of D. candidum in TIS was found to be 1 ： 24.71, which was 6.55 times to those of solid culture. The multiplication rate of A. roxburghii was higher than those of the solid culture, but the plantlets was poorer than those of solid culture at the last phase in bioreactor culture, under the culture condition tested. The multiplication rate in TIS ofL. davidii was 1：17.23 whilst the rate was only 1：4.45 on solid culture, resulting larger bulbs than those in the solid culture. [ Conclusion] The TIS designed in our study could provide a potential mean for industrial production of plandets. However, the parameters vary greatly among different species, and it is to be optimized according to plant species.

Study on Efficient Multiplication of Blueberry(Vaccinium corymbosum)Plantlets in Swinging type Temporary Immersion Bioreactors System(S-TIBs)

The swinging type temporary immersion bioreactors system （S-TTBs） is a kind of new and advanced method of tissue culture. The efficient multiplica- tion technology of blueberry （ Vaccinium corymbosum） plantlets in S-TTBs was systematically studied through L9 （3^4） orthogonal experiment with three factors （culture medimn volmne, swing angle, and inoculation density） and completely randomized experiment with two factors （swing frequency and immersion time）. The results showed that the optimal culture parameters were set as follows： the culture medium volume of 250 nil/bottle, the swing angle at 45 ° , and the inoculation density of 60 plantlets/bottle. The optimal swing frequency was 1 time/6 h, and the immersion time was set as 60 s.

Comparative study between Embosphere®and Marine gel®as embolic agents for chemoembolization of hepatocellular carcinoma

BACKGROUND While gelatin sponge particles and calibrated microspheres are commonly used as embolic materials in conventional transarterial chemoembolization(cTACE),direct comparisons between these embolic agents are rare.AIM To compare the efficacy and safety of superselective cTACE using Embosphere®or Marine gel®in patients with early-stage hepatocellular carcinoma(HCC).METHODS This retrospective study included 70 patients with small(<4 cm)HCC who underwent cTACE with Embosphere®(n=33)or Marine gel®(n=37)as the embolic agent at a single center between March 2021 and July 2022.The radiologic images and clinical data were retrospectively reviewed,with an emphasis on tumor response,procedure-related complications,and local tumor recurrence.The primary index tumor was assessed on a 1-mo follow-up image,and local progression-free survival was obtained using the Kaplan-Meier method and was compared by the log-rank test.RESULTS The median tumor size of both groups was 1.5 cm,and 69 patients achieved a complete response one month after cTACE.The cumulative local recurrence rate at 12 mo was 15.5%in the Embosphere®group and 14.4%in the Marine gel®group.The local progression-free survival was not significantly different between the two groups(P=0.83).In the multivariate analysis,high serum alphafetoprotein was the only significant poor prognostic factor for local tumor progression(P=0.01).Postembolization syndrome occurred in 36.4%of the Embosphere®group and 35.1%of the Marine gel®group,and there were no cases of biloma,biliary duct dilation,or liver abscess in either group.CONCLUSION Calibrated gelatin sponge particles(Marine gel®)and calibrated microspheres(Embosphere®)have similar outcomes in terms of tumor response for superselective cTACE of small HCC.

Discussion on Land Use Mode Reform in Coal Opencast Mining

The existing land supply mode of opencast mining is"land requisition first,then transfer",which lacks an effective recovery and withdrawal mechanism,and the reclaimed mining land is difficult to withdraw.According to the regular rules of coal opencast mining and the periodic characteristics of land use,this paper puts forward a new mode of temporary land use for coal opencast mining.It is conducive to im-proving the quality and scale of land use and reclamation utilization of opencast coal mining,and is of great significance for exploring and for-mulating reasonable land use policies for mineral resources development projects.

Theoretical Study on the Temporary Cavity Caused by a High Speed Projectile When Wounding Living Organisms

Analyzes and calculates the process of development of a temporary cavity in the muscle directly after a projectile wounds organisms at a high speed. The muscle is taken as a non compressible Voigt Kelvin viscoelastic fluid model, on the assumption of moving in a radial direction and on spherical symmetry, a theoretical model proposed using the basic equations of the non Newtonian fluid mechanics. The model can well describe the pulsation process of the temporary cavity and changes of pressure in the cavity. The calculated results are in correspondence with the experimental results. The model can be applied in the quantitative analysis of a temporary cavity.