Nitrogen Metabolism,Carbohydrates and Sucrose in Young Plants of Paricá(Schizolobium amazonicum)Submitted to Different Dosages of Aluminum

The paricá [Schizolobium amazonicum Huber ex Ducke] is a native species of the Amazon region, belonging to the Fabaceae family and is a legume that has great social and economic importance, raw material for the manufacture of wood panels. Heliophilous, with wood of light density and good workability. Amazonian soils are highly weathered and characterized by high acidity, so Al harms the growth and development of sensitive plants, as well as the presence of resistant and/or tolerant plants. Thus, in this work, we sought to study the biochemical metabolism alterations generated in young plants of Schizolobium amazonicum Huber ex Ducke affected at different dosages of AlCl3. The research was conducted in a greenhouse of the Federal Rural University of Amazonia, using pre-scarified paricá seeds, which were seeded in plastic containers of 3.5 L capacity, with black soil fertilized with NPK 15-15-20. On the 8th day after sowing (DAS), thinning of 5 seedlings was performed for 2, and on day 12 of 2 for 1 seedling. The treatments started after 1 month and 22 days of sowing and the plants were collected 24 days later. A completely randomized experimental design (RED) was used, with 6 treatments (Control, Al 15 mg/L-1, Al 30 mg/L-1, Al 45 mg/L-1, Al 60 mg/L-1 and Al 75 mg/L-1) with 5 replicates each (one plant/pot) totaling 30 experimental units. The AlCl3 dosages resulted in considerable changes in the biochemical variables evaluated, especially when the 75 mg·L-1 dosage was applied. The considerable reduction in some variables such as nitrate reductase, glycine betaine and total soluble carbohydrates of these compounds to the applied AlCl3·6H2O dosages, is a way to create resistance mechanisms to try to overcome stress or as a way of showing limitations in the applied dosages. The species was sensitive to the AlCl3 dosages, and resisted only 23 days to the imposed stress. However, it presented defense mechanisms that were able to prolong the physiological activities;since without them, the time of exposure to the stress would possibly be less.

A Survey among Texas Pain Society Physicians Regarding the Types and Dosages of Steroids Utilized Clinically in Epidural Steroid Injectates

Objective: Epidural steroid injections (ESI) are used extensively to treat radicular back pain. This study is designed to evaluate the types and dosages of steroids commonly used and understand prescribing habits of the Texas Pain Society pain management physicians. Method: From April to May 2014, we sent all 270 Texas Pain Society members a questionnaire to complete online. We collected 45 responses. Result: Type of steroid commonly used in injectate: Eighteen (41.9%) phy-sicians reported using methylprednisolone most. Fifteen (34.9%) physicians use triamcinolone, 9 (20.9%) physicians use dexamethasone, 1 (2.3%) uses betamethasone, and 2 skipped this question. Important factors influencing the type of steroid use in injectate: Half of the physicians reported that the location of the ESI was most important (19 responses, 48.7%). Ten (25.6%) reported that the approach of the ESI was most important. Another ten (25.6%) agreed that the potency of the steroid was most important. Dosage of steroid used in injectate: About half of the physicians use a fixed dose of steroid (22, 51.2%) while 21 (48.8%) use a variable dose of steroid. Of those who use a fixed dose of steroid, many use methylprednisolone 80 mg (9, 39.1%). Of those who use a variable dosage of steroid, the most important factor in their determination of the dosage is the patient’s comorbidities (20 responses, 58.8%). The use of depo-steroid in injectate: Thirty-two out of 43 (74.4%) use depo-steroid while 11 out of 43 (25.6%) wouldn’t use depo-steroid. Of those who use depo-steroid, the duration and availability in the epidural space is the most common reason for its use (23, 76.7%). Conclusion: By using a simple questionnaire detailing what types and dosages of steroids are used, compiling a list of best practices can help Texas Pain Society physicians tremendously in the treatment of radicular back pain.

Efficacy and Phytotoxicity Trial of Different Dosages of 4% Nicosulfuron SC on Weeds in Corn Fields

[Objective]The paper was to study efficacy and phytotoxicity of different dosages of 4% nicosulfuron on weeds in corn fields.[Method]With summer corn variety Zhengdan 958commonly used in field production in Hengshui area of Hebei Province of China as the test material,different dosages（1 050,1 500 and 1 950mL/hm2）of corn postemergence herbicide 4% nicosulfuron SC were sprayed during five-leaf stage of corn,and the treatments with water spraying and manual weeding were set as controls.The effects of different dosages of 4% nicosulfuron SC on weed control efficacy and safety and yield of corn were analyzed in order to determine the optimal dosage.[Result]Spraying 4% nicosulfuron SC with dosage of 1 500mL/hm2 during five-leaf stage of corn not only had better control effect against various weeds,but also did not produce phytotoxicity on corn,and the yield of corn was higher.[Conclusion]The study provided scientific information for using 4% nicosulfuron to eradicate weeds in corn fields.

Different dosages of methylprednisolone therapy for acute necrotizing encephalopathy of childhood:a 6-year multicenter retrospective study

To the Editor:Acute necrotizing encephalopathy(ANE)is a rare but often devastating neurologic disorder in children.[1]Hereditary susceptibility and cytokine storm play important roles in ANE pathogenesis,[2,3]but the specific molecular biological mechanism is unclear.

The biological functions and metabolic pathways of valine in swine

Valine is an essential amino acid and a type of branched-chain amino acid. Due to the involvement of branchedchain amino acids in various metabolic pathways, there has been a surge of interests in valine nutrition and its role in animal physiology. In pigs, the interactions between valine and other branched-chain amino acids or aromatic amino acids are complex. In this review, we delve into the interaction mechanism, metabolic pathways, and biological functions of valine. Appropriate valine supplementation not only enhances growth and reproductive performances, but also modulates gut microbiota and immune functions. Based on past observations and interpretations, we provide recommended feed levels of valine for weaned piglets, growing pigs, gilts, lactating sows, barrows and entire males. The summarized valine nutrient requirements for pigs at different stages offer valuable insights for future research and practical applications in animal husbandry.

Diagnosis and therapy of tacrolimus toxicity in a liver transplant recipient during COVID-19 treatment

To the Editor:SARS-CoV-2,the pathogen responsible for the pandemic of coronavirus disease 2019(COVID-19),has had profound impacts on human health,and its antagonist Paxlovid is a commonly used treatment option[1].However,treatment selection for immunosuppressed patients,such as liver recipients,remains uncertain due to potential drug interactions and the risk of immunosuppressant dosage adjustment,which can cause liver injury[2].

Strengthening pharmacotherapy research for COVID-19-induced pulmonary fibrosis

The global spread of severe acute respiratory syndrome coronavirus 2 has resulted in a significant number of individuals developing pulmonary fibrosis(PF),an irreversible lung injury.This condition can manifest within a short inter-val following the onset of pneumonia symptoms,sometimes even within a few days.While lung transplantation is a potentially lifesaving procedure,its limited availability,high costs,intricate surgeries,and risk of immunological rejection present significant drawbacks.The optimal timing of medication administration for coronavirus disease 2019(COVID-19)-induced PF remains controversial.Despite this,it is crucial to explore pharmacotherapy interventions,involving early and preventative treatment as well as pharmacotherapy options for advanced-stage PF.Additionally,studies have demonstrated disparities in anti-fibrotic treatment based on race and gender factors.Genetic mutations may also impact therapeutic efficacy.Enhancing research efforts on pharmacotherapy interventions,while considering relevant pharmacological factors and optimizing the timing and dosage of medication administration,will lead to enhanced,personalized,and fair treatment for individuals impacted by COVID-19-related PF.These measures are crucial in lessening the burden of the disease on healthcare systems and improving patients'quality of life.

Exploration of standard dosage for GnRH antagonist protocol and dosage adjustments after premature luteinizing hormone surge

The gonadotropin-releasing hormone (GnRH) antagonist protocol has emerged as an efficacious alternative to the GnRH agonist protocol for controlled ovarian hyperstimulation (COH) during in vitro fertilization (IVF) cycles, and has been demonstrated applicability in infertile female patients with diverse ovarian responses. While the clinical implementation of the antagonist COH protocol has achieved widespread consensus, opportunities for refinement persist. Therefore, this review article focuses on the advantages and disadvantages of GnRH antagonist protocol, the selection of optimal standard doses, and the strategies for adjusting antagonist doses after the premature luteinizing hormone (LH) surge, aiming to provide more reasonable and scientific recommendations for the application of this scheme.

Dosage Formula in Anesthesia for Manual Intrauterine Aspiration Post-Abortion in Resource-Limited Settings

Setting: Provincial General Reference Hospital of Bukavu, General Reference Hospital of Panzi, General Reference Hospital of Ciriri, General Reference Hospital of Nyatende and Biopharm Hospital Center. Objective: Contribute to the improvement of the anesthetic ECP of patients benefiting from MVA for incomplete abortion, Describe the methodology used for adoption of the dosage formula in Anesthesia for MVA, present the mathematical demonstration leading to the dosage formula in anesthesia for MVA. Materials and Methods: Our study was descriptive by mathematical demonstration of obtaining the equilibrium constant of the dosage formula of bipuvacaine 0.1% and Fentanyl 50 µg% adapted to the weight and specific size of patients treated anesthetically in MVA cases for incomplete abortion. We also carried out an operational research by first determining the interval where our equilibrium constant is included and secondly by means of the ends of the intervals found correlated to the ends of intervals of possible weights and sizes in the being normal human female of childbearing age to arrive at the real numerical value of the equilibrium constant of the BUKAVU Dosage Formula in the case of anesthesia for MVA during the management of incomplete abortions. Results: TWO-STAGE OPERATIONAL RESEARCH: • Determination of the interval where the equilibrium constant x = −0.95 x x by crossing the means between the extremes of volumes of anesthetic drugs giving a satisfactory sensory block without hemodynamic disturbance and the extremes of normal weight and height for women of childbearing age. We ended up with X = 0.37. Conclusion: At the end of our study which had the general objectives of contributing to the improvement of the anesthetic PEC of patients receiving MVA for incomplete abortion and specific objectives of describing the methodology used for adoption of the dosage formula in Anesthesia for MVA and present the mathematical demonstration which resulted in the dosage formula in nesthesia for MVA, it appears that the dosage formula of Bukavu, in case of intrathecal spinal analgesia of MVA for incomplete abortion provides precision on the specificity of the doses of bipuvacaine hypobarre 0.1% and Fentanyl 50 µg% reported to each patient according to her weight and height. Its application could therefore reduce morbidity and mortality and improve patient-practitioner comfort in the event of MVA for incomplete abortion following the dosage precision it provides.

Low dosages:new chemotherapeutic weapons on the battlefield of immune-related disease

Chemotherapeutic drugs eliminate tumor cells at relatively high doses and are considered weapons against tumors in clinics and hospitals.However,despite their ability to induce cellular apoptosis,chemotherapeutic drugs should probably be regarded more as a class of cell regulators than cell killers,if the dosage used and the fact that their targets are involved in basic molecular events are considered.Unfortunately,the regulatory properties of chemotherapeutic drugs are usually hidden or masked by the massive cell death induced by high doses.Recent evidence has begun to suggest that low dosages of chemotherapeutic drugs might profoundly regulate various intracellular aspects of normal cells,especially immune cells.Here,we discuss the immune regulatory roles of three kinds of chemotherapeutic drugs under low-dose conditions and propose low dosages as potential new chemotherapeutic weapons on the battlefield of immune-related disease.

Who may benefit from lower dosages of intravenous tissue plasminogen activator? Results from a cluster data analysis

background The risk of symptomatic intracranial haemorrhage(sICH)after thrombolysis is low but severe.Lower dose of alteplase may reduce the risk of sICH.We aim to identify subsets of patients who could benefit from lower dose of alteplase compared with standard dose.Methods Data from two observational registries were pooled together.A total of 3479 patients who had acute ischaemic stroke were entered into the interaction tree model.The response variable was the rate of sICH per the definition of the National Institute of Neurological Disorders and Stroke Study.Clinical improvement was measured by the National Institutes of Health Stroke Scale(NIHSS)and defined as NIHSS 0 or 1 or an improvement of more than 4 points(within 7 days or at discharge).Rare event logistic regression was performed to analyse the OR of safety outcome.results To optimise the interaction effect between tissue plasminogen activator(tPA)dosage(standard/lower)and patient subgroups,three subgroups based on the severity of stroke were identified:(1)NIHSS≤4,(2)NIHSS between 5 and 14,and(3)NIHSS≥15.The estimated difference of OR of having sICH was 2.71(95%CI 0.80 to 7.69,p=0.10)for mild,0.13(95%CI 0.02 to 0.68,p=0.01)for moderate,and 0.65(95%CI 0.19 to 2.55,p=0.52)for severe,respectively.In addition,patients who had moderate stroke treated with lower dose had comparable efficacy outcome(OR 1.23,95%CI 0.71 to 2.13,p=0.45).Conclusion Our analysis demonstrated that in patients who had moderate stroke,lower doses of alteplase are associated with significant sICH reduction and non-inferior performance in efficacy,compared with those in the standard dose group.

Clinical safety and efficacy of allogenic human adipose mesenchymal stromal cells-derived exosomes in patients with mild to moderate Alzheimer’s disease:a phaseⅠ/Ⅱclinical trial

Background There have been no effective treatments for slowing or reversing Alzheimer’s disease(AD)until now.Growing preclinical evidence,including this study,suggests that mesenchymal stem cells-secreted exosomes(MSCs-Exos)have the potential to cure AD.Aims The first three-arm,drug-intervention,phase I/II clinical trial was conducted to explore the safety and efficacy of allogenic human adipose MSCs-Exos(ahaMSCs-Exos)in patients with mild to moderate AD.Methods The eligible subjects were assigned to one of three dosage groups,intranasally administrated with ahaMSCs-Exos two times per week for 12 weeks,and underwent follow-up visits at weeks 16,24,36 and 48.Results No adverse events were reported.In the medium-dose arm,Alzheimer’s Disease Assessment Scale–Cognitive section(ADAS-cog)scores decreased by 2.33(1.19)and the basic version of Montreal Cognitive Assessment scores increased by 2.38(0.58)at week 12 compared with baseline levels,indicating improved cognitive function.Moreover,the ADAS-cog scores in the medium-dose arm decreased continuously by 3.98 points until week 36.There were no significant differences in altered amyloid or tau deposition among the three arms,but hippocampal volume shrank less in the medium-dose arm to some extent.Conclusions Intranasal administration of ahaMSCs-Exos was safe and well tolerated,and a dose of at least 4×10^(8)particles could be selected for further clinical trials.

Effects of probiotics and its fermented milk on constipation: a systematic review

This study reviewed clinical evidence of probiotics-mediated effects on constipation.Four databases were used in the literature searches,namely Cochrane Library,Embase,Pubmed,and Web of Science.The last retrieval time was March 2021.Collected data were analyzed by Review Manager(version 5.3)and Stata(version 14).The primary search retrieved 8418 articles after removing duplicates.Eventually,26 studies were included in the meta-analysis.Administration of probiotics signifi cantly increased stool frequency(MD:1.15 times/week;95%CI:0.59 to 1.70;P<0.0001),improved bloating(MD:-0.48;95%CI:-0.89 to-0.07;P=0.02),reduced abdominal pain(MD:-0.71;95%CI:-1.25 to-0.16;P=0.01),and improved quality of life(MD:-0.73;95%CI:-1.37 to-0.10;P=0.02).However,the clinical effect of intake of probiotics on stool consistency was non-signifi cant(MD:0.07;95%CI:-0.34 to 0.48;P=0.73).Based on our analysis,probiotic supplements were effective in relieving constipation through symptom improvement.The effectiveness of dosage forms of intervention ranked:capsules>others(tablets,powder)>fermented milk.

Knowledge of radiation exposure associated with common trauma imaging modalities among orthopaedic surgeons,emergency medicine physicians,and general surgeons in the United States

BACKGROUND:Few contemporary studies have assessed physicians’knowledge of radiation exposure associated with common imaging studies,especially in trauma care.The purpose of this study was to assess the knowledge of physicians involved in caring for trauma patients regarding the effective radiation doses of musculoskeletal(MSK)imaging studies routinely utilized in the trauma setting.METHODS:An electronic survey was distributed to United States orthopaedic surgery,general surgery,and emergency medicine(EM)residency programs.Participants were asked to estimate the radiation dose for common imaging modalities of the pelvis,lumbar spine,and lower extremity,in terms of chest X-ray(CXR)equivalents.Physician estimates were compared to the true effective radiation doses.Additionally,participants were asked to report the frequency of discussing radiation risk with patients.RESULTS:A total of 218 physicians completed the survey;102(46.8%)were EM physicians,88(40.4%)wereorthopaedicsurgeons,and28(12.8%)weregeneralsurgeons.Physicians underestimated the effective radiation doses of nearly all imaging modalities,most notably for pelvic computed tomaography(CT)(median 50 CXR estimation vs.162 CXR actual)and lumbar CT(median 50 CXR estimation vs.638 CXR actual).There was no difference between physician specialties regarding estimation accuracy(P=0.133).Physicians who regularly discussed radiation risks with patients more accurately estimated radiation exposure(P=0.007).CONCLUSION:The knowledge among orthopaedic and general surgeons and EM physicians regarding the radiation exposure associated with common MSK trauma imaging is lacking.Further investigation with larger scale studies is warranted,and additional education in this area may improve care.

Sexual dysfunction and associated factors in Thai patients with psychiatric disorders

Background Sexual dysfunction is common among patients with psychiatric disorders but might be under-reported due to Asian sociocultural factors.Recognition of sexual dysfunction and associated factors in this vulnerable population would help clinicians properly assess and manage related conditions.Aims We aimed to examine the prevalence of sexual dysfunction and its associated factors among patients with psychiatric disorders in Thailand.Methods This was a cross-sectional study.We enrolled participants aged 18 and older who visited the psychiatry clinic at King Chulalongkorn Memorial Hospital in Bangkok,Thailand between August 2020 and December 2021.Demographic and clinical data were assessed,and all psychiatric disorders and sexual dysfunctions were diagnosed by clinical interview using the Diagnostic and Statistical Manual of Mental Disorders,Fifth Edition.Statistical analysis was done to explore the association between sexual dysfunction and related factors.Results Sexual dysfunction was diagnosed in 101(50.0%)of the total 202 participants.The mean(standard deviation,SD)age was 30.2(9.0)years,and the majority of patients were men(54.5%),single(81.2%),employed(47.5%)and had a coexisting depressive disorder(48.0%).Multivariable logistic regression analysis showed a significant association between sexual dysfunction and quality of life,unemployment,and the dosage of antidepressants and benzodiazepines.Conclusions The prevalence of sexual dysfunction among this population was relatively high.However,the findings may represent only a portion of affected psychiatric patients for others with sexual dysfunction symptoms but without functional impairment did not meet the diagnostic criteria for sexual dysfunction.Improvement of quality of life and optimising antidepressant/benzodiazepine dosage should be further investigated for promoting sexual function in patients with mental disorders.

Efficacy and safety of sacubitril/valsartan after six months in patients with heart failure with reduced ejection fraction and asymptomatic hypotension

BACKGROUND It is not clear whether sacubitril/valsartan is beneficial for patients with heart failure(HF)with reduced ejec-tion fraction(HFrEF)and low systolic blood pressure(SBP).This study aimed to investigate the efficacy and tolerability of sacu-bitril/valsartan in HFrEF patients with SBP<100 mmHg.METHODS&RESULTS An observational study was conducted on 117 patients,40.2%of whom had SBP<100 mmHg wit-hout symptomatic hypotension,and 59.8%of whom had SBP≥100 mmHg in an optimized HF follow-up management system.At the 6-month follow-up,52.4%of patients with SBP<100 mmHg and 70.0%of those with SBP≥100 mmHg successfully rea-ched the target dosages of sacubitril/valsartan.A reduction in the concentration of N-terminal pro-B-type natriuretic peptide was similar between patients with SBP<100 mmHg and SBP≥100 mmHg(1627.5 pg/mL and 1340.1 pg/mL,respectively;P=0.75).The effect of sacubitril/valsartan on left ventricular ejection fraction was observed in both SBP categories,with a 10.8%increase in patients with SBP<100 mmHg(P<0.001)and a 14.0%increase in patients with SBP≥100 mmHg(P<0.001).The effects of sac-ubitril/valsartan on SBP were statistically significant and inverse across both SBP categories(P=0.001),with an increase of 7.5 mmHg in patients with SBP<100 mmHg and a decrease of 11.5 mmHg in patients with SBP≥100 mmHg.No statistically signi-ficant differences were observed between the two groups in terms of the occurrence of symptomatic hypotension,deteriorating re-nal function,hyperkalemia,angioedema,or stroke.CONCLUSIONS Within an optimized HF follow-up management system,sacubitril/valsartan exhibited excellent tolerability and prompted left ventricular reverse remodeling in patients with HFrEF who presented asymptomatic hypotension.

Telomere-to-telomere pear (Pyrus pyrifolia) reference genome reveals segmental and whole genome duplication driving genome evolution

Previously released pear genomes contain a plethora of gaps and unanchored genetic regions.Here,we report a telomere-to-telomere(T2T)gap-free genome for the red-skinned pear,‘Yunhong No.1’(YH1;Pyrus pyrifolia),which is mainly cultivated in Yunnan Province(southwest China),the pear’s primary region of origin.The YH1 genome is 501.20 Mb long with a contig N50 length of 29.26 Mb.All 17 chromosomes were assembled to the T2T level with 34 characterized telomeres.The 17 centromeres were predicted and mainly consist of centromeric-specific monomers(CEN198)and long terminal repeat(LTR)Gypsy elements(≥74.73%).By filling all unclosed gaps,the integrity of YH1 is markedly improved over previous P.pyrifolia genomes(‘Cuiguan’and‘Nijisseiki’).A total of 1531 segmental duplication(SD)driven duplicated genes were identified and enriched in stress response pathways.Intrachromosomal SDs drove the expansion of disease resistance genes,suggesting the potential of SDs in adaptive pear evolution.A large proportion of duplicated gene pairs exhibit dosage effects or sub-/neo-functionalization,whichmay affect agronomic traits like stone cell content,sugar content,and fruit skin russet.Furthermore,as core regulators of anthocyanin biosynthesis,we found that MYB10 and MYB114 underwent various gene duplication events.Multiple copies of MYB10 and MYB114 displayed obvious dosage effects,indicating role differentiation in the formation of red-skinned pear fruit.In summary,the T2T gap-free pear genome provides invaluable resources for genome evolution and functional genomics.

Completion of 6-mo isoniazid preventive treatment among eligible under six children:A cross-sectional study,Lagos,Nigeria

BACKGROUND Nigeria is one of the thirty high burden countries with significant contribution to the global childhood tuberculosis epidemic.Tuberculosis annual risk for children could be as high as 4%particularly in high tuberculosis(TB)prevalent communities.Isoniazid(INH)Preventive Therapy has been shown to prevent TB incidence but data on its implementation among children are scarce.AIM To determine the completion of INH among under six children that were exposed to adults with smear positive pulmonary TB in Lagos,Nigeria.METHODS This was a hospital-based retrospective cross-sectional review of 265 medical records of eligible children<6 years old enrolled for INH across 32 private hospitals in Lagos,Nigeria.The study took place between July and September 2020.Data was collected on independent variables(age,gender,type of facility,TB screening,dose and weight)and outcome variables(INH outcome and proportion lost to follow up across months 1-6 of INH treatment).RESULTS About 53.8%of the participants were female,95.4%were screened for TB and none was diagnosed of having TB.The participants’age ranged from 1 to 72 mo with a mean of 36.01±19.67 mo,and 40.2%were between the ages of 1-24 mo.Only 155(59.2%)of the 262 participants initiated on INH completed the six-month treatment.Cumulatively,107(41.0%)children were lost to follow-up at the end of the sixth month.Of the cumulative 107 loss to follow-up while on INH,largest drop-offs were reported at the end of month 2,52(49%)followed by 20(19%),17(16%),11(10.2%)and 7(6.5%)at months 3,4,5 and 6 respectively.The analysis showed that there was no significant association between age,gender,type of facility and completion of INH treatment(P>0.005).CONCLUSION This study demonstrated suboptimal INH completion rate among children with only 6 out of 10 children initiated on INH who completed a 6-mo treatment in Lagos,Nigeria.The huge drop-offs in the first 2 mo of INH calls for innovative strategies such as the use of 60-d INH calendar that would facilitate reminder and early engagement of children on INH and their caregivers in care and across the entire period of treatment.

Weak Expansive Soil Physical Properties Modification by Means of a Cement-Jute Fiber

Sixteen groups of comprehensive tests have been conducted to investigate the modifications in the physical properties of a weak expansive soil due to the addition of a cement jute fiber.The tests have been conducted to analyze the liquid plastic limit,the particle distribution and the free expansion rate.The results show that:(1)With an increase in the cement-jute fiber content,the free expansion rate of the modified expansive soil gradually decreases,however,such a rate rebounds when the fiber content exceeds 0.5%and the cement content exceeds 6%.(2)With an increase in the cement percentage,the particle unevenness coefficient(Cu)and curvature coefficient(Cc)of the modified expansive soil tend to grow gradually.The Cc coefficient reaches 1.0 when the cement content is 6%.The unevenness coefficient of 16 soil samples is greater than 5.0,however,the Cu coefficient decreases when the cement content reaches 6%.(3)The plastic limit of soil increases as the cement content is made higher,while the liquid limit and plastic index decrease gradually.When the content of the modified material is 2%+0.1%~2%+0.7%(Cement content+jute fiber content),the change of particle size distribution is most obvious.(4)When the contents of cement and jute fiber are is 6%and 0.5%,respectively,the modification induced in the physical properties of soil samples corresponds to the best case.

Optimization of the Plugging Agent Dosage for High Temperature Salt Profile Control in Heavy Oil Reservoirs

After steam discharge in heavy oil reservoirs,the distribution of temperature,pressure,and permeability in different wells becomes irregular.Flow channels can easily be produced,which affect the sweep efficiency of the oil displacement.Previous studies have shown that the salting-out plugging method can effectively block these channels in high-temperature reservoirs,improve the suction profile,and increase oil production.In the present study,the optimal dosage of the plugging agent is determined taking into account connection transmissibility and inter-well volumes.Together with the connectivity model,a water flooding simulation model is introduced.Moreover,a non-gradient stochastic disturbance algorithm is used to obtain the optimal plugging agent dosage,which provides the basis for the high-temperature salting-out plugging agent adjustment in the field.