A Tutorial on Common Differential Equations and Solutions Useful for Modeling Epidemics Like COVID-19: Linear and Non-Linear Compartmentation Models

Purpose: To review some of the basic models, differential equations and solutions, both analytic and numerical, which produce time courses for the fractions of Susceptible (S), Infectious (I) and Recovered (R) fractions of the population during the epidemic and/or endemic conditions. Methods: Two and three-compartment models with analytic solutions to the proposed linear differential equations as well as models based on the non-linear differential equations first proposed by Kermack and McKendrick (KM) [1] a century ago are considered. The equations reviewed include the ability to slide between so-called Susceptible-Infected-Recovered (SIR), Susceptible-Infectious-Susceptible (SIS), Susceptible-Infectious (SI) and Susceptible-Infectious-Recovered-Susceptible (SIRS) models, effectively moving from epidemic to endemic characterizations of infectious disease. Results: Both the linear and KM model yield typical “curves” of the infected fraction being sought “to flatten” with the effects of social distancing/masking efforts and/or pharmaceutical interventions. Demonstrative applications of the solutions to fit real COVID-19 data, including linear and KM SIR fit data from the first 100 days following “lockdown” in the authors’ locale and to the total number of cases in the USA over the course of 1 year with SI and SIS models are provided. Conclusions: COVID-19 took us all by surprise, all wondering how to help. Spreading a basic understanding of some of the mathematics used by epidemiologists to model infectious diseases seemed like a good place to start and served as the primary purpose for this tutorial.

The relationship between compartment models and their stochastic counterparts:A comparative study with examples of the COVID-19 epidemic modeling

Deterministic compartment models(CMs)and stochastic models,including stochastic CMs and agent-based models,are widely utilized in epidemic modeling.However,the relationship between CMs and their corresponding stochastic models is not well understood.The present study aimed to address this gap by conducting a comparative study using the susceptible,exposed,infectious,and recovered(SEIR)model and its extended CMs from the coronavirus disease 2019 modeling literature.We demonstrated the equivalence of the numerical solution of CMs using the Euler scheme and their stochastic counterparts through theoretical analysis and simulations.Based on this equivalence,we proposed an efficient model calibration method that could replicate the exact solution of CMs in the corresponding stochastic models through parameter adjustment.The advancement in calibration techniques enhanced the accuracy of stochastic modeling in capturing the dynamics of epidemics.However,it should be noted that discrete-time stochastic models cannot perfectly reproduce the exact solution of continuous-time CMs.Additionally,we proposed a new stochastic compartment and agent mixed model as an alternative to agent-based models for large-scale population simulations with a limited number of agents.This model offered a balance between computational efficiency and accuracy.The results of this research contributed to the comparison and unification of deterministic CMs and stochastic models in epidemic modeling.Furthermore,the results had implications for the development of hybrid models that integrated the strengths of both frameworks.Overall,the present study has provided valuable epidemic modeling techniques and their practical applications for understanding and controlling the spread of infectious diseases.

Unicompartmental knee arthroplasty vs high tibial osteotomy for knee osteoarthritis:A comparison of clinical and radiological outcomes

BACKGROUND Unicompartmental knee arthroplasty(UKA)and high tibial osteotomy(HTO)are well-established operative interventions in the treatment of knee osteoarthritis.However,which intervention is more beneficial to patients with knee osteoarthritis remains unknown and a topic of much debate.Simultaneously,there is a paucity of research assessing the relationship between radiographic parameters of knee joint alignment and patient-reported clinical outcomes,preoperatively and following HTO or UKA.AIM To compare UKAs and HTOs as interventions for medial-compartment knee osteoarthritis:Examining differences in clinical outcome and investigating the relationship of joint alignment with respect to this.METHODS This longitudinal observational study assessed a total of 42 patients that had undergone UKA(n=23)and HTO(n=19)to treat medial compartment knee osteoarthritis.Patient-reported outcome measures(PROMs)were collected to evaluate clinical outcome.These included two disease-specific(Knee Injury and Osteoarthritis Outcome Score,Oxford Knee Score)and two generic(EQ-5D-5L,Short Form-12)PROMs.The radiographic parameters of knee alignment assessed were the:Hip-knee-ankle angle,mechanical axis deviation and angle of Mikulicz line.RESULTS Statistical analyses demonstrated significant(P<0.001),preoperative to postoperative,improvements in the PROM scores of both groups.There were,however,no significant inter-group differences in the postoperative PROM scores of the UKA and HTO group.Several significant correlations associated a more distolaterally angled Mikulicz line with worse knee function and overall health preoperatively(P<0.05).Postoperatively,two clusters of significant correlations were observed between the disease-specific PROM scores and knee joint alignment parameters(hip-knee-ankle angle,mechanical axis deviation)within the HTO group;yet no such associations were observed within the UKA group.CONCLUSION UKAs and HTOs are both efficacious operations that provide a comparable degree of clinical benefit to patients with medial compartment knee osteoarthritis.Clinical outcome has a limited association with radiographic parameters of knee joint alignment postoperatively;however,a more distolaterally angled Mikulicz line appears associated with worse knee function/health-related quality of life preoperatively.

Should we perform decompressive laparotomy during severe acute pancreatitis with intra-abdominal hypertension below 25 mmHg:Only the gut knows

We suggest that during severe acute pancreatitis(SAP)with intra-abdominal hypertension,practitioners should consider decompressive laparotomy,even with intra-abdominal pressure(IAP)below 25 mmHg.Indeed,in this setting,non-occlusive mesenteric ischemia(NOMI)may occur even with IAP below this cutoff and lead to transmural necrosis if abdominal perfusion pressure is not promptly restored.We report our experience of 18 critically ill patients with SAP having undergone decompressive laparotomy of which one third had NOMI while IAP was mostly below 25 mmHg.

Anatomic location of the first dorsal extensor compartment for surgical De-Quervain’s tenosynovitis release:A cadaveric study

BACKGROUND De-Quervain’s tenosynovitis is a disorder arising from the compression and irritation of the first dorsal extensor compartment of the wrist.Patients who fail conservative treatment modalities are candidates for surgical release.However,risks with surgery include damage to the superficial radial nerve and an incomplete release due to inadequate dissection.Currently,there is a paucity of literature demonstrating the exact anatomic location of the first dorsal extensor compartment in reference to surface anatomy.Thus,this cadaveric study was performed to determine the exact location of the first extensor compartment and to devise a reliable surgical incision to prevent complications.AIM To describe the location of the first dorsal compartment in relation to bony surface landmarks to create replicable surgical incisions.METHODS Six cadaveric forearms,including four left and two right forearm specimens were dissected.Dissections were performed by a single fellowship trained upper extremity orthopaedic surgeon.Distance of the first dorsal compartment from landmarks such as Lister’s tubercle,the wrist crease,and the radial styloid were calculated.Other variables studied included the presence of the superficial radial nerve overlying the first dorsal compartment,additional compartment subsheaths,number of abductor pollicis longus(APL)tendon slips,and the presence of a pseudo-retinaculum.RESULTS Distance from the radial most aspect of the wrist crease to the extensor retinaculum was 5.14 mm±0.80 mm.The distance from Lister’s tubercle to the distal aspect of the extensor retinaculum was 13.37 mm±2.94 mm.Lister’s tubercle to the start of the first dorsal compartment was 18.43 mm±2.01 mm.The radial styloid to the initial aspect of the extensor retinaculum measured 2.98 mm±0.99 mm.The retinaculum length longitudinally on average was 26.82 mm±3.34 mm.Four cadaveric forearms had separate extensor pollicis brevis compartments.The average number of APL tendon slips was three.A pseudo-retinaculum was present in four cadavers.Two cadavers had a superficial radial nerve that crossed over the first dorsal compartment and retinaculum proximally(7.03 mm and 13.36 mm).CONCLUSION An incision that measures 3 mm proximal from the radial styloid,2 cm radial from Lister’s tubercle,and 5 mm proximal from the radial wrist crease will safely place surgeons at the first dorsal compartment.

Carbon concentrations and carbon storage capacity of three old-growth forests in the Sila National Park,Southern Italy

Old-growth forests play a key-role in reducing atmospheric carbon dioxide(CO_(2)) concentrations by storing large CO_(2)amounts in biomass and soil over time.This quantifies the carbon pool into different forest compartments in three Mediterranean old-growth forests of Southern Italy populated by Pinus laricio,Fagus sylvatica and Abies alba.Ecosystem carbon pools have been assessed per compartment,i.e.,living trees,dead wood,litterfall(foliar and woody),roots and 0-20 cm topsoil,combining the whole old-growth forest mass,(i.e.,using tree allometric relationships,deadwood factor conversions,root-to-shoot ratios,litterfall and soil samplings) by the respective organic carbon concentrations.The results show the considerable capacity of these forest ecosystems in storing CO_(2)in biomass and soil,with carbon pool values ranging from 532.2to 596.5 Mg C ha-1.Living trees and 0-20 cm topsoil had larger carbon pool,contributing 53.0 and 22.1%,respectively.In most cases,organic carbon concentration was higher(more than 60%) than the average carbon conversion rate of 50%,especially in living trees,deadwood,and woody litterfall.This study contributes further scientific evidence of the capacity of old-growth forests in storing CO_(2)in their different compartments,with special evidence on tree biomass,litterfall and mineral soil,thereby highlighting the key role of old-growth forests within the challenge of climate change mitigation.

Green manuring facilitates bacterial community dispersal across different compartments of subsequent tobacco

Green manure–crop rotation is a sustainable approach to protect crops against diseases and improve yield.However,the mechanism by which green manuring manipulates the crop-associated microbial community remains to be elucidated.In this study,we explored the horizontal processes of bacterial communities in different compartments of the soil–root interface(bulk soil,rhizosphere soil,rhizoplane and endosphere)of tobacco by performing a field experiment including four rotation practices,namely,tobacco rotated with smooth vetch,ryegrass,radish,and winter fallow(without green manure).Results showed that the co-occurrence networks constructed by adjacent compartments of the soil–root interface with green manuring had more edges than without green manuring,indicating dramatic microbial interactions.Green manuring increased the dispersal-niche continuum index between bulk soil and other compartments,indicating that it facilitated the horizontal dispersal of microbes.For the different green manuring practices,the neutral community model explained 24.6–27.6%of detection frequency for bacteria,and at least one compartment under each practice had a normalized stochasticity ratio higher than the 50%boundary point,suggesting that the deterministic and stochastic processes jointly shaped the tobacco microbiome.In conclusion,green manuring generally facilitates bacterial community dispersal across different compartments and enhances potential interactions among adjacent compartments.This study provides empirical evidence for understanding the microbiome assembly under green manure–crop rotation.

Surgical decompression for the management of abdominal compartment syndrome with severe acute pancreatitis: A narrative review

Intra-abdominal hypertension(IAH)and abdominal compartment syndrome(ACS)play a pivotal role in the pathophysiology of severe acute pancreatitis(SAP)and contribute to new-onset and persistent organ failure.The optimal management of ACS involves a multi-disciplinary approach,from its early recognition to measures aiming at an urgent reduction of intra-abdominal pressure(IAP).A targeted literature search from January 1,2000,to November 30,2022,revealed 20 studies and data was analyzed on the type and country of the study,patient demographics,IAP,type and timing of surgical procedure performed,post-operative wound management,and outcomes of patients with ACS.There was no randomized controlled trial published on the topic.Decom-pressive laparotomy is effective in rapidly reducing IAP(standardized mean difference=2.68,95%confidence interval:1.19-1.47,P<0.001;4 studies).The morbidity and complications of an open abdomen after decompressive laparotomy should be weighed against the inadequately treated but,potentially lethal ACS.Disease-specific patient selection and the role of less-invasive decompressive measures,like subcutaneous linea alba fasciotomy or component separation techniques,is lacking in the 2013 consensus management guidelines by the Abdominal Compartment Society on IAH and ACS.This narrative review focuses on the current evidence regarding surgical decompression techniques for managing ACS in patients with SAP.However,there is a lack of high-quality evidence on patient selection,timing,and modality of surgical decompression.Large prospective trials are needed to identify triggers and effective and safe surgical decompression methods in SAP patients with ACS.

Gouty tenosynovitis with compartment syndrome in the hand: A case report

BACKGROUND Gout is a common type of inflammatory arthritis caused by the deposition of monosodium urate crystals in the joints and surrounding tissues.It typically appears with abrupt and intense pain,redness,and swelling in the affected joint.It frequently targets the lower extremities,such as the big toe.However,rarely,gout can manifest in atypical locations,including the hands,leading to an uncommon presentation known as gouty tenosynovitis.However,it can result in significant morbidity owing to the potential for severe complications,such as myonecrosis and compartment syndrome.CASE SUMMARY An 82-year-old male patient with a history of hypertension,cerebral infarction,Parkinson's disease,and recurrent gout attacks sought medical attention because of progressive pain and swelling in the right hand.Imaging findings revealed forearm swelling,raising concerns of possible tenosynovitis,bursitis,septic arthritis,and compartment syndrome.A fasciotomy was performed to decompress the patient’s hands and forearms.The procedure revealed diffuse tenosynovitis,tophi with a pus-like discharge surrounding the carpal tunnel,and involvement of the flexor and extensor tendon sheaths.However,microbiological investigations,including Gram staining,acid-fast bacilli,tuberculosis,and nontuberculous mycobacteria,yielded negative results.The patient was ultimately diagnosed with a severe gouty attack with compartment syndrome and myonecrosis.Septic arthritis and infectious flexor tenosynovitis were ruled out.Serial debridement and inflammation control were initiated,followed by staged closure with a skin graft.CONCLUSION Septic-like complications can occur in the absence of infection in severe gout attacks with pus-like discharges due to compartment syndrome and myonecrosis.Cultures can be used to differentiate between gouty attacks,septic arthritis,and infectious tenosynovitis.Involvement of the flexor and extensor muscles,as in this case,is rare.This study contributes to the literature by reporting a rare case of successful fasciotomy and serial debridement in an elderly patient with multiple comorbidities.

Assessing reservoir connectivity with pressure/rate surveillance data

Estimating reservoir connectivity is critical for assessing infill-drilling prospects and initiating fluid injection in enhanced oil recovery operations. Several methods have appeared in the literature over decades to meet these business needs, given that all tools, including seismic imaging, have limitations. Besides imaging, geochemical fingerprinting constitutes a powerful tool to gauge the compartmentalization question. However, real-time pressure/rate surveillance data allows assessing interwell connectivity vis-à-vis the overall drainage volume.This study presents a simplified approach to using the reciprocal-productivity index (RPI) vs. the total-material-balance time (tTMB) plot. This tool exhibits the same slope for those wells in the same compartment beyond the start of the boundary-dominated flow (BDF) period. The wells showing different slopes imply that they are in separate drainage volumes. The early-time transient period remains muted to minimize confusion on this Cartesian plot. We validated the proposed tool's efficacy with 2D and 3D models with increased degrees of reservoir complexity, followed by the verification phase with four field examples. The use of other analytical tools complemented our findings.

Finger compartment syndrome due to a high-pressure washer injury:A case report

BACKGROUND Although the finger compartment syndrome is not common,it compresses the neurovascular bundles in a limited space and blocks blood flow to the fingers,causing necrosis of the fingertips.Finger fasciotomy through unilateral or bilateral midline release of the finger can achieve decompression of the finger compartment.Herein,we report a case of the compartment syndrome in a finger injury caused by a high-pressure water flow which is commonly used in car washing stations.CASE SUMMARY A 60-year-old man injured his right middle finger while using a high-pressure washer at a car washing station.The patient complained of severe pain in his middle finger and a 0.2 cm punctured open wound on the volar side of the distal phalangeal joint of the middle finger.The fingertip was pale,numb,and characterized by severe swelling and a limited range of motion.Finger radiography showed that there was no fracture in the finger.Digital decompression was performed through finger fasciotomy by bilateral midline incision.On the second day after surgery,the color of the fingertip returned to pink,swelling was resolved,and the range of motion returned to normal.The sensation of the fingertip was completely restored,and the capillary refill test and pinprick test were positive.CONCLUSION The fingertip compartment syndrome can be caused by a high-pressure water flow damage to the fingers when using high-pressure washers at a car washing station.To avoid finger necrosis,rapid diagnosis of the finger compartment syndrome and appropriate digital decompression are essential to better outcome.

Isolated lateral leg compartment syndrome:A case report

BACKGROUND Acute leg compartment syndrome is a well-known orthopedic emergency associated with potentially devastating consequences if not treated immediately.Multiple compartments are usually involved with a clear history of trauma and classic symptoms and signs.However,isolated lateral leg compartment syndrome is relatively rare and is often misdiagnosed due to the atypical presentation of no trauma and the lack of pathognomonic signs.CASE SUMMARY A 31-year-old male patient presented to our emergency room with excruciating left calf pain and inability to mobilize one-day after participating in a football match despite no clear history of preceding trauma.The patient went to another hospital before presenting to us where he was diagnosed to have a soft tissue injury and was discharged home on simple analgesics.On clinical examination,the left leg showed a tense lateral compartment with severe tenderness.The pain was aggravated by dorsiflexion and ankle inversion.Neurovascular examination of the limb was normal.We suspected a compartment syndrome but as the presentation was atypical and an magnetic resonance imaging(MRI)was readily available in our institution,we immediately performed an MRI and this confirmed a large hematoma in the lateral compartment with a possible partial proximal peroneus longus muscle tear.The patient was taken immediately for an emergency open fasciotomy.The patient is now 18 mo postoperatively having recovered completely and engages fully in sports with no restrictions.CONCLUSION Atypical presentation due to the lack of pathognomonic signs makes the diagnosis of isolated lateral leg compartment syndrome difficult.Pain on passive inversion and dorsiflexion and weak active eversion may be suggested as sensitive signs.

Nursing outcomes of traditional Chinese medicine adjunctive therapy on osteofascial compartment syndrome:a review

The rate of disability due to acute osteofascial compartment syndrome(OCS)is high,and the therapeutic effect of decompressive fasciotomy is not ideal.This paper retrospectively reviews the modern treatment of OCS,including Western medicine and Traditional Chinese medicine(TCM),mainly in the context of the advantages of TCM in the treatment process of decompressive fasciotomy or conservative treatment to the patients who are suffering from OCS.It was found that TCM treatment reduced the levels of serum creatine kinase(CK),lactate dehydrogenase(LDH),and aspartate aminotransferase(AST);it is beneficial to the elimination of swelling and pain.TCM adjunctive therapy promotes patients’postoperative functional recovery and decreases the occurrence of fasciotomy in patients;TCM can relieve tissue hypoxia of compartments and prevent necrosis of muscle and nerve tissue.TCM treatment improves the quality of medical service and ensures the safety of OCS patients.This paper aims to summarize the function of TCM in the treatment of OCS,provide reference for the clinical treatment of OCS,and improve the nursing/medical outcomes of OCS.

Collagen fleece(Tachosil®)for treating testis torsion:A case report

BACKGROUND Testicular torsion is an emergent disease in urology,and there has been discussion of the treatment of testicular torsion.Testicular decompression has been established as a critical treatment for testicular compartment syndrome(TCS),which occurs after detorsion in a patient who is diagnosed with testis torsion.Until now,testicular fasciotomy and incision of tunica albuginea with tunica vaginalis flap(TVF)graft have been suggested for decompression,and some studies about the efficacy of TVF were reported.However,this method is time consuming and needs meticulous technique,so other methods such as orchio-septopexy are suggested.The objective of this clinical case report was to propose new surgical method using collagen fleece(Tachosil®)instead of tunica vagina flap.CASE SUMMARY A 5-year-old boy with scrotal pain visited our hospital 24 h after symptom onset.After history taking,physical examination,and scrotum ultrasonography,he was diagnosed with testis torsion.Emergency surgery was performed after diagnosis.Following the incision of scrotum and fasciotomy,we covered his tunica albuginea with collagen fleece called Tachosil®instead of covering with TVF.CONCLUSION Short-term follow-up showed normal blood flow in testis without a TCS.This is the first case report of using Tachosil®in testicular torsion surgery,and its advantages were already reported in other surgeries like Peyronie’s disease.Our case suggests this new technique is an appropriate method because of its advantages including its cost-effective and time-saving characteristics.The main limitation is the short follow-up,so more studies are needed to provide a high level of evidence about its efficacy and safety.

Synergistic effect of Si and K in improving the growth,ion distribution and partitioning of Lolium perenne L.under saline-alkali stress

The application of Si or K has proven to be beneficial for the growth of plants under saline-alkali stress. However, the synergistic effect of Si and K in improving the growth, ion distribution, and partitioning in Lolium perenne L. under saline-alkali stress remains unclear. In this study, the growth characteristics and ion-selective absorption of ryegrass(Lolium perenne L.) exposed to different levels of saline-alkali stress were evaluated. The growth parameters of ryegrass were significantly improved when Si was applied by itself or coupled with K under low saline-alkali stress. Under a high saline-alkali level, only simultaneous application of Si and K could significantly improve the growth of ryegrass. When Si and K were applied together, the K^(+)/Na^(+) and Ca^(2+)/Na^(+) ratios in root, stem, and leaf of ryegrass were maximally improved as compared to the individual treatments and control. The K^(+) and Ca^(2+) concentrations in the vacuole, cell wall, and organelle of leaf were increased dramatically. This improvement was due to the ability of applied ions to compete with Na^(+), allowing the plant to maintain osmotic potential and leaf water content. The concentration of Na^(+) was significantly reduced when Si and K were applied and mainly concentrated in the soluble fraction and cell wall. The Si concentration in ryegrass increased markedly by the combined application of Si and K, and most of it was accumulated in the cell wall and soluble fraction, which could help in chlorophyll synthesis, reduce membrane injury, and increase water absorption under saline-alkali stress. This study emphasized the advantage of Si and/or K on the growth of plants under different saline-alkaline levels and provided a guide for the production of Si-K fertilizer and its application in saline-alkali soil.

酵母双杂交技术筛选宫颈癌HeLa细胞cDNA文库中FAM92A1-289关联蛋白

目的应用酵母双杂交技术从宫颈癌He La细胞c DNA文库中筛选FAM92A1-289关联蛋白。方法构建酵母双杂交p GBKT7-FAM92A1-289诱饵载体,转化至酵母AH109感受态细胞中。利用Clontech GAL4酵母双杂交系统筛选He La细胞c DNA文库中与FAM92A1-289相互作用的蛋白质,用营养缺陷型培养基和X-a-Gal双重筛选实验进行筛选,对筛选结果进行生物信息学分析,对克隆重复率较高的蛋白进行回转验证,将β-半乳糖苷酶活性阳性的克隆进行测序并分析。结果成功构建酵母双杂交p GBKT7-FAM92A1-289诱饵载体,可在酵母细胞中正常表达FAM92A1-289,且对酵母细胞无毒性,不存在自激活现象。筛选出在SD/-Ade/-His/-Leu/-Trp四缺培养基及含X-a-Gal的SD/-Ade/-His/-Leu/-Trp四缺培养基上均能生长且β-半乳糖苷酶活性阳性的克隆9个。经生物信息学分析发现4种蛋白重复率较高,即增殖细胞核抗原(PCNA)、半乳糖凝集素1(Galectin-1)、内质网高尔基体中间室标记物53(ERGIC-53)、重组人BCL2相关永生基因1(BAG1),并均与FAM92A1-289存在相互作用。结论利用酵母双杂交技术在Hela细胞c DNA文库中成功筛选出与FAM92A1-289相互作用的蛋白,为进一步研究FAM92A1-289的功能提供了新线索。

Nitrogen cycling of atmosphere-plant-soft system in the typical Calamagrostis angustifolia wetland in the Sanjiang Plain,Northeast China

The nitrogen （N） distribution and cycling of atmosphere-plant-soil system in the typical meadow Calamagrostis angustifolia wetland （TMCW） and marsh meadow Calamagrostis angustifolia wetland （MMCW） in the Sanjiang plain were studied by a compartment model. The results showed that the N wet deposition amount was 0.757 gN/（m^2·a）, and total inorganic N （TIN） was the main body （0.640 gN/（m^2·a））. The ammonia volatilization amounts of TMCW and MMCW soils in growing season were 0.635 and 0.687 gN/m^2, and the denitrification gaseous lost amounts were 0.617 and 0.405 gN/m^2, respectively. In plant subsystem, the N was mainly stored in root and litter. Soil organic N was the main N storage of the two plant-soil systems and the proportions of it were 93.98% and 92.16%, respectively. The calculation results of N turnovers among compartments of TMCW and MMCW showed that the uptake amounts of root were 23.02 and 28.18 gN/（m^2·a） and the values of aboveground were 11.31 and 6.08 gN/（m^2·a）, the re-translocation amounts from aboveground to root were 5.96 and 2.70 gN/（m^2·a）, the translocation amounts from aboveground living body to litter were 5.35 and 3.38 gN/（m^2·a）, the translocation amounts from litter to soil were larger than 1.55 and 3.01 gN/（m^2·a）, the translocation amounts from root to soil were 14.90 and 13.17 gN/（m^2·a）, and the soil （0-15 cm） N net mineralization amounts were 1.94 and 0.55 gN/（m^2·a）, respectively. The study of N balance indicated that the two plant-soil systems might be situated in the status of lacking N, and the status might induce the degradation of C. angustifolia wetland.

Open abdomen in gastrointestinal surgery:Which technique is the best for temporary closure during damage control?

AIM To compare the 3 main techniques of temporary closure of the abdominal cavity,vacuum assisted closure(vacuum-assisted closure therapy- VAC),Bogota bag and Barker technique,in damage control surgery.METHODS After systematic review of the literature,33 articles were selected to compare the efficiency of the three procedures.Criteria such as cost,infections,capacity of reconstruction of the abdominal wall,diseases associated with the technique,among others were analyzed.RESULTS The Bogota bag and Barker techniques present as advantage the availability of material and low cost,what is not observed in the VAC procedure.The VAC technique is the most efficient,not only because it reduces the tension on the boarders of the lesion,but also removes stagnant fluids and debris and acts at cellular level increasing cell proliferation and division.Bogota bag presents the higher rates of skin laceration and evisceration,greater need for a stent for draining fluids and wash-ups,higher rates of intestinal adhesion to the abdominal wall.The Barker technique presents lack of efficiency in closing the abdominal wall and difficulty on maintaining pressure on the dressing.The VAC dressing can generate irritation and dermatitis when the drape is applied,in addition to pain,infection and bleeding,as well as toxic shock syndrome,anaerobic sepsis and thrombosis.CONCLUSION The VAC technique,showed to be superior allowing a better control of liquid on the third space,avoiding complications such as fistula with small mortality,low infection rate,and easier capability on primary closure of the abdominal cavity.

Abdominal compartment syndrome:Often overlooked conditions in medical intensive care units

Intra-abdominal hypertension(IAH)and abdominal compartment syndrome are well recognized entities among surgical patients.Nevertheless,a number of prospective and retrospective observational studies have shown that IAH is prevalent in about half of the critically ill patients in the medical intensive care units(ICU)and has been widely recognized as an independent risk factor for mortality.It is alarming to note that many members of the critical care team in medical ICU are not aware of the consequences of untreated IAH and the delay in making the diagnosis leads to increased morbidity and mortality.Frequently it is underdiagnosed and undertreated in this patient population.Elevated intraabdominal pressure decreases the blood flow to the kidneys and other abdominal viscera and also results in reduced cardiac output and difficulties in ventilating the patient because of increased intrathoracic pressure.When intraabdominal hypertension is not promptly recognized and treated,it leads to abdominal compartment syndrome,multiorgan dysfunction syndrome and death.Large volume fluid resuscitation is very common in medical ICU patients presenting with sepsis,shock and other inflammatory conditions like pancreatitis and it is one of the major risk factors for the development of intra-abdominal hypertension.This article presents an overview of the epidemiology,definitions,risk factors,pathophysiology and management of IAH and abdominal compartment syndrome in critically ill medical ICU patients.

Damage control orthopaedics: State of the art

Damage control orthopaedics(DCO) originally consisted of the provisional immobilisation of long bone-mainly femur-fractures in order to achieve the advantages of early treatment and to minimise the risk of complications, such as major pain, fat embolism, clotting, pathological inflammatory response, severe haemorrhage triggering the lethal triad, and the traumatic effects of major surgery on a patient who is already traumatised(the "second hit" effect). In recent years, new locations have been added to the DCO concept, such as injuries to the pelvis, spine and upper limbs. Nonetheless, this concept has not yet been validated in well-designed prospective studies, and much controversy remains.Indeed, some researchers believe the indiscriminate application of DCO might be harmful and produce substantial and unnecessary expense. In this respect, too,normalised parameters associated with the acid-base system have been proposed,under a concept termed early appropriate care, in the view that this would enable patients to receive major surgical procedures in an approach offering the advantages of early total care together with the apparent safety of DCO. This paper discusses the diagnosis and treatment of severely traumatised patients managed in accordance with DCO and highlights the possible drawbacks of this treatment principle.