Occurrence Of Leakage Research Articles

Abstract 17501: Initial Experience With a Novel Transcatheter Aortic Valve With Open-Cell Design and Staged Delivery for Challenging Anatomies in a Developing Country

Introduction: Overcoming challenges of transcatheter aortic valve (TAVI) implantation, as coronary access, conduction disturbances and paravalvular leak are goals of device development. We aimed to describe the initial experience with a recently-approved self-expandable bioprosthetic valve, with supravalvular leaflets, a novel open-cell design and 2-stage deployment, in terms of efficacy and safety. Methods: Consecutive patients with aortic valve (AV) stenosis and indication for TAVI with favorable anatomy for self-expandable prostheses were prospectively enrolled in a high-volume center in Belo Horizonte, Brazil. Demographic, clinical and procedural data were collected in an online dedicated database (Coreware, RIBAC). Echocardiographic and CT-angio measurements were performed by 2 experts with proprietary software (Phillips Heart Navigator). Outcomes were prospectively collected. Results: At total, 23 patients eligible for the Acurate Neo/Neo2 TAVI were enrolled, being 15 men, mean age of 82±6 years (69 - 93). Hypertension was present in 20, diabetes in 8 and dyslipidemia in 17, and all were severely symptomatic, being 20 in functional class 3. The STS-score (morbi-mortality) was high: 19±6%. The mean AV area on echo was 0.7±0.2 cm 2 , with mean gradient of 44±15 mmHg. In CT-angio, the median calcium score was 2284, mean annular perimeter was 72±5 mm, and the height of the right and left coronary ostia were 15.2±2.6 mm and 11.9±3.2 mm (<10 mm in 5 cases). All implants were transfemoral (14F) and with general anesthesia, given the high-risk profile. Pre-dilation was performed in 20 (91%) and the TAVI was deployed without repositioning in all cases, with no coronary compromise. Post-dilation was required in 13 cases, being 11 due to mild and 2 due to moderate paravalvular leak: all regressed to trivial. Vascular complications requiring surgery occurred in 1 case, and 1 (4%) patient underwent permanent pacing. All patients were discharged home, with a mean AV gradient of 9.7±3.7 mmHg. Conclusion: The initial experience in Brazil with the novel Acurate Neo/Neo2 prosthesis was promising, with high success rates in challenging anatomical scenarios, and low rates of pacemaker implantation and no occurrence of coronary obstruction or significant leak.

A Rivest–Shamir–Adleman-Based Robust and Effective Three-Factor User Authentication Protocol for Healthcare Use in Wireless Body Area Networks

In healthcare, wireless body area networks (WBANs) can be used to constantly collect patient body data and assist in real-time medical services for patients from physicians. In such security- and privacy-critical systems, the user authentication mechanism can be fundamentally expected to prevent illegal access and privacy leakage occurrences issued by hacker intrusion. Currently, a significant quantity of new WBAN-oriented authentication protocols have been designed to verify user identity and ensure that body data are accessed only with a session key. However, those newly published protocols still unavoidably affect session key security and user privacy due to the lack of forward secrecy, mutual authentication, user anonymity, etc. To solve this problem, this paper designs a robust user authentication protocol. By checking the integrity of the message sent by the other party, the communication entity verifies the other party’s identity validity. Compared with existing protocols, the presented protocol enhances security and privacy while maintaining the efficiency of computation.

An Engineering Geological Appraisal of the Leakage Problem in Dora-1 Earthen Dam, Tigray: Implications for its Stability

Leakage is one of the major problems facing the functionality and sustainability of dams. It occurs through the embankment body, reservoir, foundation, and abutments. This study was conducted to identify the main causes of the leakage problem at the Dora-1 dam, located in the northern part of Ethiopia. It is an earthfill dam with a height of 43.5 m, crest length of 454 m, and reservoir capacity of 4.67 million cubic meters. Part of the embankment body was wet and swampy up to 20 m high from the ground due to leaking water. Geological investigation, laboratory test of the construction materials (including grain size analysis, specific gravity and water absorption, Atterberg limit, free swell, dispersion, permeability, and shear strength), and electrical resistivity investigation were used to identify and pinpoint the possible causes of the leakage problem. Results of the study show that the favorable geological features responsible for the occurrence of leakage include: (a) geological contact between sandstone and moderately to highly weathered basalt unit at the left abutment, (b) the gravelly sand deposit at the central foundation and (c) dyke outcrop at the river course within the reservoir running in the upstream-downstream direction. Results of laboratory tests for clay core show medium to high compressibility, good to poor workability, and semi-pervious to impervious permeability when compacted. The water absorption and the percentage finer of the filter material don’t satisfy the filter criteria and the shell material was found to be semi-previous. The anomalous in the resistivity survey result confirms the situation. Slope stability analysis of the embankment showed instability conditions at full reservoir level. Close follow-up and a downstream stabilization structure, including rock and gravel support, were recommended.
 Construction material; Embankment dam; Site investigations; Ethiopia.

Variations of the hepatic artery and bile duct in patients with pancreaticobiliary maljunction: Impact on postoperative outcomes.

Preoperative comprehension of the anatomical variations of the hepatic artery and bile duct is essential for safe laparoscopic surgery for pancreaticobiliary maljunction (PBM). This study aimed to investigate the impact of anatomical variations of the hepatic artery and bile duct on surgical technique and postoperative complications. We conducted a retrospective review of patients with PBM who underwent laparoscopic surgery at our institution between January 2014 and December 2022 to investigate anatomical variations in the hepatic artery and bile duct, surgical technique, and postoperative complications. We included 112 patients with PBM, with a median age of 4 years (interquartile range, 0-55). Overall, 29 of 112 patients had an aberrant right hepatic artery (ARHA) running ventral to the common hepatic duct (CHD), and they underwent hepaticojejunostomy on the ventral side of the ARHA. Additionally, eight of 112 patients had an aberrant posterior hepatic duct (APHD), which was joined to the CHD in all but one case. The presence of APHD was associated with postoperative bile leak occurrence. Performing hepaticojejunostomy ventral to the ARHA is important to prevent complications. Furthermore, APHD may be a risk factor for postoperative bile leak and requires careful bile duct plasty.

Post-operative cerebrospinal fluid leak: single-continuous versus double-breasted dural repair of myelomeningocele

BackgroundMyelomeningocele is the most common neural tube defect in our environment. Initial surgical management involves untethering and water-tight dural closure. Single-continuous dural repair is more straightforward and faster than the double-breasted repair, even though the latter offers more strength to the reconstructed dura as the repair is in two layers. Preference was given to single-continuous repair even though the two techniques were not compared in terms of post-operative cerebrospinal fluid leak. The aim of this study was to compare the frequency of cerebrospinal fluid (CSF) leak following single-continuous versus double-breasted dural repair of myelomeningocele.Patients and methodsThis was a randomized prospective study that reviewed all patients that presented to Usmanu Danfodiyo University Teaching Hospital (UDUTH) Sokoto, Nigeria, with myelomeningocele who met the inclusion criteria. Fifty-four patients were enrolled into the study randomized into two groups of 27 patients each. Group 1 had single-continuous repair, while group 2 had double-breasted technique. Post-operatively, patients were assessed for post-operative cerebrospinal fluid leak and pseudomeningocele. Data collected were analysed using the statistical package for social sciences version 22.0. The value for significance was set at 0.05.ResultsThe median age at presentation for both groups was 5 months. Both groups showed female preponderance with a female-to-male ratio of 1.3:1 and 1.7:1. Post-operative CSF leak occurred in 2(7.4%) patients in the single-continuous group compared to 3(11.1%) patients in the double-breasted group. Only 1(3.7%) patient in the single-continuous group developed pseudomeningocele and none in the double-breasted.ConclusionDural repair technique of myelomeningocele does not influence the occurrence of post-operative cerebrospinal fluid leak.

Optimization of Cargo Pump Treatment by Hydrochloric Acid (HCl) Loading at MT. Cipta Anyer

The research is motivated by the occurrence of mechanical seal leakage in cargo pumps, which hampers the efficiency of the loading and unloading process. A mechanical seal is a mechanical component used in various industrial applications, such as pumps, to prevent leakage from the rotating shaft and stationary wall.
 The research method used in this thesis is qualitative descriptive, employing the SWOT (Strengths, Weaknesses, Opportunities, and Threats) approach to facilitate data analysis. The data collection methods utilized by the author include observation, interviews, and documentary studies to strengthen the data analysis. The objectives of this research are to identify the causes of damage to the mechanical seal, the handling of mechanical seal damage, and the efforts/methods to prevent mechanical seal damage on MT. Cipta Anyer.
 The conclusion revolves around the causes of mechanical seal damage, the methods to handle such damage and preventive measures. The causes of damage include surface wear connected to the pump shaft, direct contact of hydrochloric acid (HCl) with the cargo pump, and incorrect installation of spare parts for the mechanical seal. Solutions to address the damage involve identifying the specific issues, replacing them with genuine and compliant spare parts, and ensuring proper and procedure-compliant installation. To prevent damage, it is advisable to utilize modern equipment, maintain supervision by engineers, and select experienced crew members.

Anastomotic leak in colorectal cancer surgery: Contribution of gut microbiota and prediction approaches.

To monitor prospectively the occurrence of colorectal anastomotic leakage (CAL) in patients with colon cancer undergoing resectional surgery, characterizing the microbiota in both faeces and mucosal biopsies of anastomosis. In a second stage, we investigated the ability to predict CAL using machine learning models based on clinical data and microbiota composition. A total of 111 patients were included, from whom a faecal sample was obtained, as well as biopsy samples from proximal and distal sites in the healthy margins of the tumour piece. The microorganisms present in the samples were investigated using microbial culture and 16S rDNA massive sequencing. Collagenase and protease production was determined, as well as the presence of genes responsible for expressing enzymes with these activities. Machine learning analyses were developed using clinical and microbiological data. The incidence of CAL was 9.0%, and CAL was associated with collagenase/protease-producing Enterococcus. Significant differences were found in the microbiota composition of proximal and distal biopsy samples, but not in faecal samples, among patients who developed CAL. Clinical predictors of CAL were 5-day C-reactive protein and heart disease, whereas 3-day C-reactive protein and diabetes were negative predictors. Biopsy samples from surgical margins, rather than faecal samples, are the most appropriate samples for exploring the contribution of the intestinal microbiota to CAL. Enterococci are only enriched in the anastomosis after surgery, and their collagenases and proteases are involved in the degradation of the anastomotic scar.

A computer vision approach to improve maintenance automation for thermal power plants lubrication systems

PurposeLubricating oil leakage is a common issue in thermal power plant operation sites, requiring prompt equipment maintenance. The real-time detection of leakage occurrences could avoid disruptive consequences caused by the lack of timely maintenance. Currently, inspection operations are mostly carried out manually, resulting in time-consuming processes prone to health and safety hazards. To overcome such issues, this paper proposes a machine vision-based inspection system aimed at automating the oil leakage detection for improving the maintenance procedures.Design/methodology/approachThe approach aims at developing a novel modular-structured automatic inspection system. The image acquisition module collects digital images along a predefined inspection path using a dual-light (i.e. ultraviolet and blue light) illumination system, deploying the fluorescence of the lubricating oil while suppressing unwanted background noise. The image processing module is designed to detect the oil leakage within the digital images minimizing detection errors. A case study is reported to validate the industrial suitability of the proposed inspection system.FindingsOn-site experimental results demonstrate the capabilities to complete the automatic inspection procedures of the tested industrial equipment by achieving an oil leakage detection accuracy up to 99.13%.Practical implicationsThe proposed inspection system can be adopted in industrial context to detect lubricant leakage ensuring the equipment and the operators safety.Originality/valueThe proposed inspection system adopts a computer vision approach, which deploys the combination of two separate sources of light, to boost the detection capabilities, enabling the application for a variety of particularly hard-to-inspect industrial contexts.

Risk Factors and Management Approaches for Staple Line Leaks Following Sleeve Gastrectomy: A Single-Center Retrospective Study of 402 Patients.

Sleeve gastrectomy (SG) has gained ever-increasing popularity among laparoscopic surgeons involved in bariatric surgery. This single-institution, retrospective cohort study aims to evaluate the prevalence of postoperative staple line leakage (PSLL) after LSG and identify risk factors for its development. We included patient data that underwent LSG at our institution for a span of 17 years-starting in January 2005 and ending in December 2022. We set the investigation of correlations of patient-related factors (age, weight, BMI, smoking status, presence of diabetes mellitus) with the occurrence of postoperative leaks. A total of 402 patients were included in our study. Of them, 26 (6.46%) developed PSLL. In total, 19 (73%) patients underwent percutaneous drainage and 14 patients (53.8%) were treated with intraluminal endoscopic stenting. Finally, five patients (19.2%) were treated with endoscopic clipping of the defect. Operative management was required in only one patient. There were no statistically significant differences in patient age, mean weight at the time of operation, and mean BMI. Abnormal drain amylase levels were associated with earlier detection of PSLL. More consideration needs to be given to producing a consensus regarding the management of PSLL, prioritizing nonoperative management with the combination of percutaneous drainage and endoscopic stenting as the safest and most efficient approach.

Preoperative planning of compact zone trajectory is necessary in treating osteoporotic vertebral compression fracture with endplate involvement: A prospective randomized controlled study.

This prospective randomized controlled study compares the clinical and radiological outcomes between reduction methods with or without compact trabecular bone during percutaneous kyphoplasty in osteoporotic vertebral fractures. The cohort of 100 patients who underwent percutaneous kyphoplasty was randomly divided into groups A (guide pin and balloon introduced directly into fracture site) and B (guide pin and balloon inserted away fracture site). The surgery duration, clinical and radiological outcomes postoperatively and at follow-up, and complications of cement leakage and adjacent fracture were recorded. Patients were followed up for an average of 20.18 months. The clinical outcomes were assessed using the Oswestry disability index and visual analogue scale. The 2 groups had similar patient demographics, surgery times, and volume of cement injected. The method using elevation of the collapsed endplate indirectly had no significant influence on radiological outcomes but significantly decreased the occurrence of intradiscal cement leakage and improved 1- and 12-month postoperative functional outcomes. Elevating and reinforcing the collapsed endplate rather than just filling the defect during percutaneous kyphoplasty is safe and effective. This technique decreased pain and improved function with lower rates of further collapse of the osteoporotic vertebrae compared to defect-filling alone.

Temporary Stomas after Rectal Cancer Resection; Predilection of Being Permanent and Predictors of Complications?

AbstractStomas are essential for colorectal surgery and are widely used not only for selected cases for bowel obstructions but also in rectal cancer operations to divert stool away from low rectal anastomosis. On the other hand, complications with stomas/ stomas reversal are not uncommon. In this study, we aimed at studying the frequency and the predictors of temporary stomas being permanent, and the contributing factors of surgical stoma/stoma closure related complications. In our cohort, only about 40% of the patient closed their initially planned temporary stomas. The occurrence of intestinal leak, wound sepsis, or any type of morbidity with 30 days of operation were significant predictors of permanent stomas. In addition, alarmingly although Hartmann's procedure was uncommon in our practice, only 9% of those who underwent Hartmann's have had it reversed. Moreover, the only factor that significantly increased stoma related complications was having an end colostomy. There was a tendency toward late closure of stomas with median 8.2 months, however early closure did not correlate to complications. In conclusion, further studies are needed to delineate the low rate of stoma closure. Patients who develop postoperative complications, even wound sepsis, would be at a higher risk of living with permanent stomas. Hartmann's procedures are commonly associated with stoma problems, and reluctance to reverse the stomas.

Protocol of a randomised controlled phase II clinical trial investigating PREoperative endoscopic injection of BOTulinum toxin into the sphincter of Oddi to reduce bile leakage after hepatic resection: the PREBOT-II trial

IntroductionBile leakage represents a major cause of morbidity following hepatic resection. Although most patients can be managed non-operatively, this complication requires diagnostics and therapeutic interventions. Preoperative endoscopic injection of botulinum...

Comparison of the clinical effects of lamina replantation and screw fixation after laminectomy in the treatment of intraspinal tumours

IntroductionIntraspinal tumours are common diseases in neurosurgery and spinal surgery. Due to the fact that most of them are benign tumours, surgical resection is usually effective, and it is also the main treatment for these tumours. To maintain the stability of the spine and to reduce the incidence of kyphosis, pedicle screw fixation is required after traditional laminectomy, but there are many complications. In recent years, tumour resection and laminectomy have become increasingly favoured by clinicians. However, the comparison of the clinical effects of lamina complex replantation and pedicle screw fixation after laminectomy in the treatment of intraspinal tumours is still unknown. This paper systematically compared the two methods from many aspects and discussed their advantages and disadvantages to obtain better clinical guidance.Materials and methodsIn this study, a retrospective analysis was conducted to select 58 patients who underwent posterior approach tumour resection in the spinal surgery department of our hospital from January 2017 to January 2020. Among them, 32 patients underwent tumour resection and laminoplasty, and 26 patients underwent tumour resection and screw internal fixation. The age, sex, body mass index (BMI), smoking status, duration of symptoms, operation time, length of hospital stay, postoperative complications, amount of bleeding and other data were summarized, calculated and compared.Results1. The age, sex, BMI, smoking status and symptom duration of the two groups were compared. The abovementioned results were not statistically significant. 2. The operation time, hospital stay, postoperative complications, intraoperative bleeding and adjacent segment degeneration (ASD) were counted and compared between the two groups. There was no significant difference in hospital stay or intraoperative bleeding between the two groups; in addition, the operation time, postoperative complications and incidence of ASD were statistically significant. 3. The visual analog scale (VAS) score, Oswestry Disability Index (ODI) score of thoracic and lumbar spines and Neck Disability Index (NDI) score of cervical spine patients in the two groups were counted, and the preoperative and postoperative data, as well as their changes, were counted and compared between groups and within groups. There was no statistical significance between the two groups; moreover, the postoperative scores were all significantly lower than preoperative in the group. 4. According to the spinal cord function ASIA grade, the preoperative, final follow-up and change values of the two groups were counted, and intragroup and intergroup comparisons were made. There was no significant difference between the two groups; in addition, the scores of the final follow-up were significantly higher than preoperative in the group. 5. The spinal mobility was measured and recorded before the operation and at the final follow-up. There was no significant difference between preoperative and postoperative cervical mobility, and there was no statistical significance observed; furthermore, the range of flexion, extension, rotation and lateral bending of the thoracic and lumbar spines in the screw fixation group was significantly lower than that in the lamina replantation group.ConclusionsLamina replantation can be used as splendid methods for the treatment of Intraspinal tumour. Lamina replantation can reduce the operation time, as well as reduce the occurrence of postoperative cerebrospinal fluid leakage, iatrogenic spinal stenosis, posterior soft tissue adhesion and ASD. These complications are reduced in comparison to the other mode of management and better preserve the mobility of the spine.

Augmentation leak-prevention scheme using an auxiliary classifier in GAN-based image generation

Although a generative adversarial network (GAN) can generate realistic and distinct images, it requires numerous training data. Data augmentation is a popular method of incrementing data using various augmentation operations. However, data augmentation for training GANs can lead to augmentation leaks where unintended distortion effects in augmented images appear in images generated by the GAN. This augmentation leaks occur because the GAN is trained to generate images similar to the training dataset containing augmented images. Although recent studies have revealed that maintaining the invertibility of data augmentation can prevent augmentation leaks, maintaining it for various data augmentation configurations and datasets is challenging. This paper proposes a novel auxiliary neural network called an auxiliary augmentation operation classifier (AAOC) to prevent augmentation leaks. The AAOC learns the classification of augmentation operations during GAN training, guiding the GAN to avoid generating images with unintended distortions. Due to its simple and lightweight architecture, the AAOC does not increase the training time of GANs. Extensive experiments on the three public datasets revealed that the AAOC reduced the occurrence of augmentation leaks by a factor of 30 compared to the basic method and improved image quality by 50% for leak-free images.

Reuse of Nasoseptal Flaps for Endoscopic Endonasal Skull Base Reconstruction.

Introduction Pedicled nasoseptal flap (NSF) placement is a critical component of skull base reconstruction after endoscopic endonasal approaches (EEAs). The effectiveness of NSF reuse has not been thoroughly studied. Prior reports using flaps harvested at one center and reused at another may have technical variability bias. Methods We identified patients who underwent both their initial and NSF-reused surgeries at Weill Cornell Medical College from 2004 to 2022 using a prospective database of all EEAs. Surgical pathology, intraoperative leak grade, use of cerebrospinal fluid (CSF) diversion and skull base coverage were examined. The primary outcome measure was occurrence of CSF leak. Results Fourteen patients (six women, eight men) underwent 14 first time and 14 revision operations with median age of 36.6 years (interquartile range [IQR]: 23.9-61.3) at the time of the NSF reuse. The median interval between the first NSF use and reuse was 70.6 months (IQR: 16.6-87). Eight patients were operated on for pituitary adenoma. Nonadenomas included three craniopharyngiomas and one case each of epidermoid, ependymoma, and chordoma. There were 16 high-flow, 8 low-flow intraoperative leaks, and 4 with no leak. CSF diversion was used in 24 operations. There were three postoperative leaks, one after a first operation and two after NSF reuse. All postoperative CSF leaks, whether first or second operations, occurred in cases with both high-flow intraoperative CSF leak and incomplete NSF coverage ( p = 0.006). Conclusion NSF reuse is effective at preventing postoperative CSF leak. The primary predictors of leak are high-flow intraoperative leak and inadequate defect coverage with NSF, regardless of the operation number.

Influence of Magnetic and Rheological Properties on a Leakage Channel in a Fluid Ring in Ferrofluid Seal

A ferrofluid ring can be compared to a liquid O-ring seal. This liquid ring is used in various applications, such as seals, valves, compressors, dampers, or thrust bearings. Its main advantage is that it maintains tightness and is held in a given place by a magnetic field. One of the main problems is the occurrence of leakage due to pressure differences. This affects the volume of liquid ejected outside the ferrofluid ring region and the value of the leakage itself. The research area of this publication is related to the recognition of how magnetic and rheological properties influence the mechanism of leakage channel formation in a single fluid ring. The purpose was to research basic parameters that characterize the leakage channel, such as the pressure jump value, the cross-sectional area, airflow, and leakage value. The results allow us to understand this problem better and provide insight into the behavior of magnetic particles in a colloid. Studies have shown that an increase in the number of magnetic nanoparticles increases the cross-sectional area of the leakage channel. The opposite effect is observed when a viscosity increase affects fluid resistance to deformation. The study also shows that the share of large particles does not significantly influence the leakage channel. However, the magnetic particles viscous drag affects the ability of particles to react to change.

Bioremediation of Oil-contaminated Sand

The energy demand is set to grow very rapidly and the potential demand for oil around the world is at its highest level. Apart from indigenous oil sources, crude oil is imported by water transportation to fulfill local demand. The occurrence of oil leakage during drilling and transportation in pipelines is a major concern. As a result of this, soil is getting polluted and its geotechnical properties are altered. In this study, the effect of engine oil and diesel contamination on the geotechnical parameters of sea sand has been studied. Further, to enhance the properties of oil-contaminated sand, the bioremediation method was adopted. Sea sand from Ganagalla Peta beach, Andhra Pradesh state, India was taken up for the study. In the laboratory, 4%, 8%, 12% and 16% of engine oil and diesel were used to artificially contaminate the sea sand and geotechnical parameters; namely, compaction, shear strength and permeability, were studied for oil-contaminated sand and compared with those of virgin sea sand. In the next stage, bioremediation of engine oil-and diesel-contaminated sand was carried out to improve the geotechnical properties. It has been found that the geotechnical properties had improved after three days of bioremediation. Fourier transform infrared spectroscopy (FTIR) analysis showed that the contaminated sand is of a lipopeptide nature and showed the presence of carboxyl groups, whereas the IR absorption pattern of the treated sand matches with N-Methyl-N-Vinyl Acetamide. KEYWORDS: Engine-oil contamination, Diesel contamination, Bioremediation, Bacillus subtilis, Geotechnical properties, Compaction characteristics, Shear-strength characteristics, Permeability, FTIR analysis.

Enabling Encrypted Cloud Emails with Data Encryption using Advanced Encryption Techniques

Abstract: Cloud computing offers a flexible and convenient means of exchanging data, with several advantages for both society and individuals. With the widespread usage of cloud emails and frequent reports of large-scale email leakage occurrences, the security property known as forward secrecy has become desirable and necessary for both users and cloud email service providers to increase the security of cloud email systems. Typical techniques of attaining forward secrecy, such as Diffie-Hellman key exchange and forward-secure public-key encryption, have not been extensively authorized and used because they fail to meet the security and practicality requirements of email systems at the same time. We introduce a new cryptographic primitive called forward-secure puncturable identity-based encryption (fs-PIBE) in this paper to capture forward secrecy of encrypted cloud email systems without sacrificing practicability. It allows an email user to perform fine-grained decryption capacity revocation. In the standard model, we design a framework for encrypted cloud email systems and instantiate it with a concrete fs-PIBE structure that has constant ciphertext size and proved security. We enhance the proposed fs-PIBE scheme to provide end-to-end encryption and outsourced decryption, respectively, to improve the security and efficiency of the presented framework.

Anastomotic leak risk factors following colon cancer resection: a systematic review and meta-analysis.

Despite improved surgical techniques, anastomotic leakage is still a serious complication that can occur after colon cancer resection, resulting in increased morbidity and mortality. The aim of this study was to evaluate the risk factors for anastomotic leakage after colon cancer surgery, provide a theoretical basis for reducing its occurrence, and guide the practice of clinicians. A systematic review of PubMed, Ovid, Web of Science and Cochrane Central Register of Controlled Trials databases was conducted by using a combination of subject terms and free words for online searches. The databases were searched from their inception to 31 March 2022, and all cross-sectional, cohort or case‒control studies examining the risk factors for the development of anastomotic fistula after surgery for colon cancer were identified. A total of 2133 articles were searched for this study, and 16 publications were ultimately included, all of which were cohort studies. A total of 115,462 subjects were included, and a total of 3959 cases of anastomotic leakage occurred postoperatively, with an incidence of 3.4%. The odds ratio (OR) and 95% confidence interval (CI) were used for evaluation. Male sex (OR = 1.37, 95% CI: 1.29-1.46, P < 0.00001), BMI (OR = 1.04, 95% CI: 1.00-1.08, P = 0.03), diabetes (OR = 2.80, 95% CI: 1.81-4.33, P < 0.00001), combined lung disease (OR = 1.28, 95% CI: 1.15-1.42, P < 0.00001), anaesthesia ASA score (OR = 1.35, 95% CI: 1.24-1.46, P < 0.00001), ASA class ≥ III (OR = 1.34, 95% CI: 1.22-1.47, P < 0.00001), emergency surgery (OR = 1.31, 95% CI: 1.11-1.55, P = 0.001), open surgery (OR = 1.94, 95% CI: 1.69-2.24, P < 0.00001) and type of surgical resection (OR = 1.34, 95% CI: 1.12-1.61, P = 0.002) are risk factors for anastomotic leakage after colon cancer surgery. There is still a lack of strong evidence on whether age (OR = 1.00, 95% CI: 0.99-1.01, P = 0.36) and cardiovascular disease (OR = 1.18, 95% CI: 0.94-1.47, P = 0.16) are factors influencing the occurrence of anastomotic leakage after colon cancer surgery. Male sex, BMI, obesity, coexisting pulmonary disease, anaesthesia ASA score, emergency surgery, open surgery and type of resection were risk factors for anastomotic leakage after colon cancer surgery. The effect of age and cardiovascular disease on postoperative anastomotic leakage in patients with colon cancer needs further study.

Flow field and convective heat transfer of small-scale Taylor-Couette flow induced by end leakage

More and more researchers have paid attention to Taylor-Couette flow whose axial dimension is much larger than other dimensions. However, featured by the limited axial length of the bearing, its flow field and convective heat transfer between the rotator and the stator are highly conglutinated with the leakage at the end of the clearance. An investigation was conducted on the flow field and convective heat transfer of small-scale Taylor-Couette flow induced by end leakage through means of numerical simulation and experimental measurement. The static pressure and temperature of the stator were captured by a micromanometer and a time-resolved infrared camera, respectively. Large Eddy Simulation (LES) was performed to reveal the instantaneous and mean flow field of the shearing flow. Results show that the flow field and convective heat transfer are tightly associated with the presence of end leakage. As approaching the end of the clearance, the flow is dominated by the axial flow induced by the end leakage, and then a series of Taylor vortices gradually distorts and tilts as moving downstream. Along the angular direction, the maximum and minimum static pressures take place near minimum clearance height, respectively. The static pressure along the angular direction and the axial velocity near the minimum clearance height as well as the Nusselt number increase with increases of the rotational Reynolds number and the eccentricity ratio while decreasing with an increase of the dimensionless clearance height. Both natural convection by buoyancy and forced convection by the shearing flow play a significant role in convective heat transfer. Compared with classic Taylor-Couette flow, the occurrence of leakage decreases the maximum static pressure while increasing the minimum static pressure. The formation and evolution of the Taylor vortex are dominated by the axial flow.