Causes of epigastric pain and vomiting after laparoscopic-assisted radical right hemicolectomy-superior mesenteric artery syndrome

BACKGROUND Superior mesenteric artery syndrome(SMAS)is a rare condition causing functional obstruction of the third portion of the duodenum.Postoperative SMAS following laparoscopic-assisted radical right hemicolectomy is even less prevalent and can often be unrecognized by radiologists and clinicians.AIM To analyze the clinical features,risk factors,and prevention of SMAS after laparoscopic-assisted radical right hemicolectomy.METHODS We retrospectively analyzed clinical data of 256 patients undergoing laparoscopicassisted radical right hemicolectomy in the Affiliated Hospital of Southwest Medical University from January 2019 to May 2022.The occurrence of SMAS and its countermeasures were evaluated.Among the 256 patients,SMAS was confirmed in six patients(2.3%)by postoperative clinical presentation and imaging features.All six patients were examined by enhanced computed tomography(CT)before and after surgery.Patients who developed SMAS after surgery were used as the experimental group.A simple random sampling method was used to select 20 patients who underwent surgery at the same time but did not develop SMAS and received preoperative abdominal enhanced CT as the control group.The angle and distance between the superior mesenteric artery and abdominal aorta were measured before and after surgery in the experimental group and before surgery in the control group.The preoperative body mass index(BMI)of the experimental group and the control group was calculated.The type of lymphadenectomy and surgical approach in the experimental and control groups were recorded.The differences in angle and distance were compared preoperatively and postoperatively in the experimental group compared.The differences in angle,distance,BMI,type of lymphadenectomy and surgical approach between the experimental and control groups were compared,and the diagnostic efficacy of the significant parameters was assessed using receiver operating characteristic curves.RESULTS In the experimental group,the aortomesenteric angle and distance after surgery were significantly decreased than those before surgery(P<0.05).The aortomesenteric angle,distance and BMI were significantly higher in the control group than in the experimental(P<0.05).There was no significant difference in the type of lymphadenectomy and surgical approach between the two groups(P>0.05).CONCLUSION The small preoperative aortomesenteric angle and distance and low BMI may be important factors for the complication.Over-cleaning of lymph fatty tissues may also be associated with this complication.

Acute interstitial edematous pancreatitis:Findings on non-enhanced MR imaging

AIM： To study the appearances of acute interstitial edematous pancreatitis （IEP） on non-enhanced MR imaging. METHODS： A total of 53 patients with IEP diagnosed by clinical features and laboratory findings were underwent MR imaging. MR imaging sequences included fast spoiled gradient echo （FSPGR） fat saturation axial T1-weighted imaging, gradient echo T1-weighted （in phase）, single shot fast spin echo （SSFSE） T2-weighted, respiratory triggered （R-T） T2-weighted with fat saturation, and MR cholangiopancreatography. Using the MR severity score index, pancreatitis was graded as mild （0-2 points）, moderate （3-6 points） and severe （7-10 points）. RESULTS： Among the 53 patients, IEP was graded as mild in 37 patients and as moderate in 16 patients. Forty-seven of 53 （89%） patients had at least one abnormality on MR images. Pancreas was hypointense relative to liver on FSPGR T1-weighted images in 18.9% of patients, and hyperintense in 25% and 30% on SSFSE T2-weighted and R-T T2-weighted images, respectively. The prevalences of the findings of IEP on R-T T2-weighted images were, respectively, 85% for pancreatic fascial plane, 77% for left renal fascial plane, 55% for peripancreatic fat stranding, 42% for right renal fascial plane, 45% for perivascular fluid, 40% for thickened pancreatic Iobular septum and 25% for peripancreatic fluid, which were markedly higher than those on in-phase or SSFSE T2-weighted images （P 〈 0.001）. CONCLUSION： IEP primarily manifests on non- enhanced MR images as thickened pancreatic fascial plane, left renal fascial plane, peripancreatic fat stranding, and peripancreatic fluid. R-T T2-weighted imaging is more sensitive than in-phase and SSFSE T2- weighted imaging for depicting IER

Efect of high temperature and high strain rate on the dynamic mechanical properties of Fe-30Mn-3Si-4Al TWIP steel

The dynamic mechanical properties of Fe-30Mn-3Si-4A1 twinning induced plasticity （TWIP） steel were studied by the split-Hopkinson pressure bar （SHPB） at temperatures of 298-1073 K and strain rates of 700, 2500, and 5000 s-1. The TWIP steel indicates strain rate hardening effect between 700 and 2500 s-1, but it shows strain rate softening effect between 2500 and 5000 s-1. In addition, the strain rate softening effect enhances with an increase in deformation temperature. After deformation, the microstructures were studied by optical microscopy （OM）. It is shown that the deformation bands become more convergence, a part of which become interwoven with an increase in strain rate, and the dynamic recovery and recrystallization are enhanced with an increase in both temperature and strain rate.

Chronic hepatitis B:Enlarged perihepatic lymph nodes correlated with hepatic histopathology

AIM:To assess the value of enlarged perihepatic lymph nodes in determining hepatic histopathology for chronic hepatitis B(CHB) by magnetic resonance imaging(MRI).METHODS:Sixty-seven patients who were clinically and histologically diagnosed with CHB and 18 healthy subjects without history of liver disease underwent abdominal MRI.Histological diagnosis and hepatic inflammation(grade 0-4) and fibrosis(stage 0-4) were assessed by a simplified system for scoring in chronic viral hepatitis.The major imaging protocol included an axial breath-hold fat suppressed fast spoiled gradient echo T2-weighted imaging(T2WI),axial breath-trigger fat suppressed fast recovery fast spin echo T2WI,and axial and coronal fast imaging employing steady-state acquisition.Perihepatic lymph nodes larger than 5 mm in shortest diameter were noted.RESULTS:The numbers and size indexes of lymphnodes greater than 5 mm in shortest diameter in hepatic hilum suggested inflammatory activity for subjects with grade 2 or higher,with a high accuracy of diagnosis(the area under the curves > 0.9,P < 0.001).The numbers of lymph nodes were 2 or more with a sensitivity of 87.27%,a specificity of 90.00%,an accuracy of 88.24%,a positive predictive value of 94.12%,and a negative predictive value of 79.41% in patients with grade 2 or higher,and the size indexes were no less than 180 mm 2 with a sensitivity of 83.64%,a specificity of 100%,an accuracy of 89.41%,a positive predictive value of 100%,and a negative predictive value of 76.92%.The numbers and size indexes of lymph nodes were not correlated with hepatic fibrosis.The signal intensity indexes of lymph nodes were no significant correlation with histological grading or staging of liver.CONCLUSION:The numbers and size indexes of enlarged perihepatic lymph nodes for patients with CHB suggest inflammatory activity for subjects with grade 2 or higher.

Effect of pediatric tuina on hypothalamic metabolites in young rabbits using liquid chromatography-mass spectrometry

Objective: To investigate the changes in the hypothalamic metabolites of lipopolysaccharide(LPS) febrile young rabbits after the treatment with pediatric tuina.Methods: A total of 30 young rabbits were randomly assigned into three groups: the normal group, the model group, and the tuina group. Both the model group and the tuina group were injected intravenously with LPS. “Six antipyretic manipulations”(pushing Tianmen, pushing Kangong, kneading Taiyang,kneading Erhougaogu, clearing Tianheshui, and pushing Jizhu) were administered 1 h after the LPS injection in the tuina group. The rectal temperatures of the young rabbits were monitored during the experiment to explore the antipyretic effect. Three hours after the injection, the content of interleukin-1β(IL-1β), tumor necrosis factor(TNF)-a, and prostaglandin E;(PGE;) in the serum was detected. In addition, liquid chromatography-mass spectrometry(LC-MS) was used for the hypothalamus metabolomics.Results: Compared with the model group, the rectal temperature of the tuina group was decreased at 2 h and 3 h after the LPS injection(P =.04, P =.03, respectively), and the content of IL-1β, TNF-a, and PGE2was decreased(P =.03, P =.003, and P =.008, respectively). The metabolomics results showed that there were 23 potential biomarkers after the tuina intervention, enriching 27 pathways. Lipid metabolites,especially glycerophospholipids, were a majority of the altered metabolites. The primary metabolic pathways affected by tuina included the arachidonic acid metabolism, the GABAergic synapse, D-glutamine and D-glutamate metabolism, and the glutamatergic synapse.Conclusion: Pediatric tuina reduced the temperature of the febrile rabbits and downregulated the expression of IL-1β, TNF-a, and PGE2, and the antipyretic mechanism may be related to changes in metabolites and metabolic pathways in the hypothalamus.

S^3 LQA: A Link Quality Assessment Metric for WSNs Based on Symbol Error and Received Signal Strength

With the rapid evolution of WSNs technology, it is very important to evaluate link quality quickly and accurately, so that the routing protocols can take relevant strategies in time to keep the entire network working steadily and efficiently. However, the issue of layer is still open to research. To tackle this issue, a improving link quality assessment methods on physical novel link quality assessment metric called S3LQA is proposed, which estimates the link quality of wireless sensor networks by CC2420 wireless radio frequency transceiver principles and free space propagation theory. The metric adopts both complete and incomplete packages to improve the evaluation performance effectively based on IEEE802. 15.4 frame format and DSSS-O- QPSK mechanism. The experimental results show that the proposed method can improve energy cost and achieves hatter real-timin nerformance than traditional counting-based （PRR） link aualitv assessment metric.

Fabrication of kW-level chirped and tilted fiber Bragg gratings and filtering of stimulated Raman scattering in high-power CW oscillators

Suppression of stimulated Raman scattering(SRS)by means of chirped and tilted fiber Bragg gratings(CTFBGs)has become a key topic.However,research on high-power systems is still lacking due to two problems.Firstly,after the inscription,there are a large number of hydroxyl compounds and hydrogen molecules in CTFBGs that cause significant heating due to their strong infrared absorption.Secondly,CTFBGs can couple Stokes light from the core to the cladding and the coating,which causes serious heating in the coating of the CTFBG.Aimed at overcoming these bottlenecks,a process that combines constant-low-temperature and variable-high-temperature annealing is used to reduce the thermal slope of the CTFBG.Also,a segmented-corrosion cladding power stripping technology is used on the CTFBG to remove the Stokes light which is coupled to the cladding,which solves the problem of overheating in the coating of the CTFBG.Thereby,a CTFBG with both a kilowatt-level power-carrying load and the ability to suppress SRS in a fiber laser has been developed.Further,we establish a kW-level CW oscillator to test the CTFBG.Experimental results demonstrate that the power-carrying load of the CTFBG is close to 1 kW,the thermal slope is lower than 0.015 ℃/W,and the SRS suppression ratio is nearly 23 dB.

Effect of Temperature on Microstructure and Deformation Mechanism of Fe-30Mn-3Si-4Al TWIP Steel at Strain Rate of 700 s^(-1)

As twinning-induced plasticity （TWIP） steel is one potential material for shaped charge liner due to the combination of high strength and high plasticity, deformation mechanism at high strain rate and high temperature is required to study. Compression experiments of Fe 30Mn-3Si-4Al TWIP steel were conducted using a Gleeble 1500 thermal simulation machine and a split-Hopkinson pressure bar （SHPB） between 298 and 1073 K at strain rates of 10 3 and 700 s-1 , respectively. Microstructures were observed using optical microscopy （OM） and transmission e- lectron microscopy （TEM）. Results show that flow stress and densities of deformation twins and dislocations de crease with increasing deformation temperature at strain rates of 10 3 and 700 s -1. The stack fault energy （SFE） values （Г） of Fe-30Mn-3Si-4Al TWIP steel at different temperatures were calculated using thermodynamic data. Based on corresponding microstructures, it can he inferred that at 700 s -1 , twinning is the main deformation mecha- nism at 298-573 K for 30 mJ/m2≤Г≤63 mJ/m2 , while dislocation gliding is the main deformation mechanism above 1 073 K for Г≥145 mJ/m2. In addition, with increasing strain rate from 10-3 to 700 s -1 , the SFE range of twinning is enlarged and the SEF value of twinning becomes higher.

Lineage Specifers:New Players in the Induction of Pluripotency

Pluripotency-associated factors and their rivals, lineage specifiers, have long been consid- ered the determining factors for the identity of pluripotent and differentiated cells, respectively. Therefore, factors that are employed for cellular reprogramming in order to induce pluripotency have been identified mainly from embryonic stem cell （ESC）-enriched and pluripotency-associated factors. Recently, lineage specifiers have been identified to play important roles in orchestrating the process of restoring pluripotency. In this review, we summarize the latest discoveries regarding cell fate conversion using pluripotency-associated factors and lineage specifiers. We highlight the value of the ＂seesaw＂ model in defining cellular identity, opening up a novel scenario to consider pluri- potency and lineage specification.

Variable stiffness wires based on magnetorheological liquid metals

Magnetorheological fluid(MRF)has shown its great potential in the development of large mechanical devices,such as dampers,shock absorbers,rotary brakes,clutches,and prosthetic joints.Recently,more research focus has been invested on using MRF to develop soft,stretchable,and miniaturized devices with variable stiffness for realizing functionalities that cannot be achieved using solid smart materials.Here,based on liquid metal magnetoactive slurries(LMMS),a variable stiffness wire with excellent electrical conductivity is demonstrated.Without exposure to a magnetic field,the LMMS wire has an extremely low stiffness,and can be easily stretched while maintaining an excellent electrical conductivity.When applying a magnetic field,the wire becomes much stiffer and can retain its shape even under a load.The combination of properties of flexibility,high electrical conductivity,and variable stiffness of the wire is harnessed to make a flexible gripper that can grasp objects of various shapes.Moreover,by using gallium instead of its liquid metal alloys,the tunable stiffness range of the LMMS wire is signifi-cantly enhanced and can be controlled using both external magnetic fields and temperature-induced phase change.The presented LMMS wire has the potential to be applied in flexible electronics,soft robotics and so on.