Hot snare polypectomy vs endoscopic mucosal resection using bipolar snare for intermediate size colorectal lesions:Propensity score matching

BACKGROUND Endoscopic resection(ER)with bipolar snare,in which the electric current only passes through the tissue between the device’s two electrodes,is a prominent method used to prevent perforation due to electricity potentially.ER using bipolar snare with or without submucosal injection enabled safe resection of colorectal lesions measuring 10-15 mm in an ex vivo porcine model.ER with bipolar snare is expected to have good treatment outcomes in 10-15 mm colorectal lesions,with high safety even without submucosal injection.However,no clinical reports have compared treatment outcomes with and without submucosal injection.AIM To compare the treatment outcomes of bipolar polypectomy with hot snare polypectomy(HSP)to those with endoscopic mucosal resection(EMR).METHODS In this single-centre retrospective study,we enrolled 10-15 mm nonpedunculated colorectal lesions(565 Lesions in 463 patients)diagnosed as type 2A based on the Japan Narrow-band Imaging Expert Team classification,resected by either HSP or EMR between January 2018 and June 2021 at the National Cancer Center Hospital East.Lesions were divided into HSP and EMR groups,and propensity score matching was performed.In the matched cohort,en bloc and R0 resection rates and adverse events were compared between the two groups.RESULTS Of the 565 lesions in 463 patients,117 lesions each in the HSP and EMR groups were selected after propensity score matching.In the original cohort,there was a significant difference in antithrombotic drug use(P<0.05),lesion size(P<0.01),location(P<0.01),and macroscopic type(P<0.05)between the HSP and EMR groups.In the matched cohort,the en bloc resection rates were comparable between both groups[93.2%(109/117)vs 92.3%(108/117),P=0.81],and there was no significant difference in the R0 resection rate[77.8%(91/117)vs 80.3%(94/117),P=0.64].The incidence of delayed bleeding was similar in both groups[1.7%(2/117)].Perforation occurred in the EMR group[0.9%(1/117)]but not in the HSP group.CONCLUSION Using bipolar snare,ER of nonpedunculated 10-15 mm colorectal lesions may be performed safely and effectively,even without submucosal injection.

Effect of Axial Clearance on the Flow Structure around a Rotating Disk Enclosed in a Cylindrical Casing

Numerical study is performed to investigate the swirling flow around a rotating disk in a cylindrical casing. The disk is supported by a thin driving shaft and it is settled at the center of the casing. The flow develops in the radial clearance between the disk tip and the side wall of the casing as well as in the axial clearance between the disk surfaces and the stationary circular end walls of the casing. Keeping the geometry of the casing and the size of the radial clearance constant, we compared the flows developing in the fields with small, medium and large axial clearances at the Reynolds number from 6000 to 30,000. When the rotation rate of the disk is small, steady Taylor vortices appear in the radial clearance. As the flow is accelerated, several tens of small vortices emerge around the disk tip. The axial position of these small vortices is near the end wall or the axial midplane of the casing. When the small vortices appear on one side of the end walls, the flow is not permanent but transitory, and a polygonal flow with larger several vortices appears. With further increase of the rotation rate, spiral structures emerge. The Reynolds number for the onset of the spiral structures is much smaller than that for the onset of the spiral rolls in rotor-stator disk flows with no radial clearance. The spiral structures in the present study are formed by the disturbances that are driven by a centrifugal instability in the radial clearance and they are penetrated radially inward along the circular end walls of the casing.

Novel serum tumor marker, RCASl, in pancreatic diseases

AIM： As tumor markers for pancreatic carcinoma, carcinoembryonic antigen （CEA） and carbohydrate antigen （CA） 19-9 have been used, but the sensitivity and specificity are not enough for the diagnosis of pancreatic carcinoma. METHODS： A novel serum tumor marker, RCAS1, was compared with two conventional serum tumor markers, CEA （highly specific for pancreatic cancer） and CA 19-9 （highly sensitive for pancreatic cancer）, in 48 patients with pancreatic exocrine tumors. RESULTS： When the diagnosis of benign or malignant conditions was examined by one tumor marker, the sensitivity of RCAS1 alone （55%） was higher than that of CEA alone （27%） and the specificity of RCAS1 alone （92%） was greater than that of CA19-9 alone （78%）. When examined by a combination of two markers, the sensitivity of a combination of RCAS1 and CA19-9 （95%） was superior to those of CA19-9 alone （78%）, RCAS1 alone （55%, P = 0.002）, CEA alone （27%） （P〈0.001）, RCAS1 and CEA （59%） and CA19-9 and CEA （82%）. CONCLUSION： These results suggest that the combination of RCAS1 and CA19-9 is highly sensitive for pancreatic carcinoma.

Literature review of the energy sources for performing laparoscopic colorectal surgery

Laparoscopic surgery for colorectal disease has become widespread as a minimally invasive treatment.This is important because the increasing availability of new devices allows us to perform procedures with a reduced length of surgery and decreased blood loss.We herein report the results of a literature review of energy sources for laparoscopic colorectal surgery,focused especially on 6 studies comparing ultrasonic coagulating shears(UCS) and other instruments.We also describe our laparoscopic dissection techniques using UCS for colorectal cancer.The short-term outcomes of surgeries using UCS and Ligasure for laparoscopiccolorectal surgery were superior to conventional electrosurgery.Some authors have reported that the length of surgery or blood loss when Ligasure was used for laparoscopic colorectal surgery is less than when UCS was used.On the other hand,a recent study demonstrated that there were no significant differences between the short-term outcomes of UCS and Ligasure for laparoscopic colorectal surgery.It is therefore suggested that the choice of technique used should be made according to the surgeon’s preference.We also describe our laparoscopic dissection techniques using UCS(Harmonic ACE) for colorectal cancer with regard to the retroperitoneum dissection,dissection technique,dissection technique around the feeding artery,and various other dissection techniques.We therefore review the outcomes of using various energy sources for laparoscopic colorectal surgery and describe our laparoscopic dissection techniques with UCS(Harmonic ACE) for colorectal cancer.

An Energy Based Dynamic AODV Routing Protocol in Wireless Ad Hoc Networks

In recent years,with the rapid development of the Internet and wireless communication technology,wireless Ad hoc networks have received more attention.Due to the limited transmission range and energy of nodes in Ad hoc networks,it is important to establish a reliable and energy-balanced transmission path in Ad hoc networks.This paper proposes an energy-based dynamic routing protocol based on the existing AODV routing protocol,which has the following two aspects of improvement:(1)In the route discovery process,a node selects a suitable route from the minimum energy consumption route and the energy-balanced route designed in this paper according to a“Mark”bit that representing remaining energy of a node.(2)Based on(1),a route interruption update strategy was proposed to restart the route discovery process when node energy was used excessively.Simulation results demonstrate that compared with AODV and other existing routing protocols,proposed algorithm can reduce network energy consumption and balance node energy,thus extending the network lifetime.

Endoscopic removal of a tablespoon lodged within the duodenum

Here we report the case of a 34-year-old man who underwent endoscopic removal of a tablespoon from the stomach that was lodged within the duodenum.Removal required the use of a two-channel upper endoscope and polypectomy snares.Using the doublesnare technique, the spoon was grasped at the proximal and distal parts of the handle.The doublesnare was first pulled unsuccessfully and then pulled with simultaneous manual abdominal compression of the bulbus from the body surface.Compression was gently applied towards the stomach.As a result, the head of the spoon prolapsed from the bulbus, and was easily retracted from the stomach without any complications.In cases of foreign body lodging within the duodenum, the manual abdominal compression technique may help clinicians pull out the object and avoid surgery.The usefulness of manual compression is dependent on the foreign body's sharpness and the location.

Efficient management and maintenance of ultrasonic nebulizers to prevent microbial contamination

AIM:To seek the cause of Burkholderia cepacia complex(Bcc) infection outbreak and evaluate the efficacy of new methods for nebulizer maintenance. METHODS: We investigated the annual number of Bcc isolates recovered from clinical samples in our hospital between 1999 and 2013. Swab samples were randomly collected for bacterial culture before patient use from 10 each of the two machine types in August 2001; these included 20 samples from each of the following: Drain tubes, operating water chambers, oscillators, and nebulizing chambers. In addition, 10 samples each of nebulizer solutions before and after use were cultured. For environmental investigation, 10 samples were collected from sinks in the nurse stations of the wards where patients positive for Bcc were hospitalized. Numbers of Bcc isolates were compared before and after introduction of new methods for nebulizer maintenance in October 2001. In addition, randomly amplified polymorphic DNA(RAPD) assay was applied to find the genetic divergence of the Bcc isolates obtained from clinical samples and nebulizers. RESULTS: From January 1999 to December 2013, a total of 487 Bcc isolates were obtained from clinical specimens from 181 patients. Notably, 322(66.1%) Bcc isolates were obtained from clinical specimens from 1999 to 2001, including 244(115 patients) from sputum and 34(11 patients) from blood. During this period, 14 isolates were obtained from nebulizer components. Among these, six were derived from nebulizer drain tubes, five from operating water chambers, and one from the oscillator before patient use, and two from nebulizer solutions after patient use. When Bcc was isolated from the nebulizer solution after patient use, Bcc was simultaneously detected in other parts of the nebulizer. Bcc was not isolated from any nebulizer solution before use. RAPD assays revealed similar DNA profiles in isolates obtained from patients and nebulizers. Investigation revealed damaged diaphragms in many nebulizers. The new maintenance methods for nebulizers, including restriction of the usage period, thorough disinfection, and routine check for diaphragm breakage, remarkably reduced Bcc isolation(165 isolates from patients in 12 years and 0 isolate from nebulizers in periodical sampling). In particular, Bcc has been isolated from blood from only one patient since the new methods were introduced.CONCLUSION: Appropriate maintenance of ultrasonic nebulizers is crucial for preventing Bcc contamination of nebulizers and subsequent respiratory tract and blood infections.

日本压缩机、鼓风机和通风机的发展趋势

本文阐述了日本压缩机、鼓风机和通风机等气体透平机械的最新发展趋势;介绍了透平机械与能源的关系、透平机械的技术发展动向及有关的实例。

Correlation of prefrontal activity measured by near-infrared spectroscopy (NIRS) with mood, BDNF genotype and serum BDNF level in healthy individuals

Depression has been known to reduce the prefrontal activity associated with the execution of certain cognitive tasks, although whether a temporarily depressed or anxious mood in healthy individuals affects the prefrontal blood oxygen level during cognitive tasks is unknown. Combining the measurement of prefrontal activity with near-infrared spectroscopy (NIRS) and the two cognitive tasks, namely the letter version of the verbal fluency test (VFT-l) and the Stroop test, we measured the effect of a depressed or anxious mood and gender on the changes in the prefrontal oxygenated hemoglobin (Oxy-Hb) levels during those cognitive tests in healthy individuals. Depressed mood or anxious mood was assessed by the Hospital Anxiety and Depression Scale (HADS). Thereby we aimed to explore the possibility of NIRS measurement for detecting the early subclinical manifestation of major depression. Moreover, we examined the possible relationships between prefrontal activation and the functional Val66Met polymorphisms of the brain derived neurotropic factor (BDNF) gene and serum BDNF level. As a result, the increased prefrontal Oxy-Hb levels during cognitive tasks were significantly correlated with the severity of depressed mood in males. The course of the prefrontal Oxy-Hb increase was different depending on the cognitive tasks, i.e., the VFT-l or the Stroop test, in both genders. Correlations of BDNF genotype and serum BDNF level with the prefrontal Oxy-Hb levels during those cognitive tasks were negative. Our results suggest that the early subclinical manifestation of depressed mood in males might be detected by the NIRS measurement, which is not correlated with the individual properties of BDNF.

Development and Flow Modes of Vertical Taylor-Couette System with Free Surface

We have numerically and experimentally investigated the flow modes of Taylor-Couette system consisting of coaxial two cylinders with vertical axes. The inner cylinder rotates and the outer cylinder and the bottom end of the cylinders remain stationary. The upper top boundary is the free surface of the working liquid between the inner and outer cylinders and it contacts with the air. While this flow appears in fluid machinery and chemical reactors and includes industrial interests, it also contains problems of fluid mechanics, which is about the behavior of the free surface in the rotating field. In this paper, we concretely show the developments of the one cell mode flow and the three cell mode flow at a small aspect ratio. We also represent the bifurcation diagram of the flow at the moderate aspect ratio about 5.5. In the numerical simulation, the flow is rest in the initial state, and the inner cylinder is linearly or suddenly accelerated to attain a flow with a prescribed Reynolds number. When the acceleration of the inner cylinder is high, an imperfect bifurcation occurs and the flows of the secondary modes emerge. At high Reynolds numbers, the flow first has many vortices and then some of the vortices collapse and the final stable flow arises. The loci of the normal five cell mode, the anomalous six cell mode and the secondary seven cell mode are determined.

Experimental Study of Clarification of Vortex Structure by Changing Disk Acceleration Time

Disks with two different dimensions were used to clarify the differences in final vortex structures generated by the change in disk acceleration time. The experiment results and calculated results of vortex structures match when the disk thickness is 20 mm and the Reynolds number is 5000 - 15000. Also, they match when the disk thickness is 30 mm with a Reynolds number from 3000 - 5000 and 9000 - 20000. Even when the size of the disk and the Reynolds number are the same, the final vortex structures can be different due to differences in the disk acceleration time.

Time Constants of the Transition between Onset and Decay Reynolds Numbers for the Appearance of Taylor-Couette Flow

We investigate the onset and the decay of Taylor-Couette flow in finite cylinders, and we report the estimated time scales in the azimuthal section of the flow state transition between the super-critical state and the sub-critical state by fitting the numerical result to the solution of the Stuart-Landau equation. The inner cylinder rotates, and the outer cylinder and both end walls of the cylinders are stationary. Near the end walls of the cylinders, the value of the time scale is small. In the inner region, the radial velocity component has a large time scale near the center of the vortices, while the axial velocity component has a large time scale between the vortices.

Numerical Analysis of Critical Reynolds Number of Wavy Taylor Vortex Flow with Changing Aspect Ratio

Taylor vortex flow is one of the important vortex flows that have been studied since its classic study made by G. I. Taylor in 1923. State of the flow between inner and outer cylinders of a rotating co-axial cylinder transits from Couette flow to Taylor vortex flow and to wavy Taylor vortex flow as the increase of Reynolds number. This study has identified the critical Reynolds number when the flow changes from Taylor vortex flow to wavy Taylor vortex flow. The numerical analysis making use of the attractor in the chaos theory has been used in this identification of the critical Reynolds number. The calculated critical Reynolds numbers of each flow mode are almost identical to the values obtained by the visualization experiment at small aspect ratios. In the region where the aspect ratio is larger than the ratio at the peak critical Reynolds number, the distribution of the Reynolds number is qualitatively similar between the calculated and experimental values.

Experimental Investigation on Diesel Engine Performance Using Nano Air-Bubbles Mixed into Gas Oil

The authors studied diesel combustion improvement with a reformed fuel that mixed nano air-bubbles by using an EMNB （ejector-type micro-nano bubbler）. The EMNB performs adequately and is smaller （20 mm diameter, 34 mm length） than other micro-nano bubblers. It is quite possible to install it in an actual engine. An experiment was performed using a single cylinder engine with a dish or square shaped combustion chamber cavity, and in order to compare the engine speed change, we also used a four cylinder engine with a turbo-charger. The results showed that an improvement in specific fuel consumption, a decrease in the density of the exhaust smoke and an improvement in charging efficiency etc. were achieved by mixing nano bubbles into gas oil under most conditions. It is confirmed that combustion was promoted and improved by a physical and chemical action through mixing the nano bubbles into gas oil.

Numerical Simulation of Flow over an Open Cavity with Self-Sustained Oscillation Mode Switching

Numerical simulations are used to investigate the self-sustained oscillating flows past an open cavity. The two-dimensional incompressible Navier-Stokes equations are solved directly by using the finite difference method for cavities with an upstream laminar boundary layer. A series of simulations are performed for a variety of cavity length-to-depth ratio. The results show the switching among some flow modes including non-oscillation mode, shear layer mode and wake mode. The variation of the Strouhal number is in favorable agreement with available experimental data. The results of flow fields in the cavity reveal the relationship between the cavity shear layer oscillation modes and recirculating vortices in the cavity.

2019世界数据系统亚洲-大洋洲会议纪要

2019年5月7–8日,2019世界数据系统亚大区域会议(World Data System Asia-Oceania Conference 2019)在北京中国科学院地理科学与资源研究所召开。本次会议由国际科学理事会(International Science Council,ISC)世界数据系统(World Data System,WDS)主办,中国科学院地理科学与资源研究所承办,联合承办单位包括世界数据系统正式成员.

Loosening Xyloglucan Accelerates the Enzymatic Degradation of Cellulose in Wood

In order to create trees in which cellulose, the most abundant component in biomass, can be enzymatically hydrolyzed highly for the production of bioethanol, we examined the saccharification of xylem from several transgenic poplars, each overexpressing either xyloglucanase, cellulase, xylanase, or galactanase. The level of cellulose degradation achieved by a cellulase preparation was markedly greater in the xylem overexpressing xyloglucanase and much greater in the xylems overexpressing xylanase and cellulase than in the xylem of the wild-type plant. Although a high degree of degradation occurred in all xylems at all loci, the crystalline region of the cellulose microfibrUs was highly degraded in the xylem overexpressing xyloglucanase. Since the complex between microfibrils and xyloglucans could be one region that is particularly resistant to cellulose degradation, loosening xyloglucan could facilitate the enzymatic hydrolysis of cellulose in wood.

Impact of blanching pretreatment on the drying rate and energy consumption during far-infrared drying of Paprika(Capsicum annuum L.)

We incorporated a superheated steam blanching pretreatment step into a paprika drying process and compared the far-infrared(FIR)drying rates,hardness of the sample surfaces,cell membrane stabilities,and energy consumption of blanched and non-blanched paprika.The average drying rate of blanched paprika samples during FIR drying was higher than that of non-blanched samples.The hardness and cell membrane stability of dried blanched samples were lower than those of non-blanched samples.We estimated that the softening of the sample surfaces and injury to the cell membranes caused the drying rate to increase.The total energy consumption of the FIR drying of paprika was reduced by approximately 30%by introducing the blanching pretreatment.These findings contribute to the development of environmentally friendly FIR drying techniques for paprika.

Effects of silicon addition on optical properties of mould flux with iron oxide and estimation of apparent thermal conductivity of flux

Mould flux with high absorptivity had been obtained in the reduction process of mould flux by silicon.For further utilisation of the mould flux with high absorptivity,the effect of silicon addition on the optical property has been investigated.The synthesised mould flux powder with iron oxide was melted with the addition of silicon powder at 1703 K followed by quenching,thus forming a glassy sample.After 5-30-min reduction,the samples exhibited black opaque colour.Meanwhile,the samples that were reduced for 45-60 min had a bluish grey colour.Many iron-based particles dispersed in the samples were micrometre order in diameter.To determine the effect of iron particles on the optical properties of the sample,extinction,scattering and absorption efficiencies were calculated according to Mie theory.Result showed that both scattering on the iron particle and absorption by iron effectively increase the extinction efficiency in the mould flux.Moreover,the silicon particle in the flux has large scattering efficiency.The black opaque colour is contributed by the existence of silicon and iron particles.The apparent thermal conductivity was calculated for the solid flux.Results also indicated that the entire glassy mould flux would effectively work for mild cooling in a continuous casting process owing to high absorptivity and small thermal conductivity.