6 research outputs found
Influence of antacids operations at histamine concentration in plasma and the risk of malignancies of the colon
Aim; identify communication between antacid operations and malignant tumors of the digestive system. Material and methods. The study was conducted on the 72 Wistar rats. The effect of the stem vagotomy and resection of the distal 2/3 of the stomach and antrumectomy to the concentration of gastrin in plasma were investigated. The effect of intraperitoneal injection of the azoksimetan on the incidence of malignant tumors of the colon was investigated. Re-sults. Increase of the plasma concentration of the gastrin in the postoperative period after stem vagotomy was found. Reduction of the concentration of the gastrin after distal gastrectomy to values close to zero with slight its rise and subsequent stabilization was found. The incidence of colon tumors in animals after stem vagotomy in conjunction with intraperitoneal injection of the chemical carcinogen azoximetan was higher compared to the animals after isolated injection of the azoximetan. The incidence of tumors in animals after resection of the distal 2/3 of the stomach differed not statistically significant from control animals. Conclusion. Vagal denervation of the abdominal cavity leads for significant increase of the concentration of the histamine of the blood plasma. Resection of the 2/3 distal stomach causes a significant reduction in the production of the gastrin. Truncal vagotomy increases the risk of neoplazms of the peritoneal cavity in the rats
Results of application of the PTFE-conduits in the reconstruction of the main veins of the abdominal cavity mesenteric-portal system in locally advanced pancreatic cancer
Aim: study of immediate and long-term results of the surgical treatment of the locally advanced pancreatic cancer with tumor invasion of the main veins of the abdominal cavity. Material and methods. Pancreaticoduodenectomy with resection and plasty of the main veins of the abdominal cavity were performed 315 patients. 143 patients underwent for prosthetics of the main veins at their reconstruction of different vascular prosthesis. Patients have been divided into three groups. Group I (basic) — PTFE-conduits have been used in the reconstruction of the main veins (82 patients). Group II — FLL-conduits have been used in the reconstruction of the main veins (36 patients). Group III — autovenous
conduits have been used in the reconstruction of the main veins (25 patients). Comparison of the duration of operation and its reconstruction stage, the quantity of blood loss, frequency of venous thrombosis in the early postoperative period and long-term patency of the reconstructed veins traced ultrasonic method in a period of 6 months, 1, 2, and 3 years after surgery have been carried. The morbidity, the frequency of the infectious complications, the hospital mortality, the mean postoperative hospital stay, median of survival have been studied after surgery. Results. Application of the PTFE-conduits resulted for decrease of the duration of the reconstruction stage of the operation, as well as the duration of the surgery and the amount of intraoperative blood loss. Decrease of the morbidity, of the postoperative hospital stay and the mortality have been noted in the I group of patients compared to groups II and III patients. Thrombosis of the prosthesis after reconstruction of the veins that led for fatal outcome has been marked in 2 patients (5.5%) in group II of the patients. The long-term patency of vascular PTFE-conduits and reconstructed veins in group 1 has been 100% in all period's observations in the postoperative period. Conclusion. PTFE-conduits are universal plastic material. Application of the PTFE-conduits for the reconstruction of the main veins of the mesenteric-portal system can reduce the duration of the reconstruction vascular stage and the operation as a whole. Applications of the PTFE-conduits reduce the morbidity, the frequency of infectious complications, postoperative hospital-stay, hospital mortality, as well as improved performance patency of the reconstructed vessels
Skewness and kurtosis of mean transverse momentum fluctuations at the LHC energies
The first measurements of skewness and kurtosis of mean transverse momentum (〈pT〉) fluctuations are reported in Pb–Pb collisions at sNN = 5.02 TeV, Xe–Xe collisions at sNN = 5.44 TeV and pp collisions at s=5.02 TeV using the ALICE detector. The measurements are carried out as a function of system size 〈dNch/dη〉|η|<0.51/3, using charged particles with transverse momentum (pT) and pseudorapidity (η), in the range 0.2<pT<3.0 GeV/c and |η|<0.8, respectively. In Pb–Pb and Xe–Xe collisions, positive skewness is observed in the fluctuations of 〈pT〉 for all centralities, which is significantly larger than what would be expected in the scenario of independent particle emission. This positive skewness is considered a crucial consequence of the hydrodynamic evolution of the hot and dense nuclear matter created in heavy-ion collisions. Furthermore, similar observations of positive skewness for minimum bias pp collisions are also reported here. Kurtosis of 〈pT〉 fluctuations is found to be in good agreement with the kurtosis of Gaussian distribution, for most central Pb–Pb collisions. Hydrodynamic model calculations with MUSIC using Monte Carlo Glauber initial conditions are able to explain the measurements of both skewness and kurtosis qualitatively from semicentral to central collisions in Pb–Pb system. Color reconnection mechanism in PYTHIA8 model seems to play a pivotal role in capturing the qualitative behavior of the same measurements in pp collisions
System-size dependence of the hadronic rescattering effect at energies available at the CERN Large Hadron Collider
International audienceThe first measurements of K*(892)0 resonance production as a function of charged-particle multiplicity in Xe-Xe collisions at sNN=5.44 TeV and pp collisions ats=5.02 TeV using the ALICE detector are presented. The resonance is reconstructed at midrapidity (|y| < 0.5) using the hadronic decay channel K*0 →K±π∓. Measurements of transverse-momentum integrated yield, mean transverse-momentum, nuclear modification factor of K*0, and yield ratios of resonance to stable hadron (K*0/K) are compared across different collision systems (pp, p-Pb, Xe-Xe, and Pb-Pb) at similar collision energies to investigate how the production of K*0 resonances depends on the size of the system formed in these collisions. The hadronic rescattering effect is found to be independent of the size of colliding systems and mainly driven by the produced charged-particle multiplicity, which is a proxy of the volume of produced matter at the chemical freeze-out. In addition, the production yields of K*0 in Xe-Xe collisions are utilized to constrain the dependence of the kinetic freeze-out temperature on the system size using the hadron resonance gas–partial chemical equilibrium model
Pseudorapidity dependence of anisotropic flow and its decorrelations using long-range multiparticle correlations in Pb–Pb and Xe–Xe collisions
The pseudorapidity dependence of elliptic (v2), triangular (v3), and quadrangular (v4) flow coefficients of charged particles measured in Pb–Pb collisions at a centre-of-mass energy per nucleon pair of sNN=5.02TeV and in Xe–Xe collisions at sNN=5.44TeV with ALICE at the LHC are presented. The measurements are performed in the pseudorapidity range −3.5<η<5 for various centrality intervals using two- and multi-particle cumulants with the subevent method. The flow probability density function (p.d.f.) is studied with the ratio of flow coefficient v2 calculated with four- and two-particle cumulant, and suggests that the variance of flow p.d.f. is independent of pseudorapidity. The decorrelation of the flow vector in the longitudinal direction is probed using two-particle correlations. The results measured with respect to different reference regions in pseudorapidity exhibit differences, argued to be a result of saturating decorrelation effect above a certain pseudorapidity separation, in contrast to previous publications which assign this observation to non-flow effects. The results are compared to 3+1 dimensional hydrodynamic and the AMPT transport model calculations. Neither of the models is able to simultaneously describe the pseudorapidity dependence of measurements of anisotropic flow and its fluctuations. The results presented in this work highlight shortcomings in our current understanding of initial conditions and subsequent system expansion in the longitudinal direction. Therefore, they provide input for its improvement
Charged-particle production as a function of the relative transverse activity classifier in pp, pPb, and PbPb collisions at the LHC
International audienceMeasurements of charged-particle production in pp, pPb, and PbPb collisions in the toward, away, and transverse regions with the ALICE detector are discussed. These regions are defined event-by-event relative to the azimuthal direction of the charged trigger particle, which is the reconstructed particle with the largest transverse momentum () in the range GeV. The toward and away regions contain the primary and recoil jets, respectively; both regions are accompanied by the underlying event (UE). In contrast, the transverse region perpendicular to the direction of the trigger particle is dominated by the so-called UE dynamics, and includes also contributions from initial- and final-state radiation. The relative transverse activity classifier, , is used to group events according to their UE activity, where is the charged-particle multiplicity per event in the transverse region and is the mean value over the whole analysed sample. The energy dependence of the distributions in pp collisions at , 5.02, 7, and 13 TeV is reported, exploring the Koba-Nielsen-Olesen (KNO) scaling properties of the multiplicity distributions. The first measurements of charged-particle spectra as a function of in the three azimuthal regions in pp, pPb, and PbPb collisions at TeV are also reported. Data are compared with predictions obtained from the event generators PYTHIA 8 and EPOS LHC. This set of measurements is expected to contribute to the understanding of the origin of collective-like effects in small collision systems (pp and pPb)