Spin measurements for 147Sm+n resonances: Further evidence for non-statistical effects

We have determined the spins J of resonances in the 147Sm(n,gamma) reaction by measuring multiplicities of gamma-ray cascades following neutron capture. Using this technique, we were able to determine J values for all but 14 of the 140 known resonances below En = 1 keV, including 41 firm J assignments for resonances whose spins previously were either unknown or tentative. These new spin assignments, together with previously determined resonance parameters, allowed us to extract separate level spacings and neutron strength functions for J = 3 and 4 resonances. Furthermore, several statistical test of the data indicate that very few resonances of either spin have been missed below En = 700eV. Because a non-statistical effect recently was reported near En = 350 eV from an analysis of 147Sm(n,alpha) data, we divided the data into two regions; 0 < En < 350 eV and 350 < En < 700 eV. Using neutron widths from a previous measurement and published techniques for correcting for missed resonances and for testing whether data are consistent with a Porter-Thomas distribution, we found that the reduced-neutron-width distribution for resonances below 350 eV is consistent with the expected Porter-Thomas distribution. On the other hand, we found that reduced-neutron-width data in the 350 < En < 700 eV region are inconsistent with a Porter-Thomas distribution, but in good agreement with a chi-squared distribution having two or more degrees of freedom. We discuss possible explanations for these observed non-statistical effects and their possible relation to similar effects previously observed in other nuclides.Comment: 40 pages, 13 figures, accepted by Phys. Rev.

Constraints on new interactions from neutron scattering experiments

Constraints for the constants of hypothetical Yukawa-type corrections to the Newtonian gravitational potential are obtained from analysis of neutron scattering experiments. Restrictions are obtained for the interaction range between 10^{-12} and 10^{-7} cm, where Casimir force experiments and atomic force microscopy are not sensitive. Experimental limits are obtained also for non-electromagnetic inverse power law neutron-nucleus potential. Some possibilities are discussed to strengthen these constraints.Comment: 18 pages, 3 figure

Long-term outcomes of a novel method of femoropopliteal bypass

Aim. To analyze the long-term outcomes of a novel method of femoropopliteal bypass (FPB) surgery.Material and methods. This retrospective, open-label, comparative study for the period from October 1, 2016 to December 25, 2019 at the Research Institute of the S. V. Ochapovsky Regional Clinical Hospital №1 (Krasnodar Krai) included 473 patient who underwent FBP. Depending on the type of graft, 5 groups were formed: group 1 (n=266) — reversed vein (great saphenous vein (GSV)); group 2 (n=59) — autologous vein graft (GSV) prepared in situ; group 3 (n=66) — autologous vein graft (GSV) prepared ex situ; group 4 (n=9) — synthetic graft (Jotec, Germany); group 5 (n=73) — upper limb veins. In all cases, Multislice computed tomography angiography revealed an extended (25 cm or more) Trans-Atlantic Inter-Society Consensus (TASC II) class D occlusion of the superficial femoral artery. The longterm follow-up period was 16,6±10,3 months. The technical result of novel FPB technique was achieved using proposed type of an autologous vein graft preparation, in which, after GSV isolation, ex situ valvulotomy was performed, followed by the non-reversed subfascial orthotopic graft passage along the neurovascular bundle by tunneling (Sheath Tunneler Set; Peripheral Vascular, USA) soft tissues. The GSV ex situ was prepared as follows: the GSV was isolated from the saphenofemoral fistula in the distal direction to the required length and removed from the wound. Further, valvulotomy was performed through the proximal end of GSV. Then the valvulotome was removed and a metal cannula was inserted. Through it, a saline solution at indoor temperature with unfractionated heparin was injected into the GSV lumen, simulating blood flow, and the quality of the performed valvulotomy was assessed.Results. In the inhospital postoperative period, all complications developed in groups 1, 2, 3 and 5. However, no significant intergroup statistical differences were found. In the long-term follow-up, there were no significant intergroup differences in the prevalence of deaths (group 1: 4,6%; group 2: 1,7%; group 3: 4,6%; group 4: 0%; group 5: 2,8%; p=0,78), myocardial infarction (group 1: 1,9%; group 2: 0%; group 3: 1,5%; group 4: 0%; group 5: 0%; p=0,62), ischemic stroke (group 1: 0,8%; group 2: 1,7%; group 3: 1,5%; group 4: 0%; group 5: 0%; p=0,8) and shunt thrombosis (group 1: 14,5%; group 2: 19,3%; group 3: 18,5%; group 4: 44,4%; group 5: 19,7%; p=0,16). However, the highest number of limb amputations (group 1: 4,2%; group 2: 5,3%; group 3: 9,2%; group 4: 22,2%; group 5: 1,4%; p=0,03) and the highest rate of composite endpoint (sum of all complications) (group 1: 26,0%; group 2: 28,1%; group 3: 35,4%; group 4: 66,7%; group 5: 23 ,9%; p=0,05) were observed in patients with synthetic prosthesis.Conclusion. FPB with the autologous vein graft ex situ is characterized by a comparable inhospital and long-term outcomes with BPS using the reversed autologous vein and autologous vein in situ. Thus, this surgical technique may become one of the preferable operations for patients with extended occlusion of the superficial femoral artery

New measurement of neutron capture resonances of 209Bi

The neutron capture cross section of Bi209 has been measured at the CERN n TOF facility by employing the pulse-height-weighting technique. Improvements over previous measurements are mainly because of an optimized detection system, which led to a practically negligible neutron sensitivity. Additional experimental sources of systematic error, such as the electronic threshold in the detectors, summing of gamma-rays, internal electron conversion, and the isomeric state in bismuth, have been taken into account. Gamma-ray absorption effects inside the sample have been corrected by employing a nonpolynomial weighting function. Because Bi209 is the last stable isotope in the reaction path of the stellar s-process, the Maxwellian averaged capture cross section is important for the recycling of the reaction flow by alpha-decays. In the relevant stellar range of thermal energies between kT=5 and 8 keV our new capture rate is about 16% higher than the presently accepted value used for nucleosynthesis calculations. At this low temperature an important part of the heavy Pb-Bi isotopes are supposed to be synthesized by the s-process in the He shells of low mass, thermally pulsing asymptotic giant branch stars. With the improved set of cross sections we obtain an s-process fraction of 19(3)% of the solar bismuth abundance, resulting in an r-process residual of 81(3)%. The present (n,gamma) cross-section measurement is also of relevance for the design of accelerator driven systems based on a liquid metal Pb/Bi spallation target.Comment: 10 pages, 5figures, recently published in Phys. Rev.

Прогнозирование развития тромбоза бедренноподколенного шунта в отдаленном периоде наблюдения

Aim of study. The development of a program for predicting thrombosis with subsequent amputation of a limb in the long-term period after femoral-popliteal bypass (FPB).Material and methods. This is a retrospective open comparative study performed from January 10, 2016 to December 25, 2019 at Research Institute – Professor S.V. Ochapovsky Regional Clinical Hospital No. 1 of the Ministry of Health of the Krasnodar Territory, Krasnodar, which included 473 patients who underwent FPB. Depending on the type of bypass, five groups were formed: Group 1 (n=266), reversed vein (great saphenous vein (GSV); Group 2 (n=59), autovenous vein (GSV), prepared in situ; Group 3 (n=66), autovenous vein (GSV), prepared ex situ; Group 4 (n=9) synthetic graft (Jotec, Germany); Group 5 (n=73), veins of the upper limb (forearm and shoulder). In all cases of observation, multislice computed tomography with angiography revealed an extensive (25 cm or more) atherosclerotic occlusive lesion of the superficial femoral artery, corresponding to type D according to the transatlantic consensus (TASC II). The long-term followup period was 16.6±10.3 months.Results. During the hospital postoperative period, all complications developed in groups 1, 2, 3 and 5. However, no significant intergroup statistical differences were found. In the long-term follow-up period, according to the mortality rate (group 1: 4.6%; group 2: 1.7%; group 3: 4.6%; group 4: 0%; group 5: 2.8%; p=0.78), myocardial infarction (group 1: 1.9%; group 2: 0%; group 3: 1.5%; group 4: 0%; group 5: 0%; p=0.62), ischemic stroke (group 1: 0.8%; group 2: 1.7%; group 3: 1.5%; group 4: 0%; group 5: 0%; p=0.8) and bybass thrombosis (group 1: 14.5%; group 2: 19.3%; group 3: 18.5%; group 4: 44.4%; group 5: 19.7%; p=0.16), no significant intergroup differences were identified. However, the largest number of limb amputations (group 1: 4.2%; group 2: 5.3%; group 3: 9.2%; group 4: 22.2%; group 5: 1.4%; p=0.03) and the maximum composite endpoint (sum of all complications) (group 1: 26.0%; group 2: 28.1%; group 3: 35.4%; group 4: 66.7%; group 5: 23 .9%; p=0.05) were observed after the use of a synthetic graft. Using “random forest” analysis, a model and computer program was created that allows, the risk (low, medium, high) of developing bypass thrombosis to be assessed interactively, based on clinical, anamnestic, demographic and perioperative data, with subsequent amputation after FPB in the long-term follow-up period.Conclusions. Revascularization strategy for patients with extended atherosclerotic lesions of the femoropopliteal segment should be determined individually and only by a multidisciplinary council. The conduit of choice for femoral-popliteal bypass surgery is an autovenous graft. Synthetic prostheses can only be used in the absence of the latter. To identify a group of patients with a high risk of thrombosis of the femoral-popliteal bypass and limb amputation in the long-term follow-up period, the created risk stratification program for the development of these complications can be used. Precision supervision of these patients in the postoperative period will make it possible to prevent these adverse events in time.Цель. Разработка программы прогнозирования тромбоза шунта с последующей ампутацией конечности в отдаленном периоде после бедренно-подколенного шунтирования (БПШ).Материал и методы. В настоящее ретроспективное открытое сравнительное исследование за период с 10.01.2016 по 25.12.2019 год в ГБУЗ «Научно-исследовательский институт – Краевая клиническая больница № 1 им. профессора С.В. Очаповского» Министерства здравоохранения Краснодарского края, Краснодар были включены 473 пациента, которым выполняли БПШ. В зависимости от вида шунта сформировано пять групп: 1-я группа (n=266) — реверсированная вена (большая подкожная вена (БПВ)); 2-я группа (n=59) — аутовена (БПВ), подготовленная “in situ”; 3-я группа (n=66) — аутовена (БПВ), подготовленная “ex situ”; 4-я группа (n=9) — синтетический протез (Jotec, Германия); 5-я группа (n=73) — вены верхней конечности (предплечье и плечо). Во всех наблюдениях по данным мультиспиральной компьютерной томографии с ангиографией было выявлено протяженное (25 см и более) атеросклеротическое окклюзионное поражение поверхностной бедренной артерии, соответствующее типу D согласно трансатлантическому консенсусу (TASC II). Отдаленный период наблюдения составил 16,6±10,3 месяца.Результаты. В госпитальном послеоперационном периоде все осложнения развились в 1-й, 2-й, 3-й и 5-й группах. Тем не менее, значимых межгрупповых статистических различий выявлено не было. В отдаленном периоде наблюдения по частоте смертельного исхода (группа 1: 4,6%; группа 2: 1,7%; группа 3: 4,6%; группа 4: 0%; группа 5: 2,8%; р=0,78), инфаркта миокарда (группа 1: 1,9%; группа 2: 0%; группа 3: 1,5%; группа 4: 0%; группа 5: 0%; р=0,62), ишемического инсульта (группа 1: 0,8%; группа 2: 1,7%; группа 3: 1,5%; группа 4: 0%; группа 5: 0%; р=0,8) и тромбоза шунта (группа 1: 14,5%; группа 2: 19,3%; группа 3: 18,5%; группа 4: 44,4%; группа 5: 19,7%; р=0,16) значимых межгрупповых различий не выявлено. Однако наибольшее число ампутаций конечности (группа 1: 4,2%; группа 2: 5,3%; группа 3: 9,2%; группа 4: 22,2%; группа 5: 1,4%; р=0,03) и максимальный показатель комбинированной конечной точки (сумма всех осложнений) (группа 1: 26,0%; группа 2: 28,1%; группа 3: 35,4%; группа 4: 66,7%; группа 5: 23,9%; р=0,05) наблюдались после применения синтетического протеза. С применением анализа «случайного леса» была создана модель и компьютерная программа, позволяющая в интерактивном режиме на основе клинико-анамнестических, демографических и периоперацинных данных оценить риск (низкий, средний, высокий) развития тромбоза шунта с последующей ампутацией после БПШ в отдаленном периоде наблюдения.Заключение. Стратегия реваскуляризации пациентов с протяженным атеросклеротическим поражением бедренно-подколенного сегмента должна определяться персонифицированно и только мультидисциплинарным консилиумом. Кондуитом выбора для бедренно-подколенного шунтирования является аутовенозный трансплантат. Синтетические протезы могут применяться только в отсутствии последнего. Для идентификации когорты больных с высоким риском тромбоза бедренноподколенного шунта и ампутации конечности в отдаленном периоде наблюдения может применяться созданная программа стратификации риска развития данных осложнений. Прецизионная курация этих пациентов в послеоперационном периоде позволит вовремя предотвращать перечисленные неблагоприятные события

Ten-year long-term outcomes of conventional and eversion carotid endarterectomy. Multicenter study

Aim. To analyze the immediate and long-term outcomes of eversion and conventional carotid endarterectomy (CE) with patch angioplasty.Material and methods. For the period from February 1, 2006 to September 1, 2021, the present retrospective multicenter open comparative study included 25106 patients who underwent CE. Depending on the technique of operation, the following groups were formed: group 1 (n=18362) — eversion CE; group 2 (n=6744) — conventional CE with patch angioplasty. The long-term follow-up period was 124,7±53,8 months.Results. In the hospital postoperative period, the groups were comparable in incidence of all complications: lethal outcome (group 1: 0,19%, n=36; group 2: 0,17%, n=12; p=0,89; odds ratio (OR) =1,1; 95% confidence interval (CI) =0,57- 2,11); myocardial infarction (MI) (group 1: 0,15%, n=28; group 2: 0,13%, n=9; p=0,87; OR=1,14; 95% CI=0,53-2,42); stroke (group 1: 0,33%, n=62; group 2: 0,4%, n=27; p=0,53; OR=0,84; 95% CI=0,53-1,32); bleeding with hematoma formation (group 1: 0,39%, n=73; group 2: 0,41%, n=28; p=0,93; OR=0,95; 95% CI=0,61-1,48); internal carotid artery (ICA) thrombosis (group 1: 0,05%, n=11; group 2: 0,07%, n=5, p=0,9; OR=0,8; 95% CI=0,28-2,32). In the long-term follow-up, the groups were comparable only in MI incidence: group 1: 0,56%, n=103; group 2: 0,66%, n=45; p=0,37; OR=0,84; 95% CI=0,59-1,19. All other complications were more frequent after conventional CE with patch angioplasty: all-cause death (group 1: 2,7%, n=492; group 2: 9,1%, n=616; p&lt;0,0001; OR=0,27; 95% CI=0,24-0,3); lethal ischemic stroke (group 1: 1,0%, n=180; group 2: 5,5%, n=371; p&lt;0,0001; OR=0,17; 95% CI=0,14-0,21); non-lethal ischemic stroke (group 1: 0,62%, n=114; group 2: 7,0%, n=472; p&lt;0,0001; OR=0,08; 95% CI=0,06-0,1); ICA restenosis &gt;60%, requiring re-revascularization (group 1: 1,6%, n=296; group 2: 12,6%, n=851; p&lt;0,0001; OR=0,11; 95% CI=0,09-0,12). Thus, the composite endpoint (lethal ischemic stroke + non-lethal ischemic stroke + MI) after conventional CE with patch angioplasty was more than 6 times higher than this parameter of eversion CE: group 1: 2,2%, n=397; group 2: 13,2%, n=888; p&lt;0,0001; OR=0,14; 95% CI=0,12-1,16.Conclusion. Conventional CE with patch angioplasty is not prefer for cerebral revascularization in the presence of hemodynamically significant ICA stenosis due to the high prevalence of deaths, stroke, and ICA restenosis in the long-term follow-up