128 research outputs found

    Superconducting zinc heat switch for continuous nuclear demagnetization refrigerator and sub-mK experiments

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    We have developed and tested a zinc superconducting heat switch suitable for magnetic refrigeration and calorimetric experiments at sub-millikevin (sub-mK) temperatures. The specific application here is an adiabatic demagnetization refrigerator with two PrNi5_{5} nuclear stages, which can keep a temperature of 0.8 mK continuously, (CNDR) proposed by Toda et al. (J. Phys.: Conf. Ser. 969, 012093 (2018). The switch consists of six high-purity zinc foils of 0.25 mm thick which contact seven silver foils by diffusive bonding. The silver foils are electron beam welded to silver rods that are thermal links to other components. The choice of the thin zinc foils is due to reduce the magnetic latent heat on switching and the contact thermal resistance under a constraint on the aspect ratio of the switch element. The measured thermal conductance of the whole switch assembly in the normal (closed) state, KclosedK_\mathrm{closed}, agrees very well down to 70 mK with the value estimated from the residual electrical resistance 114 nΩ\mathrm{\Omega} at 4.2 K, indicating the validity of the Wiedemann-Franz law for zinc. The measured thermal conductance in the superconducting (open) state, KopenK_\mathrm{open}, follows nicely the prediction from the BCS theory and approaches the value expected from the Debye model for thermal phonons near 70 mK. The heat leak through the HSW from the higher temperature side of 30 mK at most is estimated to be less than 0.5 nW, which is much lower than the expected cooling power (=10= 10 nW) of the CNDR at 0.8 mK . The switching ratio Kclosed/KopenK_\mathrm{closed}/K_\mathrm{open} extrapolated to 30 mK, is as high as 5×104\times10^4. All the test results meet the requirements for the CNDR and, for example, heat capacity measurements at sub-mK.Comment: 15 pages, 5 figure

    Isoform D of vascular endothelial growth factor in systemic capillary leak syndrome : a case report

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    Background: Systemic capillary leak syndrome is a rare condition characterized by episodic attacks of hypovolemia due to systemic capillary hyperpermeability, which results in profound hypotension and edema. Although the implication of vascular endothelial growth factor, angiopoietin-2, and C-X-C motif chemokine 10 has been suggested, the pathogenesis of systemic capillary leak syndrome remains unclear. In this report, we describe a case of systemic capillary leak syndrome in which serum isoform D of vascular endothelial growth factor was elevated. To the best of our knowledge, this is the first reported case of systemic capillary leak syndrome in which isoform D of vascular endothelial growth factor is suggested as the plausible biomarker. Case presentation: A 41-year-old Japanese man was transferred to our emergency department. He was hypotensive, tachycardic, and edematous over the trunk and all four limbs. He received aggressive intravenous fluid therapy and underwent fasciotomy of the right forearm to prevent muscle necrosis. A diagnosis of systemic capillary leak syndrome was suspected. The presence of serum monoclonal immunoglobulin G and κ light chain supported this diagnosis. Prevention of hypotensive crises was unsuccessfully attempted with theophylline, intravenous immunoglobulin, high-dose dexamethasone, bortezomib, melphalan, and prednisolone; however, the patient’s attacks dramatically disappeared after the introduction of thalidomide. The serum of the patient was stored soon after the onset of hypotensive crisis and analyzed to profile possible mediators responsible for the capillary leak. The concentration of vascular endothelial growth factor, angiopoietin-2, and C-X-C motif chemokine 10 were all within normal ranges. Meanwhile, we found that isoform D of vascular endothelial growth factor was elevated, which was normalized after the introduction of thalidomide. Conclusions: In our patient, isoform D of vascular endothelial growth factor (instead of vascular endothelial growth factor) may have been a causative factor of hypotensive crises, since isoform D contributes to vascular endothelial growth factor receptor-2 signaling, which is the major mediator of the permeability-enhancing effects of vascular endothelial growth factor. We suggest the measurement of isoform D of vascular endothelial growth factor in patients with systemic capillary leak syndrome in whose serum vascular endothelial growth factor is not elevated

    Case Report: Retropancreatic fascia hernia protruding into the thoracic cavity through a Bochdalek hernia

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    Retropancreatic fascia hernia is a novel internal hernia originating from the retropancreatic fascial defect, which subsequently expands toward the dorsal aspect of the pancreatic body and migrates into the retroperitoneal space. We encountered a rare case of concomitant retropancreatic fascia and Bochdalek hernias. Here, we describe the imaging characteristics of this hernia type and its surgical strategies

    Case report: Laparoscopic gastrojejunostomy for duodenal atresia with situs inversus and preduodenal portal vein: a report of two cases

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    Congenital duodenal atresia with situs inversus is occasionally accompanied by a preduodenal portal vein (PDPV), which is incidentally diagnosed during surgery. Duodenoduodenostomy is the most common and effective treatment. However, some patients require other anastomoses. Here, we present two cases of laparoscopic gastrojejunostomy for congenital duodenal atresia with situs inversus and PDPV and describe the reason for selecting gastrojejunostomy. The optimal surgical strategy is patient specific and should be determined based on the patient's general and physical condition

    Laparoscopic restorative proctocolectomy with ileal-J-pouch anal canal anastomosis without diverting ileostomy for total colonic and extensive aganglionosis is safe and feasible with combined Lugol's iodine staining technique and indocyanine green fluorescence angiography

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    BackgroundWe present the surgical technique and outcomes of reduced-port laparoscopic restorative proctocolectomy with ileal-J-pouch anal canal anastomosis (IPACA) without diverting ileostomy for total colonic and extensive aganglionosis (TCA+).MethodsWe retrospectively reviewed TCA+ cases between 2014 and 2022. Preoperative ileostomy was performed when transanal bowel irrigation was ineffective. Radical surgery for TCA+ was performed at approximately 6 kg. The surgery was performed using laparoscopy through a multi-channel trocar with or without an additional 3-mm trocar and IPACA reconstruction with indocyanine green fluorescence angiography (ICG) to assess anastomotic perfusion and Lugol's iodine staining to visualize the surgical anal canal.ResultsTen patients with TCA+ were included. Ileostomy was performed in seven cases. The median operation time and blood loss were 274.5 min and 20 ml, respectively. No significant postoperative complications were found. All patients experienced frequent liquid stools and perianal excoriation in the early postoperative period, requiring anti-flatulence or codeine. The median follow-up period was 3.5 years. Three patients required irrigation management 1 year postoperatively, and the others defecated a median of 3.5 times per day. The median Kelly's clinical score was 5 in 5 patients aged >4 years.ConclusionReduced-port surgery, combined with Lugol's iodine staining and ICG, was safe, feasible, and had cosmetically and clinically acceptable mid-term outcomes

    Вклад А.А.Вагина в развитие советской методики преподавания истории

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    В работе рассматривается вклад ученого-методиста Алексея Алексеевича Вагина в развитие советской методики преподавания истории в общеобразовательных школах

    Josephson current in s-wave superconductor / Sr_2RuO_4 junctions

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    The Josephson current between an s-wave and a spin-triplet superconductor Sr2_2RuO4_4 (SRO) is studied theoretically. In spin-singlet / spin-triplet superconductor junctions, there is no Josephson current proportional to sinϕ\sin \phi in the absence of the spin-flip scattering near junction interfaces, where ϕ\phi is a phase-difference across junctions. Thus a dominant term of the Josephson current is proportional to sin2ϕ\sin 2\phi . The spin-orbit scattering at the interfaces gives rise to the Josephson current proportional to cosϕ\cos\phi, which is a direct consequence of the chiral paring symmetry in SRO

    Targeting Notch-1 positive acute leukemia cells by novel fucose-bound liposomes carrying daunorubicin

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    Complete remission by induction therapy in acute myelogenous leukemia (AML) can be achieved due to improvements in supportive and optimized therapy. However, more than 20% of patients will still need to undergo salvage therapy, and most will have a poor prognosis. Determining the specificity of drugs to leukemia cells is important since this will maximize the dose of chemotherapeutic agents that can be administered to AML patients. In turn, this would be expected to lead to reduced drug toxicity and its increased efficacy. We targeted Notch-1 positive AML cells utilizing fucose-bound liposomes, since activation of Notch-1 is required for O-fucosylation. Herein, we report that intravenously injected, L-fucose-bound liposomes containing daunorubicin can be successfully delivered to AML cells that express fucosylated antigens. This resulted in efficient tumor growth inhibition in tumor-bearing mice and decreased proliferation of AML patient-derived leukemia cells. Thus, biological targeting by fucose-bound liposomes that takes advantage of the intrinsic characteristics of AML cells could be a promising new strategy for Notch-1 positive-AML treatment
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