This work presents the microstructure and properties of two‐phase amorphous melt‐spun alloys ejected from the crucible with partition between liquids. The microstructure was studied by scanning ...electron microscopy and transmission electron microscopy and the phase composition was studied by X‐ray diffraction. The thermal stability of the alloys was determined using differential scanning calorimetry. The microstructure study proves that the composite alloys are heterogeneous because of the existence of the two amorphous phases obtained due to the use of a partition between the liquids. This microstructure correlates with complex thermal characteristics not found in homogeneous alloys of the same nominal composition. The layered structure of these composites influences the formation of fractures during tensile tests.
LAY DESCRIPTION
The aim of this investigation is to present the special features and properties of the glassy two‐component melt‐spun alloys in comparison to the melt‐spun alloys ejected from single‐chamber crucible. The studies of the composite microstructure were performed using transmission electron microscopy and scanning electron microscopy. The alloys also were heated to elevated temperatures and their characteristics were studied by means of differential scanning calorimetry. The phase composition of the alloys was investigated using X‐ray diffraction. The results of the microstructure examination show that these alloys are heterogeneous due to the production method. The special feature of the alloys is that they essentially inherit the transformations possible to occur in the precursor alloys after amorphisation of the these precursors. Results of thermal analysis also confirm the occurrence of transformations of the regions from the transition zones of the intermediate compositions between the two main constituents A and B. These transformations are found to be similar to the transformations identified in the amorphous alloys of the averaged compositions, that is, the homogeneous chemical compositions that are possible for obtaining, when alloys A and B are molten together to form a single liquid phase before ejection into a spinning cylinder. Unique feature of these composite alloys is lamellar morphology. This microstructure consists mainly of the stripes/layers of precursor alloys A and B that are inserted into each chamber of the two‐chamber crucibles. After ejection of the alloys into the surface of the spinning cooper wheel, they form the microstructure of the layered morphology. This band‐like morphology affects formation of the ductile fracture. Actually, this relationship is confirmed by observation of the fracture surfaces of the composite samples. The scanning electron microscopy observations with mappings of the chemical composition performed for all of the composite ribbons show that their microstructure consists of the layers of differentiated chemical compositions parallel to the surface of the ribbon. The arrangement of vein‐like pattern of the fractures coincides with the boundaries between the regions of the differentiated chemical compositions.
Pb(Hf1−xSnx)O3 single crystals with x = 0.08 were characterized using single‐crystal X‐ray diffraction and Raman scattering, in a wide temperature range. The information concerning the structure of ...two intermediate phases (IMs), situated between low‐temperature antiferroelectric A1 and high‐temperature paraelectric PE phases, was obtained. The lower temperature IM, A2, is characterized by incommensurate displacive modulations in the Pb sublattice. The higher temperature IM, is characterized by tilting of oxygen octahedra, and serious disorder coming from lead ions represented by X‐ray diffuse scattering. Optical phonons and phase transitions in Pb(Hf1−xSnx)O3 single crystals were investigated by temperature‐dependent Raman spectra. It was found that several soft modes control the phase transition between two antiferroelectric phases indicating its displacive character, whereas, in the paraelectric phase, both soft modes and Rayleigh scattering were observed.
In recent years an increase in incidence of cholelithiasis in children has been observed. Among the various factors predisposing to the occurrence of cholelithiasis, some are modifiable and some are ...non-modifiable (including 25% of gallstones caused by genetic factors). One of the factors predisposing to the occurrence of cholelithiasis is obesity. The article describes the methods of prevention, diagnosis and treatment of uncomplicated and complicated cholelithiasis in children. Attention was paid to the new guidelines for the use of ursodeoxycholic acid in gallstone disease, as well as the molecular basis and research progress that has been made in this field.
Materials Physics: Emerging Dielectric, Piezoelectric, and Ferroelectric Ceramic and Crystalline Materials and their Applications is an open Special Issue of Materials, which aims to publish original ...and review papers on new scientific and applied research and make great contributions to the identification and understanding of ceramic and crystalline materials which today enable applications that were previously virtually unimaginable ...
Progressive familial intrahepatic cholestasis type 3 (PFIC-3) is a rare autosomal recessive cholestatic liver disorder caused by mutations in the ABCB4 gene. The aim of this study was to present the ...phenotypic and genotypic spectrum of 4 Polish PFIC-3 patients diagnosed in a one-referral centre.
The study included 4 patients with cholestasis and pathogenic variants in the ABCB4 gene identified by next-generation sequencing (NGS) of a targeted-gene panel or whole exome sequencing (WES). Clinical, laboratory, histological, and molecular data were collected.
Four patients (three males) were identified. The age at first noted clinical signs and symptoms was 6, 2.5, 14, and 2 years respectively; the mean age was 6 years. Those signs and symptoms include pruritus (2 out of 4 patients) and hepatomegaly with splenomegaly (4 out of 4 patients). The age at the time of referral to our centre was 9, 3, 15, and 2.5 years respectively, while the mean age was 7 years. Chronic cholestatic liver disease of unknown aetiology was established in all of them. The NGS analysis was performed in all patients at the last follow-up visit. Three novel variants including c.902T>A, p.Met301Lys, c.3279+1G>A, p.?, and c.3524T>A, p.Leu1175His were identified. The time from the first consultation to the final diagnosis was 14, 9, 3, and 1 year respectively; the mean was 6.8 years. A detailed follow-up was presented.
The clinical phenotype of PFIC-3 could be variable. The clinical and biochemical diagnosis of PFIC-3 is difficult, thus the NGS study is very useful in making a proper diagnosis.
The aim of our paper was to present current knowledge, review literature and available practice guidelines of international hepatological associations regarding the effect of severe acute respiratory ...syndrome coronavirus 2 coronavirus on the liver, patients with underline liver disease, awaiting on liver transplantation (LTx) or being after LTx in the pandemic coronavirus disease 2019 area.
Background & Aims Progressive familial intrahepatic cholestasis (PFIC) with normal serum levels of gamma-glutamyltranspeptidase can result from mutations in ATP8B1 (encoding familial intrahepatic ...cholestasis 1 FIC1) or ABCB11 (encoding bile salt export pump BSEP). We evaluated clinical and laboratory features of disease in patients diagnosed with PFIC, who carried mutations in ATP8B1 (FIC1 deficiency) or ABCB11 (BSEP deficiency). Our goal was to identify features that distinguish presentation and course of these two disorders, thus facilitating diagnosis and elucidating the differing consequences of ATP8B1 and ABCB11 mutations. Methods A retrospective multi-center study was conducted, using questionnaires and chart review. Available clinical and biochemical data from 145 PFIC patients with mutations in either ATP8B1 (61 “FIC1 patients”) or ABCB11 (84 “BSEP patients”) were evaluated. Results At presentation, serum aminotransferase and bile salt levels were higher in BSEP patients; serum alkaline phosphatase values were higher, and serum albumin values were lower, in FIC1 patients. Elevated white blood cell counts, and giant or multinucleate cells at liver biopsy, were more common in BSEP patients. BSEP patients more often had gallstones and portal hypertension. Diarrhea, pancreatic disease, rickets, pneumonia, abnormal sweat tests, hearing impairment, and poor growth were more common in FIC1 patients. Among BSEP patients, the course of disease was less rapidly progressive in patients bearing the D482G mutation. Conclusions Severe forms of FIC1 and BSEP deficiency differed. BSEP patients manifested more severe hepatobiliary disease, while FIC1 patients showed greater evidence of extrahepatic disease.
Living donor liver transplantation (LDLT) in patients with acute liver failure (ALF) has become an acceptable alternative to transplantation from deceased donors (DDLT). The aim of this study was to ...analyze outcomes of LDLT in pediatric patients with ALF based on our center's experience.
We enrolled 63 children (at our institution) with ALF who underwent liver transplantation between 1997 and 2016. Among them 24 (38%) underwent a LDLT and 39 (62%) received a DDLT. Retrospectively analyzed patient clinical data included: time lapse between qualification for transplantation and transplant surgery, graft characteristics, postoperative complications, long-term results post-transplantation, and living donor morbidity. Overall, we have made a comparison of clinical results between LDLT and DDLT groups.
Follow-up periods ranged from 12 to 182 months (median 109 months) for LDLT patients and 12 to 183 months (median 72 months) for DDLT patients. The median waiting time for a transplant was shorter in LDLT group than in DDLT group. There was not a single case of primary non-function (PNF) in the LDLT group and 20 out of 24 patients (83.3%) had good early graft function; 3 patients (12.5%) in the LDLT group died within 2 months of transplantation but there was no late mortality. In comparison, 4 out of 39 patients (10.2%) had PNF in DDLT group while 20 patients (51.2%) had good early graft function; 8 patients (20.5%) died early within 2 months and 2 patients (5.1%) died late after transplantation. The LDLT group had a shorter cold ischemia time (CIT) of 4 hours in comparison to 9.2 hours in the DDLT group (p<0.0001).
LDLT is a lifesaving procedure for pediatric patients with ALF. Our experience showed that it may be performed with very good results, and with very low morbidity and no mortality among living donors when performed by experienced teams following strict procedures.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Biallelic pathogenic variants in the neuroblastoma amplified sequence (
NBAS
) gene were firstly (2015) identified as a cause of fever-triggered recurrent acute liver failure (RALF). Since then, some ...patients with NBAS deficiency presenting with neurologic features, including a motor delay, intellectual disability, muscular hypotonia and a mild brain atrophy, have been reported. Here, we describe a case of pediatric patient diagnosed with NBAS deficiency due to a homozygous c.2809C > G, p.(Pro937Ala) variant presenting with RALF with severe hyperammonemia, acquired microcephaly and progressive brain atrophy. Not reported in the literature findings include severe hyperammonemia during ALF episode, and neurologic features in the form of acquired progressive microcephaly with brain atrophy. The latter raises the hypothesis about a primary neurologic phenotype in NBAS deficiency.
In this paper, we studied some ferroelectric properties of archetypal oxide uniaxial ferroelectric single crystals of Pb5Ge3O11 modified by Ba ions. They include dielectric, DSC, ferroelectric ...polarization, and electrocaloric effect (ECE) measurements. The measurements show that increasing Ba doping considerably influences all the measured parameters, mainly by lowering the Curie temperature, gradually diffusing the phase transition, and decreasing values of polarization as well as the coercive field. The decrease in overall ECE is influenced by decreasing polarization. Compared with the pure PGO single crystals, this decrease is from 1.2 K to 0.2 K. However, the effect of diffusing the phase transition increases the range of its occurrence (up to 30 K), which might be beneficial in applications.
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