153 research outputs found
A woman with a rare p.Glu74Gly transthyretin mutation presenting exclusively with a rapidly progressive neuropathy: a case report
Introduction: Familial amyloid polyneuropathy is a rare autosomal dominant disorder caused by mutations in the transthyretin gene, TTR. Diagnosis can be challenging, especially if other family members are not affected or an obvious systemic involvement is lacking. The patients are often misdiagnosed, leading to a delay in the initiation of therapy. Case presentation: A 35-year-old woman of Turkish origin presented to our outpatient clinic with severe polyneuropathy associated with distally pronounced tetraparesis and hypesthesia of 2 to 3 years’ duration. In addition, small nerve fiber involvement with impaired detection of cold temperatures and tingling pain in the lower legs was reported. She did not complain of autonomic dysfunction or visual disturbance. Her family history was empty regarding neuromuscular disorders. The routine diagnostic work-up was unremarkable. A sural nerve biopsy disclosed amyloid deposits, which led to the identification of a rare heterozygous transthyretin mutation (p.Glu74Gly; old classification: p.Glu54Gly). Conclusions: Few cases with this very heterozygous mutation can be found in the literature. In contrast to the case of our patient, all of the previously described patients in the literature presented with additional severe autonomic symptoms, involvement of the eyes and a positive family history. In this case report, we emphasize that, in patients with progressive neuropathy with small fiber involvement, an amyloid neuropathy should be considered in the differential diagnosis, even if the family history is empty and other organs are not affected
Binder content and storing conditions of inorganically-bound foundry cores determine the intensity and onset time of gas release in metal casting
Organically-bound foundry cores are substituted by inorganically-bound cores increasingly. This trend is due to regulatory efforts, workplace safety issues, and increasing costs for waste deposits. Changing the binder system reduces the emissions to mostly water vapor, solving health and safety issues. Yet, the difference in the behavior of the gas phase, namely, the condensation potential of water, changes the casting process drastically. In contrast with the continuous generation and discharge of combustion products in the case of organic binders, water accumulates within the foundry core. Only once the cold spots of the core reach boiling temperature noteworthy amounts of vapor are created, increasing the chance for gas defects of the cast parts. Countermeasures have to be taken when designing the core’s geometry. We conducted the following research to improve the understanding of core gas release and its interactions with the foundry core’s binder content and storage conditions. Both binder content and relative humidity during storage were varied in three steps. Their influence on the core gas amount, time of gas generation, and gas permeability of the cores were investigated. The experiments were performed in the institute’s Induction Analysis Furnace and an aluminum melt bath. We found a strong dependency of storage humidity, further increased by increasing binder content on the gas amount and time of the gas release
Электрохимические свойства наночастиц серебра на графитовом электроде
В настоящей работе было показано, что наночастицы серебра, полученные при молярном соотношении реагентов [AgNO3]: [Na3C6H5O7] = 1:1 в условии отсутствии стабилизатора с высоким молекулярным весом, обладают максимальной электрохимической активностью, что связано с неполным восстановлением ионов серебра. Этот факт соотносится с данными УФ-спектроскопии. Наночастицы серебра, полученные в избытке восстановителя при молярном соотношении реагентов [AgNO3]: [Na3C6H5O7] = 1:5 электрохимически неактивны, что также соответствует данным УФ- спектроскопии. Увеличение активности наночастиц серебра происходит в условии увеличения диапазона изменения потенциала, что может быть вызвано образованием перекиси водорода, обладающей активационной способностью. В данной работе установлены оптимальные условия, в которых наночастицы серебра являются наиболее электрохимически активны
Recommended from our members
LIQUID METAL JETTING OF ALUMINUM PARTS WITH SALT SUPPORT STRUCTURES
Liquid metal jetting (LMJ) bears the potential of being a fast part manufacturing
technology while using a cheap raw material. LMJ is a subtype of material jetting (MJT) and the
parts are built by successively depositing droplets of molten metal onto a build platform. For full
3D capability, support structures are necessary, which must be removed in subsequent processes.
In previous investigations, we proposed the usage of water-soluble salt as a support material,
selected a suitable salt, and analyzed the influence of this material on aluminum parts made in
LMJ. The present work shows a duplex MJT print head for processing aluminum alloys and KClNaCl salt. Various printing sequences and support structure strategies are compared. The results
show that the sequence of printing aluminum and salt is crucial. Furthermore, using thin layers of
the support material as a release layer appears promising.Mechanical Engineerin
Ликвидация несанкционированных врезок в трубопроводы
Объектом исследования являются несанкционированные врезки в магистральные нефте- и нефтепродуктопроводы и методы их ликвидации. В процессе исследования выполнен анализ существующих методов ликвидации врезок магистрального нефтепровода. Цель работы - рассмотрение различных методов ликвидации несанкционированных врезок. В результате исследования сделано заключение о том, что ежегодно количество врезок в трубопроводы уменьшается, но они становятся совершеннее в технологическом плане, и на их обнаружение и ликвидацию уходят значительные финансовые средства, что ведет к убыткам компаний занимающихся транспортировкой нефти и нефтепродуктов.The object of the study is unauthorized tapping into the main oil and oil products pipelines and methods of their elimination. In the course of the research the analysis of existing methods of elimination of the main oil pipeline tie-ins is carried out. The aim of this work ? consideration of various methods of elimination of illegal taps. As a result of the study, it was concluded that the number of pipe tie-ins is decreasing annually, but they are becoming more technologically advanced, and their detection and elimination requires significant financial resources, which leads to losses of companies engaged in the transportation of oil and oil products
Real-Time Evaluation of Optic Nerve Sheath Diameter (ONSD) in Awake, Spontaneously Breathing Patients
(1) Background: Reliable ultrasonographic measurements of optic nerve sheath diameter
(ONSD) to detect increased intracerebral pressure (ICP) has not been established in awake patients
with continuous invasive ICP monitoring. Therefore, in this study, we included fully awake patients with and without raised ICP and correlated ONSD with continuously measured ICP values.
(2) Methods: In a prospective study, intracranial pressure (ICP) was continuously measured in
25 patients with an intraparenchymatic P-tel probe. Ultrasonic measurements were carried out three
times for each optic nerve in vertical and horizontal directions. ONSD measurements and ICP were
correlated. Patients with ICP of 2.0–10.0 mmHg were compared with patients suffering from an ICP
of 10.1–24.2 mmHg. (3) Results: In all patients, the ONSD vertical and horizontal measurement for
both eyes correlated well with the ICP (Pearson R = 0.68–0.80). Both measurements yielded similar
results (Bland-Altman: vertical bias: −0.09 mm, accuracy: ±0.66 mm; horizontal bias: −0.06 mm,
accuracy: ±0.48 mm). For patients with an ICP of 2.0–10.0 mmHg compared to an ICP of 10.1–24.2,
ROC (receiver operating characteristic) analyses showed that ONSD measurement accurately predicts elevated ICP (optimal cut-off value 5.05 mm, AUC of 0.91, sensitivity 92% and specificity
90%, p < 0.001). (4) Conclusions: Ultrasonographic measurement of ONSD in awake, spontaneously
breathing patients provides a valuable method to evaluate patients with suspected increased ICP.
Additionally, it provides a potential tool for rapid assessment of ICP at the bedside and to identify
patients at risk for a poor neurological outcome
Potential links between Baltic Sea submarine terraces and groundwater seeping
Submarine groundwater discharge (SGD) influences ocean chemistry, circulation, and the spreading of nutrients and pollutants; it also shapes sea floor morphology. In the Baltic Sea, SGD was linked to the development of terraces and semicircular depressions mapped in an area of the southern Stockholm archipelago, Sweden, in the 1990s. We mapped additional parts of the Stockholm archipelago, areas in Blekinge, southern Sweden, and southern Finland using high-resolution multibeam sonars and sub-bottom profilers to investigate if the sea floor morphological features discovered in the 1990s are widespread and to further address the hypothesis linking their formation to SGD. Sediment coring and sea floor photography conducted with a remotely operated vehicle (ROV) and divers add additional information to the geophysical mapping results. We find that terraces, with general bathymetric expressions of about 1 m and lateral extents of sometimes > 100 m, are widespread in the surveyed areas of the Baltic Sea and are consistently formed in glacial clay. Semicircular depressions, however, are only found in a limited part of a surveyed area east of the island of Asko, southern Stockholm archipelago. While submarine terraces can be produced by several processes, we interpret our results to be in support of the basic hypothesis of terrace formation initially proposed in the 1990s; i.e. groundwater flows through siltier, more permeable layers in glacial clay to discharge at the sea floor, leading to the formation of a sharp terrace when the clay layers above seepage zones are undermined enough to collapse. By linking the terraces to a specific geologic setting, our study further refines the formation hypothesis and thereby forms the foundation for a future assessment of SGD in the Baltic Sea that may use marine geological mapping as a starting point. We propose that SGD through the submarine sea floor terraces is plausible and could be intermittent and linked to periods of higher groundwater levels, implying that to quantify the contribution of freshwater to the Baltic Sea through this potential mechanism, more complex hydrogeological studies are required.Peer reviewe
Risk factor paradox: No prognostic impact of arterial hypertension and smoking in patients with ventricular tachyarrhythmias
Background: Data regarding the outcome of patients with ventricular tachyarrhythmias related to arterial hypertension (AHT) and smoking is limited. The study sought to assess the prognostic impact of AHT and smoking on survival in patients presenting with ventricular tachyarrhythmias. Methods: All consecutive patients surviving ventricular tachycardia (VT) and ventricular fibrillation (VF) upon admission to the University Medical Center Mannheim (UMM), Germany from 2002 to 2016 were included and stratified according to AHT and smoking by propensity score matching. The primary prognostic endpoint was all-cause mortality at 30 months.Results: A total of 988 AHT-matched patients (494 each, with and without AHT) and a total of 872 smoking-matched patients (436 each, with and without smoking) were included. The rates of VT and VF were similar in both groups (VT: AHT 60% vs. no AHT 60%; smokers 61% vs. non-smokers 62%; VF: AHT 35% vs. no AHT 38%; smokers 39% vs. non-smokers 38%). Neither AHT nor smoking were associated with the primary endpoint of long-term all-cause mortality at 30 months (long-term mortality rates: AHT/no AHT, 26% vs. 28%; log-rank p = 0.525; smoking/non-smoking, 22% vs. 25%; log-rank p = 0.683).Conclusions: Paradoxically, neither AHT nor smoking were associated with differences of long-term all-cause mortality in patients presenting with ventricular tachyarrhythmias
Importance of the Initial Conditions for Star Formation - II. Fragmentation Induced Starvation and Accretion Shielding
We investigate the impact of different initial conditions for the initial
density profile and the initial turbulence on the formation process of
protostellar clusters. We study the collapse of dense molecula r cloud cores
with three-dimensional adaptive mesh refinement simulations. We focus our
discussion on the distribution of the gas among the protostellar objects in the
turbulent dynamical cores. Despite the large variations in the initial
configurations and the resulting gas and cluster morphology we find that all
stellar clusters follow a very similar gas accretion behaviour. Once secondary
protostars begin to form, the central region of a cluster is efficiently
shielded from further accretion. Hence, objects located close to the centre are
starved of material, as indicated by a strong decrease of the central acc
retion rate. This Fragmentation Induced Starvation occurs not only in
rotationally supported discs and filaments, but also in more spherically
symmetric clusters with complex chaotic motions.Comment: 15 pages, MNRAS, in press, small changes (referee's suggestions and
comments
- …