Broken Kramers Degeneracy in Altermagnetic MnTe.

Altermagnetism is a newly identified fundamental class of magnetism with vanishing net magnetization and time-reversal symmetry broken electronic structure. Probing the unusual electronic structure with nonrelativistic spin splitting would be a direct experimental verification of an altermagnetic phase. By combining high-quality film growth and in situ angle-resolved photoemission spectroscopy, we report the electronic structure of an altermagnetic candidate, α-MnTe. Temperature-dependent study reveals the lifting of Kramers degeneracy accompanied by a magnetic phase transition at T_{N}=267 K with spin splitting of up to 370 meV, providing direct spectroscopic evidence for altermagnetism in MnTe.

Direct observation of antiferromagnetic parity violation in the electronic structure of Mn2Au.

Using momentum microscopy with sub-µm spatial resolution, allowing momentum resolved photoemission on individual antiferromagnetic domains, we observe an asymmetry in the electronic band structure,E(k)≠E(-k), in Mn2Au. This broken band structure parity originates from the combined time and parity symmetry,PT, of the antiferromagnetic order of the Mn moments, in connection with spin-orbit coupling. The spin-orbit interaction couples the broken parity to the Néel order parameter direction. We demonstrate a novel tool to image the Néel vector direction,N, by combining spatially resolved momentum microscopy withab-initiocalculations that correlate the broken parity with the vectorN.

Time-Dependent Screening Explains the Ultrafast Excitonic Signal Rise in 2D Semiconductors.

We calculate the time evolution of the transient reflection signal in an MoS2 monolayer on a SiO2/Si substrate using first-principles out-of-equilibrium real-time methods. Our simulations provide a simple and intuitive physical picture for the delayed, yet ultrafast, evolution of the signal whose rise time depends on the excess energy of the pump laser: at laser energies above the A- and B-exciton, the pump pulse excites electrons and holes far away from the K valleys in the first Brillouin zone. Electron-phonon and hole-phonon scattering lead to a gradual relaxation of the carriers toward small Active Excitonic Regions around K, enhancing the dielectric screening. The accompanying time-dependent band gap renormalization dominates over Pauli blocking and the excitonic binding energy renormalization. This explains the delayed buildup of the transient reflection signal of the probe pulse, in excellent agreement with recent experimental data. Our results show that the observed delay is not a unique signature of an exciton formation process but rather caused by coordinated carrier dynamics and its influence on the screening.

Three-Dimensional Printing of Abrasive, Hard, and Thermally Conductive Synthetic Microdiamond-Polymer Composite Using Low-Cost Fused Deposition Modeling Printer.

A relative lack of printable materials with tailored functional properties limits the applicability of three-dimensional (3D) printing. In this work, a diamond-acrylonitrile butadiene styrene (ABS) composite filament for use in 3D printing was created through incorporation of high-pressure and high-temperature (HPHT) synthetic microdiamonds as a filler. Homogenously distributed diamond composite filaments, containing either 37.5 or 60 wt % microdiamonds, were formed through preblending the diamond powder with ABS, followed by subsequent multiple fiber extrusions. The thermal conductivity of the ABS base material increased from 0.17 to 0.94 W/(m·K), more than five-fold following incorporation of the microdiamonds. The elastic modulus for the 60 wt % microdiamond containing composite material increased by 41.9% with respect to pure ABS, from 1050 to 1490 MPa. The hydrophilicity also increased by 32%. A low-cost fused deposition modeling printer was customized to handle the highly abrasive composite filament by replacing the conventional (stainless-steel) filament feeding gear with a harder titanium gear. To demonstrate improved thermal performance of 3D printed devices using the new composite filament, a number of composite heat sinks were printed and characterized. Heat dissipation measurements demonstrated that 3D printed heat sinks containing 60 wt % diamond increased the thermal dissipation by 42%.

[Treatment with rituximab as an opportunity for the prevention of infectious complications]. / Lécba rituximabem jako výzva k prevenci infekcních komplikací.

UNLABELLED: Rituximab, a monoclonal antibody against the surface antigen of B-lymphocytes CD20 is beeing used in the treatment of numerous hematological, hematooncological and autoimmune disorders. After administration of ritu-ximab, quick and almost complete depletion of B-lymphocytes with the exception of pre-B-lymphocytes and plasma cells occur. Neutropenia and low serum antibody levels in classes IgA, IgM and IgG may also develop. These changes usually persist for 6-12 months, rarely for several years. In the consequence, patients with the rituximab treatment are more prone to infections - usually of bacterial and viral origin. Concomitantly, rituximab treatment influences negatively postvaccination antibody production and therefore adequate preventive measures are necessary before the beginning of the treatment. The authors offer complex overview of actual literature, emphasize adequate education of patients as well as of healthcare providing staff and discuss the vaccination recommendation against preventable communicable diseases like influenza, pneumococcal diseases, tetanus, diphtheria and pertussis. KEY WORDS: autoimmune disease - immunosupression - infectious complications - prevention - rituximab - vaccination.

[Surgical treatment for proximal humerus fracture]. / Operacní lécba zlomenin proximálního humeru.

PURPOSE OF THE STUDY: The aim of the study was to compare the medical aspects of alternative surgical methods for treatment of proximal humerus fractures in specific indications (two- and three- fragment fractures). MATERIAL AND METHODS: A prospective randomised study on surgical treatment of two- and three-fragment fractures of the proximal humerus was carried out at the Department of Surgery, University Hospital in Hradec Králové, from January 2006 till January 2010. The study comprised patients with proximal humerus fractures indicated for surgical treatment. Study inclusion criteria were as follows: informed consent, AO fracture types A2, A3, B1 or C1, age between 18 and 80 years, and patient compliance. Exclusion criteria included open fracture, associated injury (AIS . 2), open growth plates, or such state of the patient's health that would limit the extent of surgery. Two groups were compared. One included patients treated by the Zifko method of minimally invasive osteosynthesis with intramedullary K-wire insertion (MIO group) and the other (ORIF group) consisted of patients undergoing open reduction with angle-stable osteosynthesis using a Philos plate (Synthes, Switzerland). The patients were randomised to the groups by a computer programme which facilitates the maintenance of homogeneity of the groups compared. The procedure in each patient was based on the sealed-envelope method. RESULTS: The ORIF group comprised 28 patients. It took them an average of 27.2 weeks (9-72) to regain normal upper limb function. The final CM score was 86.6% (64-100%) as compared with the healthy limb. Excellent and good results were achieved in 89% of the patients; complications were recorded in 39% of them. The MIO group included 27 patients. The fractures healed in all of them. Normal upper limb function was regained at an average of 21.4 weeks (13-36). The final CM score was 87.5% (52-100%) in comparison with the healthy limb. Excellent and good results were achieved in 89% and complications developed in 33% of the patients. CONCLUSIONS: The statistical evaluation of the results, using the unpaired t-test, did not show any significant differences either in functional outcomes or the number of complications between the two groups. The only significant difference was found in operative times (117 min and 72 min in ORIF and MIO groups, respectively). The difference in time needed to regain limb function (27 and 21 weeks) was at a marginal level of statistical significance. With both methods 89% of excellent and good results were achieved, and a similar number of patients had complications (11 and 9).

Evaluation of cytotoxic activity of Schisandra chinensis lignans.

Using exhaustive chromatographic separation we have isolated (-)-tigloyl-deangeloyl-gomisin F as a novel dibenzocyclooctadiene lignan from schisandra chinensis. With the help of HPLC, we further isolated (+)-schisandrin, (+)-deoxyschisandrin, (+)-γ-schisandrin, (-)-gomisin J, (+)-gomisin A, (-)-gomisin N, (-)-tigloyl-gomisin P, (-)-wuweizisu C, (-)-gomisin D, rubrisandrin A, (-)-gomisin G, (+)-gomisin K (3) and (-)-schisantherin C. A full NMR description of (-)-schisantherin C was carried out with the aim to confirm previous reports of its structure. Compounds isolated were identified on the basis of UV, IR, (1)H- and (13)C-NMR and MS. The cytotoxicity of lignans was tested for the BY-2 cell line alone and as a synergistic effect with the cytotoxic agent camptothecin. Lignans showed various toxicity and synergistic and antagonistic effects on camptothecin-induced cytotoxicity. Cytotoxicity against colon cancer cell line LoVo was also tested.

[Preparation of patients with haemostatic disorder for invasive medical interventions]. / Príprava pacientu s poruchou hemostázy k invazivním lékarským zákrokum.

The current trend in medicine is to sustain the possibility for necessary procedures to be performed in patients who suffer from haemostatic disorders which complicate eventual surgery. Among such disorders are congenital blood coagulation disorders, haemostatic disorders concomitant with other diseases and also therapies which affect haemostasis either on purpose or as part of adverse effects. Among coagulation disorders are congenital haemorrhagic or thrombotic conditions, acquired blood coagulation disorders--combined in the vast majority of cases-- and associated with pregnancy, severe internal diseases and surgery related diseases, severe injuries, wounds, burns, malignancies, systemic connective tissue diseases, inflammatory bowel disease, and a number of other diseases. A separate issue is that ofanticoagulation therapy--both antiplatelet, used in the treatment or prevention of venous thrombosis, and anticoagulation, predominantly used to manage venous thromboembolism. Also considered should be any therapy which may have a negative impact on coagulation due to its adverse effects.

Cytotoxic activity of C-geranyl compounds from Paulownia tomentosa fruits.

The newly discovered 5,7-dihydroxy-6-geranylchromone ( 1) was isolated from PAULOWNIA TOMENTOSA fruit and subsequently characterized. The structure of the isolated compound was elucidated on the basis of extensive NMR experiments including HMQC, HMBC, COSY, and NOESY, as well as HR-MS, IR, and UV. The cytotoxicity of 1 was evaluated using a plant cell model represented by tobacco BY-2 cells. The other phytoconstituents ( 2 - 8) previously isolated from P. TOMENTOSA were similarly evaluated together with the known flavanones 10 and 11. The cytotoxicity (human erythro-leukaemia cell line K562) and activity on erythroid differentiation of compounds 2 - 9 and 12 and 13 have also been evaluated. Acteoside ( 2) was determined to be the most toxic of the compounds tested on BY-2 cells, diplacone ( 6) on the K562 cell line. Some aspects of the relationship between the flavanone skeleton substitution and the metabolic activation necessary for a toxic effect are discussed.

[Surgical management of proximal humeral fractures using the Hackethal (Zifko) method--a case review]. / Operacní lécba zlomenin proximálního humeru metodou podle Hackethala (Zifka)--case serie.

BACKGROUND: Fractures of the proximal humerus actually represent 5% of all fractures and 45% of all humeral fractures with the highest incidence in women over 60 years of age. The outcomes of the greatest concern at these patients (pain, function of the shoulder and activities of daily living) get worse with age, osteoporosis, grading of fracture type and of initial fracture displacement. According to the literature (Evidence Based Medicine--EBM level II-III) operative treatment of displaced fractures reduces pain and need for assistance in activities of daily living, but open reduction with internal fixation by conventional screws and plates was connected with implant loosening, infection and avascular necrosis, whereas closed reduction with different methods of miniinvasive percutaneous stabilisation is threatened by primary malreduction. AIM: Evaluation of clinical and functional outcomes and analysis of results of proximal humerus fractures treated by closed or percutaneous reduction and intramedullary fixation by means of bundle of Kirschner wires after Zifko. DESIGN: Retrospective descriptive study--case serie. MATERIAL AND METHODS: Within January 1, 2005 - December 31, 2005 there were 87 patients with 87 two- and three-fragments fractures of proximal humerus (according to Neers classification) operated at our institution, from which 76 by the method after ZiFko. 36 patients from these 76 came to final evaluation (follow-up rate 47%). AO fracture types were: A2-36%, A3-33%, B1-19%, C1-12%. RESULTS: The resulting Constant-Murley (CM) score reached in mean 89 points with 89% of excellent--good functional results. Complications were recorded in 30% of cases and were represented mainly by proximal migration of K-wires. Avascular necrosis of humeral head occured in two cases (5.5%). CONCLUSION: In spite of low follow-up rate we conclude, that the method of closed reduction and intramedullary fixation of two- and three-part fractures of proximal humerus after Zifko offers above-average final results with acceptable rate of complications, mostly not severe ones. The essential pre-condition of good result is proper reduction--closed of percutaneous one. On the contrary, suboptimal results correlate with primary and secondary malreductions. The incidence of latter increases in intraarticular fracture types with small fragment of head and thus with insuficient implant retention. To evaluate the merit of the method in relation to angle-stable extra-/or intramedullary implants, the prospective trials are needed.

[Operation treatment of the humeral shaft fractures]. / Operacní lécba zlomenin diafýzy humeru.

INTRODUCTION: Nowadays the humeral shaft fractures represent about 4% of all fractures. Most of them can be treated conservatively. In this type of treatment the cooperation of the patient is necessary, treatment is long lasting and needs the extremity to be immobilized. That's why still more fractures are indicated for the operation treatment, which enables an early rehabilitation and selfcare of the patient. AIM: The aim of our work was to assess the functional and clinical results in patients after the operation of the humeral shaft fractures treated by closed reposition and intramedullary fixation or by open reposition and plate osteosynthesis (ORIF). DESIGN: Retrospective descriptive study--case serie MATERIAL AND METHODS: In our department within the years 2001-2006 we operated on 101 patients with humeral shaft fractures. 65 patients came to be checked, the follow up rate--65%. Fractures were classified according AO: A--50%, B--29%, C--21%. The ORIF was used in 18 patients, closed reduction and locked intramedullary nail in 21 patients, and closed reduction and K-wires bundle (Hackethal) in 26 patients. RESULTS: The resulting conditions we evaluated by Constant-Murley and Liverpool elbow scoring system. The mean value reached 86/8.9. In 82% of patients we have reached good to excellent results. Complications were noted in 34 CONCLUSION: In spite of limited number of patients in our study the results of ours generally are not in contradiction to the current literature data. The best results were achieved by ORIF. On the contrary, the worst outcomes with greatest number of complications were in Hackethal group.

[The preparation of a patient with long-term anticoagulant cumarin treatment for invasive surgery]. / Príprava nemocných na dlouhodobé antikoagulacní lécbe kumariny k invazivním zákrokum.

Coumarins belong to drugs widely used and the spectrum of their use is going to grow. From this point of view and/or because the coumarins are adminstrated in patients who are treated for the other diseases--medical or surgical--at the same time, it is necessary to modify, interrupt or replace peroral anticoagulant treatment in the dependence on various aspects. It requires to compound different algorithms for given situations solution. It is always to decide, if the situation is imperative from the view of solution planed, what risk brings proposed treatment and what is the risk of anticoagulant treatment modification.

[Recurrent Crohn's disease]. / Príspevek k problematice recidivující Crohnovy choroby.

In 1973-1990, i.e. in the course of 18 years, at the Surgical Clinic in Hradec Králové 148 patients with Crohn's disease were operated. The author gives an account of the localization of the disease and surgical interventions performed. Thirty-four patients were operated on account of relapses, i.e. 23%. One re-operation was performed in 22 patients (64%), two re-operations in 6 patients (17.6%) and three and more re-operations also in 6 patients (17.6%). The authors mention the types and total number of re-operations which amounted to 56 operations. They evaluate some causes such as the patients age, sex, site of relapse, duration of disease before the primary operation and some other factors which could have an impact on relapses and re-operations of Crohn's disease.

[The effect of prior experience of dyspnea on measured degrees of dyspnea induced by obstruction in healthy persons. Methodology in the use of Borg's scale]. / Vliv predchozího prozitku dusnosti na zmerené hodnoty dusnosti, vyvolané obstruckci u zdravých osob. Metodické sdelení k aplikaci Borgova merítka.

The object of the investigation was to assess the influence of previously experienced maximal dyspnoea on assessed values of dyspnoea in healthy volunteers. In these subjects threshold to medium dyspnoea was evoked by application of three different flow resistances of 1 or 2 or 4 kPa-1.s-1 for a period of 2 mins. Maximum dyspnoea was evoked by occlusion of the airways for a period of several breathes. The control and experimental group comprised a total of 16 healthy volunteers aged 21 to 22 years. To evaluate the dyspnoea the 10-point Borg visual analogue scale was used. It was revealed that the magnitude of different resistances in blind and random inclusion of these resistances was reliably differentiated by the subjects regardless whether they had a previous experience of maximal dyspnoea. A significantly higher grade of dyspnoea was, however, recorded in all three tested resistances in subjects who had a previous experience of dyspnoea. This phenomenon is explained by the sensation of anxiety and threatened vital function closely before the model obstruction in the experimental group. The authors recommend based on their own experience and data in the literature Borg's ventical scale for quantification of dyspnoea. When assessment are made it must be, however, stated how the examined subjects were instructed in advance and whether they had a previous experience of dyspnoea.

[Colonoscopy in the diagnosis of hemorrhage in the colorectal area]. / Koloskopie jako príspevek k diagnostice a lécbe krvácení z kolorektální oblasti.

The authors submit a retrospective study based on their own material, pertaining to experience with coloscopies in acute and chronic haemorrhage from the colorectal region. They analyze the causes of haemorrhage, and give a detailed histological classification in particular of polyps as possible precancerous conditions. They also compare the clinical value of coloscopy with other examination methods according to their own experience and data in the literature.

[Interspecies differences in the reactivity of smooth tracheobronchial muscles]. / K mezidruhovým rozdílum v reaktivite hladkého tracheobronchiálního svalu.

There are considerable differences in the reactivity of tracheobronchial muscles to bronchoconstricting substances in guinea pigs and rats. The aim of the present investigation was to assess whether these functional differences have a morphological or biochemical background. Therefore specimens of this tissue were taken for histological and biochemical examination i. e. assessment of cyclic nucleotides. While in the nucleotide content no interspecific differences were found, there were some morphological differences which may explain the less marked response of smooth muscles of the rat to bronchoconstricting stimuli.