Experimental investigation of a four-qubit linear-optical quantum logic circuit.

We experimentally demonstrate and characterize a four-qubit linear-optical quantum logic circuit. Our robust and versatile scheme exploits encoding of two qubits into polarization and path degrees of single photons and involves two crossed inherently stable interferometers. This approach allows us to design a complex quantum logic circuit that combines a genuine four-qubit C(3)Z gate and several two-qubit and single-qubit gates. The C(3)Z gate introduces a sign flip if and only if all four qubits are in the computational state |1〉. We verify high-fidelity performance of this central four-qubit gate using Hofmann bounds on quantum gate fidelity and Monte Carlo fidelity sampling. We also experimentally demonstrate that the quantum logic circuit can generate genuine multipartite entanglement and we certify the entanglement with the use of suitably tailored entanglement witnesses.

Faithful conditional quantum state transfer between weakly coupled qubits.

One of the strengths of quantum information theory is that it can treat quantum states without referring to their particular physical representation. In principle, quantum states can be therefore fully swapped between various quantum systems by their mutual interaction and this quantum state transfer is crucial for many quantum communication and information processing tasks. In practice, however, the achievable interaction time and strength are often limited by decoherence. Here we propose and experimentally demonstrate a procedure for faithful quantum state transfer between two weakly interacting qubits. Our scheme enables a probabilistic yet perfect unidirectional transfer of an arbitrary unknown state of a source qubit onto a target qubit prepared initially in a known state. The transfer is achieved by a combination of a suitable measurement of the source qubit and quantum filtering on the target qubit depending on the outcome of measurement on the source qubit. We experimentally verify feasibility and robustness of the transfer using a linear optical setup with qubits encoded into polarization states of single photons.

[Lynch Syndrome -  the Pathologist's Diagnosis]. / Diagnóza Lynchova syndromu od patologa.

Lynch syndrome (formerly known as hereditary non-polyposis colorectal cancer) is the most com-mon hereditary colorectal cancer syndrome. The syndrome is caused by a germline mutation of one of the mismatch repair (MMR) genes responsible for DNA replication error repair. Impaired function of the proteins encoded by these genes leads to microsatellite instability (MSI), which is associated with increased incidence of neoplasms: mainly colorectal cancer. According to recent estimates, up to 5% of all colorectal cancers are associated with Lynch syndrome. Due to this relatively high frequency, familial occurence, absence of premorbid phenotype, and development of malignant tumors at a reproductive age, a correct diagnosis is important not only from an ethical but also from an economical point of view. Unfortunately, clinical means of diagnosis, namely, the revised Bethesda guidelines designed to detect patients suitable for genetic testing for Lynch syndrome, lack sufficient sensitivity. The methods associated with modern pathology are more sensitive than the clinical criteria used to detect patients suspected of having Lynch syndrome. Pathological diagnostics are based on direct or indirect detection of MSI. Indirect methods include analysis of morphological signs associated with MSI in histological samples from colorectal carcinoma patients and immunohistochemical investigation of MMR protein expression. To rule out sporadic cases caused by epigenetic inactivation of an MMR gene, molecular genetic investigation of the BRAF gene and methylation analysis of the MLH1 promoter are performed during diagnostic workup. A suspicion of Lynch syndrome based on the results of the methods mentioned above should be proven by detection of a germline mutation in an MMR gene in peripheral blood leukocytes.

Coexistence of Antiferromagnetism and Superconductivity in Heavy Fermion Cerium Compound Ce3PdIn11.

Many current research efforts in strongly correlated systems focus on the interplay between magnetism and superconductivity. Here we report on coexistence of both cooperative ordered states in recently discovered stoichiometric and fully inversion symmetric heavy fermion compound Ce3PdIn11 at ambient pressure. Thermodynamic and transport measurements reveal two successive magnetic transitions at T1 = 1.67 K and TN = 1.53 K into antiferromagnetic type of ordered states. Below Tc = 0.42 K the compound enters a superconducting state. The large initial slope of dBc2/dT ≈ - 8.6 T/K indicates that heavy quasiparticles form the Cooper pairs. The origin of the two magnetic transitions and the coexistence of magnetism and superconductivity is briefly discussed in the context of the coexistence of the two inequivalent Ce-sublattices in the unit cell of Ce3PdIn11 with different Kondo couplings to the conduction electrons.

Three tetracoordinate Co(II) complexes [Co(biq)X2] (X = Cl, Br, I) with easy-plane magnetic anisotropy as field-induced single-molecule magnets.

Three mononuclear complexes [Co(biq)X2] (biq = 2,2'-biquinoline; X = Cl, Br, I) were prepared by a solvothermal method and characterized by single-crystal X-ray diffraction. In all three complexes the Co(ii) atom is tetrahedrally coordinated by one biq ligand bonded in a chelate manner and two halogenido ligands. Hydrogen bonding interactions (C-HX) along with the π-π interactions contribute to the stability of the formed packing. Magnetic measurements as well as ab initio calculations revealed that the complexes possess a sizable easy-plane magnetic anisotropy (D > 0). They display a superparamagnetic behaviour in an applied external field that culminates between BDC = 0.2-0.3 T. Two relaxation processes are observed; the faster can be analysed in terms of the direct and Orbach processes yielding U/kB = 42.6 K and τ0 = 1.9 × 10(-10) s for X = Cl, U/kB = 39.6 K and τ0 = 1.2 × 10(-10) s for X = Br and U/kB = 57.0 K and τ0 = 3.2 × 10(-13) s for X = I at BDC = 0.2 T.

Antimicrobial activity, DNA cleavage, thermal analysis data and crystal structure of some new CdLX2 complexes: A supramolecular network.

Some new cadmium(II) Schiff base complexes CdLX2 (where X=Cl(-), Br(-), I(-), SCN(-) and N3(-) and L=N,N-bis((E)-3-(4-(dimethylamino)phenyl)allylidene)benzene-1,2-diamine) were synthesized and characterized by elemental analysis, FT-IR, UV-visible, (1)HNMR spectra, and conductivity measurements. Moreover, the structure of the CdLI2 was determined by single crystal X-ray crystallography. CdLI2 crystallizes in a triclinic system with space group P 1̅. The molecular structure shows distorted tetrahedral coordination geometry. The CH....π and π-π stacking interactions connect the molecules to a supramolecular network. The thermal properties of the compounds were investigated from the room temperature to 800 °C with a heating rate of 10 °C/min and decomposition activation parameters were evaluated from the TG/DTG plots. Antibacterial/antifungal activities of the compounds were screened by the disk diffusion method against the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, the Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis and the fungi strain Aspergillus niger and Candida albicans. The antimicrobial activities were determined for all compounds and the complexation was found to enhance the inhibitory activity. Finally, the DNA cleavage potential of the compounds was investigated by agarose gel electrophoresis method.

Synthesis, spectral, crystal structure, thermal behavior, antimicrobial and DNA cleavage potential of two octahedral cadmium complexes: a supramolecular structure.

Two new cadmium(II) complexes with the formula of CdL2(NCS)2 and CdL2(N3)2 (in which L is 2,2-dimethyl-N,N'-bis-(3-phenyl-allylidene)-propane-1,3-diamine) have been synthesized and characterized by elemental analysis, molar conductivity measurements, FT/IR, UV-Visible, (1)H and (13)C NMR spectra and X-ray studies. The crystal structure analysis of CdL2(NCS)2 indicated that it crystallizes in orthorhombic system with space group of Pbca. Two Schiff base ligands are bonded to cadmium(II) ion as N2-donor chelate. Coordination geometry around the cadmium ion was found to be partially distorted octahedron. The Cd-Nimine bond distances are found in the range of 2.363(2)-2.427(2)Å while the Cd-Nisothiocyanate bond distances are 2.287(2)Å and 2.310(2)Å. The existence of C-H⋯π and C-H⋯S interactions in the CdL2(NCS)2 crystal leads to a supramolecular structure in its network. Then cadmium complexes were screened in vitro for their antibacterial and antifungal activities against two Gram-negative and two Gram-positive bacteria and also against Candida albicans as a fungus. Moreover, the compounds were subjected for DNA-cleavage potential by gel electrophoresis method. Finally thermo-gravimetric analysis of the complexes was applied for thermal behavior studies and then some thermo-kinetics activation parameters were evaluated.

Efficient experimental estimation of fidelity of linear optical quantum Toffoli gate.

We propose an efficiently measurable lower bound on quantum process fidelity of N-qubit controlled-Z gates. This bound is determined by average output state fidelities for N partially conjugate product bases. A distinct advantage of our approach is that only fidelities with product states need to be measured while keeping the total number of measurements much smaller than what is necessary for full quantum process tomography. As an application, we use this method to experimentally estimate quantum process fidelity F of a three-qubit linear optical quantum Toffoli gate and we find that F≥0.83. We also demonstrate the entangling capability of the gate by preparing Greenberger-Horne-Zeilinger-type three-qubit entangled states from input product states.

Selected reaction monitoring method to determine the species origin of blood-based binding agents in meats: a collaborative study.

Binding products or food 'glues' are used throughout the food industry to increase the meat use rate or to augment economic efficiency. Some of these binders contain thrombin from bovine and porcine blood. The European parliament has recently banned thrombin-based additives and labelling legislation governs their use in the US. A mass spectrometry screening method is available to detect the addition of thrombin agents to foods as there is a need to protect consumers and to avoid misleading trade practices. We report the details of an inter-laboratory trial to determine the transferability of this method to operators in various food testing laboratories, each using a different triple quadrupole mass spectrometer design. The trial was successful with the species origin of the binding agent contained in each of the 43 test materials being correctly reported by the participants. This is consistent with a false positive and false negative rate of 0%. This is the first collaborative study, as far as we are aware, which involves a liquid chromatography mass spectrometry (LC-MS/MS) application to approach a food authenticity issue.

[Examination of lymph nodes in resected colon segments with colorectal carcinoma]. / Hodnocení lymfatických uzlin v resekátech tlustého streva s kolorektálním karcinomem.

INTRODUCTION: Optimized staging of colorectal carcinoma (CRC) is essential for treatment planning and for estimating the prognosis of the disease. In addition to tumour size and the depth of bowel wall infiltration, the lymph node status is very important for the determination of the disease stage. For this reason, detection and assessment of the maximum number of lymph nodes is emphasized in the examination of resected segments of the large bowel. The number of lymph nodes (LNs) found in the segments resected depends on various circumstances. In our study, we focused on factors which could influence the number of pericolic LNs. MATERIAL AND METHODS: We examined two groups of CRC patients. The first group included 30 patients within the age range of 32-50 years (average: 47.5 years) and the second group consisted of 90 patients aged between 51 and 87 years (average: 68 years). The tumours were localized in various parts of the colon, predominantly in the descending colon and the sigmoid colon. Rectal tumour was present in 23 patients; 13 of them underwent preoperative chemoradiation therapy and 10 of them received no preoperative therapy. The length of the resected colon segments (radical intervention) ranged from 6 to 51 cm. The size of CRC ranged from 0.5 to 15 cm (average: 4.5 cm). The maximum tumour invasion depth reached into the subserosal tissue and pericolic adipose tissue. RESULTS: The number of LNs found in 120 resected colon segments ranged from 1 to 60 LNs per case. The number of LNs showed differences among the patients and also depended on the location of CRC within the large intestine. In the resected segments of the ceacum with CRC, the average number of LNs was 11.5, whereas it was only 7 in rectal CRC. The largest volume of pericolic adipose tissue was found in the caecum, whereas the smallest volume was seen on the rectal circumference. In CRC patients aged 50 years or younger, the number of LNs was from 2 to 60 (average: 17). In contrast, the number of LNs ranged from 1 to 46 (average: 11) in patients older than 50 years. In resected segments that were 6 to 12 cm long, the number of LNs ranged from 1 to 18 (average: 8). In resected segments that were 12 to 51 cm long, the number of LNs was from 1 to 60 (average: 13.8). In 13 cases of rectal CRC with preoperative chemoradiation therapy, small LNs of an average length of 1-3 mm predominated, and the number of LNs ranged between 1 and 13 (average: 5). The required number of 12 LNs was reached in 4 resected parts of the rectum (31%). CONCLUSION: The number of pericolic LNs found in the resected segments of the colon and the rectum with CRC depends on various factors. Besides individual differences, the number of LNs is influenced by the CRC location in the colon, the extent of the resected pericolic adipose tissue, the patients age and the length of the segment resected. In cases of rectal CRCs, it is also influenced by preoperative chemoradiation therapy.

Noiseless loss suppression in quantum optical communication.

We propose a protocol for conditional suppression of losses in direct quantum state transmission over a lossy quantum channel. The method works by noiselessly attenuating the input state prior to transmission through a lossy channel followed by noiseless amplification of the output state. The procedure does not add any noise; hence, it keeps quantum coherence. We experimentally demonstrate it in the subspace spanned by vacuum and single-photon states, and consider its general applicability.

Experimental implementation of the optimal linear-optical controlled phase gate.

We report on the first experimental realization of optimal linear-optical controlled phase gates for arbitrary phases. The realized scheme is entirely flexible in that the phase shift can be tuned to any given value. All such controlled phase gates are optimal in the sense that they operate at the maximum possible success probabilities that are achievable within the framework of postselected linear-optical implementations with vacuum ancillas. The quantum gate is implemented by using bulk optical elements and polarization encoding of qubit states. We have experimentally explored the remarkable observation that the optimum success probability is not monotone in the phase.

Multiple stress fractures in a young female runner.

The effect of exercise on female's bone metabolism has received much attention in recent years. We report on unusual case of a female runner with low body mass and amenorrhea, who suffered 4 stress fractures. Three of the stress fractures occurred during her sports career, and the fourth occurred 7 years after the cessation of sports activities. It seems that exercise-induced amenorrhea together with food restriction in the young age may cause long-term consequences on bone metabolism.

Multiple fibroepithelial polyps of the upper ureter in a 17-year-old boy--case report and review of the literature.

Benign tumours and primary malignant tumours of the ureter are uncommon in adults and extremely rare in children. The clinical symptoms are flank pain, urinary tract infection, and macro/micro-haematuria. There is an incomplete ureteral obstruction and filling defect on intravenous urography (IVU). Optimum treatment of this lesion results in renal preservation. Uretero-renoscopy is currently the best method available for the identification and histological diagnosis of ureteral polyps. Recommended operative procedures are pyeloureteric junction (PUJ) resection with Anderson-Hynes pyeloplasty, ureteric resection with end-to-end anastomosis or with uretero-cysto-neoanastomosis (UCNA), ureteric resection with renal autotransplantation. Ureteronephrectomy is not indicated. A case of ureteral polyps in a 17-year-old boy with the chief complaint of left flank pain is reported here. The excretory urogram and renal scan showed left hydronephrosis. Resection of the pyeloureteral junction, partial resection of the upper ureter containing the lesions--multiple branching 30-40 mm long polyps with a common basis--and Anderson-Hynes pyeloplasty were performed. The pathological diagnosis was benign fibroepithelial polyps of the ureter. Convalescence was uneventful and after 4 years of follow-up, excretory urogram and ultrasonography showed good renal function and improvement of hydronephrosis.

[Uncommon clinical aspects of appendicitis]. / Méne obvyklé prubehy apendicitidy.

During the period between 1980-2000 at the authors department 5114 children with acute appendicitis were operated (on average 245 per year). From this period the year 1999 was selected when 160 children were operated on account of acute appendicitis. Thirty-eight children had an advanced finding--gangrenous appendicitis or an abscess. Gangrenous appendicitis or empyema of the appendix without perforation were recorded in 16 patients (10%), gangrenous appendicitis with perforation in 9 patients (5.6%), a periappendicular abscess in 13 (8.1%), phlegmonous appendicitis was recorded in 108 patients (67.5%) and in 14 patients the histological examination revealed mesenterial lymphadenitis (8.7%). The authors demonstrate on selected case-histories the problem of appendicitis not recognized in time and appendicitis with an atypical course. They draw attention to the uncommon clinical course in 5 patients where at first a tumour of the upper mediastinum, tumour of the abdominal cavity, twice diarrhoeal disease and a tumour in the lesser pelvis was suspected. The authors emphasize that even at a time when special examinations are available (ultrasonography, computed tomgraphy) it is important to make repeated clinical examinations of the patients at least in the course of three days.

Five-dimensional structure refinement of natural melilite, (Ca(1.89)Sr(0.01)Na(0.08)K(0.02))(Mg(0.92)Al(0.08)-(Si(1.98)Al(0.02))O(7).

The structure of a crystal of natural melilite from San Venanzo, Umbria (Italy) of the general formula X(2)T1(T2)(2)O(7), where X = Ca(0.945)Sr(0.005)Na(0.04)K(0.01), T1 = Mg(0.92)Al(0.08) and T2 = Si(0.99)Al(0.01), has been solved and refined as an incommensurate structure in five-dimensional superspace. The structure is tetragonal, superspace group P(-)42(1)m:p4mg, cell parameters a = 7.860 (1), c = 5.024 (1) A, modulation vectors q(1) = 0.2815 (3)(a* + b*), q(2) = 0.2815 (3)(-a* + b*). The data collection was performed on a KumaCCD diffractometer. The structure was refined from 7606 reflections to final R = 0.0481. A special modification of the refinement program Jana2000 was necessary to take into account overlapping of satellite reflections m x n = +/-1, which could not be properly separated in the integration procedure. The final model includes modulations of the atomic positions as well as modulations of the thermal parameters. The latter are induced by strong differences in the neighbourhood of the actual modulated positions. The occupational modulation was neither significant for X nor for T1 sites and the sites were supposed to be occupied only by Ca and Mg, respectively. As a consequence of the Ca and O positional modulations six-, seven- and eightfold Ca coordination occur throughout the structure and the thermal ellipsoid changes its shape correspondingly. The positional modulation of the atoms causes variations in the interatomic distances which, however, do not affect bond-valence sums considerably, but induce flattening and rotation in T1 and T2 tetrahedra, respectively.

[Treatment of hypospadias in childhood]. / Lécba hypospadie v detském veku.

The aim of the paper is to compare different techniques of correction of hypospadias with the author's own group of patients and to compare the results with those achieved at other departments. Between 1992-1999 at the Department of Paediatric Surgery, Teaching Hospital Motol 348 operations were made in 219 boys. A plastic operation with a distal shift of the urethra a and conization of the glans in 112 patients predominated. Other methods included in 39 patients the creation of a ventral circumference of the urethra from the inner laver of the prepuce while preserving the urethral plate ("onlay island flap") and a parameatally everted flap according to Mathieu in 11 patients. A plastic operation by complete tubulization of the inner laver of the prepuce was used in 19 patients, in 2 boys the method of Duplay-Byars tubulization of the urethral plate. In one patient the urethra was replaced by a free flap as described by Nove Josserand. Another 129 operations included formerly used and now abandoned two-stage operations to straighten the penis, operations to reconstruct the prepuce and operations on account of complications. The latter comprised 16.4% fistulae, 9.58% dehiscences and 1.36% strictures.

Modulated structure of La2Co1.7 from neutron and X-ray diffraction data

An La(2)Co(1.7) crystal was investigated by single-crystal neutron and X-ray diffraction. The neutron measurement was performed with a Laue white-beam technique at 15 K and room temperature, using a large position-sensitive detector. The X-ray measurements were obtained at room temperature from a CCD detector. The average structure of La(2)Co(1.7) is hexagonal with cell parameters a = 4. 885 (1), c = 4.273 (2) A and space group P6(3)/mmc. The satellites are located at the vertices of small hexagons perpendicular to the c axis. The modulated crystal was indexed assuming a sixfold twinned 3 + 1 dimensional structure with q = (alpha, 0, gamma). The structure was solved in the pseudoorthorhombic cell, with a = 8.461 (1), b = 4. 885 (1), c = 4.273 (2) A, in the superspace group C2/m(alpha, 0, gamma). Owing to space requirements, the Co atoms cannot fit precisely into the octahedral sites of the La h.c.p. (hexagonal close packing). Instead, the Co atoms adopt a different periodicity, which is not commensurate with the periodicity of the La atoms. Two structure models have been refined in order to describe this behaviour, one using the sawtooth function for the positional modulation of cobalt and the other describing the structure as a composite system. The chemical composition calculated from the composite model is La(2)Co(1.8 (1)) with the estimated standard deviation arising from the variation of q for different samples. In both models lanthanum is incommensurately modulated, while the position of cobalt seems not to be affected by any relative periodic displacement.

Determination of the modulated structure of Sr14/11CoO3 through a (3 + 1)-dimensional space description and using non-harmonic ADPs.

Sr(14/11)CoO(3) (i.e. Sr(14)Co(11)O(33), tetradecastrontium undecacobalt tritriacontaoxide), a new phase in the hexagonal perovskite Sr(x)CoO(3) system, has been prepared and its structure solved from single-crystal X-ray data within the (3 + 1)-dimensional formalism. Sr(14/11)CoO(3) crystallizes in the trigonal symmetry, R3;m(00gamma)0s superspace group with the following lattice parameters: a(s) = 9.508 (2), c(s) = 2.5343 (7) Å, q = 0.63646 (11)c(*) and V(s) = 198.40 (13) Å(3). With the commensurate versus incommensurate test not being conclusive, the structure was considered as commensurate (P32 three-dimensional space group), but refined within the (3 + 1)-dimensional formalism to a residual factor R = 0.0351 for 47 parameters and 1169 independent reflections. Crenel functions were used for the oxygen and cobalt description and a Gram-Charlier expansion up to the third order of the atomic displacement parameter was employed for one Co atom. The structure is similar to that of Sr(6/5)CoO(3), but with a different sequence of the octahedra and trigonal prism polyhedra along the [CoO(3)] chains. An interesting feature evidenced by the non-harmonic expansion is the displacement of the prismatic Co atoms from the site center, towards the prism rectangular faces.

[Use of duplex sonography in selecting the most suitable part of the great saphenous vein (parva) for myocardial revascularization]. / Vyuzití duplexní sonografie k vyhledání nejvhodnejsího useku v. saphena magna (parva) k revaskularizacní operaci myokardu.

The submitted investigation deals with the first experiences with duplex sonography using to evaluate the superficial vein system on patients before aortocoronary bypass grafting. We examined 40 patients. In all cases we already could evaluate the quality of vein bed (diameter, anatomy, pathology) before operation and we could determine the best part of vein bed for harvesting. The advantages of this noninvasive method are smaller number of incisions (it results in better healing with less wound infectious complications), better quality and shorter time of harvesting.