Coherent singlet-triplet oscillations in a silicon-based double quantum dot.

Silicon is more than the dominant material in the conventional microelectronics industry: it also has potential as a host material for emerging quantum information technologies. Standard fabrication techniques already allow the isolation of single electron spins in silicon transistor-like devices. Although this is also possible in other materials, silicon-based systems have the advantage of interacting more weakly with nuclear spins. Reducing such interactions is important for the control of spin quantum bits because nuclear fluctuations limit quantum phase coherence, as seen in recent experiments in GaAs-based quantum dots. Advances in reducing nuclear decoherence effects by means of complex control still result in coherence times much shorter than those seen in experiments on large ensembles of impurity-bound electrons in bulk silicon crystals. Here we report coherent control of electron spins in two coupled quantum dots in an undoped Si/SiGe heterostructure and show that this system has a nuclei-induced dephasing time of 360 nanoseconds, which is an increase by nearly two orders of magnitude over similar measurements in GaAs-based quantum dots. The degree of phase coherence observed, combined with fast, gated electrical initialization, read-out and control, should motivate future development of silicon-based quantum information processors.

[Effectiveness of chronopharmacotherapy in salt-sensitive and salt-resistant patients with chronic heart failure and preserved ejection fraction].

The aim of the study was to evaluate the influence of chronopharmacotherapy on the indices of the structural and functional state of the left ventricular myocardium in patients with arterial hypertension (AH), type 2 diabetes mellitus and heart failure with preserved ejection fraction (HFpEF) considering of salt-sensitivity. MATERIALS AND METHODS: Included 130 patients with uncontrolled AH, type 2 diabetes and HFpEF (81 women and 49 men), median age - 59 (38-72) years. Patients were divided into 2 groups: saltsensitive (group 1) and salt-resistant (group 2), and then randomized to 2 subgroups depending on the treatment option: morning ramipril and indapamide retard, in the evening amlodipine (subgroup 1A and 2A) or in the evening ramipril, in the morning indapamide-retard and amlodipine (subgroup 1B and 2B). Initially and after 24 weeks of antihypertensive therapy, an echocardiographic study was carried out with an assessment of the main indicators of the structural and functional state of the left ventricular (LV) myocardium, a 6-minute walk test for determining the functional state of patients. RESULTS: After 24 weeks in all subgroups there was a reliable positive dynamics of echocardiographic indicators. In the group of salt-sensitive patients, the reception of the angiotensin converting enzyme inhibitor (ACE inhibitor) in the evening and thiazide diuretic (TD) + calcium antagonists (AC) in the morning provided a signifcantly more signifcant reduction in the majority of LV myocardial remodeling parameters compared with the administration of ACE inhibitor + TD in the morning and AK in the evening. In the case of salt-resistant patients, comparable positive changes in echocardiographic indicators were noted against the background of both dosing regimens during the day. Against the background of the treatment, irrespective of the salt sensitivity and dosing regimen, an unreliable and comparable increase in the distance of the 6-minute walk test was recorded during the day. CONCLUSION: In salt-sensitive patients with AH, type 2 diabetes and HFpEF, the use of ACE inhibitor before bedtime provided signifcantly more signifcant regression of the parameters of the structural and functional state of LV myocardium compared with the morning reception. In the group of salt-resistant patients, the efcacy of both dosing regimens during the day was comparable.

Reduced Sensitivity to Charge Noise in Semiconductor Spin Qubits via Symmetric Operation.

We demonstrate improved operation of exchange-coupled semiconductor quantum dots by substantially reducing the sensitivity of exchange operations to charge noise. The method involves biasing a double dot symmetrically between the charge-state anticrossings, where the derivative of the exchange energy with respect to gate voltages is minimized. Exchange remains highly tunable by adjusting the tunnel coupling. We find that this method reduces the dephasing effect of charge noise by more than a factor of 5 in comparison to operation near a charge-state anticrossing, increasing the number of observable exchange oscillations in our qubit by a similar factor. Performance also improves with exchange rate, favoring fast quantum operations.

Undoped accumulation-mode Si/SiGe quantum dots.

We report on a quantum dot device design that combines the low disorder properties of undoped SiGe heterostructure materials with an overlapping gate stack in which each electrostatic gate has a dominant and unique function-control of individual quantum dot occupancies and of lateral tunneling into and between dots. Control of the tunneling rate between a dot and an electron bath is demonstrated over more than nine orders of magnitude and independently confirmed by direct measurement within the bandwidth of our amplifiers. The inter-dot tunnel coupling at the [Formula: see text] charge configuration anti-crossing is directly measured to quantify the control of a single inter-dot tunnel barrier gate. A simple exponential dependence is sufficient to describe each of these tunneling processes as a function of the controlling gate voltage.

[Compressive-distractive method for complex lower and upper jaw defects restoration in preparative procedures before implant placement].

Distraction method in reconstructive maxillofacial surgery allows achieving optimal aesthetic and functional results. The study included 198 patients with various alveolar bone defects and 224 dental implants placed after successful alveolar bone distraction. Complex oral rehabilitation was possible after 4 month retention period.

Single-spin qubits in isotopically enriched silicon at low magnetic field.

Single-electron spin qubits employ magnetic fields on the order of 1 Tesla or above to enable quantum state readout via spin-dependent-tunnelling. This requires demanding microwave engineering for coherent spin resonance control, which limits the prospects for large scale multi-qubit systems. Alternatively, singlet-triplet readout enables high-fidelity spin-state measurements in much lower magnetic fields, without the need for reservoirs. Here, we demonstrate low-field operation of metal-oxide-silicon quantum dot qubits by combining coherent single-spin control with high-fidelity, single-shot, Pauli-spin-blockade-based ST readout. We discover that the qubits decohere faster at low magnetic fields with [Formula: see text] µs and [Formula: see text] µs at 150 mT. Their coherence is limited by spin flips of residual 29Si nuclei in the isotopically enriched 28Si host material, which occur more frequently at lower fields. Our finding indicates that new trade-offs will be required to ensure the frequency stabilization of spin qubits, and highlights the importance of isotopic enrichment of device substrates for the realization of a scalable silicon-based quantum processor.

Telemedicine and international disaster response. Medical consultation to Armenia and Russia via a Telemedicine Spacebridge.

UNLABELLED: The Telemedicine Spacebridge, a satellite-mediated, audio-video-fax link between four United States and two Armenian and Russian medical centers, permitted remote American consultants to assist Armenian and Russian physicians in the management of medical problems following the December 1988 earthquake in Armenia and the June 1989 gas explosion near Ufa. METHODS: During 12 weeks of operations, 247 Armenian and Russian and 175 American medical professionals participated in 34 half-day clinical conferences. A total of 209 patients were discussed, requiring expertise in 20 specialty areas. RESULTS: Telemedicine consultations resulted in altered diagnoses for 54, new diagnostic studies for 70, altered diagnostic processes for 47, and modified treatment plans for 47 of 185 Armenian patients presented. Simultaneous participation of several US medical centers was judged beneficial; quality of data transmission was judged excellent. CONCLUSION: These results suggest that interactive consultation by remote specialists can provide valuable assistance to on-site physicians and favorably influence clinical decisions in the aftermath of major disasters.

Telemedicine and international disaster response: medical consultation to Armenia and Russia via a Telemedicine Spacebridge.

UNLABELLED: The Telemedicine Spacebridge, a satellite-mediated, audio-video-fax link between four United States and two Armenian and Russian medical centers, permitted remote American consultants to assist Armenian and Russian physicians in the management of medical problems following the December 1988 earthquake in Armenia and the June 1989 gas explosion near Ufa. METHODS: During 12 weeks of operations, 247 Armenian and Russian and 175 American medical professionals participated in 34 half-day clinical conferences. A total of 209 patients were discussed, requiring expertise in 20 specialty areas. RESULTS: Telemedicine consultations resulted in altered diagnoses for 54, new diagnostic studies for 70, altered diagnostic processes for 47, and modified treatment plans for 47 of 185 Armenian patients presented. Simultaneous participation of several US medical centers was judged beneficial; quality of data transmission was judged excellent. CONCLUSION: These results suggest that interactive consultation by remote specialists can provide valuable assistance to on-site physicians and favorably influence clinical decisions in the aftermath of major disasters.

[The surgical procedure in acute calculous cholecystitis]. / O khirurgicheskoi taktike pri ostrom kal'kuleznom kholetsistite.

The conservative treatment in the cases of primary attack of acute calculous cholecystitis is not effective, this is one of the results of the analysis made on the basis of the experience of thirty years and treatment of 3520 patients with acute cholecystitis. Thus, 90% of such acute attacks turn into chronic, and frequently into relapse forms, besides this 75% of patients get complicated forms of illness already in the first year of treatment. Active surgical and medical tactics give the possibility to reduce the postoperative lethality by 6 times and the number of postoperative complications by more than 2.5 times.

[Animal and human cestoda infection (sparganosis)]. / Spirometroz (sparganoz) zhivotnykh i cheloveka.

Spirometrosis (sparganosis) in animals and man is a serious ecological problem in Russia, which requires the constant attention of veterinary and medical services. The paper presents data on the biology of the parasite Spirometra erinacei europaei Muller, 1937, an account and diagram of a developmental cycle, and original photos of parasitic eggs, plerocercoids, strobiles, and cestode joint from animals.

Economic aspects of health.

This study described in this article was undertaken to assess the possibility of getting a general picture of the public health situation to be used in such economically oriented models as cost-benefit, cost-effectiveness and cost-utility. Problems of data bases encountered in this assessment of various republics, regions and administrative entities are also considered. New mathematicodemographic statistical models and a family of potential factographic automated information reference systems (FAIRS) based on these models and designed to be utilized in projects, programmes and regional systems of public health are analysed.

[Myocardial reaction of the right ventricle to lung resection]. / Reaktsiia miokarda pravogo zheludochka serdtsa na rezektsii legkikh.

Right-sided pulmonectomy (resection of 63-65% of the lung parenchyma) in white noninbred rats resulted in development of chronic cor pulmonale, that develops according to the stages: I--from the time of the operation up to the 10th-15th days after the operation--the stage of acute disturbances and mobilization forces of the organism; II--from the 11th-15th up to the 90th day is the stage of a relative steady compensatory hypertrophy of the cardiac right ventricle; III--after the 90th day--the stage of decompensation. The hypertrophy of the right ventricle myocardium transfers into its dilatation. Amount of cardiomyocytes and their nuclei in 1 mg of the right ventricle tissue progressively decreases, quantity of multinuclear cardiomyocytes increases, ploidy of the nuclei changes: number of tetraploid nuclei decreases, octaploid nuclei appear. Lethality among the animals is 56%.

[The innovative process in public health institutions as mirrored by public opinion]. / Innovatsionnyi protsess v uchrezhdeniiakh zdravookhraneniia v prizme obshchestvennogo mneniia.

Problems related to innovations in the health care system and the susceptibility of medico-prophylactic institutions to advanced methodologies are discussed. Analysis of questionnaires has revealed the absence of a well-organized work for the introduction of innovations in the medical collectives, and a low interest in their introduction and exploration on the part of physicians and their authorities. The innovative activity is high enough in regional health units, but in those dealing with mass-scale medical care, rural in particular, introduction of new methodologies is much slower. At the same time, collectives of medical workers show their potential readiness to accept and explore the new advanced methodologies, which has not been realized due to the poor economic basis, low organizational level, and deficient resources. Ways to improve the process of introduction of innovative methodologies into clinical practice are offered for discussion.