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1.
Nano Lett ; 21(9): 3715-3720, 2021 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-33635656

RESUMO

The rapid development of artificial neural networks and applied artificial intelligence has led to many applications. However, current software implementation of neural networks is severely limited in terms of performance and energy efficiency. It is believed that further progress requires the development of neuromorphic systems, in which hardware directly mimics the neuronal network structure of a human brain. Here, we propose theoretically and realize experimentally an optical network of nodes performing binary operations. The nonlinearity required for efficient computation is provided by semiconductor microcavities in the strong quantum light-matter coupling regime, which exhibit exciton-polariton interactions. We demonstrate the system performance against a pattern recognition task, obtaining accuracy on a par with state-of-the-art hardware implementations. Our work opens the way to ultrafast and energy-efficient neuromorphic systems taking advantage of ultrastrong optical nonlinearity of polaritons.


Assuntos
Inteligência Artificial , Redes Neurais de Computação , Encéfalo , Humanos , Neurônios , Semicondutores
2.
Phys Rev Lett ; 127(19): 190401, 2021 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-34797125

RESUMO

Spin-orbit interactions which couple the spin of a particle with its momentum degrees of freedom lie at the center of spintronic applications. Of special interest in semiconductor physics are Rashba and Dresselhaus spin-orbit coupling. When equal in strength, the Rashba and Dresselhaus fields result in SU(2) spin rotation symmetry and emergence of the persistent spin helix only investigated for charge carriers in semiconductor quantum wells. Recently, a synthetic Rashba-Dresselhaus Hamiltonian was shown to describe cavity photons confined in a microcavity filled with optically anisotropic liquid crystal. In this Letter, we present a purely optical realization of two types of spin patterns corresponding to the persistent spin helix and the Stern-Gerlach experiment in such a cavity. We show how the symmetry of the Hamiltonian results in spatial oscillations of the spin orientation of photons traveling in the plane of the cavity.

3.
Nano Lett ; 20(5): 3506-3512, 2020 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-32251601

RESUMO

Machine learning software applications are ubiquitous in many fields of science and society for their outstanding capability to solve computationally vast problems like the recognition of patterns and regularities in big data sets. In spite of these impressive achievements, such processors are still based on the so-called von Neumann architecture, which is a bottleneck for faster and power-efficient neuromorphic computation. Therefore, one of the main goals of research is to conceive physical realizations of artificial neural networks capable of performing fully parallel and ultrafast operations. Here we show that lattices of exciton-polariton condensates accomplish neuromorphic computing with outstanding accuracy thanks to their high optical nonlinearity. We demonstrate that our neural network significantly increases the recognition efficiency compared with the linear classification algorithms on one of the most widely used benchmarks, the MNIST problem, showing a concrete advantage from the integration of optical systems in neural network architectures.

4.
Chemistry ; 25(58): 13309-13317, 2019 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-31328310

RESUMO

The synthesis of the protected form of 2-methylthio-N6 -threonylcarbamoyl adenosine (ms2 t6 A) was developed starting from adenosine or guanosine by using the optimized carbamate method and, for the first time, an isocyanate route. The hypermodified nucleoside was subsequently transformed into the protected ms2 t6 A-phosphoramidite monomer and used in a large-scale synthesis of the precursor 17nt ms2 t6 A-oligonucleotide (the anticodon stem and loop fragment of tRNALys from T. brucei). Finally, stereochemically secure ms2 t6 A→ms2 ct6 A cyclization at the oligonucleotide level efficiently afforded a tRNA fragment bearing the ms2 ct6 A unit. The applied post-synthetic approach provides two sequentially homologous ms2 t6 A- and ms2 ct6 A-oligonucleotides that are suitable for further comparative structure-activity relationship studies.


Assuntos
Adenosina/análogos & derivados , Oligorribonucleotídeos/síntese química , RNA de Transferência/química , Treonina/análogos & derivados , Adenosina/química , Sequência de Bases , Carbamatos/química , Ciclização , Guanosina/química , Isocianatos/química , Conformação de Ácido Nucleico , Compostos Organofosforados/química , Relação Estrutura-Atividade , Treonina/síntese química , Treonina/química
5.
Nucleic Acids Res ; 45(4): 2137-2149, 2017 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-27913732

RESUMO

N6-Threonylcarbamoyladenosine (t6A) and its derivatives are universally conserved modified nucleosides found at position 37, 3΄ adjacent to the anticodon in tRNAs responsible for ANN codons. These modifications have pleiotropic functions of tRNAs in decoding and protein synthesis. In certain species of bacteria, fungi, plants and protists, t6A is further modified to the cyclic t6A (ct6A) via dehydration catalyzed by TcdA. This additional modification is involved in efficient decoding of tRNALys. Previous work indicated that the chemical structure of ct6A is a cyclic active ester with an oxazolone ring. In this study, we solved the crystal structure of chemically synthesized ct6A nucleoside. Unexpectedly, we found that the ct6A adopted a hydantoin isoform rather than an oxazolone isoform, and further showed that the hydantoin isoform of ct6A was actually present in Escherichia coli tRNAs. In addition, we observed that hydantoin ct6A is susceptible to epimerization under mild alkaline conditions, warning us to avoid conventional deacylation of tRNAs. A hallmark structural feature of this isoform is the twisted arrangement of the hydantoin and adenine rings. Functional roles of ct6A37 in tRNAs should be reconsidered.


Assuntos
Adenosina/análogos & derivados , Hidantoínas/química , RNA de Transferência/química , RNA de Transferência/metabolismo , Adenosina/síntese química , Adenosina/química , Adenosina/metabolismo , Escherichia coli/genética , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Estrutura Molecular , Conformação de Ácido Nucleico , RNA Bacteriano/química , RNA Bacteriano/metabolismo
6.
Nucleic Acids Res ; 45(4): 2124-2136, 2017 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-27913733

RESUMO

Transfer RNA modifications play pivotal roles in protein synthesis. N6-threonylcarbamoyladenosine (t6A) and its derivatives are modifications found at position 37, 3΄-adjacent to the anticodon, in tRNAs responsible for ANN codons. These modifications are universally conserved in all domains of life. t6A and its derivatives have pleiotropic functions in protein synthesis including aminoacylation, decoding and translocation. We previously discovered a cyclic form of t6A (ct6A) as a chemically labile derivative of t6A in tRNAs from bacteria, fungi, plants and protists. Here, we report 2-methylthio cyclic t6A (ms2ct6A), a novel derivative of ct6A found in tRNAs from Bacillus subtilis, plants and Trypanosoma brucei. In B. subtilis and T. brucei, ms2ct6A disappeared and remained to be ms2t6A and ct6A by depletion of tcdA and mtaB homologs, respectively, demonstrating that TcdA and MtaB are responsible for biogenesis of ms2ct6A.


Assuntos
Adenosina/análogos & derivados , RNA de Transferência/química , RNA de Transferência/metabolismo , Treonina/análogos & derivados , Adenosina/química , Adenosina/metabolismo , Bacillus subtilis/genética , Bacillus subtilis/metabolismo , Sequência de Bases , Conformação de Ácido Nucleico , Fenótipo , RNA de Plantas/química , RNA de Plantas/metabolismo , Espectrometria de Massas por Ionização por Electrospray , Treonina/química , Treonina/metabolismo
7.
Opt Express ; 26(5): 6267-6275, 2018 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-29529818

RESUMO

By designing an appropriate defect potential in a nonresonantly pumped exciton-polariton condensate, the polariton dyad consisting of two spatially separated condensates with phase locking can be realized. We use the phase coupling of the polariton dyad to investigate the existence of both dark and anti-dark solitons in the condensates. Surprisingly, these dissipative solitons appear to be stable and are not affected by the noise both from the initial condition and from the propagation. We show that these stable solitons are transformed from a spontaneously created metastable states by choosing the state with the highest particle number.

9.
Urol Int ; 101(3): 277-284, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30227437

RESUMO

PURPOSE: To evaluate if there are differences in toxicity and efficacy between different Bacillus Calmette-Guerin (BCG) stains used for intravesical immunotherapy in patients with non-muscle invasive bladder cancer. METHODS: We retrospectively analysed a group of 844 patients who received TICE, RIVM and Moreau BCG strains. The allocation of the strain to each patient was random, stemming from differences in supply and distribution. The patients were analysed in terms of toxicity, recurrence-free (RFS), progression-free (PFS), cancer-specific (CSS) and overall survival (OS). RESULTS: In the survival analysis, statistical significance was not reached in any tumour group for any clinical event. TICE caused more local and mild adverse effects and severe complications were mainly associated with RIVM strain. In a group in which the strain was changed during the course of the therapy, significantly more severe complications were observed and, in most of these cases, complications appeared right after the strain change. CONCLUSIONS: There were no differences in terms of RFS, PFS, CSS and OS after use of TICE, RIVM and Moreau strains. The complication profile differed statistically between used strains with TICE causing mostly mild complications. Also, strain change during the therapy course was associated with the increased risk of moderate to severe toxicity occurrence.


Assuntos
Vacina BCG/toxicidade , Vacina BCG/uso terapêutico , Neoplasias da Bexiga Urinária/tratamento farmacológico , Administração Intravesical , Adulto , Idoso , Idoso de 80 Anos ou mais , Progressão da Doença , Intervalo Livre de Doença , Feminino , Humanos , Imunoterapia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Estudos Retrospectivos , Especificidade da Espécie , Resultado do Tratamento , Neoplasias da Bexiga Urinária/mortalidade
10.
Bioorg Med Chem Lett ; 24(12): 2703-6, 2014 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-24794109

RESUMO

A cyclic form of N(6)-threonylcarbamoyladenosine bearing an oxazolone moiety (ct(6)A) was discovered very recently at the position 37 in several tRNA sequences. Our study on the synthesized 5',3',2'-O-acetylated derivative of ct(6)A confirmed high stability of the modified nucleoside under physiological conditions (PBS buffer, pH 7.4) and revealed remarkable stability of the oxazolone ring in acidic (100mM HCl, pH 1) and basic (0.1mM NaOH, pH 10) conditions. This feature may allow for the post-synthetic conversion of t(6)A into ct(6)A in assembled oligoribonucleotides.


Assuntos
Adenosina/análogos & derivados , Descoberta de Drogas , RNA de Transferência/química , Adenosina/química , Ciclização , Estabilidade de Medicamentos , Espectroscopia de Ressonância Magnética , Estrutura Molecular
11.
Phys Rev Lett ; 110(4): 045303, 2013 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-25166176

RESUMO

We consider a phase transition from an antiferromagnetic to a phase separated ground state in a spin-1 Bose-Einstein condensate of ultracold atoms. We demonstrate the occurrence of two scaling laws, for the number of spin domain seeds just after the phase transition, and for the number of spin domains in the final, stable configuration. Only the first scaling can be explained by the standard Kibble-Zurek mechanism. We explain the occurrence of two scaling laws by a model including postselection of spin domains due to the conservation of condensate magnetization.

12.
Ann Agric Environ Med ; 30(1): 142-147, 2023 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-36999867

RESUMO

INTRODUCTION AND OBJECTIVE: In COVID-19, the rapid prediction of the severity of a patient's condition using modern biomarkers can accelerate the implementation of appropriate therapy, and thus improve the patient's prognosis. MATERIAL AND METHODS: A meta-analysis was conducted of data available in the literature on the differences in baseline suPAR blood concentration between patients (1) who tested positive and negative for COVID-19, (2) who had severe and non-severe COVID-19, and (3) COVID-19 survivors and non-survivors. RESULTS: SuPAR levels in SARS-CoV-2 negative and positive patients varied and amounted to 3.61±1.59 ng/ml vs. 6.45±3.13 ng/ml, respectively (MD = -3.18; 95%CI: -4.71 to -1.66; p<0.001). suPAR levels among non-severe and severe COVID-19 patients were 7.06±2.64 ng/ml and 5.06±3.16 ng/ml (MD = 0.18; 95%CI: -2.48 to 2.83; p=0.90), respectively. Pooled analysis showed that suPAR levels between severe versus critical COVID-19 patients to be 5.59±1.54 ng/ml and 6.49±1.43 ng/ml, respectively (MD = -1.00; 95%CI: -1.31 to -0.70; p<0.001). The suPAR levels between ICU survivors versus non-survivors amounted to 5.82±2.33 ng/ml and 8.43±4.66 ng/ml (MD = -3.59; 95%CI: -6.19 to -1.00; p=0.007). In the case of in-hospital mortality, the mean suPAR level among survivors to hospital discharge was 5.63±1.27 ng/ml, compared to 7.85±2.61 ng/ml for patients who did not survive (MD = -3.58; 95%CI: -5.42 to -1.74; p<0.001). CONCLUSIONS: SuPAR levels are significantly elevated in severe COVID-19 illness and maybe useful in predicting mortality. Further studies are needed to determine cut-off points and clarify the association of suPAR levels with disease progression. This is of utmost importance given the ongoing pandemic and overburdened health care systems.


Assuntos
COVID-19 , Receptores de Ativador de Plasminogênio Tipo Uroquinase , Humanos , SARS-CoV-2 , Progressão da Doença , Biomarcadores
13.
Expert Rev Med Devices ; 20(11): 943-950, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37668350

RESUMO

BACKGROUND: Airway management in life-threatening emergencies is essential for children, and endotracheal intubation is the gold standard. It protects against regurgitation and enables mechanical ventilation. New types of airway management equipment are being developed and implemented to meet the needs of medical personnel. RESEARCH DESIGN AND METHODS: This prospective, randomized, cross-over simulation trial evaluated the success of endotracheal intubation in three scenarios: normal airway (scenario-A), tongue edema (scenario-B), and continuous chest compression (scenario-C), using the bébé Vie Scope™ laryngoscope (VieScope) and the Macintosh blade laryngoscope (MAC) as a comparative tool performed by nurses with limited tracheal intubation experience. RESULTS: The results of the study showed that in scenario-A, there were no significant differences in the first attempt success rate or endotracheal intubation time between VieScope and MAC. However, VieScope was associated with better visualization of the glottis. In scenarios B and C, VieScope was significantly more effective than MAC in terms of first-pass success rate, time to intubate, Cormack-Lehane grade, POGO score, and ease of endotracheal intubation. CONCLUSIONS: Bébé VieScope may be useful for endotracheal intubation in pediatric patients, particularly in cases of tongue edema and ongoing chest compression, providing a higher first-pass success rate than conventional laryngoscopes.


Assuntos
Reanimação Cardiopulmonar , Laringoscópios , Humanos , Criança , Estudos Prospectivos , Manequins , Manuseio das Vias Aéreas , Intubação Intratraqueal , Edema
14.
Phys Rev Lett ; 108(6): 060401, 2012 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-22401039

RESUMO

We investigate the ground states of a Bose-Einstein condensate of indirect excitons coupled to an electron gas. We show that in a properly designed system the crossing of a roton minimum into the negative energy domain can result in the appearance of the supersolid phase, characterized by periodicity in both real and reciprocal space. Accounting for the spin-dependent exchange interaction of excitons we obtain ferromagnetic supersolid domains. The Fourier spectra of excitations of weakly perturbed supersolids show pronounced diffraction maxima which may be detected experimentally.

15.
Artigo em Inglês | MEDLINE | ID: mdl-36361485

RESUMO

Cystatin C is a specific biomarker of kidney function. We perform this meta-analysis to determine the association of Cystatin C with the COVID-19 severity. In this systematic review and meta-analysis, we searched PubMed, EMBASE, Cochrane library, and Web of Science for studies published until 2nd September 2022 that reported associations between Cystatin C levels and COVID-19 severity. The analysis was performed using a random-effects model to calculate pooled standard mean difference (SMD). Twenty-five studies were included in the meta-analysis. Pooled analysis showed statistically significant differences of Cystatin C levels among survive vs. decreased patients (0.998 ± 0.225 vs. 1.328 ± 0.475 mg/dL, respectively; SMD = -2.14; 95%CI: -3.28 to -1.01; p < 0.001). Cystatin C levels in COVID-19 severe vs. non-severe groups varied and amounted to 1.485 ± 1.191 vs. 1.014 ± 0.601 mg/dL, respectively (SMD = 1.81; 95%CI: 1.29 to 2.32; p < 0.001). Additionally, pooled analysis showed that Cystatin C levels in patients with acute kidney injury (AKI) was 1.562 ± 0.885 mg/dL, compared to 0.811 ± 0.108 mg/dL for patients without AKI (SMD = 4.56; 95%CI: 0.27 to 8.85; p = 0.04). Summing up, Cystatin C is a potentially very good marker to be used in the context of COVID-19 disease due to the prognosis of patients' serious condition, risk of AKI and mortality. In addition, Cystatin C could be used as a marker of renal complications in COVID-19 other than AKI due to the need to monitor patients even longer after leaving the hospital.


Assuntos
Injúria Renal Aguda , COVID-19 , Humanos , Injúria Renal Aguda/epidemiologia , Injúria Renal Aguda/etiologia , Biomarcadores , Cistatina C , Prognóstico
16.
J Clin Med ; 11(21)2022 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-36362828

RESUMO

The SARS-CoV-2 (COVID-19) pandemic is a major issue that necessitates the use of cutting-edge disease prediction models. The aim of the study was to assess the existing evidence regarding association between Krebs von den Lungen-6 levels and COVID-19 severity. A literature search was performed on Web of Science, PubMed, Scopus and Cochrane Central Register of Controlled Trials databases from 1 January 2020 up to 2 August 2022. The electronic database search was supplemented by searching Google Scholar. In addition, reference lists of relative articles were also reviewed. KL-6 levels among COVID-19 positive vs. negative patients varied and amounted to 443.37 ± 249.33 vs. 205.73 ± 86.8 U/mL (MD = 275.33; 95%CI: 144.57 to 406.09; p < 0.001). The KL-6 level was 402.82 ± 261.16 U/mL in the severe group and was statistically significantly higher than in the non-severe group (297.38 ± 90.46 U/mL; MD = 192.45; 95%CI: 118.19 to 266.72; p < 0.001). The KL-6 level in the mild group was 272.28 ± 95.42 U/mL, compared to 268.04 ± 55.04 U/mL in the moderate COVID-19 group (MD = −12.58; 95%CI: −21.59 to −3.57; p = 0.006). Our meta-analysis indicates a significant association between increased KL-6 levels and SARS-CoV-2 infection. Moreover, KL-6 levels are significantly higher in patients with a more severe course of COVID-19, indicating that KL-6 may be a useful predictor to identify patients at risk for severe COVID-19.

17.
Biomolecules ; 11(12)2021 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-34944460

RESUMO

BACKGROUND: Uroplakins (UPs) are glycoproteins that play a specific role in the structure and function of the urothelium. Disorders which affect the normal expression of UPs are associated with the pathogenesis of infections and neoplasms of the urinary tract, primary vesicoureteral reflux, hydronephrosis and renal dysfunction. The appearance of uroplakins in the urine and/or plasma may be of potential importance in the detection of urinary tract dysfunction. The aim of the present study was to investigate uroplakin IIIa (UPIIIa) and uroplakin II (UPII) expression in patients with selected urological diseases. METHODS: Plasma and urine from patients with benign prostatic hyperplasia (BPH), urethral stricture (US), urinary tract infection (UTI) and urolithiasis were compared to healthy people without urological disorders. UPs concentrations were measured by the immunoenzymatic method. RESULTS: In patients with BPH and UTI, concentrations of UPIIIa in urine and plasma, as well as UPII in urine, were statistically significantly higher than in the control groups. In the US group, only the plasma UPIIIa concentration differed significantly from the control. CONCLUSION: The conducted research shows that benign urological diseases may affect the state of the urothelium, as manifested by increased concentrations of both UPs in patients' urine and plasma, especially in BPH and UTI.


Assuntos
Doenças Urológicas , Uroplaquina II , Adulto , Humanos , Pessoa de Meia-Idade , Uroplaquina III
18.
IEEE Trans Neural Netw Learn Syst ; 32(7): 3148-3155, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32735539

RESUMO

Reconstructing quantum states is an important task for various emerging quantum technologies. The process of reconstructing the density matrix of a quantum state is known as quantum state tomography. Conventionally, tomography of arbitrary quantum states is challenging as the paradigm of efficient protocols has remained in applying specific techniques for different types of quantum states. Here, we introduce a quantum state tomography platform based on the framework of reservoir computing. It forms a quantum neural network and operates as a comprehensive device for reconstructing an arbitrary quantum state (finite-dimensional or continuous variable). This is achieved with only measuring the average occupation numbers in a single physical setup, without the need of any knowledge of optimum measurement basis or correlation measurements.

19.
Phys Rev Lett ; 105(2): 020405, 2010 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-20867690

RESUMO

We show that metastable phases of an antiferromagnetic spin-1 condensate in a simple model with pure contact interactions can exhibit a rotonlike minimum in the excitation spectrum. The introduction of a magnetic field gives rise to the instability of roton modes, which can lead to spontaneous emergence of regular periodic, polygonal, polyhedral, or crystalline patterns, as shown in numerical simulations within the truncated Wigner approximation. An explanation of the occurrence of rotonlike instability is given based on the energy and spin conservation laws.

20.
J Oncol ; 2020: 4848752, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33343662

RESUMO

During the last decade, a significant increase in the incidence of bladder cancer (BC) has been observed. Angiogenesis plays a key role in the process of tumor growth and metastasis. Additionally, the participation of oxidative stress and chronic inflammation in BC pathogenesis is indicated. The aim of the study was to evaluate the urinary levels of parameters of angiogenesis, stimulating angiogenin (ANG) and inhibiting angiostatin (ANGST), 8-iso-prostaglandin F2α (8-iso-PGF2α) as a marker of oxidative stress, É£-synuclein (SNCG) as a cancer progression parameter, and interleukin-13 (IL-13) as an anti-inflammatory immunomodulator. The levels of ANG, ANGST, 8-iso-PGF2α, SNCG, and IL-13 in the urine of BC patients and healthy controls were measured by the enzyme-linked immunosorbent assay. These parameters were examined in the whole group of BC patients and in subgroups depending on the clinical stage: nonmuscle-invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC); histopathologic malignancy: low grade (LG) and high grade (HG) and in primary and recurrent BC. Significantly, higher urinary parameters were found in BC patients in comparison to controls. Levels of all parameters increased with the development of cancer, with the exception of 8-iso-prostaglandin F2α, in which the level was higher in the early stages of the disease, but these differences were not statistically significant. Some correlations have been demonstrated between parameters in BC patients. Based on the receiver operating characteristic curves, ANG and ANGST had the best diagnostic value for BC. The obtained results indicate the important role of the examined parameters of angiogenesis, oxidative stress, and inflammation in the pathogenesis and development of BC. It is reasonable to continue research in order to thoroughly assess the impact of various associated processes on the course of BC. It is also important to carry out similar tests in patients with other urological diseases.

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