594 research outputs found
Pulse and quench induced dynamical phase transition in a chiral multiferroic spin chain
Quantum dynamics of magnetic order in a chiral multiferroic chain is studied.
We consider two different scenarios: Ultrashort terahertz (THz) excitations or
a sudden electric field quench. Performing analytical and numerical exact
diagonalization calculations we trace the pulse induced spin dynamics and
extract quantities that are relevant to quantum information processing. In
particular, we analyze the dynamics of the system chirality, the von Neumann
entropy, the pairwise and the many body entanglement. If the characteristic
frequencies of the generated states are non-commensurate then a partial loss of
pair concurrence occurs. Increasing the system size this effect becomes even
more pronounced. Many particle entanglement and chirality are robust and
persist in the incommensurate phase. To analyze the dynamical quantum
transitions for the quenched and pulsed dynamics we combined the Weierstrass
factorization technique for entire functions and Lanczos exact diagonalization
method. For a small system we obtained analytical results including the rate
function of Loschmidt echo. Exact numerical calculations for a system up to 40
spins confirm phase transition. Quench- induced dynamical transitions have been
extensively studied recently. Here we show that related dynamical transitions
can be achieved and controlled by appropriate electric field pulses.Comment: 13 pages, 10 figures, submitted in PR
Generating GHZ state in 2m-qubit spin network
We consider a pure 2m-qubit initial state to evolve under a particular
quantum me- chanical spin Hamiltonian, which can be written in terms of the
adjacency matrix of the Johnson network J(2m;m). Then, by using some techniques
such as spectral dis- tribution and stratification associated with the graphs,
employed in [1, 2], a maximally entangled GHZ state is generated between the
antipodes of the network. In fact, an explicit formula is given for the
suitable coupling strengths of the hamiltonian, so that a maximally entangled
state can be generated between antipodes of the network. By using some known
multipartite entanglement measures, the amount of the entanglement of the final
evolved state is calculated, and finally two examples of four qubit and six
qubit states are considered in details.Comment: 22 page
Lack of association between two ACE gene polymorphisms (rs4291 and Alu I/D) and late onset Alzheimer’s disease
Alzheimer’s disease (AD) is a prevalent disorder and the most common cause of dementia in elderly populations. Genetic and environmental factors together play a role in developing late onset Alzheimer's disease (LOAD). According to the recent published papers, ACE is one of the candidate susceptibility genes for LOAD. In this study, allele and genotype frequencies for rs4291 and rs1799752 polymorphisms of ACE gene, for 100 Iranian patients, affected with AD and 100 healthy controls were compared using Chi-square test. No statistically significant differences were found in genotype and allele frequencies of rs4291 and rs1799752 polymorphisms between our LOAD patients and controls. The pair-wise haplotype analysis of rs4291 -240 A/T and rs1799752 Alu I/D polymorphisms were also performed, but no significant associations were identified.Key words: ACE, Alzheimer’s disease, Iranian, association, polymorphism
Penerapan Model Pembelajaran Learning Cycle pada Materi Lingkaran Siswa Kelas VIII MTsS Darussyari'ah Banda Aceh
Matematika merupakan salah satu mata pelajaran wajib disetiap jenjang pendidikan, baik di jenjang pendidikan dasar, menengah maupun perguruan tinggi. Tetapi kurangnya minat para siswa terhadap bidang studi matematika dikarenakan adanya kecenderungan bahwa yang ditampilkan oleh guru kepada siswa adalah deretan rumus-rumus yang abstrak dan membosankan, sehingga mengakibatkan hasil belajar siswa dalam pelajaran matematika rendah atau kurang memuaskan. Untuk itu, dalam belajar matematika perlu diadakan sebuah model pembelajaran yang cocok terhadap materi lingkaran. Salah satu model pembelajaran yang dapat digunakan dalam proses belajar matematika adalah penerapan model pembelajaran Learning Cycle. Ciri khas model Learning Cycle adalah suatu pembelajaran melalui Enggagement, Exploration, Explanation, Elaboration, dan Evaluation. Berdasarkan hal tersebut maka dilakukan penelitian tentang model pembelajaran Learning Cycle pada materi lingkaran Kelas VIII MTsS Darussyariah Banda Aceh. Penelitian ini bertujuan untuk mengetahui kegiatan pembelajaran melalui model pembelajaran Learning Cycle. Adapun populasi dalam penelitian ini adalah seluruh siswa kelas VIII MTsS Darussyariah Banda Aceh, sampel dalam penelitian ini adalah siswa kelas VIIIB MTsS Darussyariah Banda Aceh yang berjumlah 25 siswa. Pengumpulan data dilakukan dengan menggunakan tes tertulis yang terdiri dari pretest dan postest, serta observasi berupa data yang menyangkut aktifitas guru adalah 4,17 dan aktifitas siswa menujukkan kategori efektif pada tabel 4.16, sehingga model pembelajaran Learning Cycle dapat melibatkam guru secara aktif dan siswa secara efektif. Data yang diperoleh dari hasil penelitian dianalisis dengan menggunakan statistik uji-t dari hasil pengolahan data tersebut diperoleh nilai rata-rata siswa setelah belajar dengan menggunakan model Learning Cycle adalah 1,87 >1,68. Hasil analisis data menunjukkan bahwa penggunaan penerapan model pembelajaran Learning Cycle lebih baik diterapkan dalam pembelajaran matematika pada materi lingkaran kelas VIIIB MTsS Darussyariah Banda Aceh
Mesenchymal stem cell-derived exosomes: A promising therapeutic ace card to address autoimmune diseases
With the development of novel treatments for autoimmune disorders, it has become a popular research focus which mesenchymal stem cells (MSCs) have the capacity to counteract with autoimmune diseases progression. One of the underlying mechanisms behind their activities is the release of extracellular vesicles especially exosomes. MSC-derived exosomes are hypoimmunogenic nanocarriers which contain numerous immunoregulatory factors and similar to other exosomes, are able to pass through boundaries like the blood-brain barrier (BBB). Accumulating evidence provided by animal studies has demonstrated that MSC-derived exosomes, as a novel therapy, can re-induce self-tolerance, without subsequent complications reported for other treatments. Therefore, therapeutic applications of MSC-derived exosomes are contributing to core advances in the field of autoimmune diseases. Here, we briefly describe the biological characteristics of MSC-derived exosomes and review the experimentally verified outcomes for autoimmune disease therapy purposes. © 2020 by the Korean Society for Stem Cell Research
A review of friction models in interacting joints for durability design.
This paper presents a comprehensive review of friction modelling to provide an understanding of design for durability within interacting systems. Friction is a complex phenomenon and occurs at the interface of two components in relative motion. Over the last several decades, the effects of friction and its modelling techniques have been of significant interests in terms of industrial applications. There is however a need to develop a unified mathematical model for friction to inform design for durability within the context of varying operational conditions. Classical dynamic mechanisms model for the design of control systems has not incorporated friction phenomena due to non-linearity behaviour. Therefore, the tribological performance concurrently with the joint dynamics of a manipulator joint applied in hazardous environments needs to be fully analysed. Previously the dynamics and impact models used in mechanical joints with clearance have also been examined. The inclusion of reliability and durability during the design phase is very important for manipulators which are deployed in harsh environmental and operational conditions. The revolute joint is susceptible to failures such as in heavy manipulators these revolute joints can be represented by lubricated conformal sliding surfaces. The presence of pollutants such as debris and corrosive constituents has the potential to alter the contacting surfaces, would in turn affect the performance of revolute joints, and puts both reliability and durability of the systems at greater risks of failure. Key literature is identified and a review on the latest developments of the science of friction modelling is presented here. This review is based on a large volume of knowledge. Gaps in the relevant field have been identified to capitalise on for future developments. Therefore, this review will bring significant benefits to researchers, academics and industrial professionals
Androgen-induced cerebral venous sinus thrombosis in a young body builder: case report
BACKGROUND: Cerebral venous sinus thrombosis is an infrequent disease with a variety of causes. Pregnancy, puerperium, contraceptive pills and intracranial infections are the most common causes. The patient may present with headache, focal neurological deficits and seizures. The clinical outcome is highly variable and treatment with heparin is advised. CASE PRESENTATION: The patient is a 22 year old male who presented with headache, repeated vomiting and papilledema. He was a bodybuilder doing exercise since 5 years ago, who had used nandrolone decaonoate 25 milligrams intramuscularly during the previous 5 months. Brain MRI and MRV showed superior sagital and transverse sinus thrombosis and extensive investigations did not reveal any known cause. CONCLUSIONS: We suggested that androgen was the predisposing factor in our patient. Androgens may increase coagulation factors or platelet activity and cause arterial or venous thrombosis. As athletes may hide using androgens it should be considered as a predisposing factor for thrombotic events in such patients
Cloning of the GH gene from the beluga sturgeon (Huso huso) into a lentivial & none viral constructs and its expression in HEK cell lines
Caviar-producing fish with their economically valuable product are important in fisheries. The cDNA growth hormone (GH) of Beluga sturgeon (Huso huso) was constructed using total RNA from pituitary glands. To construct the recombinant and active lentiviruses carring GH gene, this DNA sequence was inserted into the cloning vector pTZ57R/T and subsequently cutted from pTZ57R/T by endonuclease enzyme and incorporated into lentivirus vector pNL-EGFP/CMV-WPRE on upstream of an IRES cassette. We also insert a reporter EGFP gene downstream of IRES so transfection and transduction steps can be traced. Using this vector plus virus packaging and envelope vectors, HEK293T cells was co-transfected by DNA-Lipofectamine complexes method. Cell supernatant full of virions was collected 48 hours later and concentrated using Amicon columns to obtain a high-titer virus stock. Nearly 1/5 of this stock was applied to a new batch of cultured HEK-293T. After 72h expression of EGFP gene was detected and the cells was collected for further analysis. Total RNA of these transduced cells was extracted and GH mRNA expression was revealed by RT-PCR. Results showed that, lentiviral vectors (LV) as a gene transfer system provide efficient delivery, integration and long-term expression by establishing a stable provirus in target cells and could be important tool in aquaculture and fisheries biotechnology research to increase the growth rate of farmed fish by transferring growth hormone (GH) transgenes into fish
Cloning of the GH gene from the beluga sturgeon (Huso huso) into a lentivial & none viral constructs and it’s expression in HEK cell lines
Caviar-producing fish with their economically valuable product are important in fisheries. The cDNA growth hormone (GH) of Beluga sturgeon (Huso huso) was constructed using total RNA from pituitary glands. To construct the recombinant and active lentiviruses carring GH gene, this DNA sequence was inserted into the cloning vector pTZ57R/T and subsequently cutted from pTZ57R/T by endonuclease enzyme and incorporated into lentivirus vector pNL-EGFP/CMV-WPRE on upstream of an IRES cassette. We also insert a reporter EGFP gene downstream of IRES so transfection and transduction steps can be traced. Using this vector plus virus packaging and envelope vectors, HEK293T cells was co-transfected by DNA-Lipofectamine complexes method. Cell supernatant full of virions was collected 48 hours later and concentrated using Amicon columns to obtain a high-titer virus stock. Nearly 1/5 of this stock was applied to a new batch of cultured HEK-293T. After 72h expression of EGFP gene was detected and the cells was collected for further analysis. Total RNA of these transduced cells was extracted and GH mRNA expression was revealed by RT-PCR. Results showed that, lentiviral vectors (LV) as a gene transfer system provide efficient delivery, integration and long-term expression by establishing a stable provirus in target cells and could be important tool in aquaculture and fisheries biotechnology research to increase the growth rate of farmed fish by transferring growth hormone (GH) transgenes into fish
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