570 research outputs found
The effect of zinc and iron supplementation on the status of iron and zinc in the primary schoolchildren
چکیده: زمینه و هدف: کمبود ریزمغذی ها یکی از مهمترین مشکلات بهداشتی جهان است. در بین ریزمغذی ها کمبود آهن و روی شیوع بیشتری داشته و از اهمیت زیادی برخوردار است. هدف از این مطالعه مقایسه تأثیر مکمل یاری آهن و روی به تنهایی و همراه با هم بر وضعیت آهن و روی در کودکان ابتدایی بود. روش بررسی: در این مطالعه که بصورت کار آزمایی بالینی دو سوکور انجام گرفت 81 دانش آموز پایه پنجم ابتدائی شهر خرم آباد به سه گروه تقسیم شدند. گروه اول مکمل آهن (20 میلی گرم آهن در روز)، گروه دوم مکمل روی (20 میلی گرم روی در روز) و گروه سوم مکمل آهن+ روی (20 میلی گرم آهن+20 میلی گرم روی) را به مدت 4 ماه دریافت نمودند. در آغاز و پایان مداخله شاخص های هموگلوبین با دستگاه سل کانتر، فریتین سرم با روش رادیوایمینواسی و با استفاده از دستگاه گاماکانتر و روی سرم با روش جذب اتمی اندازه گیری شد. از آزمون های ANOVA، t زوجی، کروسکال والیس و ویلکاکسون جهت تجزیه و تحلیل داده ها استفاده شد. یافته ها: نتایج بدست آمده نشان داد در گروه دریافت کننده مکمل روی به تنهایی، آهن همراه با روی و آهن به تنهایی میزان روی سرم نسبت به قبل از مداخله به ترتیب 1/2±5، 7/2±5/4 و 2/2±6/3 میکرومول در لیتر افزایش یافت (05/0
Quantum Teleportation from a Propagating Photon to a Solid-State Spin Qubit
The realization of a quantum interface between a propagating photon used for
transmission of quantum information, and a stationary qubit used for storage
and manipulation, has long been an outstanding goal in quantum information
science. A method for implementing such an interface between dissimilar qubits
is quantum teleportation, which has attracted considerable interest not only as
a versatile quantum-state-transfer method but also as a quantum computational
primitive. Here, we experimentally demonstrate transfer of quantum information
carried by a photonic qubit to a quantum dot spin qubit using quantum
teleportation. In our experiment, a single photon in a superposition state of
two colors -- a photonic qubit is generated using selective resonant excitation
of a neutral quantum dot. We achieve an unprecedented degree of
indistinguishability of single photons from different quantum dots by using
local electric and magnetic field control. To teleport a photonic qubit, we
generate an entangled spin-photon state in a second quantum dot located 5
meters away from the first and interfere the photons from the two dots in a
Hong-Ou-Mandel set-up. A coincidence detection at the output of the
interferometer heralds successful teleportation, which we verify by measuring
the resulting spin state after its coherence time is prolonged by an optical
spin-echo pulse sequence. The demonstration of successful inter-conversion of
photonic and semiconductor spin qubits constitute a major step towards the
realization of on-chip quantum networks based on semiconductor nano-structures.Comment: 12 pages, 3 figures, Comments welcom
Hybrid Quantum Dot-2D Electron Gas Devices for Coherent Optoelectronics
We present an inverted GaAs 2D electron gas with self-assembled InAs quantum
dots in close proximity, with the goal of combining quantum transport with
quantum optics experiments. We have grown and characterized several wafers --
using transport, AFM and optics -- finding narrow-linewidth optical dots and
high-mobility, single subband 2D gases. Despite being buried 500 nm below the
surface, the dots are clearly visible on AFM scans, allowing precise
localization and paving the way towards a hybrid quantum system integrating
optical dots with surface gate-defined nanostructures in the 2D gas.Comment: 4 pages, 5 figures (color
Internet Addiction and its Predictors in Guilan Medical Sciences Students, 2012
Background: Internet is one of the technologies of the modern era that is being extensively used around the world. It is believed that excessive Internet use can be pathological and addictive. Though, academic use of the Internet is primarily intended for learning and research, students are one of the groups at risk of Internet addiction.
Objectives: Due to the expanding use of Internet among the university students, this study was conducted to examine the Internet addiction and its predictors among Guilan University of Medical Sciences students.
Materials and Methods: A cross-sectional study was conducted on 583 students during the first semester of 2012. A two-stage stratified random sampling was conducted and a two-part instrument was used for data collection. The first part of the instrument was consisted of questions about demographic characteristics and the second part was the Young's Internet addiction inventory. Chi-square, Kruskal-Wallis testes, Spearman correlation coefficient and ranked logistic regression were used for data analysis.
Results: About 5.7% of the students were moderately dependent to the Internet, while 44.1% were at risk for Internet addiction. Significant relationships were observed between the Internet addiction with age (P < 0.001), gender (P < 0.001), marital status (P < 0.001), major (P = 0.016), Grade point average (P = 0.017), semester of studying (P = 0.009) and student residence place (P = 0.014). However, no significant relationship was observed between the internet addiction score and level of discipline, parental job status and education level or the students’ accommodation.
Conclusion: About half of the participants in this study were at risk of Internet addiction. This finding can be a warning sign for the authorities in universities to pay more attention to this issue. A wide range of education along with empowering programs may be needed to inform the university students about the advantages and disadvantages of internet and the correct manner of using it
Thyroid disorders induced by checkpoint inhibitors
Immune checkpoint inhibitors are drugs that inhibit the "checkpoint molecules". Different types of cancer immune checkpoint inhibitors have been approved recently: CTLA-4 monoclonal antibodies (as ipilimumab); anti-PD-1 monoclonal antibodies (as pembrolizumab and nivolumab); and anti-PD-L1 monoclonal antibodies (as atezolizumab, avelumab, and durmalumab). The increased immune response induced by these agents leads to immune-related adverse events (irAEs), that can vary from mild to fatal, according to the organ system and severity. Immune-related endocrine toxicities are thyroid dysfunctions, hypophysitis, adrenal insufficiency, and type 1 diabetes mellitus, and are usually irreversible in 50%. In particular, hypophysitis is the most frequent anti-CTLA-4-antibodies-related irAE, while thyroid abnormalities (as hypothyroidism, thyrotoxicosis, painless thyroiditis, or even "thyroid storm") are more frequently associated with anti-PD-1-antibodies. The combination of anti-CTLA-4-antibodies, with anti-PD-1-antibodies, is associated with about 30% of irAEs. Clinical signs and symptoms vary according to the influenced target organ. Endocrinopathies can often be managed by the treating oncologist. However in more severe cases (i.e. in the presence of insulin-dependent diabetes, adrenal insufficiency, or disorders of gonadal hormones, or severe hyperthyroidism, or hypothyroidism, or long-lasting management of hypophysitis) an endocrinological evaluation, and a prompt therapy, are needed
High circulating N-terminal pro-brain natriuretic peptide and tumor necrosis factor-alpha in mixed cryoglobulinemia
AIM: To evaluate serum levels of N-terminal pro-brain natriuretic peptide (NTproBNP) and tumor necrosis factor alpha (TNF-alpha) in a large series of patients with hepatitis C associated with mixed cryoglobulinemia (MC+HCV).METHODS: Serum NTproBNP and TNF-alpha levels were assayed in 50 patients with MC+HCV, and in 50 sex- and age-matched controls.RESULTS: Cryoglobulinemic patients showed significantly higher mean NTproBNP and TNF-alpha levels than controls (P < 0.001; Mann-Whitney U test). By defining high NTproBNP level as a value higher than 125 pg/mL (the single cut-off point for outpatients under 75 years of age), 30% of MC+HCV and 6% of controls had high NTproBNP (c2, P < 0.01). With a cut-off point of 300 pg/mL (used to rule out heart failure (HF) in patients under 75 years of age), 8% of MC+HCV and 0 controls had high NTproBNP (c2, P < 0.04). With a cut-off point of 900 pg/mL (used for ruling in HF in patients aged 50-75 years; such as the patients of our study), 6% of MC+HCV and 0 controls had high NTproBNP (c2, P = 0.08).CONCLUSION: The study demonstrates high levels of circulating NTproBNP and TNF-alpha in MC+HCV patients. The increase of NTproBNP may indicate the presence of a subclinical cardiac dysfunctio
Chemical thinning of flowers and fruits of the peach cultivar Coral with hydrogen cyanamide
A textile platform using mechanically reinforced hydrogel fibres towards engineering tendon niche
INTRODUCTION: Tendon injuries can result from tendon overuse or trauma, resulting in substantial pain and disability. Given that natural or surgical repair of tendons lead to a poor outcome in terms of mechanical properties and functionality, there is a great need for tissue engineering strategies. Textile platforms enable the generation of biomimetic constructs [1]. Therefore, the main goal of this study is the development of cell-laden hybrid hydrogel fibers reinforced with a mechanically robust core fiber and their assembly into braided constructs towards replicating tendon mechanical properties and architecture. METHODS: To fabricate mechanically reinforced hydrogel fibres, a commercially available suture was coated using a cell-hydrogel mixture of methacryloyl gelatine (GelMA) and alginate. Composite fibres (CFs) were obtained by ionic crosslinking of alginate followed by photocrosslinking of GelMA. CFs were assembled using braiding technique and the mechanical properties of single fibres and braided constructs were evaluated. Different cells were encapsulated in the hydrogel layer, including MC-3T3, mesenchymal stem cells (MSCs) and human tendon-derived cells (TDCs). Cell viability and metabolic activity were evaluated by LIVE/DEAD staining and presto blue assay of metabolic activity. The expression of tendon-related markers and matrix deposition were also investigated. RESULTS: CFs were fabricated with a GelMA:alginate hydrogel layer and using multifilament twisted cotton or biodegradable suturing threads. The biocompatibility of this system was evaluated on encapsulated cells (Fig.1a). Cells (MC-3T3, MSCs and TDCs) were homogeneously distributed along the hydrogel layer, being viable up to 14 days in culture. In addition, TDCs were spreading inside the hydrogel after less than 48 h. Moreover, to further improve the mechanical properties of CFs, braided constructs were generated (Fig. 1b). Braiding CFs together enhanced their tensile strength and the process did not affect the viability of encapsulated cells.DISCUSSION & CONCLUSIONS: CFs were generated with a load bearing core and a hydrogel layer towards mimicking both mechanical properties and the matrix-rich microenvironment of tendon tissue. Accordingly, cell behaviour can be further modulated by modifying the hydrogel composition or, ultimately, through the addition of bioactive cues. Finally, braiding CFs together allows tuning the mechanical properties of developed constructs to match those of native tendon tissues.Fundação para a Ciência e a Tecnologia in the framework of FCT-POPH-FSE, the PhD grant SFRH/BD/96593/2013 of R.C-
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