657 research outputs found
Control of spatiotemporal rogue waves by harmonic pump modulation in a semiconductor laser with a saturable absorber
Through numerical simulations, statistical and dynamical properties of extreme events in a broad-area semiconductor laser with intracavity saturable absorber are investigated. By inclusion of a diffusion coefficient for the field, formation of rogue waves in a state of extended turbulence is studied and shown to be affected by harmonic perturbations. In particular, we propose a control technique based on periodic modulation of the pump parameter which can either drive the state of the system closer to or away from the chaotic attractors respectively enhancing or suppressing the generation of rogue waves. By statistical and dynamical analysis of the events in terms of intensity and optical gain, we show that when the system is under resonant modulation with frequency close to that of the dominant oscillations in the turbulent state (which is equal to the relaxation oscillation frequency typical of semiconductor lasers), more rogue waves are triggered with larger intensities and shorter lifetimes. On the other hand, off-resonant modulations restrain the formation of rogue waves where they appear in lower intensities and longer lifetimes. An example of special cases where the proposed scheme can completely forbid or allow the emission of rogue waves is also presented
Comparing Vitamin D Level Between Patients with Psoriasis and Healthy Individuals: A Systematic Review and Meta-Analysis
Background: Psoriasis is nowadays regarded as a systemic inflammatory disorder. Among the topicals, vitamin D derivates are often applied on the skin for their anti-inflammatory and immune-modulatory properties. Vitamin D serum levels in psoriasis (PsO) patients are still debated and an eventual depletion may offer the rational to integrate anti-psoriatic therapies with oral vitamin D. Then, we aimed to perform a systematic review and meta-analysis on the current evidence towards serum vitamin D level in PsO. Methods: We searched in PubMed, Scopus, Web of Sciences, ScienceDirect and Science Information Database (SID) using the terms “Vitamin D” and “Psoriasis” including manuscripts in English, Italian and Persian. Duplications were excluded using EndNote software and records were screened by title, abstract and full-text. Quality assessment of studies was assessed using Newcastle Ottawa Checklist (NOS). Psoriasis odds ratio (OR) and mean serum vitamin D levels were calculated and displayed in Forest-plots. Heterogeneity indexes were evaluated using I2 and Q. Sensitivity analysis and publication biases were also considered. Results: From 3006 records extracted, after removing duplicates and analyzing full texts we finally included 19 manuscripts involving a total of 1387 PsO cases and 6939 controls. PsO patients exhibited a substantial odds ratio (3.07, 95% CI: 1.56-6.04) for lower serum vitamin D levels compared to the control group. Standardized Mean Difference (SMD) of vitamin D in PsO versus controls was −0.92 (−1.33 to −0.51). Conclusion: Psoriatic patients displayed higher risk to have a vitamin D deficiency. Interventional studies to verify the preventive value are mandatory
Differential gene-expression of metallothionein 1M and 1G in response to zinc in sertoli TM4 cells
Background: Zinc (Zn) as an important trace element is essential for testicular development and spermatogenesis. Molecular mechanism of Zn action in the reproductive system may be related to metal binding low-molecular weight proteins, metallothioneins (MT). Our objective was to determine the effect of Zn on two important isoforms of MT, MT1M and MT1G genes expression on testicular sertoli cells. Methods: Cultured sertoli TM4 cells were exposed to different concentrations of Zn at different time points. Cellular uptake of Zn was tested using flame atomic absorption spectrometry. The cellular viability and gene expression were assessed by MTT and real-time PCR methods, respectively. Results: The treated cells resulted in higher Zn concentration and cellular viability. The expression of MT1M and MT1G genes in the treated cells were greater than those of the untreated cells (P<0.05). In the high dosage treated group (100 and 500 μM), Zn concentration and expression of MT1M and MT1G genes increased three h after treatment; MT1G gene expression increased more at sixth h. At 18th h of treatment, the expression of both genes especially MT1G, increased dramatically while Zn concentration decreased. Conclusion: Since the increase of MT1G mRNA was coincident with cellular Zn level, it seems that MT1G has a more prominent role than MT1M in the homeostasis of Zn. In addition, Zn at dosage of 50 μM (pharmacologic concentration) may protect cells by increasing the expression of MT genes at longer periods
Regulation of mammary gland branching morphogenesis by the extracellular matrix and its remodeling enzymes.
A considerable body of research indicates that mammary gland branching morphogenesis is dependent, in part, on the extracellular matrix (ECM), ECM-receptors, such as integrins and other ECM receptors, and ECM-degrading enzymes, including matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitors of metalloproteinases (TIMPs). There is some evidence that these ECM cues affect one or more of the following processes: cell survival, polarity, proliferation, differentiation, adhesion, and migration. Both three-dimensional culture models and genetic manipulations of the mouse mammary gland have been used to study the signaling pathways that affect these processes. However, the precise mechanisms of ECM-directed mammary morphogenesis are not well understood. Mammary morphogenesis involves epithelial 'invasion' of adipose tissue, a process akin to invasion by breast cancer cells, although the former is a highly regulated developmental process. How these morphogenic pathways are integrated in the normal gland and how they become dysregulated and subverted in the progression of breast cancer also remain largely unanswered questions
Complex structures in cavities with media displaying EIT : coexistence, defects and selection mechanism
A cavity filled with a medium displaying electromagnetically induced transparency is shown to exhibit coexistence of complex transverse structures often leading to pattern competition. Because of multi-stability of the solutions, the asymptotic state in such a cavity crucially depends on the values of the control parameters and the initial conditions. The pattern competition can result in coexisting regions of pattern structures of different geometry separated by stable or metastable fronts. Here we propose a selection technique based on external periodic modulations for directing the system to a single pattern state of choice and thus removing the separation fronts. The control technique takes the system close to sub-sections in the phase space providing the operator with the choice of the final state from different multi-stable solutions. We extend the use of the technique to stationary or drifting structures composed of regions made of a single pattern state with different orientations. In this case the regularization to a pattern with a single orientation is associated with the removal of defects. The harmonic signal technique has not been used previously to control a spatio-temporal system where the multi-stability is due to the coupling of nonlinearity and diffraction
Thermal performance of resource-efficient geopolymeric mortars containing phase change materials
Energy efficiency is not only the most cost effective way to reduce emissions but also a way to improve competitiveness and create employment. This paper reports experimental results on the thermal performance of geopolymeric mortars containing different percentages of phase-change materials-PCMs. These materials have a twofold positive impact concerning eco-efficiency. On one hand, the mortars are based on industrial waste contributing for resource efficiency. And on the other hand, PCM based mortars have the capacity to enhance the thermal performance of the buildings. Five groups of alkali-activated based mortars with different PCM percentages were produced and placed on a panel within a small-scale prototype for thermal performance testing. The results show that the thermal conductivity of the mortars decreased with the increase in the percentage of the PCM. The results also show that the thermal performance of the PCM based mortars allowed for a stronger attenuation of the temperature amplitudes. Both for heating and cooling loads. The authors would like to acknowledge the financial support from the Foundation for Science and Technology (FCT) for the frame of research project with Ref. IF/00706/2014-UM.2.15 as well as C-TAC and ISISE research units.info:eu-repo/semantics/publishedVersio
Application of computed aided detection in breast masses diagnosis
Breast cancer is the most widespread cancer in women. The life-time
risk of a woman developing this disease has been established as one in
eight. Currently mammography is a standard method and could decrease
breast cancer mortality. Unfortunately, negative mammograms don\u2032t
exclude cancer. The sensitivity of mammography ranges from
approximately 70% to 90% and it should be higher. Materials and
Methods: The sample contained 255 cases taken from Imaging Center of
Imam Khomaini Hospital. Bilateral mammograms in both craniocaudal and
mediolateral oblique projections were used. Two experienced
Radiologists reviewed images before and after using CAD system. Tumors
(including malignant and benign) and normal breast tissues were
confirmed by histological correlation. Results: Of 255 cases 92 were
not recommended for further work-up. Of 163 cases 90 were normal mass,
23 malignant tumors, 16 benign tumors and 22 cysts were detected by CAD
system. The remaining cases were finalized only by biopsy. Conclusion:
CAD could be utilized for breast mass detection. This is a practical
technique with low cost
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