5,615 research outputs found

    Receptance based approach for control of floor vibrations

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    This is the author accepted manuscript. The final version is available from the publisher via the link in this record.Advances in design, materials and construction technologies, coupled with client and architectural requirements, are some of the drivers for light-weight and slender pedestrian structures, which are becoming increasingly susceptible to human induced vibrations. The use of active control techniques is progressively being viewed as a more feasible approach for suppressing such vibrations compared with traditional passive technologies. In this paper, the principles of the receptance based approach are exploited to design appropriate feedback gains that place the eigenvalues of selected vibration modes of an experimental footbridge structure at selected locations thereby enhancing its vibration performance. These studies are based on a single-input multiple-output (SIMO) controller structure comprising of a single control actuator and two sensors. It is seen that this has the potential to offer additional design freedoms beyond purely a direct velocity feedback (DVF) controller. A comparative study is carried out with a DVF controller implemented in a single-input single-output (SISO) scheme. This work presents the analytical determination of appropriate feedback gains from results of experimental modal analysis (EMA) on the structure and thereafter the experimental implementation of these feedback gains. Vibration mitigation performance is evaluated through both changes in measured transfer functions and reductions in response under single pedestrian excitation

    Expression levels of vascular endothelial growth factors A and C in patients with peptic ulcers and gastric cancer

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    Purpose: Vascular endothelial growth factor (VEGF) is one of the most important growth factors for metastatic tumors. To clarify the role of VEGF-A and C in patients with peptic ulcer disease (PUD) or gastric cancer (GC), we evaluated the expression levels of these two molecules. We also analyzed the effect of Helicobacter pylori infection on VEGF-A and C expression levels

    Bangladesh's Approach towards International Criminal Law: A Case Study of International Crimes Tribunal Bangladesh

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    The International Crimes Tribunal Bangladesh that has been found by the Bangladeshi Government to try war crimes during India Pakistan war of 1971. The tribunal is violating the fair trial rights as guaranteed by Constitution, the International Covenant on Civil and Political Rights and International Humanitarian Law and the standard of the International Crimes Tribunal Bangladesh is far below than that setup by The International Criminal Tribunal for the former Yugoslavia, the International Criminal Tribunal for Rwanda and the International Criminal Court. These irregularities imply serious concern over the proceedings of the said tribunal. Study seeks to describe the International Law about war crimes particularly with respect to fair trial provisions and it compare the proceedings of the Bangladeshi tribunal with the other internationally recognized tribunals

    Upper blepharoplasty and lateral wound dehiscence

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    Purpose: To report the frequency of lateral wound dehiscence (LWD) after upper blepharoplasty (UB), a technique and its outcome to prevent LWD. Materials and Methods:A retrospective review was performed for cases of LWD after UB presenting between 2003 and 2009, and then a prospective comparative study was performed between February 2009 and March 2013. For the comparison, subjects were divided into two groups based on intraoperative assessment of lateral wound tension (same technique and surgeon). Group 1 received 1-3 orbicularis/subcutaneous buried sutures (6-0 polyglactin) before interrupted 6-0 nylon skin closure. Group 2 underwent skin closure only. Subjects, who had re-operation, skin healing disorders, and incomplete follow-up (<6 months), were excluded. P < 0.05 was considered as statistically significant. Results: There were 14 (14/678, 2) cases with LWD with a mean age of 36.2 years in the audit (2003-2009). The prospective study included 68 subjects (68/293, 23.2) in Group 1 and 225 in Group 2. Gender and simultaneous forehead and eyebrow procedures were similar between groups (P = 0.3 and P = 0.4 respectively). Group 1 was statistically significantly younger at mean age of 41.4 years, compared to Group 2 at 56.1 years (P = 0.000). The frequency of LWD significantly (P = 0.04) decreased to 0.3 (1/293). Conclusion: In the presence of wound tension on skin closure (intraoperative assessment), tension relieving buried orbicularis/subcutaneous 6-0 polyglactin suturing of the lateral UB incision could prevent LWD. © 2015 Middle East African Journal of Ophthalmology | Published by Wolters Kluwer - Medknow

    Intranasal administration of endometrial mesenchymal stem cells as a suitable approach for Parkinson�s disease therapy

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    This study aimed to investigate the therapeutic effects of intranasal administration of human endometrium-derived stem cells (HEDSCs) in the mouse model of Parkinson�s disease (PD). Thirty days after intrastriatal injection of 6-OHDA, HEDSCs were administrated intranasally in three doses (104, 5 � 104 and 105 cells µl�1). During 120 days after stem cell administration, behavioral tests were examined. Then the mice were sacrificed and the fresh section of the substantia nigra pars compacta (SNpc) was used for detection of HEDSCs-GFP labeled by fluorescence microscopy method. In addition, immunohistochemistry was used to assay GFP, human neural Nestin, and tyrosine hydroxylase (TH) markers in the fixed brain tissue at the SNpc. Our data revealed that behavioral parameters were significantly improved after cell therapy. Fluorescence microscopy assay in fresh tissue and GFP analysis in fixed tissue were showed that the HEDSCs-GFP labeled migrated to SNpc. The data from immunohistochemistry revealed that the Nestin as a differential neuronal biomarker was expressed in SNpc. Also, TH as a dopaminergic neuron marker significantly increased after HEDSCs therapy in an optimized dose 5 � 104 cells µl�1. Our results suggest that intranasal administration of HEDSCs improve the PD symptoms in the mouse model of PD dose-dependent manner as a noninvasive method. © 2019, Springer Nature B.V

    Eigenvalue sensitivity minimisation for robust pole placement by the receptance method

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    The problem of robust pole placement in active structural vibration control by the method of receptance is considered in this paper. Expressions are derived for the eigenvalue sensitivities to parametric perturbations, which are subsequently minimised to improve performance robustness of the control of a dynamical system. The described approach has application to a vibrating system where variations are present due to manufacturing and material tolerances, damages and environment variabilities. The closed-loop eigenvalue sensitivities are expressed as a linear function of the velocity and displacement feedback gains, allowing their minimisation with carefully calculated feedback gains. The proposed algorithm involves curve fitting perturbed frequency response functions, FRFs, using the rational fraction polynomial method and implementation of a polynomial fit to the individual estimated rational fraction coefficients. This allows the eigenvalue sensitivity to be obtained entirely from structural FRFs, which is consistent with the receptance method. This avoids the need to evaluate the M,C,K matrices which are typically obtained through finite element modelling, that produces modelling uncertainty. It is also demonstrated that the sensitivity minimisation technique can work in conjunction with the pole placement and partial pole placement technique using the receptance method. To illustrate the working of the proposed algorithm, the controller is first implemented numerically and then experimentally

    Epitope Mapping of Tetanus Toxin by Monoclonal Antibodies: Implication for Immunotherapy and Vaccine Design

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    Tetanus as a life-threatening disease is characterized by muscle spasm. The disease is caused by the neurotoxin of Clostridium tetani. Active form of tetanus neurotoxin is composed of the light chain (fragment A) and the heavy chain. Fragment A is a zinc metalloprotease, which cleaves the neuronal soluble N-ethylmaleimide-sensitive attachment receptor (SNARE) protein, leading to the blockade of inhibitory neurotransmitter release and subsequent generalized muscular spasm. Two functional domains of the heavy chain are fragment C, which is required for neuronal cell binding of the toxin and subsequent endocytosis into the vesicles, and fragment B, which is important for fragment A translocation across the vesicular membrane into the neuronal cytosol. Currently, polyclonal immunoglobulins against tetanus neurotoxin obtained from human plasma of hyper-immunized donors are utilized for passive immunotherapy of tetanus; however, these preparations have many disadvantages including high lot-to-lot heterogeneity, possibility of transmitting microbial agents, and the adverse reactions to the other proteins in the plasma. Neutralizing anti-tetanus neurotoxin monoclonal antibodies (MAbs) lack these drawbacks and could be considered as a suitable alternative for passive immunotherapy of tetanus. In this review, we provide an overview of the literature discussing epitope mapping of the published neutralizing MAbs against tetanus toxin. © 2019, Springer Science+Business Media, LLC, part of Springer Nature

    Evaluation and optimization of chitosan derivatives-based gene delivery system via kidney epithelial cells

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    Purpose: Non-viral vectors have been widely proposed as safer alternatives to viral vectors, and cationic polymers have gained increasing attention because they can form self-assembly with DNA. Chitosan is also considered to be a good candidate for gene delivery systems, since it is already known as a biocompatible, biodegradable, and low toxic material with high cationic potential. However, low solubility and transfection efficiency need to be overcome prior to clinical trial. In this work, we focus on alkyl modified chitosan which might be useful in DNA condensing and efficient gene delivery. Methods: N, N- Diethyl N- Methyl (DEMC) and N- Triethyl Chitosan (TEC) were synthesized from chitosan polymer. In order to optimize the polymers for gene delivery, we used FITC-dextran (FD). Then the optimized polymer concentrations were used for gene delivery. Fluorescent microscope was used, in order to evaluate the polymers’ efficiency for gene delivery to human embryonic kidney epithelial cells (HEK 293T). Results: This modification increased chitosan’s positive charge, thus these chitosan derivatives spontaneously formed complexes with FD, green fluorescence protein plasmid DNA (pEGFP), red fluorescence protein plasmid DNA (pJred) and fluorescent labeled miRNA. Results gained from fluorescent microscope showed that TEC and DEMC were able to transfer FD, DNA and miRNA (micro RNA) to HEK cell line. Conclusion: We conclude that these chitosan derivatives present suitable characteristics to be used as non-viral gene delivery vectors to epithelial cells

    The relationship between anti-mullerian hormone in women receiving fertility assessments and age at menopause in subfertile women: evidence from large population studies

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    &lt;p&gt;Context: Anti-Müllerian hormone (AMH) concentration reflects ovarian aging and is argued to be a useful predictor of age at menopause (AMP). It is hypothesized that AMH falling below a critical threshold corresponds to follicle depletion, which results in menopause. With this threshold, theoretical predictions of AMP can be made. Comparisons of such predictions with observed AMP from population studies support the role for AMH as a forecaster of menopause.&lt;/p&gt; &lt;p&gt;Objective: The objective of the study was to investigate whether previous relationships between AMH and AMP are valid using a much larger data set.&lt;/p&gt; &lt;p&gt;Setting: AMH was measured in 27 563 women attending fertility clinics.&lt;/p&gt; &lt;p&gt;Study Design: From these data a model of age-related AMH change was constructed using a robust regression analysis. Data on AMP from subfertile women were obtained from the population-based Prospect-European Prospective Investigation into Cancer and Nutrition (Prospect-EPIC) cohort (n = 2249). By constructing a probability distribution of age at which AMH falls below a critical threshold and fitting this to Prospect-EPIC menopausal age data using maximum likelihood, such a threshold was estimated.&lt;/p&gt; &lt;p&gt;Main Outcome: The main outcome was conformity between observed and predicted AMP.&lt;/p&gt; &lt;p&gt;Results: To get a distribution of AMH-predicted AMP that fit the Prospect-EPIC data, we found the critical AMH threshold should vary among women in such a way that women with low age-specific AMH would have lower thresholds, whereas women with high age-specific AMH would have higher thresholds (mean 0.075 ng/mL; interquartile range 0.038–0.15 ng/mL). Such a varying AMH threshold for menopause is a novel and biologically plausible finding. AMH became undetectable (&#60;0.2 ng/mL) approximately 5 years before the occurrence of menopause, in line with a previous report.&lt;/p&gt; &lt;p&gt;Conclusions: The conformity of the observed and predicted distributions of AMP supports the hypothesis that declining population averages of AMH are associated with menopause, making AMH an excellent candidate biomarker for AMP prediction. Further research will help establish the accuracy of AMH levels to predict AMP within individuals.&lt;/p&gt
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