428 research outputs found
Failure strength of thin-walled cylindrical GFRP composite shell against static internal and external pressure for various volumetric fiber fraction
A study on a Circular cylindrical thin-walled shell failure made of GRP composite subjected to static internal and external pressure was carried out. The results were acquired using analytical and FEM simulation approaches for various volumetric fiber fractions. Fiber breakage, matrix breakage, interlaminate shear deformation, delamination shear deformation and micro buckling failure were investigated employing maximum failure criteria against internal and external pressure. One-ply cylindrical shell with fiber angle orientation of 0 degree was modeled in ABAQUS finite element simulation and the result was varied using analytical approaches. Moreover, the pressure fluctuations for various volumetric fiber fraction were quadratic according to plotted graphs. Meanwhile, MATLAB software was used for theoretical analysis. The comparison of two approaches was proved to be accurate. Subsequently, failure strength of various laminated GFRP cylindrical shell with different fiber angle orientations at each ply was studied for diverse volumetric fiber fraction factors. Stacking sequence, fiber angle orientations were mainly effective on failure strength
Different features in Wegener's granulomatosis: Report of five cases
Wegener's granulomatosis (WG) is an autoimmune inflammatory condition. It is often a rapidly progressive and potentially fatal disease. The clinical presentation of WG can be so diverse that the list of its differential diagnosis is vast, ranging from infectious diseases to other vasculitis (e.g. Behcet's disease), as well as malignancies. The exact aetiology of WG remains unclear. The upper airway diseases including sinusitis, oral lesions and otitis media are the most common presenting features of WG. In this paper, we have described 5 WG cases. They had different presentations and chief complaints. Some of them presented with upper airways diseases, while the others mainly suffered from the manifestations of pulmonary involvement. Although all of them were finally diagnosed as WG cases, the processes of the work up for the diagnosis as well as the outcome of the disease were not the same. So, the diversities in the presentation should be mentioned in the management of the WG suspected patients
Database Learning: Toward a Database that Becomes Smarter Every Time
In today's databases, previous query answers rarely benefit answering future
queries. For the first time, to the best of our knowledge, we change this
paradigm in an approximate query processing (AQP) context. We make the
following observation: the answer to each query reveals some degree of
knowledge about the answer to another query because their answers stem from the
same underlying distribution that has produced the entire dataset. Exploiting
and refining this knowledge should allow us to answer queries more
analytically, rather than by reading enormous amounts of raw data. Also,
processing more queries should continuously enhance our knowledge of the
underlying distribution, and hence lead to increasingly faster response times
for future queries.
We call this novel idea---learning from past query answers---Database
Learning. We exploit the principle of maximum entropy to produce answers, which
are in expectation guaranteed to be more accurate than existing sample-based
approximations. Empowered by this idea, we build a query engine on top of Spark
SQL, called Verdict. We conduct extensive experiments on real-world query
traces from a large customer of a major database vendor. Our results
demonstrate that Verdict supports 73.7% of these queries, speeding them up by
up to 23.0x for the same accuracy level compared to existing AQP systems.Comment: This manuscript is an extended report of the work published in ACM
SIGMOD conference 201
VerdictDB: Universalizing Approximate Query Processing
Despite 25 years of research in academia, approximate query processing (AQP)
has had little industrial adoption. One of the major causes of this slow
adoption is the reluctance of traditional vendors to make radical changes to
their legacy codebases, and the preoccupation of newer vendors (e.g.,
SQL-on-Hadoop products) with implementing standard features. Additionally, the
few AQP engines that are available are each tied to a specific platform and
require users to completely abandon their existing databases---an unrealistic
expectation given the infancy of the AQP technology. Therefore, we argue that a
universal solution is needed: a database-agnostic approximation engine that
will widen the reach of this emerging technology across various platforms.
Our proposal, called VerdictDB, uses a middleware architecture that requires
no changes to the backend database, and thus, can work with all off-the-shelf
engines. Operating at the driver-level, VerdictDB intercepts analytical queries
issued to the database and rewrites them into another query that, if executed
by any standard relational engine, will yield sufficient information for
computing an approximate answer. VerdictDB uses the returned result set to
compute an approximate answer and error estimates, which are then passed on to
the user or application. However, lack of access to the query execution layer
introduces significant challenges in terms of generality, correctness, and
efficiency. This paper shows how VerdictDB overcomes these challenges and
delivers up to 171 speedup (18.45 on average) for a variety of
existing engines, such as Impala, Spark SQL, and Amazon Redshift, while
incurring less than 2.6% relative error. VerdictDB is open-sourced under Apache
License.Comment: Extended technical report of the paper that appeared in Proceedings
of the 2018 International Conference on Management of Data, pp. 1461-1476.
ACM, 201
Effect of lidocaine on duration of seizure and hemodynamic alterations in electroconvulsive therapy
Background and Objective: Electroconvulsive therapy (ECT) is one of the most common methods in
treatment of different types of psychological disorder. The effectiveness of this therapy has a direct
relation with the duration of convulsion. This study was conducted to assess the effect of lidocaine on
duration of seizure and hemodynamic alterations in electroconvulsive therapy.
Materials and Methods: This clinical trial study was conducted on 72 ASA-I, II patients with psychotic
disorders in Hajar Medical Center in Shahrekord, Iran during 2010. The patients randomly divided into
intervention and control group. The interventional group was received 1.5 mg/kg lidocaine and controls
were received normal saline. For induction of anesthesia, all patients were received Sodium Thiopental
(2mg/kg), Succinylcholine (1mg/kg) and Atropine (0.5mg) Propofol and Succinylcholine during 72
sessions of ECT. Duration of objective convulsion and hemodynamic alterations including blood pressure
and heart rate were recorded (before, immediately and 3, 5 minutes after ECT). Data were analyzed using
SPSS-11.5 and t-test.
Results: Systolic and diastolic blood pressures and heart rate in 3rd minutes in interventional group
following electroconvulsive therapy were 143.38±16 mmHg, 79.86±6.7 mmHg, 91.9±9.9 mmHg,
respectively and in controls were 128.88±13.04 mmHg, 87.63±5.79 mmHg and 102.86±13 mmHg,
respectively. These difference were significant (P<0.05). The above-mentioned indices for 5th minutes in
intervention and controls were as follow: systolic (113.47±9.97 mmHg, 122.36±13 mmHg), diastolic
(73.47±4.27 mmHg, 77.63±6.26 mmHg) heart rate (84.41±4.6 in minute, 93.19±12.53 in minute). These
differences in above indices were significant (P<0.05).
Conclusion: This study showed that lidocaine administration during electroconvulsive therapy increase
the duration of convulsion and reduces heart rate and blood pressur
Bioactive glasses and glass/polymer composites for neuroregeneration: Should we be hopeful?
Bioactive glasses (BGs) have been identified as highly versatile materials in tissue engineering applications; apart from being used for bone repair for many years, they have recently shown promise for the regeneration of peripheral nerves as well. They can be formulated in different shapes and forms (micro-/nanoparticles, micro-/nanofibers, and tubes), thus potentially meeting the diverse requirements for neuroregeneration. Mechanical and biological improvements in three-dimensional (3D) polymeric scaffolds could be easily provided by adding BGs to their composition. Various types of silicate, borate, and phosphate BGs have been examined for use in neuroregeneration. In general, BGs show good compatibility with the nervous system compartments both in vitro and in vivo. Functionalization and surface modification plus doping with therapeutic ions make BGs even more effective in peripheral nerve regeneration. Moreover, the combination of BGs with conductive polymers is suggested to improve neural cell functions at injured sites. Taking advantage of BGs combined with novel technologies in tissue engineering, like 3D printing, can open new horizons in reconstructive approaches for the nervous system. Although there are great potential opportunities in BG-based therapies for peripheral nerve regeneration, more research should still be performed to carefully assess the pros and cons of BGs in neuroregeneration strategies
Nanotechnology for angiogenesis: Opportunities and challenges
Angiogenesis plays a critical role within the human body, from the early stages of life (i.e., embryonic development) to life-threatening diseases (e.g., cancer, heart attack, stroke, wound healing). Many pharmaceutical companies have expended huge efforts on both stimulation and inhibition of angiogenesis. During the last decade, the nanotechnology revolution has made a great impact in medicine, and regulatory approvals are starting to be achieved for nanomedicines to treat a wide range of diseases. Angiogenesis therapies involve the inhibition of angiogenesis in oncology and ophthalmology, and stimulation of angiogenesis in wound healing and tissue engineering. This review aims to summarize nanotechnology-based strategies that have been explored in the broad area of angiogenesis. Lipid-based, carbon-based and polymeric nanoparticles, and a wide range of inorganic and metallic nanoparticles are covered in detail. Theranostic and imaging approaches can be facilitated by nanoparticles. Many preparations have been reported to have a bimodal effect where they stimulate angiogenesis at low dose and inhibit it at higher doses. This journal i
REMOVAL OF Cr(VI) FROM SIMULATED ELECTROPLATING WASTEWATER BY MAGNETITE NANOPARTICLES
In this study, the efficiency of magnetic nanoparticles for removal of hexavalent chromium from simulated electroplating wastewater was evaluated. The nanoparticles were prepared using the sol-gel method and were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), a scanning electron microscopy energy dispersive X-ray analyzer (SEM-Edx), a particle sizer and a vibrating sample magnetometer (VSM). The results showed that synthesized nanoparticles were in the size range of 40-300 rim, had purity of about 90 percent, and had magnetization of 36.5 electromagnetic unit per gram (emu/g). In conditions including pH 2, Cr (VI) concentration of 10 mg/L, nanomagnetite concentration of 1 g/L, a shaking speed of 250 rpm and a 20 minute retention time, 82% of Cr(VI) was removed. Competition from common coexisting ions such as Na(+), Ni(2+), Cu(2+), NO(3)(-), SO(4)(2-), and Cl was negligible. The adsorption data was well fitted by the Freundlich isotherm. It was concluded that magnetite nanoparticles have considerable potential for removal of Cr(VI) from electroplating wastewaters
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