4,126 research outputs found
MmWave Massive MIMO Based Wireless Backhaul for 5G Ultra-Dense Network
Ultra-dense network (UDN) has been considered as a promising candidate for
future 5G network to meet the explosive data demand. To realize UDN, a
reliable, Gigahertz bandwidth, and cost-effective backhaul connecting
ultra-dense small-cell base stations (BSs) and macro-cell BS is prerequisite.
Millimeter-wave (mmWave) can provide the potential Gbps traffic for wireless
backhaul. Moreover, mmWave can be easily integrated with massive MIMO for the
improved link reliability. In this article, we discuss the feasibility of
mmWave massive MIMO based wireless backhaul for 5G UDN, and the benefits and
challenges are also addressed. Especially, we propose a digitally-controlled
phase-shifter network (DPSN) based hybrid precoding/combining scheme for mmWave
massive MIMO, whereby the low-rank property of mmWave massive MIMO channel
matrix is leveraged to reduce the required cost and complexity of transceiver
with a negligible performance loss. One key feature of the proposed scheme is
that the macro-cell BS can simultaneously support multiple small-cell BSs with
multiple streams for each smallcell BS, which is essentially different from
conventional hybrid precoding/combining schemes typically limited to
single-user MIMO with multiple streams or multi-user MIMO with single stream
for each user. Based on the proposed scheme, we further explore the fundamental
issues of developing mmWave massive MIMO for wireless backhaul, and the
associated challenges, insight, and prospect to enable the mmWave massive MIMO
based wireless backhaul for 5G UDN are discussed.Comment: This paper has been accepted by IEEE Wireless Communications
Magazine. This paper is related to 5G, ultra-dense network (UDN), millimeter
waves (mmWave) fronthaul/backhaul, massive MIMO, sparsity/low-rank property
of mmWave massive MIMO channels, sparse channel estimation, compressive
sensing (CS), hybrid digital/analog precoding/combining, and hybrid
beamforming. http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=730653
Down-regulation of GST and CAT gene expression by methanolic extract of Nigella sativa seed in human peripheral blood mononuclear cells
The anti-oxidant effect of Nigella sativa (NS) on human Peripheral Blood Mononuclear Cells (PBMCs) on a PHA (phytohemagglutinin) and a non-PHA stimulated proliferation were tested using SYBR Green based Real Time PCR analysis for antioxidant enzyme’s gene expression [glutathione-stransferase (GST) and catalase (CAT)]. Cells isolated from human PBMCs were treated with methanolic extract of NS for 48 h in two separate environments (PHA and non-PHA stimulated). The results obtained indicate that extracts from NS had down regulation effect. GST was down regulated to 1 and 1.5 fold after exposure to 2.5 μg/L NS extract for 48 h in PHA stimulated cells compared to respective controls whereas it decreased to 4 and 2 fold at dose of 5 μg/L in non-PHA stimulated cells compared to respective controls. Similarly, CAT was down regulated to 2 and 6 fold after exposure to 2.5 μg/L NS extract for 48 h whereas, it decreased to 4 and 2 fold at dose of 5 μg/L in PHA and non-PHA stimulated cells compared to respective controls. This in-vitro study reveals the effects of NS plant extract on GST and CAT gene expression in human PBMCs.Keywords: Nigella sativa methanolic extract, glutathione-stransferase (GST), catalase (CAT), oxidation, eripheral blood mononuclear cellsAfrican Journal of Biotechnology Vol. 12(27), pp. 4364-436
Proximate and Phytochemical composition and antioxidant properties of indigenous landraces of omani fenugreek seeds.
Background: Fenugreek (Trigonella foenum graecum L) is receiving global attention as a functional food due to its unique nutritional and medicinal properties as anti-diabetic, hypocholesterolemic, antipyretic, anti-carcinogenic and seasoning and flavoring agent.Materials and Methods: Seeds of indigenous fenugreek accessions were collected from three different ecological regions (Al-Dakhaliyah, Al- Dhahirah, and Al-Batinah) of Sultanate of Oman. The samples were analyzed for proximate chemical composition, phytochemical contents and antioxidant properties.Results: Only significant (P<0.05) differences were observed in the crude fiber and gross energy values of fenugreek seeds collected from different regions of Oman. The highest crude fiber content (8.6 %) was observed in samples collected from Al-Dhahirah region whereas the lowest value (7.1%) was found in samples collected from Al-Dakhaliyah region. No significant (P<0.05) differences were however observed in the moisture, crude protein, crude fat, and ash contents of samples collected from the three regions of Oman. The regional variability significantly (P<0.05) affected the phytochemicals composition and the highest amount of total phenolics (139.2 mg GAE/100g) were recorded in samples collected from Al-Batinah, followed by Al-Dhakhliyah (130.0 mg GAE/100g) and Al-Dhahirah (127.8 mg GAE/100g) regions, respectively. A significant correlation was also observed between the total phenolic contents and the antioxidant properties of fenugreek seeds as determined by reducing power potential (FRAP).Conclusion: Indigenous landraces of Omani fenugreek seeds are a rich source of protein, dietary fiber, and many important bioactive components, which were found to be significantly correlatedwith its antioxidant properties.Keywords: Omani fenugreek, landraces, phytochemical composition, antioxidant properties
Stability Testing of Beclomethasone Dipropionate Nanoemulsion
Purpose: To perform stability studies on a nanoemulsion formulation containing beclomethasone dipropionate (BD) and prepared by spontaneous emulsification method.Method: A nanoemulsion (o/w) containing BD was prepared using eucalyptus oil, Tween-40, ethanol and distilled water. The nanoemulsions were characterized by droplet size, pH, viscosity, conductivity and refractive index. Stability studies were performed according to International Council on Harmonization (ICH) guidelines over a period of 3 months. Droplet size, pH, viscosity, conductivity and refractive index were determined monthly for 3 months. The shelf-life of the nanoemulsion formulation was determined by accelerated stability testing.Results: The droplet size, conductivity, viscosity, pH and refractive index of the optimized formulations did not change significantly (p ≥ 0.05) after 3 months of storage at room temperature (25 ºC). The shelf life was 1.83 years at room temperature.Conclusion: The study demonstrates that the physical and chemical stability of BD is enhanced when it is formulated as a nanoemulsion.Keywords: Nanoemulsion, Beclomethasone dipropionate, Shelf-life, Accelerated stability, Viscosity, Conductivity, Refractive inde
Applying GC-MS analysis to identify chemical composition of Iranian propolis prepared with different solvent and evaluation of its biological activity
Background: Propolis as a natural product has shown beneficial effects on human health. This study was aimed to investigate the chemical compositions and biological activity of three different extracts of propolis from two distinct geographic areas in Iran. Methods: The chemical composition of Iranian propolis extracts that were collected in the Spring of 2016 from two provinces in northern Iran: Ardabil and Polur in Mazandaran Province were measured through gas chromatography-mass spectrometry (GC-MS) methods. In addition, antimicrobial activity and cytotoxicity effect on HN5 and LNCaP cell lines were evaluated. The data were analyzed using one-way ANOVA and p<0.05 was considered as significant. Results: The GC-MS analysis identified the presence of compounds that belonged to the different groups such as aromatics acids and their related esters, flavonoid and flavonoid derivatives and terpenes. Flavanone was the most dominant compound of flavonoids. The maximum growth inhibition was observed against S. aureus of ethanolic extract of propolis (p<0.05). Moreover, cytotoxicity showed that ethanolic and dichloromethane extracts had more inhibitory effects on cell lines than the water extract. Conclusion: The results determined that extracts had the highest percentage of flavonoids. Therefore, it is expected that the synergistic effect of the main components of propolis is related to the increase of biological activity of propolis
Oesophageal candidiasis in an immunocompetent adult, an adverse effect of antibiotic therapy following cardiac surgery: Case report and review of literature
Dysphagia following cardiac surgery is a frequently encountered problem, being most commonly due to the sternotomy incision and/or prolonged intubation. Oesophageal candidiasis is an increasing problem that is usually associated with immunosuppression or immunodeficiency. We report a 59 years age, immunocompetent lady whom had developed dysphagia and odynophagia following open cardiac surgery and long term course of antibiotics. Diagnosis of Candida oesophagitis was established after radiological, endoscopic and microbiological evidence, and successful treatment with combined topical and systemic antifungal therapy was achieved. Possibility of immunodeficiency was excluded. We believe that this lady developed oesophageal candidiasis due to a long term course of broad spectrum antibiotics. We discuss the various diagnostic modalities and treatment options
Parasiticidal, antifungal and antibacterial activities of Onosma griffithii Vatke
Onosma griffithii was screened for possible pharmacological activities. The crude methanolic extract (MeOH) and its fractions demonstrated parasiticidal activity (IC 50 (ìg/ml ± S.D) = 31.03 ± 0.23) against Leishmania major. Based on the IC 50 values, the potency of the standard drug (Pentamidine) and test fractions were of the order as: Pentamidine > crude extract > n-hexane fraction > ethyl acetate (ETOAc) fraction > chloroform fraction (CHCl3) fraction > n-butanol (BUOH) fraction > aqueous fraction. Similarlymoderate antifungal activity was displayed by the crude methanolic extract against Aspergillus flavus and Fusarium solani. Against the Staphylococcus aureus, the aqueous fraction demonstrated moderate antibacterial activity
Expressive Stream Reasoning with Laser
An increasing number of use cases require a timely extraction of non-trivial
knowledge from semantically annotated data streams, especially on the Web and
for the Internet of Things (IoT). Often, this extraction requires expressive
reasoning, which is challenging to compute on large streams. We propose Laser,
a new reasoner that supports a pragmatic, non-trivial fragment of the logic
LARS which extends Answer Set Programming (ASP) for streams. At its core, Laser
implements a novel evaluation procedure which annotates formulae to avoid the
re-computation of duplicates at multiple time points. This procedure, combined
with a judicious implementation of the LARS operators, is responsible for
significantly better runtimes than the ones of other state-of-the-art systems
like C-SPARQL and CQELS, or an implementation of LARS which runs on the ASP
solver Clingo. This enables the application of expressive logic-based reasoning
to large streams and opens the door to a wider range of stream reasoning use
cases.Comment: 19 pages, 5 figures. Extended version of accepted paper at ISWC 201
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