1,226 research outputs found

    Are Leaf Traits Stable Enough to Rank Native Grasses in Contrasting Growth Conditions?

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    The growing interest in classifying species in response groups relating to variations in environmental factors has triggered the search for functional traits that express differences in ecological behaviour among plant species (Lavorel & Garnier, 2002). Specific leaf area (SLA) and leaf dry matter content (LDMC) reflect a fundamental trade-off in plant functioning between a fast growth rate (high SLA, low LDMC species) and nutrient conservation (low SLA, high LDMC species). This study aimed to analyse the stability of ranking native grasses by SLA and LDMC values under different plant growing conditions

    A Novel High Frequency Encoding Algorithm for Image Compression

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    In this paper a new method for image compression is proposed whose quality is demonstrated through accurate 3D reconstruction from 2D images. The method is based on the Discrete Cosine Transform (DCT) together with a high frequency minimization encoding algorithm at compression stage and a new concurrent binary search algorithm at decompression stage. The proposed compression method consists of five main steps: (1) Divide the image into blocks and apply DCT to each block; (2) Apply a high frequency minimization method to the AC-coefficients reducing each block by 2/3 resulting in a Minimized Array; (3) Build a look up table of probability data to enable the recovery of the original high frequencies at decompression stage; (4) Apply a delta or differential operator to the list of DC-components; and (5) Apply arithmetic encoding to the outputs of steps (2) and (4). At decompression stage, the look up table and the concurrent binary search algorithm are used to reconstruct all high frequency AC-coefficients while the DC-components are decoded by reversing the arithmetic coding. Finally, the inverse DCT recovers the original image. We tested the technique by compressing and decompressing 2D images including images with structured light patterns for 3D reconstruction. The technique is compared with JPEG and JPEG2000 through 2D and 3D RMSE. Results demonstrate that the proposed compression method is perceptually superior to JPEG with equivalent quality to JPEG2000. Concerning 3D surface reconstruction from images, it is demonstrated that the proposed method is superior to both JPEG and JPEG2000

    A New Selective PPARγ Modulator Inhibits Triglycerides Accumulation during Murine Adipocytes’ and Human Adipose-Derived Mesenchymal Stem Cells Differentiation

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    Understanding the molecular basis of adipogenesis is vital to identify new therapeutic targets to improve anti-obesity drugs. The adipogenic process could be a new target in the management of this disease. Our aim was to evaluate the effect of GMG-43AC, a selective peroxisome proliferator-activated receptor \u3b3 (PPAR\u3b3) modulator, during adipose differentiation of murine pre-adipocytes and human Adipose Derived Stem Cells (hADSCs). We differentiated 3T3-L1 cells and primary hADSCs in the presence of various doses of GMG-43AC and evaluated the differentiation efficiency measuring lipid accumulation, the expression of specific differentiation markers and the quantification of accumulated triglycerides. The treatment with GMG-43AC is not toxic as shown by cell viability assessments after the treatments. Our findings demonstrate the inhibition of lipid accumulation and the significant decrease in the expression of adipocyte-specific genes, such as PPAR\u3b3, FABP-4, and leptin. This effect was long lasting, as the removal of GMG-43AC from culture medium did not allow the restoration of adipogenic process. The above actions were confirmed in hADSCs exposed to adipogenic stimuli. Together, these results indicate that GMG-43AC efficiently inhibits adipocytes differentiation in murine and human cells, suggesting its possible function in the reversal of adipogenesis and modulation of lipolysis

    Therapeutic effect of neural progenitor cells expanded in the 3D nano-engineered Nichoid substrate in a Parkinson’s disease preclinical model

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    3D microscaffoldsare becoming more and more relevant in regenerative medicine, as they lead to the creation of a structure similar to a physiologicalniche. An example is the nano-engineered Nichoid, a 3D structure in which the cells are able to proliferate. In this work,we investigated the proliferation and stemness properties of Er-NPCswhen grown inside the Nichoid, and their potential therapeutic application in the treatment of Parkinson\u2019s Disease.3D microscaffolds are becoming more and more relevant in regenerative medicine, as they lead to the creation of a structure similar to a physiological niche. An example is the nano-engineered Nichoid, a 3D structure in which the cells are able to proliferate. In this work, we investigated the proliferation and stemness properties of Er-NPCs when grown inside the Nichoid, and their potential therapeutic application in the treatment of Parkinson\u2019s Disease

    Electrically atomised formulations of timolol maleate for direct and on-demand ocular lens coatings

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link

    Investigating pharmacy students’ therapeutic decision-making with respect to antimicrobial stewardship cases

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    Background: Antimicrobial stewardship programs (ASPs) play a big role in minimizing antimicrobial resistance. Pharmacists are essential members of the health care team and in order for them to fulfill roles on ASP teams and become antimicrobial stewards, they must be prepared adequately by pharmacy schools prior to entry into actual practice. Although programming has been implemented into entry-to-practice programs worldwide, little is known about how students interpret antimicrobial stewardship (AMS) data and arrive at clinical decisions. We aimed to explore students’ cognitive processes and determine how they formulate therapeutic decisions when presented with AMS cases. Methods: This was a qualitative study conducted using a case study approach, in which a sample (n=20) of pharmacy students was recruited to interpret AMS cases. Semi-structured 1-on-1 interviews were arranged with each participant. A think-aloud procedure with verbal protocol analysis was adopted to determine students’ decision-making processes. Thematic analysis was used to interpret themes from the interview data. Results: Two themes were interpreted from the data: students’ focus and students’ approach to case interpretation. Students’ focus relates to external factors students consider when interpreting AMS case data and use to make and justify therapeutic decisions including patient-centered factors, drug-related factors, AMS interventions, and pharmacist’s role. Students’ clinical reasoning describes the approach that students use to interpret the data and the decision-making processes they employ to arrive at a clinical decision including a systematic approach versus non-systematic approach. Conclusions: Students vary in their focus and the cognitive strategies used to interpret AMS cases. Findings support the notion that clinical reasoning and decision-making should be explicitly taught in pharmacy curricula, in order to help students become aware of their own cognitive processes and decision-making abilities.This study was completed with funding from an Internal Student Grant from Qatar University (QUST-2-CPH-2020-9)

    The effect of reverse current on the dark properties of photovoltaic solar modules

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    AbstractForward and reverse dark current-voltage (I-V) and capacitance-voltage (C-V) characteristics of commercial amorphous silicon solar modules, were measured in order to study their performance under the influence of induced reverse currents. Maximum module surface temperatures were directly related to each value of the induced reverse current and in to the amount of current leakage respectively. Microscopic changes as a result of hot spots defects and overheating of the solar module, linked to reverse current effects, were also documented and discussed. Experimental evidence showed that different levels of reverse currents are confirmed to be a major degrading factor affecting the performance, efficiency, and power of solar modules

    A novel 2D image compression algorithm based on two levels DWT and DCT transforms with enhanced minimize-matrix-size algorithm for high resolution structured light 3D surface reconstruction

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    Image compression techniques are widely used in 2D and 3D image and video sequences. There are many types of compression techniques and among the most popular are JPEG and JPEG2000. In this research, we introduce a new compression method based on applying a two level Discrete Wavelet Transform (DWT) and a two level Discrete Cosine Transform (DCT) in connection with novel compression steps for high-resolution images. The proposed image compression algorithm consists of 4 steps: 1) Transform an image by a two level DWT followed by a DCT to produce two matrices: DC- and AC-Matrix, or low and high frequency matrix respectively; 2) apply a second level DCT to the DC-Matrix to generate two arrays, namely nonzero-array and zero-array; 3) apply the Minimize-Matrix-Size (MMS) algorithm to the AC-Matrix and to the other high-frequencies generated by the second level DWT; 4) apply arithmetic coding to the output of previous steps. A novel Fast-Match-Search (FMS) decompression algorithm is used to reconstruct all high-frequency matrices. The FMS-algorithm computes all compressed data probabilities by using a table of data, and then using a binary search algorithm for finding decompressed data inside the table. Thereafter, all decoded DC-values with the decoded AC-coefficients are combined into one matrix followed by inverse two level DCT with two level DWT. The technique is tested by compression and reconstruction of 3D surface patches. Additionally, this technique is compared with JPEG and JPEG2000 algorithm through 2D and 3D RMSE following reconstruction. The results demonstrate that the proposed compression method has better visual properties than JPEG and JPEG2000 and is able to more accurately reconstruct surface patches in 3D

    A novel image compression algorithm for high resolution 3D reconstruction

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    This research presents a novel algorithm to compress high-resolution images for accurate structured light 3D reconstruction. Structured light images contain a pattern of light and shadows projected on the surface of the object, which are captured by the sensor at very high resolutions. Our algorithm is concerned with compressing such images to a high degree with minimum loss without adversely affecting 3D reconstruction. The Compression Algorithm starts with a single level discrete wavelet transform (DWT) for decomposing an image into four sub-bands. The sub-band LL is transformed by DCT yielding a DC-matrix and an AC-matrix. The Minimize-Matrix-Size Algorithm is used to compress the AC-matrix while a DWT is applied again to the DC-matrix resulting in LL2, HL2, LH2 and HH2 sub-bands. The LL2 sub-band is transformed by DCT, while the Minimize-Matrix-Size Algorithm is applied to the other sub-bands. The proposed algorithm has been tested with images of different sizes within a 3D reconstruction scenario. The algorithm is demonstrated to be more effective than JPEG2000 and JPEG concerning higher compression rates with equivalent perceived quality and the ability to more accurately reconstruct the 3D models

    Chemical Characterization and Nematicidal Activity of the Essential Oil of Nepeta nuda L. ssp. pubescens and Nepeta curviflora Boiss. from Lebanon

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    The chemical characterization and the nematicidal activity of the essential oils from Nepeta nuda L. ssp. pubescens and Nepeta curviflora Boiss. growing wild in Lebanon are reported. A comparative study was carried out as, to the best of our knowledge, no information is available on Nepeta nuda L. ssp. pubescens. In addition, both Nepeta species were collected in the same geographical area in order to rule out the environmental factors influencing essential oil composition and bioactivity. The most abundant (> 5 %) components of N. nuda ssp. pubescens essential oil were pinene (12.89 %), 1-ethyl-1H-pyrrole (12.67 %), 1-cycloethyl- 1-(2-methylenecyclohexyl) ethanol (10.37 %), 3-methyl-2-cyclohexen-1-one (9.17 %) and 2,3-dimethyl-3- hexanol (5.88 %). Among oxygenated monoterpenes, two nepetalactones were identified, i.e. (E, Z)nepetalactone (2.24 %) and (Z, E)-nepetalactone (0.31 %). The major constituents (> 5 %) of N. curviflora essential oil were 2-isopropyl-5-methyl-3-cyclohexen-1-one (12.51%), (-)-spathulenol (11.73%), cis-Z-alpha-bisabolene epoxide (8.07 %), widdrol (7.0 %), (E, Z)-5,7-dodecadiene (6.93 %), dihydronepetalactone (5.57 %) and 4-propyl-cyclohexene (5.43 %). The essential oil of N. curviflora was more active than the N. nuda ssp. pubescens one against the nematode Panagrolaimus rigidus. According to the motility assay, LD50 was 0.5 mg/mL and 2.5 mg/mL 24 h after treatment with N. curviflora and N. nuda ssp. pubescens essential oil, respectively
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