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41.
Planktonic, epipelic and epiphytic algae were studied monthly, during the period from January to December 1985 in the Garmat ali river, a naturally regulated river draining to the al-Hammar marsh, Iraq. Chlorophyll-a, primary productivity and water quality variables were also measured. High light penetration was noticed during the winter and spring. The water is oligohaline, alkaline and very hard. Reactive nitrate was found in higher concentrations than nitrite, and there were low concentrations of reactive phosphate. Two peaks were noticed for chlorophyll-a concentrations during spring and autumn, whereas only one occurred during autumn for primary productivity. The study area may be characterized as typically mesotrophic. A total of 154 species of algae was identified, including 65, 89, 98 and 77 species of plankton, epipelic and epiphytic algae on Potamogeton lucens and on Ceratophyllum demersum, respectively. Only 25 species were common to all the different communities. Diatoms were the dominant group in the epipelic and epiphytic algae during the study period, as well as in the plankton during spring and autumn. Seasonal variations were clear in the total cell numbers of algae from different habitats.  相似文献   
42.
Designing rationally combined metal-organic frameworks(MOFs)with multifunctional nanogeometries is of significant research interest to enable the electrochemical properties in advanced energy storage devices.Herein,we explored a new class of binderfree dual-layered Ni-Co-Mn-based MOFs(NCM-based MOFs)with three-dimensional(3D)-on-2D nanoarchitectures through a polarityinduced solution-phase method for high-performance supercapatteries.The hierarchical NCM-based MOFs having grown on nickel foam exhibit a battery-type charge storage mechanism with superior areal capacity(1311.4μAh cm^−2 at 5 mA cm^−2),good rate capability(61.8%;811.67μAh cm^−2 at 50 mA cm^−2),and an excellent cycling durability.The superior charge storage properties are ascribed to the synergistic features,higher accessible active sites of dual-layered nanogeometries,and exalted redox chemistry of multi metallic guest species,respectively.The bilayered NCM-based MOFs are further employed as a battery-type electrode for the fabrication of supercapattery paradigm with biomass-derived nitrogen/oxygen doped porous carbon as a negative electrode,which demonstrates excellent capacity of 1.6 mAh cm^−2 along with high energy and power densities of 1.21 mWh cm^−2 and 32.49 mW cm^−2,respectively.Following,the MOF-based supercapattery was further assembled with a renewable solar power harvester to use as a self-charging station for various portable electronic applications.  相似文献   
43.
Soft tissue defects are common following trauma and tumor extirpation. These injuries can result in poor functional recovery and lead to a diminished quality of life. The healing of skin and muscle is a complex process that, at present, leads to incomplete recovery and scarring. Regenerative medicine may offer the opportunity to improve the healing process and functional outcomes. Barriers to regenerative strategies have included cost, regulatory hurdles, and the need for cell-based therapies. In recent years, exosomes, or extracellular vesicles, have gained tremendous attention in the field of soft tissue repair and regeneration. These nanosized extracellular particles (30–140 nm) can break the cellular boundaries, as well as facilitate intracellular signal delivery in various regenerative physiologic and pathologic processes. Existing studies have established the potential of exosomes in regenerating tendons, skeletal muscles, and peripheral nerves through different mechanisms, including promoting myogenesis, increasing tenocyte differentiation and enhancing neurite outgrowth, and the proliferation of Schwann cells. These exosomes can be stored for immediate use in the operating room, and can be produced cost efficiently. In this article, we critically review the current advances of exosomes in soft tissue (tendons, skeletal muscles, and peripheral nerves) healing. Additionally, new directions for clinical applications in the future will be discussed.  相似文献   
44.
For precise and accurate patient dose delivery,the dosimetry system must be calibrated properly according to the recommendations of standard dosimetry protocols such as TG-51 and TRS-398. However, the dosimetry protocol followed by a calibration laboratory is usually different from the protocols that are followed by different clinics, which may result in variations in the patient dose.Our prime objective in this study was to investigate the effect of the two protocols on dosimetry measurements.Dose measurements were performed for a Co-60 teletherapy unit and a high-energy Varian linear accelerator with 6 and 15 MV photon and 6, 9, 12, and 15 MeV electron beams, following the recommendations and procedures of the AAPM TG-51 and IAEA TRS-398 dosimetry protocols. The dosimetry systems used for this study were calibrated in a Co-60 radiation beam at the Secondary Standard Dosimetry Laboratory(SSDL) PINSTECH,Pakistan, following the IAEA TRS-398 protocol. The ratio of the measured absorbed doses to water in clinical setting,D_w(TG-51/TRS-398), was 0.999 and 0.997 for 6 and15 MV photon beams,whereas these ratios were 1.013,1.009, 1.003, and 1.000 for 6, 9, 12, and 15 MeV electron beams, respectively. This difference in the absorbed dosesto-water D_w ratio may be attributed mainly due to beam quality(K_Q) and ion recombination correction factor.  相似文献   
45.
Abstract

Increasing water scarcity, degradation of land and water resources, continuing low agricultural productivity, and increasing populations are posing the largest ever challenges for development of agricultural economies in many developing countries including Pakistan. Using panel data from irrigated settings in Chaj sub-basin of the Indus basin in Pakistani Punjab, we attempt to: (a) analyze the causes of low productivity; (b) disentangle factors (both land, water and other factors) contributing to productivity variations; and (c) identify limits and opportunities for narrowing productivity gaps and increasing overall wheat production, with a view to enhance food security for the poor. The results of the study indicate that locational inequities in distribution of canal water, use of groundwater of varying quality, differences in use of seed varieties, and other inputs lead to significant variations in wheat productivity. Key implications are that large gains in wheat productivity are possible by (a) improving the production environment at the tail-end through integrated water management practices; (b) adjusting the mix of canal and groundwater use; and (c) using technological interventions to improve the adoption of modern wheat varieties and dissemination of knowledge on planting dates and timings and application rates of inputs, especially water and fertilizer. Not only such interventions are economically, financially, and environmentally desirable, they are also pro-poor. What is needed is a strong political will and commitment.  相似文献   
46.
In a recent paper by Zhang et al. in 2012, a Mach number-invariant scaling was proposed to account for the effect of variation of free-stream Mach number in supersonic turbulent boundary layers. The present work focuses on the effect of variation of wall temperature with strong heating and cooling at the wall. Direct numerical simulation is used to study scaling and turbulence structure of a spatially evolving Mach 2 supersonic boundary layer at a friction Reynolds number of 500. A new scaling law is proposed to account for temperature-dependent fluid-property variations. This universal scaling appears superior to the existing models with the novelty that it applies not only for the mean-velocity profile but also extends to the turbulent transport, production, and dissipation terms in the budget of the turbulent kinetic energy.  相似文献   
47.
Wireless Personal Communications - This paper presents a Multilayer Partially Homomorphic Encryption Text Steganography, an invisible approach for covert communication. Existing text-based schemes...  相似文献   
48.
Multidimensional Systems and Signal Processing - Development of medical image segmentation techniques has become one of the most important challenges in many applications that employ...  相似文献   
49.
Wireless Personal Communications - The design of a fractal based slot antenna, to serve the dual-band communication applications, is proposed in this paper. The structure of the proposed antenna is...  相似文献   
50.
Wireless Personal Communications - Matched filtering has found its way in many diverse applications such as communication, signal processing and more. The emphasis of this paper is on the design...  相似文献   
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