Doppler-free Yb Spectroscopy with Fluorescence Spot Technique

We demonstrate a simple technique to measure the resonant frequency of the 398.9 nm 1S0 - 1P1 transition for the different Yb isotopes. The technique, that works by observing and aligning fluorescence spots, has enabled us to measure transition frequencies and isotope shifts with an accuracy of 60 MHz. We provide wavelength measurements for the transition that differ from previously published work. Our technique also allows for the determination of Doppler shifted transition frequencies for photoionisation experiments when the atomic beam and laser beam are not perpendicular and furthermore allows us to determine the average velocity of the atoms along the direction of atomic beam

Experimental Study of Multi Effect stages PV Panels Solar Still to Enhance the Productivity by Utilizing Water Heater and Cooling Fan.

دائما ما تعاني المناطق الصحراوية من نقص المياه النقية في أجزء كبير منها. وفي هذه المناطق، تكون المياه العذبة نادرة جدا حيث أن المياه التي يتم الحصول عليها من المستنقعات أو آبار المياه الجوفية هي مياه مالحة، ومن الضروري تنقيتها أو تقطيرها. وفي الدراسة التجريبية الحالية، تم إنشاء تصميم جديد لتحسين إنتاجية المياه العذبة لهرم التقطير الشمسي باستخدام السخان مغمور من نوع DC. إنه يبحث في تأثير المروحة الخارجية لتبريد سطح الزجاج. تم إجراء التجربة في فصل الصيف في ظروف العراق عند خط العرض (33.2 درجة شمالاً). يتم اختيار هرم التقطير الشمسي الزجاجي ذا زاوية ميل 32.5 درجة في هذا البيحث. نظرًا لأن التقطير الشمسي لا يزال يستخدم بصورة أكبر بالنسبة لأعماق المياه المنخفضة، لذلك فإن مستوى المياه في الحوض السفلي يبقى عند ارتفاع 3 سم. لوحظ من النتائج التجريبية أن انتاج المياه العذبة زادت بنسبة كبيرة قدرها 370 ٪ عندما تم استخدام سخان المياه DC لكل قدرة 350 واط. أثناء استخدام مروحة التبريد الخارجية، كانت إنتاجية المياه العذبة تتناقص بنسبة (7٪) و (15٪) لسرعات الرياح البالغة (7 م / ث) و (9 م / ث) على التوالي.A deserted reign always suffers from lack of pure water in a large part of its area. In this area, valuable fresh water from swamps or ground water wells is salt water, and it is necessary purified or distillated.  In the current experimental study, a new design is made to improve the yield of fresh water of a pyramid solar still by using an immersion type DC- water heater. It investigates the effect of an external fan to cool the glass surface. The Experiment was take placed in the summer season in Iraq conditions at latitude (33.2 ° N). A solar still with 32.5°glass slope angle is chosen in our work. As the productivity of a solar still is more for low water depths, the water level in the bottom basin maintained at 3 cm. The experimental outcomes observed that the yield of fresh water increased by a significant 370% when DC water heater each having 350 W capacities was used. During used the external cooling fan the productivity of fresh water was existed to decrease by (7%) and (15%) for wind speeds of (7 m/s) and (9 m/s) respectively. A good comparison takes placed with other experimental study was taken

Eco-biology of Mastacembelus pancalus (Ham.) and their distribution in different water bodies

The eco-biological of the spiny eel, Mastacembelus pailcalus in the river Padma, adjacent flood plains and ponds were influenced by various physico-chemical factors such as water temperature, water transparency, pH, dissolved oxygen, free carbon dioxide and alkalinity. Flood plain areas are the best habitat for the M. pancalus with maximum abundance

Exogenous melatonin enhances salt stress tolerance in tomato seedlings

Melatonin (N-acetyl-5-methoxytryptamine) is an essential molecule which regulates plant growth and development and alleviates the damaging effects of abiotic stresses. To evaluate the important functions of melatonin in response to salinity stress, the effects of exogenous melatonin on the antioxidant system and growth of tomato (Solanum lycopersicum L.) under 150 mM NaCl stress were investigated. The application of 100 μM melatonin compensated the growth inhibition caused by salt-stress. Melatonin treated seedlings had an increased fresh and dry masses of shoots and roots. The application of 1 - 200 µM melatonin notably enhanced the relative chlorophyll content (SPAD index), root characteristics, and gas exchange in tomato seedlings subjected to salt stress compared to seedlings treated with salt stress alone. Moreover, melatonin pretreatment minimized accumulation of reactive oxygen species and improved activities of antioxidative enzymes including catalase, superoxide dismutase, glutathione reductase, and ascorbate peroxidase.We would like to thank Wang Zhiwei from the College of Horticulture and Landscape Architecture, Hainan University, Haikou for his kind guidance and laboratory equipment. This program was financially supported by the Innovative Team Program of Hainan Natural Science Foundation (2018CXTD334) and the National Natural Science Foundation of China (41871041)

Cellulose Ether-Based Liquid Crystal Materials: Review Article

The development of liquid crystal materials via nanotechnology has become an interesting subject of research in optical material chemistry. One of the significant nanomaterials is cellulose-based nanoparticles. In this review article, we highlighted the classification of liquid crystal materials (LCs), and types of cellulose-NPs and their characterization as LCs materials. Finally, we present our promising data on the synergistic effect of cellulose-NPs on liquid crystal behavior of ethyl cellulose- and hydroxypropyl cellulose- nanocomposites

Evaluation of Antioxidant and Antimicrobial Potential of Two Endangered Plant Species Atropa belladonna and Matricaria chamomilla

Background: Plants are the natural source of antioxidants as well as antimicrobial compounds that has great potentials in pharmaceuticalindustry. In the present study, two medicinal plants Atropa belladonna and Matricaria chamomilla were collected from Northern areas ofPakistan.Materials and Methods: The extracts of the collected plants were obtained by microwave assisted extraction (MAE) with changing parameters, power level and time; methanol and ethanol were solvents used during  extraction. The extracts of plants were tested against different bacterialstrains.Results: It was observed that ethanolic extracts of Atropa belladonna has more significant antimicrobial activity against S.aureus than E.coli. Inparallel, methanolic extract of Matricaria chamomilla showed greater significant antibacterial activity against S.aureus when compared withE.coli. In comparison, ethanolic extracts of Matricaria chamomilla has shown more significant results against S. aureus than E.coli (p.0.05).Both plants had no antibacterial activity against S.typhi. The free radical scavenging activity observed by DPPH assay, indicate that both plantshave antioxidant activity at all levels of concentrations in solvent tested during the present work. However, methanolic extracts had greaterantioxidant activity when compared with ethanolic extracts.Conclusion: Present study is thus helpful in highlighting present potentials for antioxidant and antimicrobial properties in the selected plants.Key words: Antimicrobial, antioxidant, Atropa belladonna, Matricaria chamomill

A Frequency Reconfigurable Compact Planar Inverted-F Antenna for Portable Devices

In this paper, a low-profile, compact size, inexpensive, and easily integrable frequency reconfigurable antenna system is proposed. The proposed antenna consists of an inverted-F shape antenna, capacitors, and switching PIN diodes. The designed antenna element is fabricated on easy available and less expensive FR-4 substrate (epsilon(r) = 4.4, tan delta = 0.02). The switching diodes are incorporated within the radiating structure of the antenna design, and by changing the different states of PIN diodes, frequency reconfigurable response is achieved. While adjusting the different states of the diodes, the antenna resonates between 0.841 GHz and 2.12 GHz and covers six different frequency bands. The proposed system has compact size of 44x14x3.2 mm(3). The gain of the antenna is between 1.89 and 2.12 dBi. The measurement results shows the good agreement with simulated results for different key performance parameters. Additionally, the proposed antenna shows omni-directional far-field characteristics for various different frequencies

Bacteriological profile of wound infections and antimicrobial resistance in selected gram-negative bacteria

Background: Managing wound infections is a challenging task. Understanding their resistance pattern is an essential step at reducing its burden in hospital settings. Objective: To determine the bacteriological diversity of wound infections and the antimicrobial resistance exhibited by a selected Gram-negative bacterium in the Aljouf region of Saudi Arabia. Methods: The study retrospectively analysed the antibiograms of wound infections from hospitalized patients for the year 2019. The European Centre for Disease Control guidelines were adopted for the classification of resistant bacteria. Multidrug-, extensive drug-, and carbapenem-resistant isolates are presented as frequencies and percentages. Results: A total of 295 non-duplicate wound swab antibiograms were retrieved, 64.4% (190) and 35.6% (105) isolates were Gram-negative and Gram-positive bacterial infections respectively. Predominant pathogens included Staphylococcus species 21.0% (62), E. coli 16.3% (48) and K. pneumoniae 13.5% (40). 148 (77.9%), 42 (22.1%) and 43 (22.6%) of the Gram-negative isolates were multidrug-, extensively drug- and carbapenem-resistant. The antibiotic resistance exhibited by gram-negative bacteria was 43.4% (234/539), 59.1% (224/379) and 53.7% (101/188) towards carbapenems, 3rd - and 4th – generation cephalosporins. Conclusions: The majority of wound infections are caused by multidrug-, extensively drug- and carbapenem-resistant Gram-negative bacteria. Further studies should focus on the molecular basis of this resistance. Keywords: Wound infections; hospital; Gram-negative bacteria; antibiograms; multidrug-resistance; E. coli

Future Smartphone: MIMO Antenna System for 5G Mobile Terminals

In this article, an inverted L-shaped monopole eight elements Multiple Input Multiple Output (MIMO) antenna system is presented. The multi-antenna system is designed on a low cost 0.8 mm thick FR4 substrate having dimensions of 136 x 68 mm(2) resonating at 3.5GHz with a 6dB measured bandwidth of 450MHz, and with inter element isolation greater than 15 dB and gain of 4 dBi. The proposed design consists of eight inverted L-shaped elements and parasitic L-shaped strips extending from the ground plane. These shorted stripes acted as tuning stubs for the four inverted L-shaped monopole elements on the side of chassis. This is done to achieve the desired frequency range by increasing the electrical length of the antennas. A prototype is fabricated, and the experimental results show good impedance matching with reasonable measured isolation within the desired frequency range. The MIMO performances, such as envelope correlation coefficient (ECC) and mean effective gain (MEG) are also calculated along with the channel capacity of 38.1bps/Hz approximately 2.6 times that of 4 x 4 MIMO system. Due to its simple shape and slim design, it may be a potential chassis for future handsets. Therefore, user hand scenarios, i.e. both single and dual hand are studied. Also, the effects of hand scenarios on various MIMO parameters are discussed along with the SAR. The performance of the proposed system in different scenarios suggests that the proposed structure holds promising future within the next generation radio smart phones