bluuebunny/crossref_metadata_2025 huggingface dataset:
A new model mechanism for atmospheric oxidation of isoprene: global effects on oxidants, nitrogen oxides, organic products, and secondary organic aerosol
Authors: Bates Kelvin H. , Jacob Daniel J.
Published: July 2019

Abstract. Atmospheric oxidation of isoprene, the most abundantly emitted non-methane hydrocarbon, affects the abundances of ozone (O3), the hydroxyl radical (OH), nitrogen oxide radicals (NOx), carbon monoxide (CO), oxygenated and nitrated organic compounds, and secondary organic aerosol (SOA). We analyze these effects in box models and in the global GEOS-Chem chemical transport model using the new reduced Caltech isoprene mechanism (RCIM) condensed from a recently developed explicit isoprene oxidation mechanism. We find many similarities with previous global models of isoprene chemistry along with a number of important differences. Proper accounting of the isomer distribution of peroxy radicals following the addition of OH and O2 to isoprene influences the subsequent distribution of products, decreasing in particular the yield of methacrolein and increasing the capacity of intramolecular hydrogen shifts to promptly regenerate OH. Hydrogen shift reactions throughout the mechanism lead to increased OH recycling, resulting in less depletion of OH under low-NO conditions than in previous mechanisms. Higher organonitrate yields and faster tertiary nitrate hydrolysis lead to more efficient NOx removal by isoprene and conversion to inorganic nitrate. Only 20 % of isoprene-derived organonitrates (excluding peroxyacyl nitrates) are chemically recycled to NOx. The global yield of formaldehyde from isoprene is 22 % per carbon and less sensitive to NO than in previous mechanisms. The global molar yield of glyoxal is 2 %, much lower than in previous mechanisms because of deposition and aerosol uptake of glyoxal precursors. Global production of isoprene SOA is about one-third from each of the following: isoprene epoxydiols (IEPOX), organonitrates, and tetrafunctional compounds. We find a SOA yield from isoprene of 13 % per carbon, much higher than commonly assumed in models and likely offset by SOA chemical loss. We use the results of our simulations to further condense RCIM into a mini Caltech isoprene mechanism (Mini-CIM) for less expensive implementation in atmospheric models, with a total size (108 species, 345 reactions) comparable to currently used mechanisms.
Forest aboveground biomass stock and resilience in a tropical landscape of Thailand
Authors: Jha Nidhi , Tripathi Nitin Kumar , Chanthorn Wirong , Brockelman Warren , Nathalang Anuttara , Pélissier Raphaël , Pimmasarn Siriruk , Ploton Pierre , Sasaki Nophea , Virdis Salvatore G. P. , Réjou-Méchain Maxime
Published: July 2019

Abstract. Half of Asian tropical forests were disturbed in the last century resulting in the dominance of secondary forests in Southeast Asia. However, the rate at which biomass accumulates during the recovery process in these forests is poorly understood. We studied a forest landscape located in Khao Yai National Park (Thailand) that experienced strong disturbances in the last century due to clearance by swidden farmers. Combining recent field and airborne laser scanning (ALS) data, we first built a high-resolution aboveground biomass (AGB) map over 60 km2 of the forest landscape. We then used the random forest algorithm and Landsat time-series (LTS) data to classify landscape patches as non-forested versus forested on an almost annual basis from 1972 to 2017. The resulting chronosequence was then used in combination with the AGB map to estimate forest carbon recovery rates in secondary forest patches during the first 42 years of succession. The ALS-AGB model predicted AGB with an error of 14 % at 0.5-ha resolution (RMSE = 45 Mg ha−1) using the mean top-of-canopy height as a single predictor. The mean AGB over the landscape was of 291 Mg ha−1 showing a high level of carbon storage despite past disturbance history. We found that AGB recovery varies non-linearly in the first 42 years of the succession, with an increasing rate of accumulation through time. We predicted a mean AGB recovery rate of 6.9 Mg ha−1 yr−1, with a mean AGB gain of 143 and 273 Mg ha−1 after 20 and 40 years, respectively. These estimates are within the range of those reported for the well-studied Latin American secondary forests under similar climatic conditions. This study illustrates the potential of ALS data not only for scaling up field AGB measurements but also for predicting AGB recovery dynamics when combined with long-term satellite data. It also illustrates that tropical forest landscapes that were disturbed in the past are of utmost importance for the regional carbon budget and thus for implementing international programs such as REDD+.
A global monthly climatology of total alkalinity: a neural network approach
Authors: Broullón Daniel , Pérez Fiz F. , Velo Antón , Hoppema Mario , Olsen Are , Takahashi Taro , Key Robert M. , Tanhua Toste , González-Dávila Melchor , Jeansson Emil , Kozyr Alex , van Heuven Steven M. A. C.
Published: July 2019

Abstract. Global climatologies of the seawater CO2 chemistry variables
are necessary to assess the marine carbon cycle in depth. The climatologies
should adequately capture seasonal variability to properly address ocean
acidification and similar issues related to the carbon cycle. Total
alkalinity (AT) is one variable of the seawater CO2 chemistry
system involved in ocean acidification and frequently measured. We used the
Global Ocean Data Analysis Project version 2.2019 (GLODAPv2) to extract
relationships among the drivers of the AT variability and AT
concentration using a neural network (NNGv2) to generate a monthly
climatology. The GLODAPv2 quality-controlled dataset used was modeled by the
NNGv2 with a root-mean-squared error (RMSE) of 5.3 µmol kg−1.
Validation tests with independent datasets revealed the good generalization
of the network. Data from five ocean time-series stations showed an
acceptable RMSE range of 3–6.2 µmol kg−1. Successful modeling of
the monthly AT variability in the time series suggests that the NNGv2
is a good candidate to generate a monthly climatology. The climatological
fields of AT were obtained passing through the NNGv2 the World Ocean
Atlas 2013 (WOA13) monthly climatologies of temperature, salinity, and oxygen
and the computed climatologies of nutrients from the previous ones with a
neural network. The spatiotemporal resolution is set by WOA13:
1∘ × 1∘ in the horizontal, 102 depth levels
(0–5500 m) in the vertical and monthly (0–1500 m) to annual (1550–5500 m)
temporal resolution. The product is distributed through the data repository
of the Spanish National Research Council (CSIC;
https://doi.org/10.20350/digitalCSIC/8644, Broullón et al., 2019).
The effect of cyclones crossing the Mediterranean region on sea level anomalies on the Mediterranean Sea coast
Authors: Lionello Piero , Conte Dario , Reale Marco
Published: July 2019

Abstract. Large positive and negative sea level anomalies on the coast of the Mediterranean Sea are linked to intensity and position of cyclones moving along the Mediterranean storm track with dynamics involving different factors. This analysis is based on a model hindcast and considers nine coastal stations, which are representative of sea level anomalies with different magnitudes and characteristics. When a shallow water fetch is present, the wind around the cyclone centre is the main cause of positive and negative sea level anomalies, depending on its onshore or offshore direction. The inverse barometer effect produces a positive anomaly on the coast near the cyclone pressure minimum and a negative anomaly at the opposite side of the Mediterranean Sea. The latter is caused by the cross-basin mean sea level pressure gradient that is associated with the presence of a cyclone. This often coincides with the presence of an anticyclone above the station, which causes a local negative inverse barometer effect. Further, at some stations, negative sea level anomalies are reinforced by a residual water mass redistribution within the basin, which is associated with a transient response to the atmospheric pressure forcing. Though the link with the presence of a cyclone in the Mediterranean has comparable importance for positive and negative anomalies, the relation between cyclone position and intensity is stronger for the magnitude of positive events. The area of cyclogenesis, track of the central minimum and position at the time of the event differ depending on the location the sea level anomaly occurs and on its sign. The western Mediterranean is the main cyclogenesis area for both positive and negative anomalies overall. Atlantic cyclones mainly produce positive sea level anomalies in the western basin. At the easternmost stations, positive anomalies are caused by cyclogenesis in the eastern Mediterranean. North African cyclogenesis is a major source of positive anomalies on the central African coast and negative anomalies on the eastern Mediterranean and northern Aegean coasts.
Revised earthquake sources along Manila trench for tsunami hazard assessment in the South China Sea
Authors: Qiu Qiang , Li Linlin , Hsu Ya-Ju , Wang Yu , Chan Chung-Han , Switzer Adam D.
Published: July 2019

Abstract. Seismogenic tsunami hazard assessments are highly dependent on the
reliability of earthquake source models. Here in a study of the Manila
subduction zone (MSZ) system, we combine the geological characteristics of
the subducting plate, geometry, and coupling state of the subduction
interface to propose a series of fault rupture scenarios. We divide the
subduction zone into three rupture segments: 14–16, 16–19, and 19–21.7∘ N inferred from geological structures associated with the down-going Sunda plate. Each of these segments is capable of generating earthquakes of a magnitude between Mw=8.5+ and Mw=9+, assuming a 1000-year seismic return period as suggested by previous studies. The most poorly constrained segment of the MSZ lies between 19 and 21.7∘ N, and here we use both local geological structures and characteristics of other subduction zone earthquakes around the world, to investigate the potential rupture characteristics of this segment. We consider multiple rupture modes for tsunamigenic earthquake and megathrust-splay fault earthquakes. These rupture models facilitate an improved understanding of the potential tsunami hazard in the South China Sea (SCS). Hydrodynamic simulations demonstrate that coastlines surrounding the SCS could be devastated by tsunami waves up to 10 m if large megathrust earthquakes occur in these segments. The regions most prone to these hazards include west Luzon of Philippines, southern Taiwan, southeastern China, central Vietnam, and Palawan Island.
A Conceptual framework for web-based Nepalese landslide
information system
Authors: Meena Sansar Raj , Ghorbanzadeh Omid , Hölbling Daniel , Albrecht Florian , Blaschke Thomas
Published: July 2019

Abstract. Comprehensive and sustainable landslide management, including identification of landslide susceptible areas, requires a lot of organisations and people to collaborate efficiently. Often, landslide management efforts are made after major triggering events only, such as hazard mitigations that applied after the 2015 Gorkha earthquake in Nepal. Next, to a lack of efficiency and continuity, there is also a lack of sharing of information and cooperation among stakeholders to cope with significant disaster events. There should be a system to allow easy update of landslide information after an event. For a variety of users of landslide information in Nepal, the availability and extraction of landslide data from the database are a vital requirement. In this study, we investigate the requirements to and propose a concept for a web-based Nepalese landslide information system (NELIS) that provides users with a platform to share the location of landslide events for the further collaborations. The system will be defined as a web-based geographic information system (GIS) that supports responsible organisations to address and manage different user requirements of people working with landslides, thereby improving the current state of landslide management in Nepal. The overall aim of this research is to propose a conceptual design of NELIS and to show the current status of the cooperation between involved stakeholders. A system like NELIS could benefit stakeholders involved in data collection and landslide management in their efforts to report and provide landslide information. Moreover, such a system would allow for detailed and structured landslide documentation and consequently provide valuable information for susceptibility, hazard, and risk mapping. For the reporting of landslides directly to the system, a web portal is proposed. Stakeholders who can contribute to the reporting of landslides are mostly local communities and schools. Based on field investigations, literature reviews and user interviews, the practical structure of the landslide database and a conceptual design for the NELIS platform is proposed.
Spatially resolved soil solution chemistry in a central European atmospherically polluted high-elevation catchment
Authors: Petrash Daniel A. , Buzek Frantisek , Novak Martin , Cejkova Bohuslava , Kram Pavel , Chuman Tomas , Curik Jan , Veselovsky Frantisek , Stepanova Marketa , Myska Oldrich , Holeckova Pavla , Bohdalkova Leona
Published: July 2019

Abstract. We collected soil solutions by suction lysimeters in a
central European temperate forest with a history of acidification-related
spruce die-back in order to interpret spatial patterns of soil nutrient
partitioning, compare them with stream water chemistry and evaluate these
parameters relative to concurrent loads of anions and cations in
precipitation. Five lysimeter nests were installed in the 33 ha U dvou
loucek (UDL) mountain catchment at different topographic positions
(hilltops, slopes and valley). Following equilibration, monthly soil
solution samples were interrogated over a 2-year period with regard to their
SO42-, NO3-, NH4+, Na+, K+, Ca2+,
Mg2+ and total dissolved Al concentrations, organic carbon (DOC) and
pH. Soil pits were excavated in the vicinity of each lysimeter nest to also
constrain soil chemistry. For an estimation of phosphorus (P) availability,
ammonium oxalate extraction of soil samples was performed. Cation exchange
capacity (CEC ≤58 meq kg−1) and base saturation (BS ≤13 %) were found to be significantly lower at UDL than in other monitored
central European small catchments areas. Spatial trends and seasonality in
soil solution chemistry support belowground inputs from mineral-stabilized
legacy pollutants. Overall, the soil solution data suggest that the
ecosystem was still chemically out of balance relative to the concurrent
loads of anions and cations in precipitation, documenting incomplete
recovery from acidification. Nearly 30 years after peak acidification, UDL
exhibited similar soil solution concentrations of SO42, Ca2+ and Mg2+ as median values at the Pan-European International
Co-operative Program (ICP) Forest sites with similar bedrock lithology and
vegetation cover, yet NO3- concentrations were an order of
magnitude higher. When concentrations of SO42-, NO3- and
base cations in runoff are compared to soil pore waters, higher
concentration in runoff points to lateral surficial leaching of pollutants
and nutrients in excess than from topsoil to subsoil. With P availability
being below the lowest range observed in soil plots from the Czech Republic,
the managed forest ecosystem in UDL probably reflects growing inputs of C
from regenerating vegetation in the N-saturated soil, which leads to P
depletion in the soil. In addition, the observed spatial variability
provides evidence pointing to substrate variability, C and P
bioavailability, and landscape as major controls over base metal leaching
toward the subsoil level in N-saturated catchments.
The Meaning of Leisure and Life Satisfaction: The Sample of University Students
Authors: Er Yusuf , KOC Mustafa Can , DEMIREL Mehmet , CUHADAR Abdullah
Published: July 2019

The aim of the study is to examine the meaning of leisure time and life satisfaction levels of university students in general and students studying in faculties of tourism and sports sciences specifically. The sample group was determined from Recreation and Recreation Management students in the faculties of Tourism and Sport Sciences of universities by using appropriate sampling method based on voluntariness. The study included a total of 1345 university students, 507 women (37.7%) and 838 men (62.3%). In the study, Leisure Meanings Inventory (LMI), which included 35 items and 8 sub-dimensions and which was adapted into Turkish by Gürbüz, Özdemir and Karaküçük (2007), and the Life Satisfaction Questionnaire, which was developed by Diener et al. in 1985 and adapted into Turkish by Yetim (1993) and which included 5 items, were used. In the analysis of the data, descriptive statistical methods such as percentage and frequency were checked to determine the distribution of the personal information of the participants, and Skewness and Kurtosis values of the data were checked to determine whether the data showed normal distribution. In addition, t-test and Anova test and correlation analysis methods were used (α = 0.05). The limitations of the study and evaluations for future studies were discussed in this sense.
“In the Hope That They Can Make Their Own Future”: James H. Cone and the Third World
Authors: Harris Matthew M. , Davis Tyler B.
Published: July 2019

James Cone views Black theology as of a piece with Third World theology. Contrary to lingering criticisms that Cone's writings are politically limited by metaphysical and cultural nationalism, this article contends that for Cone the internationalist standpoint is essential to a “new way of making theology.” To this end we offer an alternative frame for appreciating Cone's theological vision by attending to his project to link Black liberation theology to Third World theology through his writings, relationships, and affiliations and through his concomitant critique of racial capitalist civilization. Our argument is that these global connections are central to understanding Cone's theology and that Cone's endorsement of a new economic order is a material corollary internal to his participation in these networks. Our goal is to attend to these neglected features in Cone's theology in order to recast his writings as a resource for the contemporary Black radical imagination.
James Cone: A Black Theologian's Reflection
Authors: Oates N'Kosi
Published: July 2019

When I interviewed Professor James Cone nearly four years ago, he reflected on his seminal text, Black Theology and Black Power. He admitted, “I was trying to write a theology that would speak to the spirit of the times in my community and I wanted to share that one can be both black and Christian.” This would be one of the last interviews Cone gave. Most interviews of Cone over the past seven years have centered on his latest book, The Cross and the Lynching Tree. This interview, however, distinguishes itself from those interviews because it places attention on Black Theology and Black Power and captures Cone's thoughts on the theologian's role in society, Black Lives Matter, and his legacy.
Qatar Digital Healthcare: An Impact Assessment Of Health Information Technologies On National Capacity Development
Authors: Niaz Rashid
Published: July 2019

Background
The health system in Qatar is going through a digital health technology transformation. Along with upgrading its facilities and medical equipment, Qatar has invested hundreds of millions of Riyals in health information systems specifically deployment of an integrated Electronic Medical Record (EMR) across its national hospitals and primary health care centers. This has introduced the age of health informatics for Qatar at a national level. Health informatics is the systematic application of information, computer science, and technology to practice of health care and research. A specialized workforce will be required to operate and manage these systems.
Objective
The primary objective of this study was to understand any constraint on national capacity development in the area of health informatics.
Methods
We reviewed Qatar’s national health and development strategy reports and interviewed 23 health care professionals with a mix of physicians, nurses and allied health practitioners.
Results
82% were aware of the health informatics technologies deployment in Qatar. 78% of the interviewees had limited understanding of health care informatics as it relates to national capacity strategy. None of the respondents were aware of any educational programs specializing in health informatics.
Conclusions
Currently, there is no degree awarding health informatics programs in Qatar. Developing the workforce to support health care informatics requires multiple actions. Comprehensive curriculum and workforce analysis is necessary to provide information about the degree gaps as well as baseline competencies. Developing health informatics competencies that complement other competency sets i.e. medical training, advanced IT training for the existing workforce; establishing coursework and degree programs in conjunction with clinical and IT awarding institutions; and developing institutional training/mentorship programs.
Implementation of Genomics Tools for Genetic Improvement of Date Palm to Black Scorch Disease
Authors: Radwan Osman , Al-Naemi Fatima A.
Published: July 2019

The ability of date palm tree to survive under adverse abiotic conditions renders it as an important fruit tree growing in hot and dry regions. Nevertheless, the optimal conditions for date palm growth and production are also suitable for fungal growth leading to major diseases such as black scorch. The aim of this work was to develop a genetic control of date palm to Thielaviopsis punctulata, the causal agent of black scorch, through understanding molecular interactions between the plant host and the pathogen. Genomics and bioinformatics tools were used to sequence, assembly and annotate the whole genome of the pathogen and to decipher the molecular mechanisms of date palm resistance to the pathogen. The whole fungal genome was assembled and functionally annotated with an estimated size of 28.1 Mb containing 5,480 predicted genes. Some of the annotated genes belong to toxin-related genes such as necrosis inducing protein (NPP1) and Cerato-platanin, reflecting a potential functional role of fungal toxins in inducing disease symptoms. On the host side, real-time PCR and RNA-Seq approaches were used to quantify the fungal infection and profile the genome expression of date palm in response to the pathogen infection in two cultivars at 1, 2, 3 and 4 day post infection (dpi). Results from real-time PCR showed that the fungal infection started early at one dpi and the highest level of infection was detected at three dpi for both cultivars. Results also showed that Khalas cultivar is less infected by the pathogen compare to Kinzy cultivar reflecting a degree of resistance in Khalas cultivar. Data from RNA-Seq is being analyzed to identify regulatory genes involved in resistance to black scorch disease. Information from the current study will lead to further understanding of the molecular interactions between T. punctulata and date palm, assisting in deriving effective genetic control strategies for black scorch disease.
High-Voltage DC Integration of Photovoltaic Power by Front-End Isolated Quasi-Z-Source Converter Modules in Series
Authors: Liu Yushan
Published: July 2019

Considering dc characteristics of Photovoltaic (PV), a higher voltage dc integration of PV power is expected to inherit the PV power's natural dc property, replace the bulky line-frequency transformer as the central inverter, eliminate the dc-side low-frequency pulsating power as the cascade multilevel inverter, and reduce power loss in distribution and transmission. However, due to the PV panel insulation demand, the voltage of series connected PV panels is restricted to one kilovolt. To overcome that defect, a quasi-Z-source modular cascaded converter (qZS-MCC) is proposed by series connection of front-end isolated qZS half-bridge (HB) dc-dc converter submodules (SMs). The qZS-HB is able to handle PV voltage and power variations, dc-link voltage balance, and HV-side dc integration. Thus, there is no requirement to control the front-end isolation converter. It greatly reduces the complexity of control and implementation comparing to that without qZS network, where the front-end isolation converters of all SMs require separate control method and gate driving. Simulation investigations based on high-power qZS-HB SMs and experimental results on downscaled prototype validated the proposed solution, providing a promising approach for the future integration and transmission of high-power PV systems.
Facile Synthesized Mo
2
C Electrocatalyst Supported on Mesoporous Carbon for Hydrogen Generations
Authors: Merzougui Belabbes
Published: July 2019

The surge in the field of renewable energy aiming to develop clean energy technology is continuing to rise. Quest for a H2-based economy derived from non-fossil resources remains at the forefront of future fuels. During the past few decades there has been intense research on the utilization of electrical energy to produce H2 in an energy efficient and environmentally benign way. Electrocatalytic hydrogen generation via water electrolysis provides an important alternative to that extracted from hydrocarbon resources. One of the most crucial components which could revolutionize H2 production is that the design and development of a novel electrocatalyst that can efficiently split water to generate H2. Currently, platinum (Pt) is known as the state-of-the art electrocatalyst for hydrogen evolution reaction (HER). However, due to cost and scarcity of Pt, research focus shifted to precious-metal-free based materials for efficient HER reaction. As results, a wide variety of transition-metal-based electrocatalysts have been developed and investigated. To this end and due to unique d-band electronic structure, Mo-based electrocatalyst such as, Mo2C and MoS2 has been the subject of intense investigation for HER reaction. Yet, functional and robust catalysts operating with reasonable current densities (J) at low overpotential in brine water are still scarce.

Herein, we demonstrate a facile synthesis of β-Mo2C embedded on mesoporous carbon support; Metal Organic Framework (MIL 53(Al)) was utilized as a novel source for mesoporous carbon support. Microscopic studies revealed the formation of monodisperse Mo2C with
Improving Water and Nutrient Use Efficiency for Crop Production in Dry Lands via Soil Amendments and Remote Sensing Techniques
Authors: Mahmoudi Henda
Published: July 2019

The soils of the Arabian Peninsula in general and GCC countries in specific are dominantly sandy (low nutrient and water holding capacity, high infiltration rate). These soils need high inputs for crop production. To be cost-effective in agriculture production these soils need careful consideration to enhance water and nutrient use efficiency and increase crop production. A number of organic and inorganic amendments have been used by various researchers in this regards. However, little has been done in this respect on UAE soils, and hence forms the focus of this study. The study aims to achieve this through soil improvement using soil amendments and assessing the efficiency through remote sensing techniques.

The green house and field trials were conducted simultaneously (January 2015) on Okra (Abelmoschus esculentus) at ICBA station using sandy soil which is dominant in the UAE and the GCC countries. Five inorganic amendments (Zeoplant, Zeoplant pellet, Meliorit, AustaHort and Palagonite) and one organic (locally produced compost) were used at different rates (0, 1.5, 3 and 4.5 kg/m2). Fresh water is used to offset the irrigation requirement of Okra equivalent to 100% and 75% ETc. The treatments were triplicated in a randomized complete block design.

Agronomic parameters (Germination, growth, flowering and fruiting) were recorded. Spectral signatures were collected in the range of 400 to 1100 nm using a hand held spectroradiometer with standardized viewing and radiation conditions for all treatments. Each parcel was monitored spectrally from the stage of being a bare parcel to the stage of 50% covered by vegetation.

Okra fruit is collected on a weekly basis and weight recorded. The SPAD meter is used in the field and greenhouse for the measurement of chlorophyll content during the growth stages.

The organic and inorganic amendments in general improved the water use efficiency as well as enhanced the biomass production to a significant extent compared to the treatment where amendments were not used. At 75% ETc the performance of amended soils was comparable to 100% ETc and fruit biomass production was similar. The use of the soil amendments can save up to 25% of the irrigation water in sandy soils.

These are preliminary results from sandy soil representing the main soil type in UAE. These amendments may behave differently in other types of soils hence further test are being started in Arabian Gulf University to test the same amendments on Bahraini soil.

Keywords

Water scarcity, Crop production, Sandy soils, Water and Nutrient Use Efficiency, Monitoring efficiency, UAE
The Effect of Chilled Water Supply Temperature on the Energy Efficiency of the Chiller System
Authors: Alyousef Abdulwahab , Bukshaisha Abdulwahab
Published: July 2019

A steady-state model for a centralized cooling system is developed and utilized to evaluate its energy efficiency. The numerical model resolves the energy equations for a cooling tower and a centralized water-cooled chiller simultaneously. It requires inputs that are readily available. The user-inputs are the ambient conditions, the cooling tower air flow rate, the condenser water flow rate, the evaporator water flow rate, the superheat and sub-cooling associated with the refrigeration cycle, and the full load design conditions. The model utilizes an empirical relationship for the compressor power as a function of load and temperature, and gives the user an option to select between a constant speed chiller and a variable speed chiller. The outputs include the chiller coefficient of performance, compressor input power and compressor isentropic efficiency. This talk will discuss the results of the assessment conducted of the effect of chilled water supply temperature on the performance and energy efficiency of the chiller system. The findings and recommendations on how to optimize chiller systems for best energy performance will also be presented.
Study and Comparison of PFC Rectifiers: Quasi Z Source, Traditional Flyback
Authors: Sabeeh Sinan Asaad , Alhuwaishel Fahad
Published: July 2019

This study focuses on comparing the Traditional Flyback PFC (F-PFC), and the Quasi Z-Source PFC (QZS PFC) on range of (36–720W) and input Voltage of (130, 200, 230V) with an output Vdc of 36 Volts while operating in Continuous Conduction Mode. The study has confirmed that F-QZS PFC has better THD%, P.F, and lower output current and voltage ripple relative with the output power. In addition, the stress on each main element has been explored and it was confirmed that the F-QZS has robust measured voltage and current across the elements due to the effect of crossed capacitance topology in the F-QZS while the F-PFC suffers from high spikes. Finally, a very precise closed loop duty ratio control was developed to optimize the performance of the F-QZS PFC.
Helminth Infections Among Long-Term-Residents and Settled Immigrants in Qatar in the Decade from 2005 to 2014: Temporal Trends and Varying Prevalence Among Subjects from Different Regional Origins
Authors: Abu-Madi Marawan , Behnke Jerzy , Doiphode Sanjay , Boughattas Sonia
Published: July 2019

We analysed the prevalence of helminth infection in a dataset of 31,008 records of subjects referred for stool examination at the Hamad Medical Corporation over the course of a decade (2005 to 2014, inclusive). Overall prevalence of combined helminthe infections was low (1.78%) but there were significant temporal trends, age and sex effects and those arising from region of origin of the subjects. The most common helminth was hookworm (overall prevalence 1.2%) which accounted for 70.3% of cases, and therefore patterns for combined helminth infections were largely driven by hookworms. In both cases, and also in Trichuris trichiura and Ascaris lumbricoides prevalence peaked in 2008, since when prevalence has been steadily falling. Helminth infections were largely concentrated among subjects from W. Asian countries, and there was a highly biased prevalence in favour of male subjects in all cases. Prevalence of all three nematodes peaked in age class 7 (mean age 25.5 years, range =  20–29) and there were significant interactions between region of origin and sex of subjects and prevalence of combined helinths, and hookworms. These results offer optimism that prevalence will continue to decline in the years ahead, especially if control is targeted at those most at risk of carrying infections.
Disinfection by-products of Chlorine
Authors: Al-Otoum Fatima , Al-Ghouti Mohammad
Published: July 2019

The occurrence of disinfection by-products (DBPs) of chlorine dioxide (ClO2) in drinking water, namely: chlorite, chlorate, and THMs as well as the concentration of ClO2 were investigated. Two hundred ninety four drinking water samples were collected during the time period from March to August 2014. The water samples were collected from seven desalination plants (DPs), four reservoirs and eight mosques distributed in South and North Qatar. The ClO2 level was ranged from 0.38 to less than 0.02 mg/L, with mean value of 0.17, 0.12, and 0.04 mg/L in the desalination plants (DPs), the reservoirs (R), and the mosques (M), respectively. The chlorite level was varied from 12.78 – 436.36 ppb with median values varied from 12.78 to 230.76, from 77.43 to 325.25, and from 84.73 to 436.36 ppb in the DPs, the reservoirs, and the mosques, respectively. While chlorate was varied from 10.66 ppb to 282.71 ppb with mean values varied from 35.58 to 282.72 ppb, from 11.02 to 200.69, and from 10.66 to 150.38 ppb in the DPs, R, and M respectively. However, the average value of THMs was 4.90 ppb, while maximum value reached 76.97. Lower disinfectant residual was observed in few samples, however this could be attributed to the normal decomposition reaction of ClO2 with organic and inorganic compounds, including biofilms, pipe materials, corrosion products, formation of slime or may due to the fact the water in distribution system experience water aging problem. Significant differences were observed in the concentration level of chlorite, chlorate and THMs between DPs, reservoirs and the mosques. However, the concentrations of all DBPs fell within the range of the regulatory limit set by GSO 149/2009, WHO and KAHRAMAA (KM). It is recommended to slightly increase the average ClO2 dosage at the DPs. Such slight increase would provide safer margin at the customer point of use in case of any microbial activities. Consideration must be given to the overall demand and should account for seasonal variations, temperature, and application points. As well as a monitoring approach is recommended for the drinking water safety assessment. Re-conducting the study to include other DPs of ClO2 is recommended.
Roadside Observational Surveys of Restraint Use by Young Children in Qatar: Initial Results and Recommendations
Authors: Malik Shahnaz
Published: July 2019

Introduction

In a report by the WHO Eastern Mediterranean Region 1, the non-use of child restraints for children was identified as a key risk factor that can be addressed by the adoption and enforcement of legislation that will increase their use. Currently, there are no child restraint laws in Qatar. The objective of the study is to report baseline data on child restraint use and to provide evidence to inform the passage of child passenger restraint laws in Qatar.

Methodology

This roadside observational survey was conducted as part of the Young Kids in Safe Seats Project funded by the Qatar Foundation. Trained observers conducted roadside observations of passenger restraint use in vehicles with children, less than 5 years, at 12 sampling sites. Standard data was collected per observation: seating position, restraint used and appropriateness of restraint used.

Results

Of 2232 observations of young child passengers; 41% were properly restrained, 21% improperly restrained and 38% unrestrained, 10.9% were on an adult's lap. The most common seating location was right 2nd row followed by left 2nd row. These 2 locations also had the highest rates of proper restraint use. The positions with the lowest restraint use were the front and 2nd row middle seat. One in 9 children observed was illegally seated in the front row, most on the lap of an adult [38.3%] or unrestrained [34.4%].

Conclusions

This is the first observational study in Qatar that measures child restraint rates in children younger than 5. Less than half of these children are traveling safely. Priority areas for intervention include: enforcement of existent laws banning children in the front seat, education about the risks for children in an adult's lap and encouraging the proper use of age/size appropriate restraint systems. These findings can inform the development of national child passenger restraint laws.
Vasoactive Intestinal Peptide Protects Cancer Stem Cells from Apoptosis by Activating Multiple Signaling Pathways
Authors: Sastry Konduru Seetharama , Chouchane Aouatef Ismail , Wang Ena , Marincola Francesco M , Chouchane Lotfi
Published: July 2019

Background

Vasoactive intestinal peptide (VIP) is a neuropeptide that controls the proliferation, differentiation, and survival of various normal and cancer cells. Elevated expression of VIP receptors has been found in prostate and breast cancer; and antagonists of VIP inhibit the growth of cancer xenografts. We previously reported the cytoprotective mechanisms activated by VIP in differentiated cancer cells that form the bulk of tumor, however, the signaling mechanisms activated in cancer stem cells (CSC) have not been identified.

Objectives

The objectives of this study are to unravel the anti-apoptotic mechanisms activated by VIP in CSC, and examine if these pathways converge on a pro-apoptotic protein BAD. Identification of mechanisms responsible for survival of CSC will help design new therapeutic strategies that target and eliminate CSC.

Methods

Sphere formation assay and Fluorescent Activated Cell Sorter (FACS) were used to enrich and purify CSC (CD44+/CD24 −  and/or CD133+) from prostate and breast cancer cells. Apoptosis of CSC was induced by inhibiting the survival kinase PI3K/Akt using pharmacological inhibitor LY294002. Caspase assay, FACS and soft agar colony formation assays were used to measure the cytoprotective effects of VIP. Western blot was used to address the phosphorylation and quantification of various signaling proteins.

Results and conclusion

Cancer stem cells were sorted to a purity of 95% and characterized for their stemness phenotype. While LY induced apoptosis in CSC by dephosphorylating BAD, VIP rescued by restoring the BAD phosphorylation at Ser112. VIP activated two non-redundant antiapoptotic signaling pathways that converge on BAD. One signaling pathway operate via activation of protein kinase A (PKA), whereas the other pathway predominately relies on MEK/MAPK pathway. Both pathways partially control BAD phosphorylation at Ser112. Either of these pathways is sufficient to protect CSC from apoptosis, thus both have to be inhibited to block cytoprotective effects of VIP. Using phosphorylation deficient mutant BAD, we show that the BAD phosphorylation is essential for the VIP-induced survival of CSC. Taken together, our findings suggest the potential usefulness of VIP receptor inhibition, and that BAD plays a critical role in CSC and thus targeting BAD might be an attractive strategy for development of novel therapeutics.
Synephrine as Antioxidant: Application in Quenching of Photo Induced Radical of Anthraquinone and Naphthoquinone
Authors: Hussein YasserH. A. , Sivakumar Velautham , Elazazy Marwa , Ganesh Karuppasamy
Published: July 2019

Photosensitive molecules such as quinones in drugs may become activated by exposure to UV-A light (320–400 nm) of the solar spectrum and cause damages to biological materials such as amino acids, nucleic acids, lipids, etc.. 9,10-anthraquinone (AQ) and 1,4-naphthoquinone (NQ), based drugs are commonly used as antibacterial, antifungal, antiviral, antitumor and antimalarial. Synephrine (SY) is used in traditional Chinese medicine, mainly for anti-hypotensive, nasal and ophthalmic decongestant. Currently it has been used in treatment of digestive disorders, in emergency treatment of asthma, and more importantly used as anti-depressant. The study of photo induced interactions of the excited quinones and drug molecules having electron donating ability is expected to have some relevance in physical pharmacy. In this in-vitro study, our aim is to understand the photo induced reaction when the quinones AQ and NQ coexisted with SY in an organic medium and exposed to UVA light. The photo induced interaction between SY and above quinones in their triplet states has been studied using nanosecond laser flash photolysis in organic medium, ethanol. The triplet excited states of the above quinones, AQT and NQT were produced by excitation with 355 nm, 5 ns laser pulse, in the presence of SY and under both deoxygenated and oxygenated conditions. In this wavelength only the quinones can be excited to triplets but not the SY, leaving it always in its ground state. Transient absorbance of the products formed was monitored in the 300–700 nm wavelength range. Both quinones, in their triplet excited state have revealed similar reactivity towards the ground state SY. Kinetics probed at the characteristic wavelengths of the triplets and ion radicals show that the formation of the quinone radical anion and the decay of the corresponding triplet are synchronous. This confirms that the photo-induced excited triplets, AQT and NQT have been quenched by SY through electron transfer process forming AQ•–, SY•+ ion pair. The lifetime of the decay of the triplets of the quinones and the growth lifetime of the radical anion of the same quinones are about 3 μs under deoxygenated condition. The presence of oxygen in the medium influences the decay of the triplet and anion radicals of the AQ, but does not affect the decay of the triplet or anion of NQ. In the presence of oxygen, AQ•– radical anion interacts with oxygen and forms superoxide anion radicals, O2•–. The overall result from the current investigation is an evidence for the controversial role of SY in oxidative stress. The ability of SY to quench the photo excited quinones could give some insight to mitigate the drug induced photosensitivity and also could broaden the clinical usage of SY in other therapeutic areas.
Substances Secreted by Starved Human Dermal Fibroblasts Enhancing the Wound Healing Process in Rat without Scar: A Potential Acellular System for Wound Healing
Authors: Hanifi-Moghaddam Pejman , Mostafazadeh Amrollah
Published: July 2019

Background

Despite being a major cellular component of various engineered skin substituent, underlying mechanism of successful fibroblast transplantation in wound healing is not clear. Here we show that substances derived from starved fibroblast accelerate wound healing process in rat.

Material and methods

Starved human fibroblast cell culture supernatant (SFS) was prepared and tested for its wound healing capacity on rat skin. Twelve Wistar adult male rats were randomized into four different groups of three. On the back of each rat two wounds were created with area of 452 mm2. Each wounds were treated daily with one milliliter of SFS or cell culture medium (DMEM). The size of the wounds was measured daily until crust formation. The animals were scarified on 4th, 8th, 11th and 15th day of experiment and skin was removed for H&E and trichrome staining. Infiltration of fibroblast and inflammatory cells and collagen formation were analyzed.

Results

The diameter of the wounds treated the SFS solution was significantly decreased within the first week of treatment, compared with control wound receiving DMEM only (p
Inhibition of p90 Ribosomal S6 Kinase Attenuates Cell Migration and Proliferation of the Human Lung Adenocarcinoma through Phospho-GSK-3b and Osteopontin
Authors: Abdulrahman Nabeel , Jaballah Maiy , Poomakkoth Noufira , Riaz Sadaf , Abdelaziz Somaya , Issa Aya , Mraiche Fatima
Published: July 2019

Background

Lung cancer is the second most common cancer in both men and women and it is the leading cause of cancer deaths worldwide. Lung cancer can be divided into two broad categories: non-small cell lung cancer (NSCLC), which consists of about 85% of all lung cancers and small cell lung cancer (SCLC), which account for 15% of all lung cancers. The evolution of lung cancer is a multistep process involving genetic and epigenetic alterations. Standard treatment therapies such as radiation therapy, chemotherapy and surgery has reached a plateau phase. As a result, much work has centered on identifying the molecular targets involved in the tumor cell proliferation, survival and metastasis in effort to identify novel therapeutic approaches. p90 ribosomal S6 kinase (p90RSK) constitutes a family of serine/threonine kinases that have been shown to be involved in cell proliferation of various malignancies via direct or indirect effects on the cell-cycle machinery.

Objectives

To investigate the role of p90RSK in lung adenocarcinomas and whether the inhibition of p90RSK diminishes cancer progression. Moreover, we investigated the involvement of glycogen synthase kinase-3β (GSK-3β) and osteopontin (OPN) in the p90 RSK induced lung adenocarcinoma progression.

Methods

p90RSK, OPN, GSK-3β protein expression were examined in the A549 human lung adenocarcinoma cell line in the presence and absence of BI-D1870 (BID), a p90RSK inhibitor. Gene expression of anti-apoptotic and pro-apoptotic markers namely Bcl2 and Bax, respectively, were studied by reverse transcription polymerase chain reaction. In addition, the A549 lung adenocarcinoma cell line was characterized for cell proliferation using the MTT assay and cell migration using the scratch migration assay.

Results

Our study revealed that the treatment of the A549 lung adenocarcinoma cell line with BID resulted in a significant reduction in protein expression of p90RSK 1 (69.32 ±  12.41% of control; P <  0.05). The inhibition of p90RSK also showed a significant suppression of cell proliferation (54.3 ±  6.73% of control; P