bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimation of Uranium Concentration in sediment Samples of the Part of the Shatt al-Arab passing in central and southern Basrah Governorate using ICP-MS Technique
Authors: Salman Thaer M. , Habeeb Ali F.
Published: November 2020

This work included measuring the concentrations of uranium element in 32 locations of sediments samples were collected from the bottom of the central and southern of shatt al- Arab in Basrah Governorate by using ICP-MS technology, which are found that the uranium concentrations ranged between 1ppm In front of Salhia River and 2ppm in Abu Flous Port located on the shores of Shatt Al-Arab. Measured samples of sediments taken from several locations in central and southern Shatt al-Arab indicate that the uranium concentration is less than 100 ppm, a concentration that characterizes the quality of waste and burdens, rather than mining reserves. This study reveals 32 samples containing uranium concentration within internationally permitted limits. The present results have shown that the uranium concentrations in the studied sediments samples are less than the allowed value (11.7 ppm) recommended by UNSCEAR, 1993.
Study the effect of thickness change on optical properties of Rhodamine B
Authors: Al-aaraji Hayder H. , Obeed H. H. , Mohammad Rajaa K. , Ridha Noor J. , Alosfur Firas K. Mohamad , Tahir Khawla J. , Madlol Rajaa , Jabar Basma Abbas , Jassim Alaa H.
Published: November 2020

The optical properties of an organic laser dye, Rhodamine B in water is an important for modern applications, the linear optical properties of the absorption and fluorescence spectrum of the liquid dye were discussed, and the highest value of quantum yield was reached at 96% at a concentration of (10−7) Ml a high quantum yield allow numerous applications of used doped host in optoelectronics applications and after knowing the most appropriate concentrations, a thin film of polyvinyl alcohol was dye, Study of the effect of film thickness on optical properties, the film has optical properties, reflexivity, refractive index, extinction coefficient, real and imaginary isolation constant, and the best thickness was at (4) μm. The energy gap was calculated and was inversely proportional to the thickness.
Assessment excess lifetime cancer risk of soils samples in Maysan neighborhood adjacent to the middle Euphrates cancer center in Najaf / Iraq
Authors: Adhab Hiba Ghmeedh , Kadhim alshebly Shaymaa Awad , Alsabari Emad Kareem
Published: November 2020

In this study, 30 samples of soils were taken from in Maysan neighborhood adjacent to the middle Euphrates cancer center in Najaf / Iraq, gamma-ray spectrometer system connected with the NaI detector was used to measure the specific activity of the (238U, 232Th, 40K) nuclei, the specific activity values were varied from(1.41±0.71Bq/kg) to (30.95±0.74 Bq/kg) with an average value(10.03± 1.04) for 226Ra, for 232Th from (0.71±0.27) to (15.44±0.30 Bq/kg) with an average value (4.96±0.37), The measurements of the specific activity of the 40K varied from 92.77±1.95 to 589.77±3.18 Bq/kg with an average value (198.43±3.13).

Radium equivalent activity, outdoor and indoor absorbed doses, the Outdoor, Indoor and total annual effective dose equivalent (AEDE), external and internal hazard index (Hex, Hin) in the range of 32.415±1.817(Bq/kg), 16.104±0.827(nGy/h), 20.936±1.075(nGy/h), 0.019±0.001014(mSv/year),0.102±0.0052(mSv/year), 0.121±0.0061(mSv/year), 0.087±0.004, 0.114±0.007 respectively, Representative level index Iγr and excess lifetime cancer risk (ELCR), Representative Alpha index (Iα) and annual gonadal dose rate (AGDE) were calculated with range, 0.248±0.012(Bq kg-1), 0.423*10−3, 0.052(Bq/Kg), 119.404( mSv/y) respectively. These results were compared with recommended values (370 Bq/kg) for Raeq, 59 nGy/h for Dout, 84 nGy/h for Din,0.07 mSv/year for Deffout, 0.41 mSv/year for Deffin,0.48 mSv/year for Defftot, ≤1 for Hex and Hin, <1 for Iγr, <1 for Iα, 300 μSv/y for AGDE by UNSCEAR International Commission on Radiological Protection (ICRP) and European Commission (EC), and Their values were less than the permissible limits except for one sample out of 30 samples have specific activity values of 40K, Annual Gonadal Equivalent Dose (AGED) in sample (S6)higher than the worldwide average value (412 Bq/kg)and( 300 μSv/y) recommended by the UNSCAER, besides, the value of ELCR was lower than the world permissible value of 1.45×10−3 (UNSCEAR,2000). As a result, health hazards originated by natural radiation from soil samples in this region is low and insignificant.
Uranium Concentrations in Urine of Maternal Samples in Baghdad Governorate
Authors: Adel Maryam M. , Tawfiq Nada F.
Published: November 2020

The trace concentration of uranium in urine samples for pregnant women and non- pregnant women were determined using fission track technique with CR-39 track detector that is employed for registration of induced fission tracks. A total of 32 urine samples were collected from Yarmouk Teaching Hospital, Department of Obstetrics and Gynecology for Pregnant women and 5 urine samples were collected from Different regions of Baghdad governorate. The results show that the uranium concentration in urine of Pregnant women were ranged from 0.58 μg/l (30 years old, living in AL- Shurta AL khamisa region) to 1.58 μg/l (23 years old living in AL–Doura region) with average 0.92±0.2 μg/l. While for non-Pregnant women, uranium concentration ranged from 0.61 μg/l (24 years old, living in AL-Doura region) to 1.16μg/l (40 years old, living in AL-Ghazaliya region) with average 0.874±0.19μg/l. It was found that the average uranium concentrations in urine samples for pregnant women living in Hayi AL-maealif region higher than other regions in Baghdad governorate.
Guided Modes in Slab Waveguide with Central Anisotropic Metamaterial Layer
Authors: Salman Hawraa H. , Yasser Hassan A.
Published: November 2020

This work studies the characteristics of TE modes in a three layers slab waveguide that contains an anisotropic metamaterial as a central layer. The results show that all modes except TE
1 achieved forward propagation and then turned backwards. The effective refractive index value at which the propagation type is reversed increases with the mode order and the thickness of the middle layer. In addition, an anisotropic property in the metamaterial layer shift the modes curves (exept TE
1 ) to left or right with respect to the isotropic case. Furthermore, the mode TE
1 is abnormal and inconsistent with the behavior of other modes. Except TE
1 mode, the confinement factor is small in the forward propagation region and reaches large values in the backward propagation region.
Influence of wood minutes (reed) on some physical and mechanical characteristics for (EP+W) composites
Authors: Abed Raya Ali , Al-sarrafand AbdulhameedRaheem , Almaamori Mohammed
Published: November 2020

By using agricultural wastes, the epoxy composites were prepared with reed minutes and with a fixed weight fraction of all samples (30%) and a particle size (212) μm. Preparation of samples carried out by using the casting method. Some mechanical properties have been investigated were included (tensile strength, bending, creep) and the results showed improvement of all properties through increased bending resistance and elasticity increased with epoxy reinforcement with wood particles. The intent of this research is to enhance the mechanical properties by adding agricultural wastes that represented by (reed).
Construction of Scaffold from MgO Nanoparticle: Bone Fracture Healing
Authors: Hassan Marwa Abdul Muhsien , Abbas Asaad M. , Mohammed Ali Mohammed J.
Published: November 2020

Magnesium oxide nanoparticles have been prepared by using chemical method. The chemical analysis of the samples was carried out using EDX measurement. The results showed that all the samples are very pure, consisting of the elements of magnesium and oxygen. XRD pattern of MgO nanoparticles prepared at a different temperature (500, 550 and 600 °C) and 3 hour time. It is seen that the peaks appear at 2θ=36.92 degrees, 2θ=43.02 degrees, 2θ=62.38 degrees, 2θ=74.56 degrees and 2θ=78.48 degrees, reflective planes reflect (111), (200), (220), (311) and (222), respectively. Scanning electron microscope of treated magnesium oxide at different temperatures was carried out. As the result showed that magnesium oxide have spherical nanoparticles in diameters ranging from 15-20 nm, systematically distributed. Histopathological evaluation showed the thick mature threads and anatomizing bone threads filled interface zone in MgO scaffold prepared at different annealing temperatures.
Effect of Gamma Irradiation on the Physical Properties of PVA Polymer
Authors: Jassim Tafahom Ahmed , Saeed Asrar Abdulmunem
Published: November 2020

Polyvinyl alcohol (PVA) films were prepared by casting method. The optical properties was measured in the wavelength rang of (200–900) nm, by using UV-visible spectroscopy. The effect of irradiation lead to degradation on the physical properties such as absorbance, transmittance, refractive index, extinction coefficient in addition of the real and imaginary part of dielectric constant was studied. This study reveals that all these parameters affected by the increasing of them irradiation, and also found that the optical energy gap has been increased with the increasing of the irradiation. The structural properties are studied by using XRD, FTIR spectrum, and FESEM.
Electron Stopping Powers of Chitin and Chitosan
Authors: Abdul Muhsin Zahraa A. , Aldhamin Ahmed Saad , Shafik Shafik S.
Published: November 2020

Chitosan can be deduced from chitin by simple chemical process. Chitosan has many applications and one of the promise application is used as nuclear shield by adopted it with some materials. Electron stopping power (SP) represents important parameter in tested the ability of any material to use it as nuclear shield. Therefore, stopping powers of electrons incident with different energies on chitin and chitosan have been calculated by using codes of National Institute of Standards and Technology (NIST) after modified it by built in the chemical structure and some other properties of chitin and chitosan in the codes. The results of total SP showed that chitosan has values larger than chitin but the differences are small and the maximum percentage difference ratio is 6.8% at 4 MeV electron energy. Total SP has approximately 35 Mev.cm2/g at 0.01 MeV electron energy, and decreasing with energy till to 1 MeV, then slowly increasing. In addition to total SP, the collision SP, radiative SP, density effect parameter, radiation yield, and electron range were calculated. The behaviors of the calculated parameters have been studied and explained. The obtained results suggested that chitosan may be used after mixing it with other materials as a shield from nuclear radiation, especially in low energies.
Properties of O(6)-U(5) transition symmetry for 122-124Cd isotopes in IBM
Authors: Kassim Huda H. , Abd-Aljbar Alyaa A. , Al-Jubbori Mushtaq Abed , Abdullah Hewa Y. , Hossain I. , Sharrad Fadhil I.
Published: November 2020

The some properties, Energy levels, B(E2) values and potential energy surface, for even-even 122,124Cd isotopes have been studied using the interacting boson model. The predicted levels (energies, spins and parities) and B(E2) values results were reasonably consistent with the experimental data. The contour plot of the potential energy surfaces shows all interest nuclei were deformed and have O(6)-U(5) transition symmetry.
Effect of laser fluencies on solar cell characterization of (CdO)1-x:Sbx/PSi thin films by laser induce plasma
Authors: Dwech Majed H. , Aadim Kadhim A. , Jihad Ghaith H.
Published: November 2020

In this paper, Cadmium Oxide: Antimony has been deposited on porous silicon substrate using laser induces plasma technique. The solar cell parameters fill factor and efficiency; have been analyzed through changing of laser energy. The results shown that the change in electron mobility resulting from the change in laser energy leads to significant improvement in fill factor and efficiency. Moreover, there is slight improvement in the efficiency of CdO: Sb/Psi solar cell as a result of changing the thickness of CdO: Sb.
Investigation on water as lubricant in combination with a structured tool surface in micro metal forming
Authors: Rathmann L , Czotscher T , Radel T , Vollertsen F
Published: November 2020

The use of lubricants in forming processes is common because they reduce friction between the tools and workpiece during the forming process. Today, mainly mineral oils are used as conventional lubricant. In order to cut their amount in the future, the friction between tools and workpiece is investigated by using water as lubricant in this work. Therefore, the tools’ surfaces are structured with laser induced periodic surface structures (LIPSS) to make them hydrophilic and strip drawing tests are carried out at different traverse velocities to evaluate the resulting friction force. The results show that at a traverse velocity of v = 10 mm/s the maximum friction force is lowest for the structured tool with water (F = 7.0 N) in comparison with unstructured tools in combination with a conventional lubricant. Consequently, the potential of water as lubricant combined with a hydrophilic surface structure is highlighted.
Influence of anisotropy evolution on strain path independent failure limits
Authors: Bandyopadhyay K , Basak S , Lee M G
Published: November 2020

Stress based forming limit diagram (SFLD) and polar effective plastic strain (PEPS FLD) diagram are two techniques reported to be independent of strain path change. Thus, these techniques are capable of predicting failure in pre-strained sheet metal samples. Therefore, in this study evolution in anisotropy properties of sheet metals were considered in terms of evolution in yield shape during conversion of conventional strain based forming limit diagram (FLD) to SFLD and PEPS-FLD. The evolution in anisotropic properties were modelled as a function of effective plastic strain depending on which the anisotropic coefficients of non-quadratic yield model Yld2000-2d were calculated. Further, to analyse the strain path change effect, metal sheets of extra deep drawing quality steels were first deformed under biaxial condition in Marciniak in-plane stretch forming setup. The pre-strained samples were subsequently deformed with hemispherical punch till the necking appears. For failure prediction, finite element modelling of the complete procedure was performed considering evolution in the yield shape. Finally, both the failure criteria were implemented for failure prediction. Implementation of the evolution in yield function in finite element analysis and failure criteria provided better results.
Determination of the properties of semi-finished parts in blanking processes
Authors: Wiesenmayer S , Frey P , Lechner M , Merklein M
Published: November 2020

Deviations of the properties of semi-finished sheet metal parts affect the finished part’s geometry and its properties. With knowledge of the deviations, forming processes can be adjusted to a certain degree in order to maintain the part quality. Typically, in mass production, the sheets are blanked before deep drawing. Within the blanking processes, the necessary cutting force and cutting stroke are both influenced by the properties of the material. Thus, by the analysis of the process data, which is obtained in blanking processes, deviations of the properties of semi-finished parts could be determined. Within the scope of the work, it is analyzed to which degree process data, which is gained during blanking processes, can be used for the determination of the properties of semi-finished parts and their deviations. For this purpose, a blanking process is investigated for two different batches of the dual phase steel DP600 with a nominal sheet thickness of 2.0 mm and varying mechanical properties. In addition, the sheet thickness of the specimens is reduced by 5 and 10 % for one batch. The recorded process data from the blanking process is correlated with the properties of the sheet materials, which are determined with uniaxial tensile tests.
The effect of friction and lubrication modelling in stamping simulations of the Ford Transit hood inner panel: a numerical and experimental study
Authors: Berahmani S , Bilgili C , Erol G , Hol J , Carleer B
Published: November 2020

Reducing weight of Body in white (BIW) is a well-known solution to tackle environmental issues in automotive industry. Replacing steel by lighter aluminium sheet material is an accepted alternative. However, this trend brings challenges like the forming of Aluminum into complex car body parts. These challenges signify the necessity of more advanced tools to obtain defect-free parts. Nowadays, it is a common practice to implement forming simulations at the early stage of part design in order to identify critical features and to optimize the production process. Although, it is known that friction and lubrication conditions are one of the most influential sources affecting product quality in aluminium sheet metal forming, it is currently not considered in detail in stamping simulations. The current application case focuses on the role of friction and lubrication modelling in stamping simulations of an aluminium hood inner part of the new Ford Transit. A comparison was made between different friction models to identify and resolve split issues in the forming simulations. Simulation results were used to guide try-out towards efficient and successful elimination of these issues on the physical panels. Finally, different possible scenarios corresponding to production conditions were investigated to define a robust process window.
Soft sensing force measurement approach in sheet metal forming facilities
Authors: Olaizola Jon , Iturrospe Aitzol , Abete Jose Manuel , Galdos Lander , Argandoña Eneko Sáenz de
Published: November 2020

Process stability and facility security are the two main purposes for measuring the force in sheet metal forming facilities. These two purposes look for guaranteeing the good health of the facility avoiding overloads and at the same time look for variations in the process force that could lead to products out of the demanded quality. Traditionally there have been different approaches to measure the force exerted by the press. Piezoelectric sensors and strain gages are the most widely used technologies. However there are some common limitations that reduce the success in the measurement of the force by the aforementioned sensors: force sensors tend to have a signal drift and the introduction of the sensors together with the electronics represents an extra cost that in some cases can be high. As an alternative to the implementation of force sensors, soft sensing approaches take advantage of the already available signals in the facility to estimate non measured variables, the force in this case. The present work aims at predicting the force curve that a servo press exerts in forming processes reading the internal servomotor signals. The approach has been evaluated with several forming processes achieving an error lower than 3% for all the cases.
Identification of methods for the in-situ measurement of cutting forces in a tool-bound punching machine
Authors: Niessner S , Liewald M
Published: November 2020

With the increasing implementation of industry 4.0 technologies in production plants, issues such as control and monitoring as well as feedback control of plants and processes are becoming more and more important in current development trends. Thereby, potential approaches to such issues are generally accompanied by an increased use of sensors in production systems, aimed at gaining operation-, product- and process-specific data. In this respect, this paper focusses on the shear cutting process of a tool-bound punching machine. One of the most important parameters for the evaluation of shear cutting processes is the cutting force required. However, the precise measurement of this highly dynamic process parameter proves to be relatively challenging. The limited installation space within the tools and the loads caused by highly dynamic axis movements decisively restrict the options for sensor-based process monitoring. In order to face these challenges during sensor implementation in such punching machines, issues regarding measuring concept, localization and resulting measurement deviation of the sensors have to be solved simultaneously. In this paper, relevant measurement concepts and their properties are discussed, and the most favourable integration possibilities are derived. Based on this, several measurement concepts are identified that could be suitable for the application considered. These measuring methods include hydraulic pressure sensors, strain gauges or piezoceramics. The major contribution of this paper is an experimentally conducted systematic comparative study of these methods, in which the accuracy of the sensors used is evaluated and the influence of different integration positions on the measurement result is investigated.
A pressure-coupled Drucker function for plasticity and fracture modelling of AA5182
Authors: Zhang Chong , Wang Yue , Lou Yanshan , Fu Lei , Zhang Saijun , Yoon Jeong Whan
Published: November 2020

In this paper, a pressure-coupled Drucker function is proposed to model the plastic deformation and fracture from shear to plane strain tension of AA5182 sheet. Experiments are conducted for AA5182 in shear, uniaxial tension and plane strain tension, and the force-stroke curves are measured during the tests. The plastic deformation is modeled by the Drucker function. The Drucker function is modified to consider the pressure effect for fracture limit stress prediction of the alloy. The pressure-coupled Drucker function for plasticity and fracture is calibrated by an inverse engineering approach. The calibrated plasticity models are then applied to numerical prediction of plastic deformation of the alloy under various loading conditions. It is observed that the pressure coupled Drucker function accurately describes the plastic deformation under large plastic deformation as well as the onset of ductile fracture under these loading conditions.
Influence of anisotropic yield criteria on simulation accuracy of the hole-expansion test
Authors: Panich S , Chongbunwatana K
Published: November 2020

Prediction accuracy of the two well-known anisotropic yield criteria, namely, Hill’48 and Yld2004-18p, on plastic deformation of AA5052-O sheet aluminium alloy experiencing compound stress was profoundly examined and contrasted in this work. To obtain the flow behaviour and anisotropy of the test material in varying loading directions, both uniaxial tensile and balanced-biaxial tests were conducted in the corresponding directions. Furthermore, a disc-compression test was carried out to reveal the biaxial r-value. Those gained mechanical properties could therefore be used to determine the material constants required by each yield criterion. The standard conical-punch hole expansion test was chosen here to impose complex stress on the sheet specimen. Forming parameters such as the punch load, stroke paths, hole expansion ratio, sheet thickness profile around the hole circumference and flange height were all monitored and investigated. It was shown that the results from the Yld2004-18p model with an exponent of eight apparently better agreed with the experimental data than those from the Hill’48 one. A conclusion could be drawn here that the yield criterion significantly affected the accuracy of the predicted deformation behaviour of the investigated aluminium alloy grade AA5052-O nevertheless in dependence on the degree of material anisotropy.
Measurement-based evaluation of interfacial polymer layer inserted in sound deadening laminated sheet
Authors: Park Hyeonil , Kim Se-Jong , Lee Jinwoo , Kim Daeyong
Published: November 2020

Mixed mode bending (MMB) test associated with measurement of crack tip opening displacement (CTOD) is a practical method to experimentally evaluate mixed-mode cohesive zone model (CZM) properties of polymer layers in various mixed-mode ratios. However, it has an obvious limitation that does not allow for plastic bending of adherends during the tests, making it difficult to evaluate the polymer layer inserted in the sound deadening laminated sheet (SDLS) comprising thin metal sheets which are vulnerable to the plastic bending. This paper provides an experimental technique to suppress the plastic bending of the thin metal sheets during the MMB test. Supporting tools were designed, and bonded to the both outer surfaces of the SDLS. Until delamination occurred, the evolution of fracture toughness (G) was evaluated, and the CTOD was measured in the stereo image using a digital image correlation system. Finally, the mixed-mode CZM properties was successfully established based on the differentiation of the relation between the evolution of G and CTOD.
The determination of friction coefficient in Nakazima test and its application in predicting FLCs with modified M-K model
Authors: Wang Yubao , Zhang Cunsheng
Published: November 2020

In this work, the friction coefficient between the punch and the specimen during the Nakazima tests is determined by comparing the experimental and the numerical strain paths. Afterwards, the FLCs of the Al-Mg-Li alloy sheet are predicted with the modified M-K model, which considers the through-thickness normal stress and the friction through introducing the expressions of the normal stress and the friction stress into M-K model. Finally, the predicted FLCs of the sheet are compared with the forming limits determined by Nakazima tests.
Material testing of magnesium alloy AZ31B using a finite element polycrystal method based on a rate independent crystal plasticity model
Authors: Vago Giorgio , Oya Tetsuo
Published: November 2020

Magnesium and its alloys are attractive structural light materials because they have a high spe-cific strength and high specific stiffness. That is why their usage in high performance automotive and aerospace applications has been increased. However, their high anisotropy and low ductility could bring to forming failure, to avoid these a better accuracy for metal forming simulation is re-quired. The identification of macroscopic parameters is expensive due to the experiments needed to find them, the use of multi-scale approach allows to find parameters for the model through easier experiments. A finite element polycrystal method, based on a rate independent polycrystal plasticity model, is implemented in order to perform the material testing of a cast magnesium alloy AZ31B. The parameters of the model are adjusted to better fit the experimental data through a trial and error process.
Inferring the surface roughness of Al-Si coated 22MnB5 steel using an in situ laser speckle characterization technique
Authors: Klassen C M , Emmert J , Daun K J
Published: November 2020

Hot stamping of aluminium-silicon (Al-Si) coated 22MnB5 steel blanks is widely used in the automotive industry to produce light yet crashworthy parts. However, the coating melts at ∼577°C and transforms into a rough intermetallic layer as iron from the base steel diffuses towards the surface. The blank surface roughness impacts the radiative properties during heating as well as weldability, paint adhesiveness, and cooling rate during forming and quenching. This study pioneers the use of laser speckle patterns, caused by the constructive and destructive interference of collimated light reflected off the blanks, to infer the evolving surface roughness of Al-Si coated steel coupons in situ. The results reveal a significant increase in surface roughness once intermetallic compounds reach the surface and that higher furnace set-points produce rougher parts.
Numerical and Experimental Investigation on Hot Stamping of TWB B-Pillar
Authors: ChiuHuang Cheng-Kai , Chiang Ming-Feng , Lee Ping-Kun
Published: November 2020

In order to achieve the targeted crashworthiness performance, the application of Tailor-Welded-Blank (TWB) on the crash-relevant components has become a trend in the automotive industry. This paper aims to investigate the mechanical property and structural performance of the hot stamped TWB B-pillars. After hot stamping, the strength grade for the hard zone is 1500 MPa while the soft zone’s strength grade is 590 MPa. The CAE model shows that the intrusion distance is decreased for the TWB design compared to the monolithic material B-pillar. The three point bending performance could be adjusted by changing the range of the soft zone. It is observed that the weld line has a low crack sensitivity during hot stamping. The transition zone between the hard zone and soft zone is less than 1mm. The ATOS scanning results show that no significant effect on the part’s size deviation for the TWB design compared to the monolithic material B-pillar.
Atrial fibrillation and oral anticoagulation in older people with frailty: a nationwide primary care electronic health records cohort study
Authors: Wilkinson Chris , Clegg Andrew , Todd Oliver , Rockwood Kenneth , Yadegarfar Mohammad E , Gale Chris P , Hall Marlous
Published: November 2020

Background

Atrial fibrillation (AF) is common in older people and is associated with increased stroke risk that may be reduced by oral anticoagulation (OAC). Frailty also increases with increasing age, yet the extent of OAC prescription in older people according to extent of frailty in people with AF is insufficiently described.

Methods

An electronic health records study of 536,955 patients aged ≥65 years from ResearchOne in England (384 General Practices), over 15.4 months, last follow-up 11th April 2017. OAC prescription for AF with CHA2DS2-Vasc ≥2, adjusted (demographic and treatments) risk of all-cause mortality, and subsequent cerebrovascular disease, bleeding and falls were estimated by electronic frailty index (eFI) category of fit, mild, moderate and severe frailty.

Results

AF prevalence and mean CHA2DS2-Vasc for those with AF increased with increasing eFI category (fit 2.9%, 2.2; mild 11.2%, 3.2; moderate 22.2%, 4.0; and severe 31.5%, 5.0). For AF with CHA2DS2-Vasc ≥2, OAC prescription was higher for mild (53.2%), moderate (55.6%) and severe (53.4%) eFI categories than fit (41.7%). In those with AF and eligible for OAC, frailty was associated with increased risk of death (HR for severe frailty compared with fit 4.09, 95% confidence interval 3.43–4.89), gastrointestinal bleeding (2.17, 1.45–3.25), falls (8.03, 4.60–14.03) and, among women, stroke (3.63, 1.10–12.02).

Conclusion

Among older people in England, AF and stroke risk increased with increasing degree of frailty; however, OAC prescription approximated 50%. Given competing demands of mortality, morbidity and stroke prevention, greater attention to stratified stroke prevention is needed for this group of the population.
Mechanisms of Vascular Remodeling in Hypertension
Authors: Humphrey Jay D
Published: November 2020

Hypertension is both a cause and a consequence of central artery stiffening, which in turn is an initiator and indicator of myriad disease conditions and thus all-cause mortality. Such stiffening results from a remodeling of the arterial wall that is driven by mechanical stimuli and mediated by inflammatory signals, which together lead to differential gene expression and concomitant changes in extracellular matrix composition and organization. This review focuses on biomechanical mechanisms by which central arteries remodel in hypertension within the context of homeostasis—what promotes it, what prevents it. It is suggested that the vasoactive capacity of the wall and inflammatory burden strongly influence the ability of homeostatic mechanisms to adapt the arterial wall to high blood pressure or not. Maladaptation, often reflected by inflammation-driven adventitial fibrosis, not just excessive intimal–medial thickening, significantly diminishes central artery function and disturbs hemodynamics, ultimately compromising end organ perfusion and thus driving the associated morbidity and mortality. It is thus suggested that there is a need for increased attention to controlling both smooth muscle phenotype and inflammation in hypertensive remodeling of central arteries, with future studies of the often adaptive response of medium-sized muscular arteries promising to provide additional guidance.
Trajectories of Alcohol Use and Related Harms for Managed Alcohol Program Participants over 12 Months Compared with Local Controls: A Quasi-Experimental Study
Authors: Stockwell T , Zhao J , Pauly B , Chow C , Vallance K , Wettlaufer A , Saunders J B , Chick J
Published: November 2020

Aim

Investigate changes in alcohol use and related harm using the first multisite, controlled, longitudinal study of Managed Alcohol Programs (MAPs). MAPs provide regular doses of alcohol, accommodation, social supports and healthcare to unstably housed people with alcohol dependence.

Methods

A multisite, quasi-experimental, longitudinal study was conducted in day centres, shelters and residential programs for unstably housed people. There were 59 MAP participants from six Canadian cities and 116 local controls. Self-reported alcohol consumption and harms were assessed at 0-2, 6 and 12 months. Liver function test results were accessed for MAP participants.

Results

Both groups had similar reductions in mean drinks per day (MAP: -8.11; controls: -8.54 controls, P < 0.001) and days drinking per month (MAP: -2.51 days, P < 0.05; control: -4.81 days, P = 0.0001) over 6–-12 months. Both reduced non-beverage alcohol consumption. MAP participants reported significantly fewer harms at both 0-2 and 6 months than controls. MAP participants had similar total consumption to controls, but spread out over more days (25.41 versus 19.64 days per month, P = 0.001). After leaving a MAP, participants’ liver status deteriorated, with increases in both aspartate transaminase and bilirubin levels. MAP sites with effective policies on outside drinking drank less and had fewer harms.

Conclusion

MAP participants drank less hazardously than controls, especially with effective management of non-MAP drinking. Reductions in alcohol use and harms occurred for both groups, although MAP participants reported fewer harms at 0-6 months. Departing an MAP was associated with deterioration in liver status. Although providing stable housing, MAPs did not worsen health or increase alcohol use.
Towards deep phenotyping pregnancy: a systematic review on artificial intelligence and machine learning methods to improve pregnancy outcomes
Authors: Davidson Lena , Boland Mary Regina
Published: November 2020

Objective

Development of novel informatics methods focused on improving pregnancy outcomes remains an active area of research. The purpose of this study is to systematically review the ways that artificial intelligence (AI) and machine learning (ML), including deep learning (DL), methodologies can inform patient care during pregnancy and improve outcomes.

Materials and methods

We searched English articles on EMBASE, PubMed and SCOPUS. Search terms included ML, AI, pregnancy and informatics. We included research articles and book chapters, excluding conference papers, editorials and notes.

Results

We identified 127 distinct studies from our queries that were relevant to our topic and included in the review. We found that supervised learning methods were more popular (n = 69) than unsupervised methods (n = 9). Popular methods included support vector machines (n = 30), artificial neural networks (n = 22), regression analysis (n = 17) and random forests (n = 16). Methods such as DL are beginning to gain traction (n = 13). Common areas within the pregnancy domain where AI and ML methods were used the most include prenatal care (e.g. fetal anomalies, placental functioning) (n = 73); perinatal care, birth and delivery (n = 20); and preterm birth (n = 13). Efforts to translate AI into clinical care include clinical decision support systems (n = 24) and mobile health applications (n = 9).

Conclusions

Overall, we found that ML and AI methods are being employed to optimize pregnancy outcomes, including modern DL methods (n = 13). Future research should focus on less-studied pregnancy domain areas, including postnatal and postpartum care (n = 2). Also, more work on clinical adoption of AI methods and the ethical implications of such adoption is needed.
Parallelized calculation of permutation tests
Authors: Ekvall Markus , Höhle Michael , Käll Lukas
Published: November 2020

Motivation

Permutation tests offer a straightforward framework to assess the significance of differences in sample statistics. A significant advantage of permutation tests are the relatively few assumptions about the distribution of the test statistic are needed, as they rely on the assumption of exchangeability of the group labels. They have great value, as they allow a sensitivity analysis to determine the extent to which the assumed broad sample distribution of the test statistic applies. However, in this situation, permutation tests are rarely applied because the running time of naïve implementations is too slow and grows exponentially with the sample size. Nevertheless, continued development in the 1980s introduced dynamic programming algorithms that compute exact permutation tests in polynomial time. Albeit this significant running time reduction, the exact test has not yet become one of the predominant statistical tests for medium sample size. Here, we propose a computational parallelization of one such dynamic programming-based permutation test, the Green algorithm, which makes the permutation test more attractive.

Results

Parallelization of the Green algorithm was found possible by non-trivial rearrangement of the structure of the algorithm. A speed-up—by orders of magnitude—is achievable by executing the parallelized algorithm on a GPU. We demonstrate that the execution time essentially becomes a non-issue for sample sizes, even as high as hundreds of samples. This improvement makes our method an attractive alternative to, e.g. the widely used asymptotic Mann-Whitney U-test.

Availabilityand implementation

In Python 3 code from the GitHub repository https://github.com/statisticalbiotechnology/parallelPermutationTest under an Apache 2.0 license.

Supplementary information

Supplementary data are available at Bioinformatics online.
Central opioid receptors mediate morphine-induced itch and chronic itch via disinhibition
Authors: Wang Zilong , Jiang Changyu , Yao Hongyu , Chen Ouyang , Rahman Sreya , Gu Yun , Zhao Junli , Huh Yul , Ji Ru-Rong
Published: November 2020

Opioids such as morphine are mainstay treatments for clinical pain conditions. Itch is a common side effect of opioids, particularly as a result of epidural or intrathecal administration. Recent progress has advanced our understanding of itch circuits in the spinal cord. However, the mechanisms underlying opioid-induced itch are not fully understood, although an interaction between µ-opioid receptor (MOR) and gastrin-releasing peptide receptor (GRPR) in spinal GRPR-expressing neurons has been implicated. In this study we investigated the cellular mechanisms of intrathecal opioid-induced itch by conditional deletion of MOR-encoding Oprm1 in distinct populations of interneurons and sensory neurons. We found that intrathecal injection of the MOR agonists morphine or DAMGO elicited dose-dependent scratching as well as licking and biting, but this pruritus was totally abolished in mice with a specific Oprm1 deletion in Vgat+ neurons [Oprm1-Vgat (Slc32a1)]. Loss of MOR in somatostatin+ interneurons and TRPV1+ sensory neurons did not affect morphine-induced itch but impaired morphine-induced antinociception. In situ hybridization revealed Oprm1 expression in 30% of inhibitory and 20% of excitatory interneurons in the spinal dorsal horn. Whole-cell recordings from spinal cord slices showed that DAMGO induced outward currents in 9 of 19 Vgat+ interneurons examined. Morphine also inhibited action potentials in Vgat+ interneurons. Furthermore, morphine suppressed evoked inhibitory postsynaptic currents in postsynaptic Vgat− excitatory neurons, suggesting a mechanism of disinhibition by MOR agonists. Notably, morphine-elicited itch was suppressed by intrathecal administration of NPY and abolished by spinal ablation of GRPR+ neurons with intrathecal injection of bombesin-saporin, whereas intrathecal GRP-induced itch response remained intact in mice lacking Oprm1-Vgat. Intrathecal bombesin-saporin treatment reduced the number of GRPR+ neurons by 97% in the lumber spinal cord and 91% in the cervical spinal cord, without changing the number of Oprm1+ neurons. Additionally, chronic itch from DNFB-induced allergic contact dermatitis was decreased by Oprm1-Vgat deletion. Finally, naloxone, but not peripherally restricted naloxone methiodide, inhibited chronic itch in the DNFB model and the CTCL model, indicating a contribution of central MOR signalling to chronic itch. Our findings demonstrate that intrathecal morphine elicits itch via acting on MOR on spinal inhibitory interneurons, leading to disinhibition of the spinal itch circuit. Our data also provide mechanistic insights into the current treatment of chronic itch with opioid receptor antagonist such as naloxone.
Comparative Genomics of Strictly Vertically Transmitted, Feminizing Microsporidia Endosymbionts of Amphipod Crustaceans
Authors: Cormier Alexandre , Chebbi Mohamed Amine , Giraud Isabelle , Wattier Rémi , Teixeira Maria , Gilbert Clément , Rigaud Thierry , Cordaux Richard
Published: November 2020

Microsporidia are obligate intracellular eukaryotic parasites of vertebrates and invertebrates. Microsporidia are usually pathogenic and undergo horizontal transmission or a mix of horizontal and vertical transmission. However, cases of nonpathogenic microsporidia, strictly vertically transmitted from mother to offspring, have been reported in amphipod crustaceans. Some of them further evolved the ability to feminize their nontransmitting male hosts into transmitting females. However, our understanding of the evolution of feminization in microsporidia is hindered by a lack of genomic resources. We report the sequencing and analysis of three strictly vertically transmitted microsporidia species for which feminization induction has been demonstrated (Nosema granulosis) or is strongly suspected (Dictyocoela muelleri and Dictyocoela roeselum), along with a draft genome assembly of their host Gammarus roeselii. Contrary to horizontally transmitted microsporidia that form environmental spores that can be purified, feminizing microsporidia cannot be easily isolated from their host cells. Therefore, we cosequenced symbiont and host genomic DNA and devised a computational strategy to obtain genome assemblies for the different partners. Genomic comparison with feminizing Wolbachia bacterial endosymbionts of isopod crustaceans indicated independent evolution of feminization in microsporidia and Wolbachia at the molecular genetic level. Feminization thus represents a remarkable evolutionary convergence of eukaryotic and prokaryotic microorganisms. Furthermore, a comparative genomics analysis of microsporidia allowed us to identify several candidate genes for feminization, involving functions such as DNA binding and membrane fusion. The genomic resources we generated contribute to establish Gammarus roeselii and its microsporidia symbionts as a new model to study the evolution of symbiont-mediated feminization.
Attitudes of Homebound Older Adults and Their Caregivers Toward Research and Participation as Research Advisors
Authors: Eaton England Ashley L , Ritchie Christine S , Mickler Alexandria , Perissinotto Carla M , Garrigues Sarah K , Leff Bruce , Sheehan Orla C , Harrison Krista L
Published: November 2020

Background and Objectives

Homebound older adults and their caregivers have not historically been engaged as advisors in patient-centered outcomes research. This study aimed to understand the attitudes of homebound older adults and their caregivers toward research and participation as research advisors.

Research Design and Methods

Descriptive thematic analysis of semistructured interviews conducted with 30 homebound older adults and caregivers recruited from home-based medical care practices. Interview questions addressed opinions on research and preferences for engaging as research advisors.

Results

Of 30 participants, 22 were female, 17 were people of color, and 11 had Medicaid. Two themes emerged related to perceptions of research overall: (a) utility of research and (b) relevance of research. Overall, participants reported positive attitudes toward research and felt that research could affect people like them. Three themes emerged related to participating as research advisors: (a) motivators, (b) barriers, and (c) preferences. Participants were open to engaging in a variety of activities as research advisors. Most participants were motivated by helping others. Common barriers included time constraints and caregiving responsibilities, and physical barriers for homebound individuals. Participants also reported fears such as lacking the skills or expertise to contribute as advisors. Many were willing to participate if these barriers were accommodated and shared their communication preferences.

Discussion and Implications

Diverse homebound older adults and caregivers are willing to be engaged as research advisors and provided information to inform future engagement strategies. Findings can inform efforts to meet new age-inclusive requirements of the National Institutes of Health.
Midlife Marital Dissolution and the Onset of Cognitive Impairment
Authors: Brown Susan L , Lin I-Fen , Vielee Alyssa , Mellencamp Kagan A
Published: November 2020

Background and Objectives

Marital dissolution has become more common in midlife with the doubling of the divorce rate among middle-aged adults. Guided by the stress model that stipulates losing economic, social, and psychological resources lowers well-being, we posited that midlife adults who experienced divorce or widowhood were at greater risk of cognitive impairment than the continuously married. Subsequent repartnering was expected to negate the increased risk.

Research Design and Methods

We used data from the 1998–2016 Health and Retirement Study to estimate discrete-time event history models using logistic regression to predict cognitive impairment onset for men and women.

Results

Roughly 27% of men who experienced spousal death in midlife went on to experience mild cognitive impairment by age 65. For women, experiencing divorce or widowhood was associated with higher odds of cognitive impairment onset although these differentials were accounted for by economic, social, and psychological resources. Men and women who repartnered after marital dissolution did not appreciably differ from their continuously married counterparts in terms of their likelihoods of cognitive impairment onset.

Discussion and Implications

A stressful life event, midlife marital dissolution can be detrimental to cognitive well-being, placing individuals at increased risk of developing dementia in later life. The growing diversity of partnership experiences during the second half of life points to the continued importance of examining how union dissolution and formation shape health and well-being.