bluuebunny/crossref_metadata_2025 huggingface dataset:
Asymmetric Star Formation Triggered by Gas Inflow in a Barred Lenticular Galaxy PGC 34107
Authors: Lu Shiying , Gu Qiusheng , Ge Xue , Ho Luis C. , Gao Yulong , Chen Zhengyi , Xu Ke , Zhang Zhi-Yu , Shi Yong , Yuan Qirong , Bao Min
Published: March 2022

Comparing the inactive and gas-poor normal lenticular galaxies (S0s) in the local universe, we study a barred star-forming S0 galaxy, PGC 34107, which has been observed by the Centro Astronómico Hispano Alemán 3.5 m telescope and the Northern Extended Millimeter Array. The spatially resolved ionized gas and molecular gas traced by 12CO(1–0), hereafter CO(1–0), show similar distribution and kinematics to the stellar component with an off-center star-forming region, ∼380 pc away from the center. The resolved kinematics of molecular CO(1–0) emission reveals that there is a blueshifted (redshifted) velocity component on the receding (approaching) side of the galaxy along the stellar bar. This might provide plausible evidence of noncircular motion, such as the bar-induced molecular gas inflow. The velocity of the molecular gas inflow decreases when approaching toward the peak of the off-center star formation in the north, which might be associated with the inner Lindblad resonance. In addition to CO(1–0), we also detect the isotopic line of 13CO(1–0). For most Hα, CO(1–0) and 13CO(1–0) emissions are concentrated on this northern star-forming region. We find that PGC 34107 follows the local stellar mass–metallicity relation, star-forming main sequence, and the Kennicutt–Schmidt law. The resolved and integrated molecular gas main sequence suggests that there is a higher gas fraction in the central region of the galaxy, which supports a scenario that the bar-induced gas reservoir provides the raw material, and subsequently triggers the central star formation.
Methanol Mapping in Cold Cores: Testing Model Predictions*
Authors: Punanova Anna , Vasyunin Anton , Caselli Paola , Howard Alexander , Spezzano Silvia , Shirley Yancy , Scibelli Samantha , Harju Jorma
Published: March 2022

Chemical models predict that in cold cores gas-phase methanol is expected to be abundant at the outer edge of the CO depletion zone, where CO is actively adsorbed. CO adsorption correlates with volume density in cold cores, and, in nearby molecular clouds, catastrophic CO freeze-out happens at volume densities above 104 cm−3. The methanol production rate is maximized there and its freeze-out rate does not overcome its production rate, while the molecules are shielded from UV destruction by gas and dust. Thus, in cold cores, methanol abundance should generally correlate with visual extinction, which depends on both volume and column density. In this work, we test the most basic model prediction that maximum methanol abundance is associated with a local
A

V
∼ 4 mag in dense cores and constrain the model parameters with the observational data. With the IRAM 30 m antenna, we mapped the CH3OH (2–1) and (3–2) transitions toward seven dense cores in the L1495 filament in Taurus to measure the methanol abundance. We use the Herschel/SPIRE maps to estimate visual extinction, and the C18O(2–1) maps from Tafalla & Hacar to estimate CO depletion. We explored the observed and modeled correlations between the methanol abundances, CO depletion, and visual extinction, varying the key model parameters. The modeling results show that hydrogen surface diffusion via tunneling is crucial to reproduce the observed methanol abundances, and the necessary reactive desorption efficiency matches the one deduced from laboratory experiments.
Discovery of Three Candidate Magnetar-powered Fast X-Ray Transients from Chandra Archival Data
Authors: Lin Dacheng , Irwin Jimmy A. , Berger Edo , Nguyen Ronny
Published: March 2022

It was proposed that a remnant stable magnetar could be formed in a binary neutron-star merger, leading to a fast X-ray transient (FXT) that can last for thousands of seconds. Recently, Xue et al. suggested that CDF-S XT2 was exactly such a kind of source. If confirmed, such emission can be used to search for electromagnetic counterparts to gravitational wave events from binary neutron-star mergers that have short gamma-ray bursts and the corresponding afterglows seen off-axis and thus too weak to be detected. Here we report the discovery of three new FXTs, XRT 170901, XRT 030511, and XRT 110919, from a preliminary search over Chandra archival data. Similar to CDF-S XT2, these new FXTs had a very fast rise (less than a few tens of seconds) and a plateau of X-ray flux of ∼1.0 × 10−12 erg s−1 cm−2 lasting for 1–2 ks, followed by a steep decay. Their optical/IR counterparts, if present, are very weak, arguing against a stellar flare origin for these FXTs. For XRT 170901, we identified a faint host galaxy with the source at the outskirts, very similar to CDF-S XT2. Therefore, our newly discovered FXTs are also strong candidates for magnetar-powered X-ray transients resulting from binary neutron star mergers.
How Many Elements Matter?
Authors: Ting 丁 Yuan-Sen 源森 , Weinberg David H.
Published: March 2022

Some studies of stars’ multielement abundance distributions suggest at least 5–7 significant dimensions, but others show that many elemental abundances can be predicted to high accuracy from [Fe/H] and [Mg/Fe] (or [Fe/H] and age) alone. We show that both propositions can be, and are, simultaneously true. We adopt a machine-learning technique known as normalizing flow to reconstruct the probability distribution of Milky Way disk stars in the space of 15 elemental abundances measured by APOGEE. Conditioning on T
eff and

log

g

minimizes the differential systematics. After further conditioning on [Fe/H] and [Mg/Fe], the residual scatter for most abundances is σ
[X/H] ≲ 0.02 dex, consistent with APOGEE’s reported statistical uncertainties of ∼0.01–0.015 dex and intrinsic scatter of 0.01–0.02 dex. Despite the small scatter, residual abundances display clear correlations between elements, which we show are too large to be explained by measurement uncertainties or by the finite sampling noise. We must condition on at least seven elements to reduce the correlations to a level consistent with the observational uncertainties. Our results demonstrate that cross-element correlations are a much more sensitive probe of a hidden structure than dispersion, and they can be measured precisely in a large sample even if the star-by-star measurement noise is comparable to the intrinsic scatter. We conclude that many elements have an independent story to tell, even for the mundane disk stars and elements produced by the core-collapse and Type Ia supernovae. The only way to learn these lessons is to measure the abundances directly, and not merely infer them.
Chemical Feedback of Pebble Growth: Impacts on CO depletion and C/O ratios
Authors: Van Clepper Eric , Bergner Jennifer B. , Bosman Arthur D. , Bergin Edwin , Ciesla Fred J.
Published: March 2022

Observations of protoplanetary disks have revealed them to be complex and dynamic, with vertical and radial transport of gas and dust occurring simultaneously with chemistry and planet formation. Previous models of protoplanetary disks focused primarily on chemical evolution of gas and dust in a static disk, or dynamical evolution of solids in a chemically passive disk. In this paper, we present a new 1D method for modeling pebble growth and chemistry simultaneously. Gas and small dust particles are allowed to diffuse vertically, connecting chemistry at all elevations of the disk. Pebbles are assumed to form from the dust present around the midplane, inheriting the composition of ices at this location. We present the results of this model after 1 Myr of disk evolution around a 1M
⊙ star at various locations both inside and outside the CO snowline. We find that for a turbulent disk (α = 10−3), CO is depleted from the surface layers of the disk by roughly 1–2 orders of magnitude, consistent with observations of protoplanetary disks. This is achieved by a combination of ice sequestration and decreasing UV opacity, both driven by pebble growth. Further, we find the selective removal of ice species via pebble growth and sequestration can increase gas phase C/O ratios to values of approximately unity. However, our model is unable to produce C/O values of ∼1.5–2.0 inferred from protoplanetary disk observations, implying selective sequestration of ice is not sufficient to explain C/O ratios >1.
The Solar Wind at (16) Psyche: Predictions for a Metal World
Authors: Collinson Glyn A. , Chen Li-Jen , Jian Lan K. , Dorelli John
Published: March 2022

NASA’s Psyche spacecraft will carry a magnetometer to main-belt asteroid (16) Psyche to search for remanent magnetic fields, and to attempt electromagnetic sounding of the interior. However, the Psyche spacecraft does not carry an instrument to measure solar wind plasmas. We thus combine data from five missions that have measured the solar wind at the orbit of asteroid (16) Psyche. We characterize these upstream conditions for future modeling and reference. We consider the implications of these ambient conditions for the interaction between (16) Psyche and the solar wind, outlining four possible resulting magnetospheres. Any magnetosphere would be dominated by ion-scale (Hall) physics and exotic electron-scale physics, requiring sophisticated physical modeling to describe. Under these different regimes, plasma generates additional electromagnetic fields, resulting in complex magnetism which may complicate the magnetic environment near asteroid (16) Psyche. Future missions to asteroids would benefit from combined magnetic field and plasma measurements.
Evidence for X-Ray Emission in Excess to the Jet-afterglow Decay 3.5 yr after the Binary Neutron Star Merger GW 170817: A New Emission Component
Authors: Hajela A. , Margutti R. , Bright J. S. , Alexander K. D. , Metzger B. D. , Nedora V. , Kathirgamaraju A. , Margalit B. , Radice D. , Guidorzi C. , Berger E. , MacFadyen A. , Giannios D. , Chornock R. , Heywood I. , Sironi L. , Gottlieb O. , Coppejans D. , Laskar T. , Cendes Y. , Duran R. Barniol , Eftekhari T. , Fong W. , McDowell A. , Nicholl M. , Xie X. , Zrake J. , Bernuzzi S. , Broekgaarden F. S. , Kilpatrick C. D. , Terreran G. , Villar V. A. , Blanchard P. K. , Gomez S. , Hosseinzadeh G. , Matthews D. J. , Rastinejad J. C.
Published: March 2022

For the first ∼3 yrs after the binary neutron star merger event GW 170817, the radio and X-ray radiation has been dominated by emission from a structured relativistic off-axis jet propagating into a low-density medium with n < 0.01 cm−3. We report on observational evidence for an excess of X-ray emission at δt > 900 days after the merger. With L

x
≈ 5 × 1038 erg s−1 at 1234 days, the recently detected X-ray emission represents a ≥3.2σ (Gaussian equivalent) deviation from the universal post-jet-break model that best fits the multiwavelength afterglow at earlier times. In the context of JetFit afterglow models, current data represent a departure with statistical significance ≥3.1σ, depending on the fireball collimation, with the most realistic models showing excesses at the level of ≥3.7σ. A lack of detectable 3 GHz radio emission suggests a harder broadband spectrum than the jet afterglow. These properties are consistent with the emergence of a new emission component such as synchrotron radiation from a mildly relativistic shock generated by the expanding merger ejecta, i.e., a kilonova afterglow. In this context, we present a set of ab initio numerical relativity binary neutron star (BNS) merger simulations that show that an X-ray excess supports the presence of a high-velocity tail in the merger ejecta, and argues against the prompt collapse of the merger remnant into a black hole. Radiation from accretion processes on the compact-object remnant represents a viable alternative. Neither a kilonova afterglow nor accretion-powered emission have been observed before, as detections of BNS mergers at this phase of evolution are unprecedented.
Nuclear-optical converters for detecting intense neutron
Authors: Baskov Pyotr B. , Marichev Gleb V. , Sakharov Vyacheslav V. , Stepanov Vladimir A.
Published: March 2022

In the design of nuclear-optical converters (NOC) for detecting intense neutron fields (fluxes over 1015 cm–2·s–1), it is proposed to use hybrid gas ionization chambers (IC), in which electrical and optical neutron detecting methods are combined. For hybrid ICs, a technology is proposed for obtaining radiation-resistant and mechanically strong radiator materials capable of operating at temperatures of up to 1000 °C. This technology is based on solid-phase boron diffusion saturation of steel. It is shown that, at thermal neutron fluxes of 1×1010 n/(cm2·s) and higher, the integral intensity of argon luminescence as a result of ionization by α-particles and 7Li ions from layers of boride phases is sufficient for detection.

The combination of optical and radiation properties of multicomponent fluoride glasses makes it possible to use them as condensed active substances of NOCs. Choosing the elemental and isotopic composition, it becomes possible to use fluoride glasses for multichannel neutron detection as well as to significantly simplify the procedure for separating gamma and neutron components of radiation under conditions of intense radiation fluxes. It has been experimentally shown that in irradiation with a neutron flux of 1×1017 n/(cm2·s), the intensity of Nd IR luminescence in glasses based on zirconium fluoride (ZBLAN) increases in the presence of Gd, which interacts with neutrons.
From worse to worse: Why is it so difficult to change English education for the better?
Authors: Reay Diane
Published: March 2022

This article, as coruscating as it is well-grounded, sketches the appallingly unfair state of contemporary education in England. It outlines the historical and contemporary drivers of that unfairness and the consequences that ensue in the lives of young people. It calls for a renewed
movement on the left to call out the education system's shocking injustice and replace the values which have made that system so resistant to progressive change with an ethos better suited to humane comprehensive education.
Portfolio choice and mental accounts: A comparison with traditional approaches
Authors: Hübner Georges , Lejeune Thomas
Published: March 2022

Cet article analyse dans quelle mesure un modèle réaliste de comptabilité mentale pour les choix de portefeuille est capable de concurrencer des alternatives d’utilité traditionnelles. Il s’agit du modèle de comptabilité mentale étendu aux dimensions d’horizon d’investissement et d’asymétrie présenté dans Hübner et Lejeune (2021). Das, Markowitz, Scheid, et Statman (2010) et Hübner et Lejeune (2021) ont démontré que le référentiel de comptabilité mentale incorpore des allocations optimales dérivées d’optimisation de l’utilité quadratique et/ou de l’hypothèse de la distribution Gaussienne. Nous complémentons leur travail en démontrant ici la flexibilité et la supériorité numérique des outputs d’optimisation qu’une version non-Gaussienne du modèle HAMA (Horizon-Asymmetry Mental Accounting) génère par rapport à deux règles traditionnelles de maximisation de l’utilité espérée produisant un spectre large et pertinent de règles d’allocation de portefeuille pour divers types d’investisseurs : l’approche du taux de décroissance de Stutzer (2003), qui est similaire à la maximisation de l’utilité espérée, et la classe des fonctions d’utilité flexibles à trois paramètres (FTP) introduite par Conniffe (2007) qui englobe un large ensemble de fonctions d’utilité.
Well-posedness and stability for semilinear wave-type equations with time delay
Authors: Paolucci Alessandro , Pignotti Cristina
Published: March 2022

In this paper, we analyze a semilinear abstract damped wave-type equation with time delay. We assume that the delay feedback coefficient is variable in time and belongs to \begin{document}$ L^1_{loc}([0, +\infty)). $\end{document} Under suitable assumptions, we show well-posedness and exponential stability for small initial data. Our strategy combines careful energy estimates and continuity arguments. Some examples illustrate the abstract results.
Simultaneous recovery of an obstacle and its excitation sources from near-field scattering data
Authors: Chang Yan , Guo Yukun
Published: March 2022

This paper is concerned with the inverse problem of determining an obstacle and the corresponding incident point sources in the Helmholtz equation from near-field scattering data. An optimization method is proposed to simultaneously recover both the obstacle and source locations. Moreover, a two-step sampling scheme with novel indicator functions is proposed to produce a good initial guess for solving the optimization problem. Theoretically, we analyze the convergence properties of the optimization method and the behaviors of the indicator functions. Several numerical examples are presented to show the effectiveness of the proposed method.
Existence of nontrivial positive solutions for generalized quasilinear elliptic equations with critical exponent
Authors: Zhang Shulin
Published: March 2022

In this paper, we are concerned with the existence of nontrivial positive solutions for the following generalized quasilinear elliptic equations with critical growth

   \begin{document}$ \begin{equation*} -{\rm{div}}(g^{p}(u)|\nabla u|^{p-2}\nabla u)+ g^{p-1}(u)g'(u)|\nabla u|^{p}+ V(x)|u|^{p-2}u = h(x, u), \; \; x\in \mathbb{R}^{N}, \end{equation*} $\end{document}

where $ N\geq3 $, $ 1 < p < N $. Under some suitable conditions, we prove that the above equation has a nontrivial positive solution by variational methods. To some extent, our results improve and supplement some existing relevant results.
A novel high accurate numerical approach for the time-delay optimal control problems with delay on both state and control variables
Authors: Hedayati Mehrnoosh , Tehrani Hojjat Ahsani , Jahromi Alireza Fakharzadeh , Skandari Mohammad Hadi Noori , Baleanu Dumitru
Published: March 2022

In this study, we intend to present a numerical method with highly accurate to solve the time-delay optimal control problems with delay on both the state and control variables. These problems can be seen in many sciences such as medicine, biology, chemistry, engineering, etc. Most of the methods used to work out time delay optimal control problems have high complexity and cost of computing. We extend a direct Legendre-Gauss-Lobatto spectral collocation method for numerically solving the issues mentioned above, which have some difficulties with other methods. The simple structure, convergence, and high accuracy of our approach are the advantages that distinguish it from different processes. At first, by replacing the delay functions of state and control variables in the dynamical method, we propose an equivalent system. Then discretizing the problem at the collocation points, we achieve a nonlinear programming problem. We can solve this discrete problem to obtain the approximate solutions for the main problem. Moreover, we prove the gained approximate solutions convergent to the exact optimal solutions when the number of collocation points increases. Finally, we show the capability and the superiority of the presented method by solving some numeral examples and comparing the results with those of others.
The Welfare Effects of Dynamic Pricing: Evidence From Airline Markets
Authors: Williams Kevin R.
Published: March 2022

Airfares fluctuate due to demand shocks and intertemporal variation in willingness to pay. I estimate a model of dynamic airline pricing accounting for both sources of price adjustments using flight‐level data. I use the model estimates to evaluate the welfare effects of dynamic airline pricing. Relative to uniform pricing, dynamic pricing benefits early‐arriving, leisure consumers at the expense of late‐arriving, business travelers. Although dynamic pricing ensures seat availability for business travelers, these consumers are then charged higher prices. When aggregated over markets, welfare is higher under dynamic pricing than under uniform pricing. The direction of the welfare effect at the market level depends on whether dynamic price adjustments are mainly driven by demand shocks or by changes in the overall demand elasticity.
Range‐Dependent Attribute Weighting in Consumer Choice: An Experimental Test
Authors: Somerville Jason
Published: March 2022

This paper investigates whether the range of an attribute's outcomes in the choice set alters its relative importance. I derive distinguishing predictions of two prominent theories of range‐dependent attribute weighting: the focusing model of Kőszegi and Szeidl (2013) and the relative thinking model of Bushong, Rabin, and Schwartzstein (2021). I test these predictions in a laboratory experiment in which I vary the prices of high‐ and low‐quality variants of multiple products. The data provide clear evidence of choice‐set dependence consistent with relative thinking: price increases that expand the range of prices in the choice set lead to
more purchases. Structural estimates imply economically meaningful effect sizes: the average participant was willing to pay around 17% more when a seemingly irrelevant option is added to their choice set.
Optimal Decision Rules for Weak GMM
Authors: Andrews Isaiah , Mikusheva Anna
Published: March 2022

This paper studies optimal decision rules, including estimators and tests, for weakly identified GMM models. We derive the limit experiment for weakly identified GMM, and propose a theoretically‐motivated class of priors which give rise to quasi‐Bayes decision rules as a limiting case. Together with results in the previous literature, this establishes desirable properties for the quasi‐Bayes approach regardless of model identification status, and we recommend quasi‐Bayes for settings where identification is a concern. We further propose weighted average power‐optimal identification‐robust frequentist tests and confidence sets, and prove a Bernstein‐von Mises‐type result for the quasi‐Bayes posterior under weak identification.
The role of cardiovascular risk assessment in addressing prevention of cardiovascular disease and cardiovascular complications of diabetes in South Asia
Authors: Mendis S.
Published: March 2022

In the face of the rising incidence of cardiovascular diseases (CVD) and diabetes in low-income and middle-income countries in South Asia, the most cost-effective and equitable strategies for prevention of heart attacks, strokes and vascular complications of diabetes need to be incorporated into primary care services. Health system and resource limitations in these countries call for directing preventive services and pharmacological treatment to people with high cardiovascular risk, identified by risk stratification using hypertension and diabetes as entry points. Absolute cardiovascular risk prediction scores should be used routinely in primary care. Individual management guidelines for hypertension, dyslipidemia and diabetes need to be replaced by integrated and simplified cardiovascular risk management guidelines.
Sustainable and Green Drilling Fluid Additives Development
Authors: Ramasamy Jothibasu , Arfaj Mohammad K.
Published: March 2022

Oil and gas drilling requires several components work simultaneously to ensure smooth and safe drilling. Drilling fluid or mud is an inseparable part of drilling oil and gas wells and circulated through out theh drilling operation. Drilling fluid contains a variety of additives or chemicals to provide various properties to drilling fluid namely viscosity, fluid loss control, emulsion stability, lubricity, etc. Developing environment friendly chemicals to provide the above-mentioned drilling fluid properties is a significant step taken towards sustainability and reducing carbon footprint besides suitability for aquifers and offshore environments. Several fatty acid-based chemicals used in drilling fluids as fatty acids offer eco-friendly and bio-degradable properties besides required drilling fluid properties. Vegatable oil contains triglycerides which is a potential source of fatty acids and their derivatives. Waste vegetable oil (WVO) provides a perpetual and sustainable source of raw material for various types of eco-friendly additives development. Waste vegetable oil is subjected to simple chemical modification of base hydrolysis process and mixtures of fatty acids have been obtained after finishing a sequence of clean-up process of reaction mixture. The fatty acids obtained are environment-friendly, bio-degradable and non-toxic. Due to technical, economic and environmental advantages of products derived from waste vegetable oils, we have undertaken several research projects to produce various chemicals from waste vegetable oil for oil and gas field applications. Fatty acid-based products mainly used in drilling fluids as lubricants to reduce torque and drag for water-based mud. In case of oil-based mud systems, fatty acid derived products are used as emulsifiers, wetting agents and rheology modifiers. However, these products have been either mixture of fatty acids and their derivatives or only derivatives of fatty acids. In our study, we have used the mixture of fatty acids obtained from chemical conversion of WVO for applications as lubricant for water-based mud and emulsifier and rheology modifier for invert emulsion oil-based mud systems. In this paper, we described the chemicals process for converting waste vegetable oil to fatty acids by base hydrolysis reaction in the first section. Application of synthesized fatty acids for water-based and oil-based mud formulation as lubricants, emulsifiers and rheology modifiers have been discussed in the second part of the paper.
3-D Micromodel for Visualization & Experimental Analysis of Flow Behavior, Surface Tension and Polymer Concentration on Enhanced Oil Recovery
Authors: Tandon Apoorv , Khan Fahad , Shukla Raman , Saxena Amit , Sharma Shivanjali , Biswas Koushik Guha
Published: March 2022

Oil recovery is a complex process involving physical and chemical interactions within the pore spaces of the reservoir. The oil recovery improves by injecting viscous and wettability-altering fluids into the reservoir. The present work aims to study the improvement in the recovery using surfactant polymer (SP) slug and discuss the mechanisms behind the oil mobilization process by visualizing the oil recovery using a glass tube filled with glass beads. Fluids were injected using a syringe pump, and the interaction of the fluid was visualized using a high-speed camera. Initially, the oil was displaced using brine which was followed by the injection of SP slug formulated using Sodium Dodecyl Sulphate (SDS) and Poly Acrylamide (PAM). The effect of the composition of the slug was studied at different concentrations 125ppm, 250ppm, 375ppm, and 500ppm. After that, the effect of flow rate of SP slug on the oil recovery process was explored. Colored non-interacting dyes aided the visualization in the glass model. Images of the oil recovery process were captured to examine the fluid displacement mechanism during SP flooding.

The total oil recovery increases from 73.33% to 83.33%, as the polymer concentration was increased gradually from 125 ppm to 500 ppm at a flow rate of 100 µL/min which further increases to 90% for 500 ppm slug at 500 µL/min of flow rate. High-quality magnified images from the camera captured the flow path of each fluid injected through the glass bead-packed channel. The effect of various forces like capillary, gravity, and viscous forces were visualized and analyzed. The pore throat and pore-diameter calculations were done using the software. The low viscous slug was subjected to higher gravity force, rendering it ineffective in displacing the oil present at the channel's top. The gravity segregation was overpowered by high viscous slugs that mobilized the oil present in the channel. The understanding and analysis of the fluid motion under oil-brine interaction and SP slug-oil interactions was studied. The study helps improve the techno-economic feasibility of the whole recovery process by limiting the use of chemicals and maximizing the oil recovery in a controlled manner.
New Formulation of Ultra-Low Ift Surfactant for Potential Eor Application
Authors: Ahmad Wazir Norhidayah , Saadon Shazleen , Ramli Anita
Published: March 2022

The paper discussed the development of an Ultra-Low Interfacial Tension (IFT) foaming surfactant based on a combination of improved as-synthesized surfactant (CBH) consist of as-synthesized oleic amido propyl betaine with mixtures of co-solvents and PETRONAS’ in-house patented foaming-based surfactant (IVF) which consist of amphoteric and anionic surfactant; as well as the performance evaluation of the surfactant in Enhanced Oil Revery (EOR) application. CBH and PETRONAS (IVF) foam-based surfactants were used in the formulation as ultra-low IFT and foaming components, respectively. The surfactant's development has been highlighted, and the findings have been discussed in detail. Due to the good foaming and IFT output at ultra-low levels, the combination of 0.3wt.% IVF and CBH at a ratio of 2: 8 was suggested. The addition of a non-ionic scleroglucan polymer from the polysaccharide group was chosen to study the stabilizing effect to the foam and the ultra-low IFT value of the formulation. Based on the findings, the presence of scleroglucan in the formulation has a significant effect on the performance of IFT and foam of the formulation when compared to the original formulation.
Optimization of Enzyme-Induced Calcite Precipitation Process for Oil and Gas Sand Consolidation Applications
Authors: AlKuroud Deem Nuaman , Tariq Zeeshan , Khalil Amjad Bajes , Mahmoud Mohamed , Alahmari Manar , Bataweel Mohammad
Published: March 2022

Sand production from a poorly consolidated reservoir formation is always considered a challenging problem in the petroleum industry. Sand production can cause erosion and corrosion to downhole and surface equipment and loss of production. Over the past few decades, sand control techniques have attracted increased attention to improve and enhance the characteristics of weak sand formations. Enzyme-induced calcite precipitation (EICP) is considered a relatively new sustainable technique studied for soil improvement. In-situ calcite precipitation in the sand can restrict the movement of the grains by forming bridges. This precipitation fills the pores and binds sand particles causing a reduction in the porosity which as a result improves sand shear strength.

In this study, different mixes of EICP solution were studied and tested in the laboratory. To cure the samples at higher temperatures Xanthan Gum (XC-polymer) was used as a temperature stabilizer. EICP solution is primarily composed of urea, calcium chloride, magnesium chloride, XC-polymer, and urease enzyme. Different concentrations and compositions of reagents were tested. The mixed solutions were left for different curing times at different curing temperatures to allow the reaction to happen. The properties of the produced precipitates were examined through different techniques such as pH, conductivity, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), and Thermogravimetric analysis (TGA).

The XRD results showed the precipitation of calcite and dolomite. The combination that produced the highest amount of thermally stable calcite with a minimal amount of aragonite, highest precipitation efficiency was further selected for the sand consolidation experiment. A solution containing 1M Urea, 0.5M CaCl2, 0.5M MgCl2, 5g/L XC-polymer, and 2g/L urease was considered as an optimum combination for an EICP process.

The novelty of this paper is that it not only describes the development of a unique formula for the EICP process used for sand control and water conformance but also provides a selection criterion for applying the EICP for these downhole applications.
An Overview of Successful Fit to Purpose Tubing Stem Test Operation on MUFFIN-X Appraisal Well to Unlock Gas Potential of Deep Formation with HPHT & High CO2-H2S Environment in MTJDA, North Malay Basin
Authors: Setiawan Avidianto Suryo , Apiwathanasorn Sippakorn
Published: March 2022

This paper will share a success story of a well-test operation performed on MUFFIN-X, an appraisal well located at the northern part of the Malaysia-Thailand Joint Development Area (MTJDA). The well was drilled in Q4-2020 and penetrated two fault blocks of northern MTJDA to appraise the area for further field development study and proposal. The objective of the test itself is to acquire new data to reduce the subsurface uncertainties and unlock the gas potential from deep formations of the area, which is well known for its multilayer reservoirs, High Pressure-High Temperature (HPHT), and high CO2-H2S content. These conditions are the key challenges to developing the area. To cope with the challenges, Carigali-PTTEPI Operating Company (CPOC) has been using a Tubing-Stem-Test (TST) approach that provides secured wellbore conditions and multiple accessibilities to multiple reservoirs, straightforward operation, and realistic production simulation. The TST of MUFFIN-X was designed to complete each zone within 24-to-36 hours for deliverability and pressure transient tests. The TST performed on MUFFIN-X has successfully unlocked 20 MMscf/d of gas and 5000 bbl/d of oil potentials from the deep formations of the block. The job was completed 16 hours earlier than the design, bringing approximately 40K USD of cost optimization.
Coreflooding Experiments on PAM/PEI Polymer Gel for Water Control in High-Temperature and High-Pressure Conditions: With and Without Crossflow Effect
Authors: Amir Zulhelmi , Mohd Saaid Ismail , Mohamed Jan Badrul Hisham
Published: March 2022

This study presents the coreflooding experiments to evaluate the performance of PAM/PEI polymer gels as conformance control agent in porous media. The experiments were designed to investigate the effectiveness of PAM/PEI polymer gels to block a high permeability zone and to divert water to low permeability zone. The work is based on four relevant elements that determine the suitability of a gel to mitigate excessive water production in a high temperature and high pressure conditions. They are adequate gelation time to achieve the target zone, reducing permeability to water, applicable injectivity, and long-term thermal stability. Two different coreflooding schemes were performed, which are coreflooding without crossflow using native sandstone, and coreflooding with crossflow using composite core that has permeability contrast. Native and composite cores represent homogeneous and heterogeneous reservoirs, respectively. Four different set of gelants, which are; 1) pure PAM/PEI polymer gelant; 2) PAM/PEI polymer gelant with NH4O; 3) PAM/PEI polymer gelant with NH4O at high salinity; and 4) Polymer gelant in high salinity and NH4Cl reinforced with SiO2 nanoparticles (NP), were prepared and injected into the cores. The selected mixture of gelants are sufficient to represent the effect of salinity, NH4Cl as retarder and solid nanoparticles on the gel in porous media. The pressure drop is an indication of the gel strength. Higher pressure drop signifies good gel strength. The highest pressure drop can be observed in the core treated with silica NP reinforced polymer gel. Compared to the gel without silica NP, the pressure drop during waterflooding post gel treatment can rise up to 1500 psi. On the oil recovery, highest recovery is established for core treated with reinforced polymer gel. Additional 24% of the trapped oil was recovered after treatment. It signifies the effectiveness of polymer gel with silica NP to divert the flow of water into where trapped oil is located. Good gel performance can be visualized through the dye stain on the surface of the core cut. When brine is injected, the dye stain will be left at the water flow path. For the core treated with reinforced gel, the dye stain is only spotted at the inlet of the core. It can be assumed that rigid gel is able to divert water to low permeability zone before water reaches further surface. The different mixture of PAM/PEI polymer gels were assessed in native and composite sandstone cores at high temperature and pressure. Results showed that PAM/PEI polymer gel reinforced with solid silica NP has proved to provide satisfactory gel strength to divert water flow, thus effective to recover more oil. Strengthening gel by addition of solid particles could be the remedy for the weakened polymer gel.
Immunohistochemical expression of interleukin 1 beta in papule biopsies from patients with acne vulgaris
Authors: Thanh Le Thai Van , Anh Le Vi , Giang Tran Huong , Hung Ta Quoc , Trung Van The , Vuong Nguyen Lam
Published: March 2022

Acne vulgaris is the most common inflammatory disease of the skin. IL-1b has been found in acne lesions and is a promising target for therapy, but the evidence is limited. Therefore, this study was conducted to investigate the immunohistochemical expression of IL-1b in papule biopsies of inflammatory acne and its association with disease severity. This study involved 20 patients with acne vulgaris (13 females, median age: 22 years). Samples were taken using punch biopsy. Immunohistochemical IL-1b expression was semi-quantitatively assessed as absent, mild, moderate or strong. Disease severity was evaluated according to the Global Acne Grading System (GAGS). There were 7 patients with mild disease and 11 patients with moderate disease. Median GAGS score was 20. Mild and moderate accounted for 65% and 30% for dermal IL-1b expression, 60% and 40% for epidermal expression, and 70% and 15% for perifollicular expression. Moderate-strong perifollicular expression had significant higher GAGS score than absent-mild expression (median: 22 versus 16). This study shows the elevated immunoreactivity of IL-1b in papule biopsies of inflammatory acne vulgaris. The levels of IL-1b expression also correlates with disease severity. IL-1b could be a good candidate for targeting treatment of acne vulgaris.
Are we adequately prepared to handle the anticipated 3rd peak of COVID-19: A KAP survey among HCWs
Authors: Singh Narendra Pal , Goyal Nisha , Saini Vikas , Kapoor Abhilasha , Gangar Seema
Published: March 2022

Experts in the field are predicting a third COVID-19 peak very soon in coming times, it is important to assess recent knowledge, attitude in view of prolonged exhaustion and adherence to preventive practices of HCWs. This cross-sectional study involved 168 HCWs (42 doctors, 42 nurses, 42 paramedical staff and 42 ANMs). Data was collected through online survey tool Google forms in July and August 2021. First section included sociodemographic information and infection with SARS-CoV- 2, section 2 assessed recent knowledge, section 3 practices of COVID-19 appropriate behavior and section 4 assessed attitude of HCWs. Shapiro Wilk test was used to determine normality of distribution of variables. Kruskal-Wallis and Mann-Whitney U tests were used to determine the association between two variables. Pairwise comparison was done following a significant Kruskal-Wallis test using Bonferroni’s correction. 42.9% of the HCWs and family members of 44.6% HCWs were infected with SARS-CoV-2. 54.1% of infected HCWs were infected during the March- May 2021 peak. 85.1% HCWs had taken COVID-19 vaccine. Mean knowledge, attitude, practice scores were 7.88±3.03(maximum score: 12), 20.35±3.2 (maximum score: 25), 69.89±9.39 (maximum score: 85) respectively. Only 48.8% HCWs had good knowledge about more recent COVID-19 information. A significant association was observed between profession and knowledge scores (p<0.001). Over 85% HCWs had good scores for attitude towards COVID-19 and 88.7% HCWs scored good in COVID-19 appropriate behavior practices. Our HCWs need to be better equipped with the more recently available knowledge about COVID-19 to improve our preparedness for the next anticipated peak.
Cultural Adaption and Psychometric Analysis of Family APGAR Scale in Iranian Older People
Authors: Karimi Zeinab , Taheri-Kharameh Zahra , Sharififard Fatemeh
Published: March 2022

Background: Family function is a necessary factor that influences older people’s health. The Family APGAR has been widely used to study family functions. However, there has been no Persian version of this instrument to assess family function in older people. The aim of this study was to determine the psychometric properties of the Persian version of the Family APGAR Scale to evaluate the perception of family functions.Methods: The “forward-backward” procedure was applied to translate the scale from English into Persian. The translated version was checked in terms of validity and reliability, with a sample of 281 older people selected from retirement centers. The factor structure of the scale was also tested using a confirmatory factor analysis. To test reliability, internal consistency and test–retest analyses were performed.Results: The results of the confirmatory factor analysis indicated a good structural model. Criterion-related validity was strongly supported by the pattern of association between the APGAR Scale and the social support survey. Cronbach’s α of the scale was 0.88 and test–retest reliability ranged from 0.96 to 0.98, indicating a good range of reliability.Conclusion: The findings of this study suggest that the Iranian version of the Family APGAR is a valid and reliable scale to evaluate family functions in health intervention programs.
Exposure to Secondhand Smoke and a Tobacco-Specific Carcinogen in Non-Smokers
Authors: Lee Jae-woo , Yang Woojung , Kim Ye-Seul , Kim Yonghwan , Yoo Hyo-Sun , Kang Hee-Taik
Published: March 2022

Background: The International Agency for Research on Cancer classifies 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) as a known carcinogen. This study aimed to investigate the association between exposure to secondhand smoke (SHS) and NNAL concentrations in non-smokers.Methods: This was a cross-sectional study based on data from the 2016 to 2018 Korea National Health and Nutrition Examination Survey. Urine NNAL concentrations were categorized into tertiles of 3,615 study participants who were non-smokers. All sampling and weight variables were stratified, and analyses to account for the complex sampling design were conducted.Results: The overall, male, and female percentages of SHS exposure among non-smokers were 22.4%, 29.2%, and 20.4%, respectively. The geometric means of urine NNAL concentrations were 1.896±0.098 pg/mL and 1.094±0.028 pg/mL in the SHS exposure and non-exposure groups, respectively. After adjusting for confounding variables, in the total group, the geometric mean of urine NNAL concentrations was significantly higher in the SHS exposure group than in the SHS non-exposure group (adjusted P-value <0.001). Compared with the non-exposure group, the adjusted odds ratios (95% confidence intervals) for the highest NNAL tertile group of overall SHS exposure in the total, men, and women groups were 2.44 (1.95–3.05), 1.65 (1.08–2.53), and 2.73 (2.11–3.52), respectively, after full adjustment.Conclusion: The urine NNAL concentration in the SHS exposure group was significantly higher than that in the non-exposure group. Exposure to SHS was associated with a higher risk of elevated urine NNAL concentrations in non-smokers.
Risk Factors Related to Serious Adverse Drug Reactions Reported through Electronic Submission during Hospitalization in Elderly Patients
Authors: Won Seon-Hye , Suh Sang-Yeon , Yim Eunji , Ahn Hong-Yup
Published: March 2022

Background: Many studies have assessed the risk factors for adverse drug reactions (ADRs) in elderly patients. However, most of these studies have focused on risk factors for ADRs, not serious ADRs (s-ADRs). s-ADRs are commonly found in hospitalized patients. s-ADRs warrant imminent but thorough investigations, given their critical impact on patient health. Therefore, this retrospective study aimed to assess the associated risk factors for s-ADRs in elderly hospitalized patients.Methods: In-patients aged >65 years having ADRs during hospitalization at a university hospital in Korea between 2010 and 2012 were included. Medical professionals spontaneously reported ADRs using an electronic submission system at the study hospital. Further, all descriptions of ADRs were characterized and categorized through the screening of electronic medical records. We compared the characteristics of patients having s-ADRs with those of patients not having s-ADRs.Results: There were 353 cases of ADRs, 67 of which were s-ADRs. Patients taking more than eight concomitant drugs showed the highest odds ratio (OR, 11.99; 95% confidence interval [CI], 3.42–42.03). The ratio of aspartate aminotransferase (AST)/alanine aminotransferase (ALT) was also significantly related to s-ADRs (OR, 2.78; 95% CI, 1.33–5.81). The use of antibiotics (OR, 2.39; 95% CI, 1.13–5.02) and antineoplastics (OR, 4.17; 95% CI, 1.09–15.94) were significant risk factors.Conclusion: Our findings highlight the importance of polypharmacy. Liver function tests (AST/ALT ratio) must be monitored carefully within high-risk groups for ADRs.
Primary Dysmenorrhea: Pathophysiology, Diagnosis, and Treatment Updates
Authors: Itani Rania , Soubra Lama , Karout Samar , Rahme Deema , Karout Lina , Khojah Hani M J
Published: March 2022

Primary dysmenorrhea (PD) is a common, disregarded, underdiagnosed, and inadequately treated complaint of both young and adult females. It is characterized by painful cramps in the lower abdomen, which start shortly before or at the onset of menses and which could last for 3 days. In particular, PD negatively impacts the quality of life (QOL) of young females and is the main reason behind their absenteeism from school or work. It is suggested that increased intrauterine secretion of prostaglandins F2α and E2 are responsible for the pelvic pain associated with this disorder. Its associated symptoms are physical and/or psychological. Its physical symptoms include headache, lethargy, sleep disturbances, tender breasts, various body pains, disturbed appetite, nausea, vomiting, constipation or diarrhea, and increased urination, whereas its psychological symptoms include mood disturbances, such as anxiety, depression, and irritability. While its diagnosis is based on patients’ history, symptoms, and physical examination, its treatment aims to improve the QOL through the administration of nonsteroidal anti-inflammatory drugs, hormonal contraceptives, and/or the use of non-pharmacological aids (e.g., topical heat application and exercise). Patients must be monitored to measure their response to treatment, assess their adherence, observe potential side effects, and perform further investigations, if needed.