bluuebunny/crossref_metadata_2025 huggingface dataset:
A Generalized Water-Drive Analysis
Authors: Hutchinson T.S. , Sikora V.J.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 216, 1959, pages 169–178.

This paper presents a method for making a water-drive analysis without prior knowledge of aquifer geometry and uniformity using a standard desk calculator. Although it is necessary to know the initial oil in place to use this method, this is a minor limitation to the scope of the method since in most reservoirs it is possible to obtain reasonably accurate volumetric oil-in-place estimates.

An equation is developed which relates pressure at the water-oil contact to the water influx rate as a function of time by a factor called the resistance function. The resistance function introduces the composite effect of the aquifer geometry and flow resistance distribution. It is pointed out that the characteristic shape of this function makes it possible to start with an approximation of the function and successively improve the approximation until the correct resistance function curve is obtained. In this fashion water-drive estimates can be made without the limitation of assuming simplified aquifer shapes and flow distributions. This is the novel feature of this development. Methods are given for extrapolating the final curve to calculate future aquifer behavior.

Equations are developed for adjusting the pressures and water influx rates where it appears that possible errors in these quantities make it difficult or impossible to obtain a useable resistance function curve without this adjustment. Application of the pressure build-up analysis technique to estimate some of the aquifer properties is also presented.

Introduction

A great many oil pools are the result of oil accumulation in some type of trap in an otherwise large and continuous porous stratum. The void space of this stratum outside of the oil pool itself is filled with water or brine. In analyzing performance of the oil pool surrounded by this water aquifer, it is quite necessary, in most cases, to include behavior of the water. When the pressure at any point in a fluid system is lowered, such as by opening a well in an oil sand, fluids in the immediate neighborhood of this point will begin flowing towards this lower pressure sink.
Nonlinear Behavior of Elastic Porous Media
Authors: van der Knaap W.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 216, 1959, pages 179–187.

A theoretical and experimental analysis is given of the change in volume of a porous medium due to changes in external and internal pressures. The results enable one to deduce directly the effect of large increments in stresses.

It is shown that the three-dimensional representation of the volume of a nonlinear porous system is a cylindrical ruled surface, the generating lines of which have a slope according to the solid rock compressibility. Analytical expression for such a surface is very simple. It follows that the bulk and pore compressibilities depend only on the difference between pore fluid and external hydrostatic pressure, i.e., the effective rock frame pressure. From measurements on a number of sandstones as well as limestones it can be concluded that for practical values of this effective frame pressure the pore compressibility falls in the range between the compressibility of water and that of undersaturated crude oil.

In general, pore compressibility is found to be higher the lower the porosity. For a particular limestone reservoir pore compressibility and porosity could be related by means of a simple empirical formula. Results from the described study find a direct application in material balance calculations and in problems of liquid flow through porous media. Since the elastic constants of the rock bulk material enter into equations for velocity of acoustic waves, the results are also of importance for calculating rates of wave propagation in these media. It is shown for sandstones with 15 to 30 per cent porosity that laboratory measured porosities may differ from those under reservoir conditions by about 1 per cent of their value. The difference for low porosity limestones can be of the order of 10 per cent. The subsidence caused by elastic deformation of reservoir rock is shown to be very small.

Introduction

General formulas relating pore and bulk volume to external and internal pressure can be derived, as has been shown by Biot, Gassmann and Geertsma. Their theories describe the differential change in volume caused by a variation in pore fluid tension and external hydrostatic tension.
Transient Heat Conduction During Radial Movement of a Cylindrical Heat Source - Applications to the Thermal Recovery Process
Authors: Ramey H.J.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 216, 1959, pages 115–122.

A general solution is presented for the transient temperature distribution caused by radial movement of a cylindrical heat source through a homogeneous medium of infinite extent. This problem represents a highly simplified model of the movement of a combustion front during the thermal recovery of oil. Numerical solutions are presented for a heat source moving at a constant velocity, and a velocity inversely proportional to the radial location of the heat source.

Numerical solutions are presented for both finite and infinite vertical thickness of the heat source, i.e., with and without vertical heat losses. The numerical solutions are used to estimate the fuel concentration needed to maintain a combustion front during the thermal recovery of oil. The sensible heat carried to the combustion front by the injected gas stream is discussed in regard to the fuel concentration. Numerical solutions for a heat source (combustion front) of finite vertical thickness indicate the field conditions that may be necessary to sustain the temperature of a combustion front above the ignition temperature of the fuel over considerable distances from an injection well. The results also have implications in regard to the quantity of heat required during ignition.

The results of this computation apply to a highly idealized model of a thermal recovery process. But the results may be used as a guide in engineering consideration of the thermal recovery process.

Introduction

The thermal recovery of crude oil has received considerable attention since the publication by Kuhn and Koch of laboratory and field tests of this method of oil recovery. Other publications since that time have dealt with various features of the thermal recovery of oil and have illustrated the extremely complex nature of this process. Vogel and Krueger described an electric analog computer designed to solve a moving heat source problem which was analogous to movement of a combustion front during the thermal recovery of oil. The heat source was maintained at constant temperature and was a cylindrical source of infinite height (no vertical heat loss) moving radially at either constant velocity, or at a velocity inversely proportional to the radial location of the heat source.
Improved High Pressure Capillary Tube Viscometer
Authors: Eakin B.E. , Ellington R.T.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 216, 1959, pages 85–91.

An apparatus and a procedure for determining the viscosity behavior of hydrocarbons at pressures up to 10,000 psia and temperatures between 77 and 400°F are described. The equipment is suitable for measuring viscosity of either the liquid or vapor phases or the fluid above the two-phase envelope for systems exhibiting retrograde phenomena, according to the phase state of the system within these ranges of temperature and pressure. Equations are developed for calculation of viscosity from the experimental measurements, and new data for the viscosities of ethane and propane at 77°F are reported.

Introduction

With the advent of higher pressures and temperatures in industrial processes and deep petroleum and natural gas reservoirs, demand has increased for accurate values of physical properties of hydrocarbons under these conditions. Proportionately, more frequent occurrence of natural gas and condensate-type fluids is encountered as fluid hydrocarbons are discovered at greater depths. This increases the importance, to the reservoir engineer, of being able to predict accurately the physical properties of light hydrocarbon systems in the dense-gas and light-liquid phase states.

Reliable gas viscosity data are limited primarily to measurements made on pure components near ambient temperature and at low pressures. Few investigations have been reported for high pressures, and except for methane, data on light hydrocarbons are subject to question. This is demonstrated by the large discrepancy between sets of data on the same component reported by different investigators. For mixtures in the dense gas and light liquid regions and for fluids exhibiting retrograde behavior there are very few published experimental data.

Viscosity data for methane have been reported by Bicher and Katz, Sage and Lacey, Comings, et al, Golubev, and Carr, with good agreement among the last three sets of data. Comings, Golubev and Carr utilized capillary tube instruments for which the theory of fluid flow is well established. The theory permits calculation of the viscosity directly from the experimental data and dimensions of the instrument alone.
Observations Relating to the Wettability of Porous Rock
Authors: Amott Earl
Published: February 2020

Published in Petroleum Transactions, AIME, Vol. 216, 1959, pages 156–162.Paper presented at Fall Meeting of Los Angeles Basin Section in Los Angeles, Calif., Oct. 16–17, 1958.

A test is described in which the wettability of porous rock is measured as a function of the displacement properties of the rock-water-oil system. Four displacement operations are carried out:spontaneous displacement of water by oil,forced displacement of water by oil in the same system using a centrifuging procedure,spontaneous displacement of oil by water, andforced displacement of oil by water.

Ratios of the spontaneous displacement volumes to the total displacement volumes are used as wettability indices.Cores having clean mineral surfaces (strongly preferentially water-wet) show displacement-by-water ratios approaching 1.00 and displacement-by-oil ratios of zero. Cores which are strongly preferentially oil-wet give the reverse results. Neutral wettability cores show zero values for both ratios. Fresh cores from different oil reservoirs have shown wettabilities in this test covering almost the complete range of the test. However, most of the fresh California cores tested were slightly preferentially water-wet. The changes in core wettabilities, as indicated by this test, resulting from various core handling procedures were observed. In some cases the wettabilities of fresh cores were changed by drying or by extracting with toluene or dioxane; in other cases they were not changed. Contact of cores with filtrates from water-base drilling muds caused little change in wettability while contact with filtrates from oil-base muds decreased the preference of the cores for water. Using this test to evaluate wettability, a study was made of the correlation of wettability with waterflood oil recovery for outcrop Ohio sandstone and for Alundum. Results indicate that no single correlation between these factors applies to different porous rock systems. It is thought that differences in pore geometry result in differences in this correlation.
Acoustic Velocity in Porous Media
Authors: Berry James E.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 216, 1959, pages 262–270.

An evaluation is made of the acoustic velocity log for measurement of formation porosity. Plots of field-observed velocities vs core-measured porosities of sandstones and limestones with intergranular porosity show that the velocity log gives a useful measure of porosity, in agreement with published data. A new method of plotting electrical and velocity log data makes it easier to recognize hydrocarbon-water contacts from log data and to make semi-quantitative estimates of hydrocarbon saturation. Two examples of this interpretation technique are given. This paper also discusses the various factors that affect acoustic velocity and shows how corrections can be made for some of these factors.

Introduction

Although the continuous velocity log was developed primarily as an aid to seismic interpretation, it is finding widespread use for measurement of porosity. The purpose of this paper is to evaluate this use of the log. Results are presented for the velocity-porosity relationship in many sandstones and one limestone. Practical applications of porosity values derived from the velocity log to improve interpretation of electrical surveys are presented.

Various parameters which affect velocity in porous media are considered. Porosity, composition, cementation, pressure difference (overburden pressure minus fluid pressure), fluid saturation, and wettability are discussed. Some of the ideas are opinions based on general considerations of well logging problems while others are supported by published data and our own observations. Major conclusions from these studies are given in the body of the paper and detailed discussions of some of the various factors affecting porosity are given in the Appendix.

Porosity

Sandstones

The primary factor affecting the velocity of sound in porous media is porosity. Wyllie, et al, have reported a time average equation for the relationship between velocity and porosity. This has found considerable acceptance in the industry. Other relationships between velocity and porosity have been proposed, none of which are entirely satisfactory. It is doubtful that any one relationship will completely describe all situations.
Reservoir Heating by Hot Fluid Injection
Authors: Marx J.W. , Langenheim R.H.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 216, 1959, pages 312–315.

The injection of heat-bearing fluid may offer a wider application to secondary and tertiary recovery from conventional oil reservoirs than underground combustion since the process is more easily controlled and the reservoir requirements, in general, are less critical. In all cases, conduction heat losses to overburden and underburden will impose an economic limit upon the size of the area which can be swept out from any one injection point for any given set of conditions.

The present report describes a method for estimating thermal invasion rates, cumulative heated area, and theoretical economic limits for sustained hot-fluid injection at a constant rate into an idealized reservoir. Full allowance is made for non-productive reservoir heat losses.

Required solutions can be obtained directly from the numerical tables given here, as soon as all operating conditions are specified, without extensive mathematical manipulation on the part of the user.

Introduction

The injection of a heat-bearing fluid into a reservoir is frequently proposed as a means of secondary or tertiary oil production. This form of thermal recovery may offer a wider application to conventional oil reservoirs than underground combustion since the process is more easily controlled and the reservoir requirements, in general, are less critical. Because of its large gross heat capacity, steam appears to be the most efficient heat injection medium, although mixtures of steam and other gases, hot water, hot oil and hot non-condensable gases also have been employed.

Whatever the nature of the injection medium, economic evaluation of such thermal recovery processes will depend upon thermal invasion rates, or rates of productive reservoir heating, at any given time after the start of heat injection. In all cases, conduction heat losses to overburden and underburden will impose an economic limit upon the size of the area which can be swept out from any one injection point, for a given set of reservoir conditions, at any given heat injection rate.

The present report describes a method for estimating thermal invasion rates, cumulative heated area and theoretical economic limits for sustained heat injection at a constant rate into an idealized reservoir, making full allowance for non-productive reservoir heat losses. Required solutions can be obtained directly from the numerical tables given here, as soon as all operating conditions are specified, without extensive mathematical manipulation.
Method for Predicting the Behavior of Mutually Interfering Gas Reservoirs Adjacent to a Common Aquifer
Authors: Coats K.H. , Tek M.R. , Katz D.L.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 216, 1959, pages 247–251.

The performance of a gas reservoir subject to water drive is often affected by interference due to gas production or injection in neighboring reservoirs adjacent to a common aquifer. Field data available on production-pressure behavior of several reservoirs indicate that prediction of reservoir performance must include the effects due to mutual interference. A method developed to predict the performance of two or more interfering gas reservoirs, subject to specified production-injection schedules, is presented. The method involves the combination of the theory of unsteady-state water movement with appropriate material balance considerations. The procedure which extends M. Mortada's treatment for interfering oil reservoirs makes use of his dimensionless pressure drop quantities presented graphically in the literature.

In order to evaluate the predictive accuracy and practical field applicability of the theory, the method has been applied to analyze the performance of two actual gas reservoirs in mutual interference. The calculations were performed on an IBM 704 computer. The predicted performances were also calculated with the interference effects ignored. The results show that considerably better agreement between calculated and observed behavior is obtained when the interference effects are included.

Introduction

Fluid communication between any number of oil or gas reservoirs adjacent to a common aquifer results in mutual interference effects on their production-pressure behavior. The theory, application and interpretation of pressure build-up behavior of oil wells, drawdown tests on oil or gas-producing formations and behavior of several storage reservoirs indicate ample experimental evidence of mutual interference. A method developed to compute the behavior of interfering oil reservoirs was published several years ago by Mortada.
Displacement Experiments in a Consolidated Porous System
Authors: Levine J.S.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 201, 1954, pages 57–66.

A series of four displacement experiments has been run in a large alundum core. Flow potential distribution in each liquid phase was measured continuously through oil-wet and water-wet capillary barriers, using a null-point pressure balance, and saturated distribution was determined from electrical resistivity measurements. A method has been devised for calculating the effective (and relative) permeability to each phase at any time and at any point in the flow system for the transient displacement process. Relative permeability points have been calculated and average curves drawn for oil displacing water and water displacing oil. The values of dynamic capillary pressure have also been determined. Data have been substituted into the generalized Buckley-Leverett fractional flow equation and a comparison between actual and theoretical breakthrough recoveries is shown.

Introduction

Displacement experiments have been performed in the laboratory for many years in an effort to determine the effect of a number of parameters on multiphase flow in porous materials. In the literature of petroleum technology, Wyckoff and Botset were among the first to develop the relative permeability concept and to show experimentally that oil, gas, and water can flow simultaneously through a porous medium in a precise way governed by certain fluid properties, by the relative saturation of each fluid, and by characteristics of the medium itself. Somewhat later, Leverett and Hassler, Brunner, and Deahl developed some theoretical concepts of capillary behavior in porous materials.

The work of Buckley and Leverett presented a theoretical analysis of immiscible liquid displacement based on the equation of continuity and the Darcy equation for viscous flow of each fluid. Subsequent investigators attempting to verify the Buckley-Leverett equation have, in general, deliberately neglected the capillary pressure term or have performed experiments in such a manner that it could be neglected.
The Mechanics of Fracture Induction and Extension
Authors: Harrison Eugene , Kieschnick W.F. , McGuire W.J.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 201, 1954, pages 252–263.

This paper concerns the induction and extension of fractures into rock formations as involved in drilling, completing, and production stimulating operations on wells. Conclusions concerning formation breakdown are derived froma review and extension of published analyses relating to mechanical theories of rock stress and the state of stress in the earth's crust anda correlation of field data from fracturing operations.

Conclusions concerning the mechanics of fracture extension, which indicate the relationship between fracture dimensions and rock properties, depth, and volume of injected fluid, are tentative and largely establish limits of relationships. These conclusions are derived from stress calculations, limited field data, and laboratory experimental studies. The experimental work involves the study of the stresses at the fracture boundaries and the geometry of pressurized fractures by means of photo-elastic modeling methods.

Results of this investigation indicate that a large majority of pressure induced well bore fractures are vertical, particularly in deeper wells; and variations in the pressures necessary to create and extend fractures can be explained largely on a basis of established rock properties. It is also shown that variations due to tectonic forces should usually be expected to be slight. Other results indicate that during that extension of fractures rather large fracture volumes are temporarily created by the parting of the formation.

Introduction

The purpose of this paper is to present the results of calculations and laboratory experiments concerning the mechanics of fracture induction and extension with a view to broadening existing knowledge relating to these phenomena. It is believed that continued progress in developing knowledge of this type is important to the further development of techniques for drilling and completing wells.
Evaluation of Acid Treatments from Pressure Build-Up Analysis
Authors: Pollard P.
Published: February 2020

Published in Petroleum Transactions, AIME, Volume 216, 1959, pages 38–43.

A method has been developed for evaluating acid treatments in fractured limestone fields by breaking down pressure drawdown into three component parts:pressure differential across "skin" near the borehole face,pressure differential due to flow resistance in the coarse communicating fissures andpressure differential between the fine voids and the coarse fissures.

It is apparent that in most successful acid treatments the first term, skin resistance, has been reduced or eliminated. Further, it is often possible to estimate the volume of coarse fissures associated with the second term, coarse fissure flow resistance. In cases where this volume is comparable with practical acid volumes it seems likely that this resistance also may be attacked with a suitably retarded acid.

Introduction

Acid treatment has been successfully applied as a general practice in the limestone wells in the Mara/ Maracaibo districts of Venezuela for some 10 years. At the same time the need has been felt for a more precise method of:evaluating the effect of an acid job andselecting wells which should benefit from an acid treatment.

The following method, based on an analysis Of build-up curves for wells producing from fractured limestone, provides a means of forecasting the effect acid will have on a well and in many cases the probable order of production rate increase which may be expected. In certain cases it is also possible to calculate the fissure volume through which the acid has to be displaced for best results.

Various approximations are introduced in the method, but within the limitations of these the analysis gives an indication of how a well, whether previously acidized or not, may be expected to respond to acid treatment.
A Life-History Perspective on Sexual Selection in a Polygamous Species
Authors: Gao Ke , Wijk Michiel van , Clement Zoe , Egas Martijn , Groot Astrid
Published: February 2020

Background: Ever since Darwin, evolutionary biologists have studied sexual selection driving differences in appearance and behaviour between males and females. An unchallenged paradigm in such studies is that one sex (usually the male) signals its quality as a mate to the other sex (usually the female), who is choosy in accepting a partner. Here, we hypothesize that in polygamous species these roles change dynamically with the mating status of males and females, depending on direct reproductive costs and benefits of multiple matings, and on sperm competition. We test this hypothesis by assessing fitness costs and benefits of multiple matings in both males and females in a polygamous moth species, as in moths not males but females are the signalers and males are the responders. Results: We found that multiple matings confer fitness costs and benefits for both sexes. Specifically, the number of matings did not affect the longevity of males or females, but only 67 % of the males and 14 % of the females mated successfully in all five nights. In addition, the female’s reproductive output increased with multiple matings, although when paired with a new virgin male every night, more than 3 matings decreased her reproductive output, so that the Bateman gradient for females fit a quadratic model better than a linear model. The male’s reproductive success was positively affected by the number of matings and a linear regression line best fit the data. Simulations of the effect of sperm competition showed that increasing last-male paternity increases the steepness of the male Bateman gradient and thus the male’s relative fitness gain from additional mating. Irrespective of last-male paternity value, the female Bateman gradient is steeper than the male one for up to three matings. Conclusion: Our results suggest that choosiness in moths may well change throughout the mating season, with males being more choosy early in the season and females being more choosy after having mated at least three times. This life-history perspective on the costs and benefits of multiple matings for both sexes sheds new light on sexual selection forces acting on sexual signals and responses.
Impact of chronic kidney disease and anemia on health-related quality of life and work productivity: Analysis of multinational real-world data
Authors: Haalen Heleen van , Jackson James , Spinowitz Bruce , Milligan Gary , Moon Rebecca
Published: February 2020

Background

Reductions in health-related quality of life (HRQoL) in patients with chronic kidney disease (CKD) are thought to be exacerbated by the low hemoglobin (Hb) levels that define anemia, a common complication of CKD. The current analysis evaluated the impact of anemia on HRQoL and work productivity in patients with non-dialysis dependent and dialysis-dependent CKD using real-world data.

Methods

Data were collected in France, Germany, Italy, Spain, the UK, the USA and China in 2012–2018 in the Adelphi Real World Disease Specific Programme™ for CKD, a large, cross-sectional, survey of physicians and their patients. Patients completed three patient-reported outcomes (PRO) instruments: the EuroQol 5-Dimension 3-level (EQ-5D-3L), the Kidney Disease Quality of Life (KDQOL-36) instrument and the Work Productivity and Activity Impairment questionnaire. PROs were assessed by CKD stage and Hb levels, and regression analyses were performed with CKD stage and Hb level as independent variables and PROs as outcome variables, while adjusting for age, sex, CKD stage, comorbidities and cardiovascular risk.

Results

Overall, 5276 patients participated in the survey, including 28% stage 4 and 36% dialysis patients. Patients with lower Hb levels more often reported problems/issues on all EQ-5D-3L domains (p<0.0001). Regression analyses showed significant associations between lower Hb levels and the probability of low (<0.8) EQ-5D-3L utility scores (p<0.0001) and low visual analog scale scores (p<0.05), indicating poorer health status. Associations were seen even when adjusting for CKD stage and other potential confounding factors. Significant associations were observed between Hb level and the 12-Item Short-Form Health Survey (SF-12) Physical Component Summary, SF-12 Mental Component Summary and the three KDQOL-36 subscales (all p<0.0001), and were confirmed using linear regression analyses adjusting for CKD stage and other potential confounders. Numerically greater work productivity losses and greater activity impairment were observed with lower Hb levels.

Conclusions

Lower Hb levels worsen the impact of CKD on HRQoL, and are associated with lower work productivity in patients with CKD. Assessment and treatment of anemia should be recognized as a key component of integral CKD management throughout all stages of the disease.
Cancer Associated Fibroblast (CAF) regulation of PDAC parenchymal (CPC) and CSC phenotypes is modulated by ECM composition.
Authors: Cannone Stefania , Greco Maria Rafaella , Guizouarn Hélène , Soriani Olivier , Tomasini Richard , Casavola Valeria , Zeeberg Katrine , Reshkin Stephan Joel , Cardone Rosa Angela
Published: February 2020

Background Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest of all cancers having one of the lowest five-year survival rates. One of its hallmarks is a dense desmoplastic stroma consisting in the abnormal accumulation of extracellular matrix (ECM) components, especially Collagen I. This highly fibrotic stroma embeds the bulk cancer (parenchymal) cells (CPCs), cancer stem cells (CSCs) and the main producers of the stromal reaction, the Cancer Associated Fibroblasts (CAFs). Little is known about the role of the acellular ECM in the interplay of the CAFs with the different tumor cell types in determining their phenotypic plasticity and eventual cell fate. Methods Here, we analyzed the role of ECM collagen I in modulating the effect of CAF-derived signals by incubating PDAC CPCs and CSCs grown on ECM mimicking early (low collagen I levels) and late (high collagen I levels) stage PDAC stroma with conditioned medium from primary cultured CAFs derived from patients with PDAC in a previously described three-dimensional (3D) organotypic model of PDAC. Results We found that CAFs (1) reduced CPC growth while favoring CSC growth independently of the ECM; (2) increased the invasive capacity of only CPCs on the ECM mimicking the early tumor and (3) favored vasculogenic mimicry (VM) especially of the CSCs on the ECM mimicking an early tumor. Conclusions: We conclude that the CAFs and acellular stromal components interact to modulate the tumor behaviors of the PDAC CPC and CSC cell types and drive metastatic progression by stimulating the behavior of each tumor cell type that contribute to metastasis: invasion in the CPCs and growth and angiogenesis in the CSCs.
Determinants of incomplete immunization among children age 12-23 months in Southwest, Ethiopia: Case Control Study
Authors: G/Mariam Meseret , Ayele Gistane , Shegaze Mulugeta , Wassihun biresaw
Published: February 2020

Background: Vaccination is recognized as an important immunization tool which is used in preventing and eradicating communicable diseases. Even though an increase in global vaccination coverage, many children in the world particularly in low resource countries still are left unvaccinated and it remains to be a public health problem. So, the main objective of this study was to identify determinants of incomplete vaccination among children 12-23 months of age in Semen Bench district, Bench Maji Zone, Southwest Ethiopia, 2018. Methods: A community based unmatched case-control study was undertaken among randomly selected children aged 12 to 23 months and with a total sample size of 312 (104 cases and 208 controls). Simple random sampling was used to get representative cases and controls. Data was collected using a structured questionnaire and analyzed using SPSS version 21 statistical software. Bivariate and multiple logistic regression analyses were done to identify independent factors for incomplete immunization status of children. P values <0.05 with 95% confidence level were used to declare statistical significance Results: From the total of selected 104 cases and 208 controls, all of the cases and controls participated in the study with a response rate of 100. Based on the multivariable analysis the incomplete immunization status of children was significantly associated with having no antenatal care visits, [AOR=8.3(95%CI; 1.87-36.91], home delivery [AOR=4.5(95%CI; 1.411-14.27], having no postnatal care visit [AOR=4.2(95%CI; 1.67-10.41], and inconvenient appointment time [AOR=3.44( 95% CI:1.65-7.16)]. Conclusion: Children of mothers having no antenatal and postnatal care, children of mothers having home delivery, children of mothers with an inconvenient appointment time, were significantly associated with incomplete immunization. To reduce the number of children with an incomplete immunization status, the district needs to consider specific planning for mothers with no ANC, and focus on promoting facility delivery and address concerns of inconvenient appointment time at a community level. This can be accomplished by integrating the immunization service to other elements of primary health care
HIV-free survival among breastfed infants born to HIV-positive women in northern Uganda: a facility-based retrospective study.
Authors: Aguti Irene , Kimbugwe Charles , Apai Patricia , Munyaga Siraji , Nyeko Richard
Published: February 2020

Background: Without interventions, the risk of mother-to-child transmission of HIV is 25% during pregnancy, labour and delivery with an additional risk of 5-20% during the breastfeeding, leading to an overall risk of 45%. The effectiveness of interventions towards prevention of mother-to-child transmission of HIV in any setting is measured by its HIV-free survival rate. We carried out a study to determine the HIV-free survival among breastfed infants enrolled by 2 months of age in a resource-poor setting. Methods: We conducted a cross-sectional survey of early infant diagnosis registers at two tertiary facilities in northern Uganda and retrospectively reviewed records of exposed infants enrolled from 2014 to 2016. We used simple random sampling and analyzed data using SPSS v16 software package. The chi-square and Student t-tests were used to compare factors among HIV-free survivors (HIV-uninfected and alive at 18 months) and those who became HIV-infected or died. Multivariate analysis using logistic regression was used to determine the factors that were independently associated with HIV-free survival. Odds ratios with 95% confidence interval were used to measure the strength of association between the outcome and predictor variables. P-value <0.05 was considered for statistical significanceResults: The mean age at enrolment of the 317 infants was 1.57 (SD 0.23), majority of whom were males 55.5% (176/317). All except two infants were initiated on Nevirapine prophylaxis. Less than one third, 29.3% (93/317) of the infants were exclusively breastfed for at least 6 months, while the breastfeeding status of 30 infants could not be ascertained. The overall HIV-free survival rate in the current study was 94.6% (300/317), while 2.5% (8/317) were HIV-infected and 2.8% (9/317) died. Gender and treatment facility were the factors independently significantly associated with HIV-free survival. Conclusions: Our study estimates that the HIV-free survival rate in the study setting for breastfed infants enrolled by 2 months of age was 94.6%, below the WHO goal of >95% HIV-free rate in breastfeeding population for virtual elimination of HIV. A further prospective study would be necessary to assess a more accurate HIV-free survival rate given the limitations of retrospective data.
A unified nomenclature for vertebrate olfactory receptors
Authors: Olender Tsviya , Jones Tamsin E.M. , Bruford Elspeth , Lancet Doron
Published: February 2020

Background Olfactory receptors (ORs) are G protein-coupled receptors with a crucial role in odor detection. A typical mammalian genome harbors ~1000 OR genes and pseudogenes; however, different gene duplication/deletion events have occurred in each species, resulting in complex orthology relationships. While the human OR nomenclature is widely accepted and based on phylogenetic classification into 18 families and further into subfamilies, for other mammals different and multiple nomenclature systems are currently in use, thus concealing important evolutionary and functional insights. Results Here we describe the Mutual Maximum Similarity (MMS) algorithm, a systematic classifier for assigning a human-centric nomenclature to any OR gene based on inter-species hierarchical pairwise similarities. MMS was applied to the OR repertoires of seven mammals and zebrafish. Altogether, we assigned symbols to 10,249 ORs. This nomenclature is supported by both phylogenetic and synteny analyses. The availability of a unified nomenclature provides a framework for diverse studies, where textual symbol comparison allows immediate identification of potential ortholog groups as well as species-specific expansions/deletions; for example, Or52e5 and Or52e5b represent a rat-specific duplication of OR52E5 . Another example is the complete absence of OR subfamily OR6Z among primate OR symbols. In other mammals, OR6Z members are located in one genomic cluster, suggesting a large deletion in the great ape lineage. An additional 14 mammalian OR subfamilies are missing from the primate genomes. While in chimpanzee 87% of the symbols were identical to human symbols, this number decreased to ~50% in dog and cow and to ~30% in rodents, reflecting the adaptive changes of the OR gene superfamily across diverse ecological niches. Application of the proposed nomenclature to zebrafish revealed similarity to mammalian ORs that could not be detected from the current zebrafish olfactory receptor gene nomenclature. Conclusions We have consolidated a unified standard nomenclature system for the vertebrate OR superfamily. The new nomenclature system will be applied to cow, horse, dog and chimpanzee by the Vertebrate Gene Nomenclature Committee and its implementation is currently under consideration by other relevant species-specific nomenclature committees.
Distant Survival for Patients Undergoing Surgery Using Volatile versus IV Anesthesia for Hepatocellular Carcinoma with Portal Vein Tumor Thrombus:A Retrospective study.
Authors: Meng Xiao-Yan , Zhang Xiu-Ping , Wang Hong-Qian , Yu Weifeng
Published: February 2020

Background Whether anesthesia type is associate with the surgical outcome of Hepatocellular carcinoma (HCC) patients with portal vein tumor thrombus (PVTT) remains to be determined. This study aims to investigate the impact of volatile inhalational anesthesia (INHA) versus total IV anesthesia (TIVA) on the survival outcomes in HCC patients with PVTT. Methods A cohort of in-patients whom were diagnosed of HCC with PVTT in Eastern Hepatobiliary Surgery Hospital, Shanghai, China, from January 1, 2008 to December 24, 2012 were identified. Surgical patients receiving the INHA and TIVA were screened out. The overall survival (OS), recurrence-free survival (RFS) and several postoperative adverse events were compared according to anesthesia types. Results A total of 1513 patients were included in this study. After exclusions are applied, 263 patients remain in the INHA group and 208 in the TIVA group. Patients receiving INHA have a lower 5-year overall survival rate than that of patients receiving TIVA [12.6% (95% CI, 9.0 to 17.3) vs. 17.7% (95% CI, 11.3 to 20.8), P=0.024]. Results of multivariable Cox-regression analysis also identify that INHA anesthesia is significantly associated with mortality and cancer recurrence after surgery compare to TIVA, with HR (95%CI) of 1.303 (1.065, 1.595) and 1.265 (1.040, 1.539), respectively. Subgroup analysis suggested that in more severe cancer patients, the worse outcome related to INHA might be more significant. Conclusion This retrospective analysis identifies that TIVA has better survival outcomes compare to INHA in HCC patients with PVTT. Future prospective researches are urgent to verify this difference and figure out underlying causes of it.
Physiological and transcriptomic analyses reveal the mechanisms underlying the salt tolerance of Zoysia japonica Steud.
Authors: Wang Jingjing , An Cong , Guo Hailin , Yang Xiangyang , Chen Jingbo , Zong Junqin , Li Jianjian , Liu Jianxiu
Published: February 2020

Background: Areas with saline soils are sparsely populated and have fragile ecosystems, which severely restricts the sustainable development of local economies. Zoysia grasses are recognized as excellent warm-season turfgrasses worldwide, with high salt tolerance and superior growth in saline-alkali soils. However, the mechanism underlying the salt tolerance of Zoysia species remains unknown. Results: The phenotypic and physiological responses of two contrasting materials, Zoysia japonica Steud. Z004 (salt sensitive) and Z011 (salt tolerant) in response to salt stress were studied. The results show that Z011 was more salt tolerant than was Z004, with the former presenting greater K + /Na + ratios in both its leaves and roots. To study the molecular mechanisms underlying salt tolerance further, we compared the transcriptomes of the two materials at different time points (0 h, 1 h, 24 h, and 72 h) and from different tissues (leaves and roots) under salt treatment. The 24-h time point and the roots might make significant contributions to the salt tolerance. Moreover, GO and KEGG analyses of different comparisons revealed that the key DEGs participating in the salt-stress response belonged to the hormone pathway, various TF families and the DUF family. Conclusions: Z011 may have improved salt tolerance by reducing Na + transport from the roots to the leaves, increasing K + absorption in the roots and reducing K + secretion from the leaves to maintain a significantly greater K + /Na + ratio. Twenty-four hours might be a relatively important time point for the salt-stress response of zoysiagrass. The auxin signal transduction family, ABA signal transduction family, WRKY TF family and bHLH TF family may be the most important families in Zoysia salt-stress regulation. This study provides fundamental information concerning the salt-stress response of Zoysia and improves the understanding of molecular mechanisms in salt-tolerant plants.
Clinical and ultrasonographic features of medullary thyroid microcarcinomas compared with papillary thyroid microcarcinomas: a retrospective analysis
Authors: Li Xiaoyu , Zhou Wei , Zhan Weiwei
Published: February 2020

Background: To identify the sonographic features that help differentiate medullary thyroid microcarcinomas (MTMCs) smaller than 10 mm and papillary thyroid microcarcinomas (PTMCs). Methods: This study included 41 patients with 46 MTMCs and 104 consecutive patients with 136 PTMCs. All the nodules were surgically and histologically proved. The age and nodule size were analyzed by independent sample t test, and the gender, multiplicity and cervical lymph node metastases were analyzed by χ 2 or Fisher’s exact tests. Univariate analysis and multivariate logistic regression analysis were performed on the sonographic features of thyroid nodules, including location, shape, boundary, margin, peripheral halo ring, echogenicity, composition, calcifications and vascularization. Results: Compared with PTMCs, there were more MTMCs patients with cervical lymph node metastases (P=0.040). There were no significant differences in age, gender, nodule size, multiplicity, location, boundary, margin, peripheral halo ring, echogenicity and microcalcification between MTMCs and PTMCs (P < 0.05 for all). However, significant differences were found in shape (P=0.000), composition (P=0.032), macrocalcification (P=0.004) and vascularity (P=0.000) between the two groups. Conclusions: MTMCs had some overlapping sonographic features with PTMCs, however, MTMCs were more likely to be >50% solid composition, ovoid to round nodules with macrocalcifications and hypervascularity, and cervical lymph node metastases were more common in MTMCs patients.
Detection of Atypical porcine pestivirus in Swedish piglets with congenital tremor type A-II
Authors: Stenberg Hedvig , Jacobson Magdalena , Malmberg Maja
Published: February 2020

Background Congenital tremor (CT) type A-II is a neurological disorder characterized by tremor of the head and body of newborn piglets. The suggested causative agent of the disease is the recently found atypical porcine pestivirus (APPV). The virus has been detected in piglets suffering from congenital tremor in central Europe, South and North America and in China but no studies has so far been performed in the Nordic countries. The overarching goal of this study was to investigate if APPV is present in the brain tissue of Swedish piglets suffering from congenital tremor. From June 2017 – June 2018, 15 piglets from four Swedish farms with ongoing outbreaks of congenital tremor and 13 piglets with splay leg originating from four different farms, were investigated for presence of APPV RNA in brain tissue. Matched healthy control piglets (n=8) were also investigated. Two APPV-specific RT-qPCR methods targeting the NS3 and NS5B region, respectively, were used. A retrospective study was performed on material from Swedish piglets with congenital tremor sampled in 2004 (n = 11) and 2011/2012 (n = 3) using the described APPV-specific RT-qPCR methods. The total number of piglets with signs of CT in this study was 29. Results Atypical porcine pestivirus-RNA was detected in 93% (27/29) of the piglets suffering from congenital tremor. All piglets with congenital tremor from 2004 (n = 11) and 2012 (n = 3) were PCR-positive with respect to APPV, whereas, all of the healthy controls (n = 11) were negative. The piglets with congenital tremor sampled 2017-2018 had an odds ratio of 91,8 (95% CI 3.9128 to 2153.7842, z = 2.807, P = 0.0050) to test positive for APPV by qRT-PCR compared to the healthy piglets (Fishers exact test p < 0.0001). These findings make it interesting to continue investigating APPV in the Swedish pig population. Conclusion This is the first description of atypical porcine pestivirus in piglets suffering from congenital tremor type A-II in Sweden and the Nordic countries. The virus has been present in the Swedish pig population since at least 2004.