bluuebunny/crossref_metadata_2025 huggingface dataset:
Managing Gas-Injection-Induced Excessive Water Production in Tight Oil Reservoirs by Optimizing Operational Constraints
Authors: Zhang Chi , Tian Ye , Wu Yu-Shu
Published: August 2020

A CO2 huff-n-puff pilot implemented in the Midland Basin demonstrated a significant oil rate improvement, but also witnessed an escalation in water-cut up to 0.3. A compositional model was established to consider the complex physics including cyclic stress changes, reopening of water-bearing layers, reopening of unpropped fractures and its resulting relative permeability shift. Our previously published work suggested that the reopening of unpropped fractures and its resulting relative permeability shift contributes most to the abnormal water cut surge after gas injection. In this study, we further proposed several operational constraints to manage such high water-cut occurrence after gas injection. The optimized simulation results suggested that around 1.5 times increase in recovery factor can be achieved after six CO2 huff-n-puff cycles. Sensitivity analysis was subsequently conducted regarding parameters such as soaking time, injection time, and bottom-hole pressure. It was found that soaking time and bottom-hole pressure did not have much influence on cumulative oil production. Setting injection time as 150 days in each cycle can achieve the highest net present value. The primary objective of this study is aimed at optimizing techniques for conducting CO2 huff and puff process to maximize oil production and minimize CO2 emission.
An Advanced Compositional Analysis of Crude Oil-Brine Interface and the Effect of Involving Interactions on the Performance of Low Salinity Water Injection
Authors: Fattahi Mehraban Mohammad , Farzaneh Seyed Amir , Sohrabi Mehran
Published: August 2020

Despite the plethora amount of research have been conducted on the Low Salinity Water Injection (LSWI) and the pertinent mechanisms, this Enhanced Oil Recovery (EOR) method still seems not to be well understood. Although the rock/fluid interactions are used to be highlighted as the main elements of chemical mechanism of LSWI, fluid/fluid interactions have been brought into attentions much more than anytime before. Formation of microdispersion within the crude oil phase leading to wettability alteration has been proposed repeatedly as the underlying mechanism of LSWI without clarifying the functional compounds of crude oil toward this EOR method. Discovering the responsible compounds of crude oils towards Low Salinity Water (LSW) and formation of microdispersion is demanding to achieve a reliable screening tool of oil reservoir toward LSWI.

For this purpose, the crude oils and brines were contacted for an extended period of time until the oil/water interface reached an equilibrium state right before taking crude oil samples from the interface. The Karl Fischer titration (KFT) analyses were carried out to quantify the amount of microdispersion within the crude oil phase. The crude oil sample with the strongest propensity toward microdispersion formation was further investigated through Fourier Transform Infrared (FT-IR) spectroscopy and Negative Electrospray Ionisation (NESI) mode of Fourier Transform Ion Cyclotron Resonance mass spectroscopy (FT-ICR) to evaluate the chemical compositional changes taking place at the interface due to salinity effect.

FT-IR analyses revealed the conjugated acidic compounds or the acidic asphaltenes within the crude oil to be the most functional compounds toward microdispersion formation. Consistently, the NESI mode of FT-ICR MS suggested the carboxylic acids (with C=O functional groups) promoting the formation of microdispersion when the crude oil is swept by LSW. Also highlighted was the structure of functional carboxylic acids during LSWI that appeared to be those compounds with DBE of 1, 2, and 3 and carbon number of C15-C20.

The results of this study represent an important step toward understanding the mechanism responsible for the LSE. The knowledge will help the oil and gas industry in the task of evaluating and ranking oil reservoirs for EOR by LSWI.
Impact of EOR Chemicals on Oil-Water Separation Processes, from Laboratory Scale to Flow Loop Scale
Authors: Cassar Cyril , Mouret Aurélie , Salaün Mathieu , Klopffer Marie-Hélène
Published: August 2020

With the use of chemically-based enchanced recovery methods, water management which has always been a major point in the production operation processes, needs to be considered and adapted as the whole water cycle will be impacted by the back-produced additives. The main issues encountered in oil-water separation processes are directly related to the risk of tight emulsions formation which may considerably complicate the water treatment surface processes.

The objective of this paper is to underline the impact of EOR chemicals (surfactants) on the produced water cycle, when they are back produced firstly, at a laboratory scale and secondly, on a large scale separation unit using an industrial size flow loop and a well instrumented separator.

At the lab scale, impact of having surfactant within produced fluids on oil/water separation (regarding the separation kinetics but also the oil and water phases qualities) will be evaluated by performing bottle tests.

Those laboratory bottle tests enabled us to screen various different parameters such as the surfactant concentration, the water cut that may strongly impact the type of formed emulsion (O/W or W/O) and its stability. The oil and water phases qualities were quantified and correlations with parameters related to the large scale experiment have been drawn, helping us in defining the key parameters for this last campaign.

Indeed, to get closer to a field case, a semi industrial-scale test platform (IFPEN GOwSP loop) was used. Main operating conditions are liquid flow rate set between 6 and 10 m3/h and temperature 50 °C. The influence of different parameters may be studied such as the concentration of surfactant, the mixing conditions (liquid flow rate), the residence time controlled by the height of water phase in separator, the water cut and the presence of chemicals that will help the separation process. Different types of emulsion were formed depending on the tests conditions and their stability were evaluated through the measurement of separation profiles using a SECAP probe within the separator.

The presented results will show how the surfactant but also the demulsifier concentration have led to different types of emulsions and have influenced the oil-water separation processes.

Laboratory workflows as well as experiments carried out at large scale using an industrial size separator could help the de-risking of operations to mitigate these challenges in terms of separation issues.

This work illustrates that water management is a major challenge for produced fluids containing EOR chemicals that need an integrated approach and should be studied beforehand.
New Insights into the Interfacial Phenomena during Miscible Displacement by Hydrocarbon Solvents and CO2 in Heavy Oil Reservoirs
Authors: Mohammed Mohammedalmojtaba , Babadagli Tayfun
Published: August 2020

Injection of solvents (hydrocarbons in liquid and gas form or CO2 and their combinations) is an alternative method for heavy and extra heavy-oil recovery where thermal methods cannot be applied, like in thin reservoirs, wormholed reservoir after-CHOPS (cold heavy-oil production with sands), or fractured reservoirs. The solvents normally exist in their liquid or supercritical phase under reservoir conditions and may not be miscible with heavy oil at first contact. Coupling with the fact that diffusion into highly viscous fluids tends to be very slow and an interface exists in the first contact of liquid solvent and oil, displacement by capillary imbibition may take place. This displacement eventually improves the contact area between oil and solvent and results in enhancement of the mixing process by diffusion.

To understand this phenomenon and fully capture the interaction of solvent and heavy oil in different rock systems, experimental investigations were conducted using sandstone and limestone core samples. The samples were saturated with different types of oils (viscosities ranging between 14 and 170,000 cP) and the solvents tested were heptane, propane, decane, CO2, and naphtha. To maintain the pressure of propane and CO2 above the saturation pressure, a specially designed high-pressure imbibition cell was used and the imbibition-diffusion process was visualized through the glass window of the cell. The color of the mixture and the amount and the shape of produced oil over time was used to analyze the mass transfer and flow behavior qualitatively and quantitatively by observing the evolution of oil production from core samples that were saturated with heavy oil and then immersed into solvents.

We observed that in the solvent/heavy oil system, where molecular diffusion is a slow process, a dynamic interfacial tension IFT exists, but vanishes over time; when the CO2 is in the non-wetting phase the capillary force acts to retain the oil in porous media. As the IFT is reduced, capillary force is weakened and gravity governs the process. Hence, the fluid saturation in the porous media is totally determined by density and viscosity difference. If the wettability of the rock is altered during the process from oil-wet to more CO2 wet, because of oil-rock interaction, then it is possible for the porous media to spontaneously imbibe CO2.
A Case Study of SACROC CO2 Flooding in Marginal Pay Regions: Improving Asset Performance
Authors: Kalteyer John
Published: August 2020

Since the beginning of injection in 1972, carbon dioxide has been utilized at the SACROC Unit of the Kelly-Snyder Field to improve and enhance oil recovery. As one of the first fields in the world to attempt this technique, SACROC provides a unique opportunity to study, learn from, and improve upon the development of this technology.

Between initial gas injection and the year 2000, approximately 1 TCF of CO2 had been injected into the Canyon Reef reservoir. While multiple pilot programs from this time period reported incremental response following CO2 injection, many of these volumes are now attributed to residual waterflood affects as many of these projects were not truly miscible CO2 floods. Since that time, advances in technology, improvements in reservoir knowledge, and increases in scale have expanded the boundaries of economically viable enhanced oil recovery. As a result, projects that were once considered marginal in reservoir quality and redevelopment potential are now exhibiting improved recovery responses across the field. Since taking over as operator at SACROC in 2000, Kinder Morgan has redeveloped more than 25 major project areas including more than 600 patterns within the unit. Under Kinder Morgan operations, cumulative CO2 injection has surpassed 7 TCF yielding a cumulative enhanced oil recovery of over 180 million barrels.

This case study will review the history of enhanced oil recovery at SACROC, discuss changes in theory over time, and provide a forward look at what remains for this field. This analysis will focus on the first CO2 injection pilot programs, dimensionless oil and CO2 recovery performance and their impact on forecasting, and inclusion of the transition zone and other marginal pay areas in redevelopment. Additionally, this study will highlight the major operational issues encountered over time and the associated improvements that have contributed to enhanced oil recovery. These advancements include conformance improvements, upgraded field surveillance, and proper management of the overall injection- production system. In conclusion, the case will review the Hawaii and East Flank CO2 Flood Expansions: two recently developed marginal pay projects undergoing miscible CO2 flooding at SACROC. Successful redevelopment of these marginal pay projects is allowing for expansion to areas of the field once considered marginal in quality and accordingly uneconomic.
Thermally Activated Particles Injection for Deep Conformance Control to Improve Oil Recovery in an Argentina Mature Waterflooded Reservoir: Cerro Dragon Field. Design, Field Implementation and Results
Authors: Iuliano Alberto , Gómez Javier E. , Martínez Christian R. , Alonso Laura C. , Kazempour Mahdi , Kiani Mojtaba , Alzate Daniela , Singh Praveen , Jerauld Gary
Published: August 2020

The interplay among reservoir heterogeneities, structural complexities and unfavorable mobility ratios are usually responsible for premature water breakthrough in brown fields across the world. Recently, a deep conformance control technology, known as Thermally Activated Particle (TAP), has been successful in addressing this challenge. Limited intervention and lower deployment cost make it very attractive for mature waterflooded fields.

Cerro Dragón is a giant field located in San Jorge Gulf basin with multi-layered channel deposits. Presence of highly conductive channels and unfavorable mobility ratios have severely impacted the sweep efficiency, resulting in low oil recovery and high water production. Building on the learnings from the previous pilots, TAP has been recently deployed at a segment scale in one of the blocks of Cerro Dragón field. This paper shares the technical details behind the screening, designing and the deployment of TAP technology.

After initial screening of multiple candidates, a reservoir segment has been selected for TAP implementation. Inter well tracer data with comprehensive injection/production data analysis identified the communicating wells and thief zones volumes were then estimated around each injector. The estimated thief zones volumes were also confirmed by volumetric calculation. Thermal modeling and numerical simulation were utilized using a representative and history matched model to finalize the size, concentration and the proper activation of injected TAP molecules.

Subsequently, in early 2018, nearly 360 metric tons of TAP was safely deployed into six target injectors. This campaign met all design guidelines, all planned surveillance data was acquired, and the project was executed on time and on budget. Post deployment, frequent sampling at offset producers was performed confirming no breakthrough of un-activated polymeric particles. Oil rates and WOR trends are currently being monitored, as part of the longer-term surveillance plan, to quantify incremental benefits from TAP EOR technology.

Previous 2011 implementation and positive results in other segments of the field were an important input and they are also described in this paper.

The results of this treatment will provide very helpful guidelines that can be used in any brown fields to improve the efficiency of waterflooding especially in highly heterogeneous reservoirs with low waterflooding performance.
Seismic AvO Inversion and Net Sand Estimation in Deep Water Turbidite Sands, Kangaroo Field, Offshore Nigeria
Authors: Osayande Francesca , Oguntola Somime , Sonde Adenike , Biambo Tamunotonye , Osho Olaseni , Okpako Kelvin , Musa Joel , Anaevune Austin , Mora-Glukstad Miguel , Yamusa Idris
Published: August 2020

The Kangaroo is a field located in the Deepwater Nigeria in water depths ranging from 950 to 1,500 meters. Structurally, the field can be described as a NW-SE trending shale-cored anticline with crestal faulting. Several wells have been drilled encountering primarily oil, in a series of Upper to Middle Miocene channelized turbidite reservoirs. The Kangaroo field is a brown field with challenges of unlocking its full potentials. The key subsurface uncertainties identified, were sand distribution and intra-reservoir connectivity. The existing reservoir models did not fully describe the reservoir net sand thickness and as a result, recent drillings have highlighted series of surprises warranting a study, to gain more insights into the sand distribution and reservoir heterogeneity.

This study highlights a multi-stack simultaneous seismic inversion used in conjunction with rock physics analysis, for a detailed reservoir characterisation, re-mapping of key reservoirs and prediction of Net-to-gross away from well control. Five offset angle seismic sub-stacks have been inverted with a Simultaneous Inversion algorithm, ultimately converting the reflectivity seismic data into rock property models, generating acoustic impedance (Zp), shear impedance (Zs), and density (ρ).

A feasibility study including crossplots of petrophysical and elastic properties from well data was carried out to establish rock property relationships in the interval of interest and this formed the basis for the seismic inversion studies. Key business driving value for this study, is the derivation of a robust estimates of net sand distribution, its impact on modelling reservoir parameters, and consequent estimation of in-place volumes.
A single oral fixed-dose praziquantel-miltefosine nanocombination for effective control of experimental schistosomiasis mansoni
Authors: Eissa Maha Mohamed , El-Azzouni Mervat , El-Khordagui Labiba Khalil , Bary Amany Abdel , El-Moslemany Riham Mohamed , Salam Sara Ahmed Abdel
Published: August 2020

Background: The control of schistosomiasis has been centered to date on a single drug, praziquantel, with shortcomings including treatment failure, reinfection, and emergence of drug resistance. Drug repurposing, combination therapy or nanotechnology were explored to improve antischistosomal treatment. The aim of the present study was to utilize a novel combination of the three strategies to improve the therapeutic profile of praziquantel. This was based on a fixed dose nanocombination of praziquantel and miltefosine, an antischistosomal repurposing candidate, co-loaded at reduced doses into lipid nanocapsules, for single dose oral therapy. Methods: Two nanocombinations were prepared to provide 250 mg praziquantel-20 mg miltefosine/kg (higher fixed dose) or 125 mg praziquantel-10 mg miltefosine/kg (lower fixed dose) respectively. Their antischistosomal efficacy in comparison with nontreated control and their praziquantel or miltefosine singly loaded counterparts was assessed in murine schistosomiasis mansoni. A single oral dose of either formulation was administered on the initial day of infection, the 21st and 42nd days post infection. Scanning electron microscopic, parasitological and histopathological studies were used for assessment. Preclinical data were subjected to analysis of variance and Tukey post hoc test for pairwise comparisons. Results: Lipid nanocapsules (~58 nm) showed high entrapment efficiency of both drugs (>97%). Compared to singly loaded praziquantel-lipid nanocapsules, the higher dose nanocombination showed a significant increase in antischistosomal efficacy in terms of statistically significant decrease in mean worm burden, particularly against invasive and juvenile worms, and amelioration of hepatic granulomas (p ≤0.05). In addition, scanning electron microscopic examination showed extensive dorsal tegumental damage with noticeable deposition of nanostructures. Conclusions: The therapeutic profile of praziquantel could be improved by a novel multiple approach integrating drug repurposing, combination therapy and nanotechnology. Multistage activity and amelioration of liver pathology could be achieved by a new praziquantel-miltefosine fixed dose nanocombination providing 250 mg praziquantel-20 mg miltefosine/kg. To the best of our knowledge, this is the first report of a fixed dose nano-based combinatorial therapy for schistosomiasis mansoni. Further studies are needed to document the nanocombination safety and explore its prophylactic activity and potential to hinder the onset of resistance to the drug components.
Feasibility of Using Infant Testing during Immunization to Estimate HIV Mother-to-Child-Transmission Rates in Zambia
Authors: Simbaya Joseph , Funjika Patricia , Moonga Arthur , Mwale John , Kankasa Chipepo
Published: August 2020

Background : This study piloted the feasibility of infant testing in immunization services as a strategy for estimating MTCT rates among the population of HIV exposed infants in Zambia. Methods : The study recruited a cross-sectional sample of 8,042 caregiver-baby pairs in 38 high volume immunization sites in 7 towns across 3 provinces of Zambia. All mothers who brought their children below the age of one year for immunization at the study facilities were invited to participate in the study. All consenting mothers were interviewed and blood drawn from their babies for; rapid HIV antibody test to determine exposure and DNA PCR test for samples of all HIV-exposed babies to determine HIV infection. Results : Of 8,042 recruited caregiver-baby pairs, 1,409 (17.5 %) babies were HIV-exposed. Approximately 90.2 percent of all mothers of HIV exposed infants reported that they attended ANC visits more than two times and facility based deliveries stood at 91.6 percent. Exclusive breastfeeding among HIV exposed infants reduced with increase in age of infant; it was highest at 6 weeks (82.2 %) followed by 10 weeks (74.0 %) and 14 weeks (58.2 %) . MTCT rates were relatively lower than what was reported before at 4.7 percent among Penta 1 seekers, 2.8 percent among Penta 2 seekers, 2.1 percent among Penta 3 seekers and 5.0 percent among Measles vaccination seekers. The overall MTCT rate stood at 3.8 percent. About 48.1 percent of HIV positive babies were male compared to 51.9 percent females. Babies of mothers below the age of 25 years accounted almost half (51.9 %) of all HIV infected babies in the study. Reported exclusive breastfeeding among HIV positive babies was 77.8 percent for Penta 1 seekers, 75.0 percent for Penta 2 seekers and 100 percent for Penta 3 seekers. Conclusion: The study succeeded in estimating MTCT rates using infant testing in immunization services, demonstrating that it is feasible to use routine infant testing in immunization services as a strategy for estimating MTCT rates among the population of HIV-exposed infants in countries with high HIV burden and immunization coverage.
The awareness, visibility and support for young carers across Europe: a Delphi study
Authors: Nap Henk Herman , Hoefman Renske , de Jong Nynke , Lovink Lieke , Glimmerveen Ludo , Lewis Feylyn , Santini Sara , D’Amen Barbara , Socci Marco , Boccaletti Licia , Casu Giulia , Manattini Alessandra , Brolin Rosita , Sirk Karina , Hlebec Valentina , Rakar Tatjana , Hudobivnik Tjasa , Leu Agnes , Berger Fabian , Magnusson Lennart , Hanson Elizabeth
Published: August 2020

Background Across Europe there is limited attention paid in media, policy and empirical research to the situation of young carers (YCs) and their needs for support, while similarly to adult carers, they provide care to ill family members. The Delphi study, a qualitative research methodology, which provides the focus for this article, had the overall aim of exploring existing successful strategies to support YCs. Compared to YCs, even less is known about AYCs (Adolescent Young Carers), a group that is in a critical life transition phase. The study forms part of an EU Horizon 2020 funded research project on AYCs aged 15-17 years. MethodsA two-round Delphi study was conducted with 66 experts on YCs from 10 European countries. Topics included: (1) visibility and awareness raising of YCs at local, regional, and national levels, (2) current interventions to support YCs, and (3) future strategies to support YCs. ResultsExperts reported that there is a lack of visibility and awareness about YCs in general and AYCs in particular. Although awareness is slowly increasing in most countries, with the UK ranked highest, experts acknowledged that it remains challenging to identify YCs in many countries. Furthermore, the level and type of support available for YCs differs, with most countries mainly offering support on a local level. Diverse views were expressed regarding future strategies to support YCs. Experts highlighted the importance of specific legislation to formalize the rights of YCs, and the issue of whether young people should be safeguarded from caregiving or if this is part of regular family life. They also emphasised the relevance of available integrated support services for YCs, including schools, family, health and social care.Conclusion(s) with key messageIn most European countries, there is a lack of awareness and visibility on YCs. Identification of YCs is a crucial first step and a common definition of YCs is called for, together with greater opportunities for young adults to identify themselves as YCs.StatementIdentification alone is not sufficient, rather recognition of YCs by society is needed combined with the necessary resources to ensure integrated YC friendly support services.
RNAi mediated silencing of Nanog expression suppresses the growth of human colorectal cancer stem cells
Authors: Zhang Chen , Zhao Yuanyuan , Yang Yongjing , Zhong Chunlian , Ji Tianju , Duan Jinyue , Wang Yi
Published: August 2020

Background: Colorectal cancer (CRC) is the third most common cancer in the world known for its poor recurrence-free prognosis. Previous studies have shown that it is closely linked with cancer stem cells (CSCs), which have self-renewal potential and the capacity to differentiate into diverse populations. Nanog is an important transcription factor that functions to maintain the self-renewal and proliferation of embryonic stem cells; however, many recent studies have shown that Nanog is also highly expressed in many cancer stem cells. Methods: To investigate whether Nanog plays a crucial role in maintaining the stemness of colorectal CSCs (CCSCs), RNA interference was used to downregulate Nanog expression in the CRC stem cell line, EpCAM + CD44 + HCT-116. We examined the anti-tumor function of Nanog in vitro and in vivo, using small interfering RNA. Results: Our results revealed that the Nanog mRNA expression level in CCSCs was higher than that in HCT-116 cells. We found that the depletion of Nanog inhibited proliferation and promoted apoptosis in EpCAM + CD44 + HCT-116 cells. In addition, the invasive ability of EpCAM + CD44 + HCT-116 cells was markedly restricted when Nanog was silenced by small interfering RNA. Furthermore, we found that the silencing of Nanog decreased tumor size and weight and improved the survival rate of tumor-bearing mice. Conclusions: In conclusion, these findings collectively demonstrate that Nanog, which is highly expressed in CRC stem cells, is a key factor in the development of tumor growth, and it may serve as a potential marker of prognosis and a novel and effective therapeutic target for the treatment of CRC.
Outcomes of Treatment With CHOP and EPOCH in Patients With HIV Associated NHL in a Low Resource Setting
Authors: Okello Clement Dove , Omoding Abrahams , Ddungu Henry , Mulumba Yusuf , Orem Jackson
Published: August 2020

Background: The optimal chemotherapy regimen for treating HIV associated NHL in low resource settings is unknown. We conducted a retrospective study to describe survival rates, treatment response rates and adverse events in patients with HIV associated NHL treated with CHOP and dose adjusted-EPOCH regimens at the Uganda Cancer Institute. Methods: A retrospective study of patients diagnosed with HIV and lymphoma and treated at the Uganda Cancer Institute from 2016 – 2018 was done. Results: One hundred eight patients treated with CHOP and 12 patients treated with DA-EPOCH were analysed. Patients completing 6 or more cycles of chemotherapy were 51 (47%) in the CHOP group and 8 (67%) in the DA-EPOCH group. One year overall survival (OS) rate in patients treated with CHOP was 54.5% (95% CI, 42.8 – 64.8) and 80.2% (95% CI, 40.3 – 94.8) in those treated with DA-EPOCH. Factors associated with favourable survival were BMI 18.5-24.9 kg/m 2 , (p=0.03) and completion of 6 or more cycles of chemotherapy, (p<0.001). The overall response rate was 40% in the CHOP group and 59% in the DA-EPOCH group. Severe adverse events occurred in 19 (18%) patients in the CHOP group and 3 (25%) in the DA-EPOCH group; these were neutropenia (CHOP=13, 12%; DA-EPOCH=2, 17%), anaemia (CHOP=12, 12%; DA-EPOCH=1, 8%), thrombocytopenia (CHOP=7, 6%; DA-EPOCH=0), sepsis (CHOP=1), treatment related death (DA-EPOCH=1) and hepatic encephalopathy (CHOP=1). Conclusion: Treatment of HIV associated NHL with curative intent using CHOP and infusional DA-EPOCH is feasible in low resource settings and associated with >50% one year survival.
Evaluation of Small Bowel Motion and Feasibility of using the Peritoneal Space to Replace Bowel Loops for Dose Constraints during Intensity-Modulated Radiotherapy for Rectal Cancer
Authors: Li Siyuan , Gong Yanping , Yang Yongqiang , Guo Qi , Qian Jianjun , Tian Ye
Published: August 2020

Background

The goal of this study was to assess small bowel motion and explore the feasibility of using peritoneal space (PS) to replace bowel loops (BL) via the dose constraint method to spare the small bowel during intensity-modulated radiotherapy (IMRT) for rectal cancer.

Methods

A total of 24 patients with rectal cancer who underwent adjuvant radiotherapy were selected. Weekly repeat CT scans from pre-treatment to the fourth week of treatment were acquired and defined as Plan, 1W, 2W, 3W, and 4W. BL and PS contours were delineated in all of the scans. Two IMRT plans called P PS and P BL were designed on Plan CT using two dose PS and BL constraint methods, respectively, and then copied to CT 1~4W. The shift%, dose volume, and NTCP of the small bowel in P PS and P BL during treatment were evaluated.

Results

Overall, 109 sets of CT scans from 24 patients were acquired, and 218 plans were designed and copied. The PS and BL volumes were 1339.28 cc and 250.27 cc. The BL and PS shift% V 15 was 28.48% and 11.79% ( p =0.000), which was less in the prone position than in the supine position (25.24% vs 32.10%, p =0.000; 9.9% vs 14.85%, p =0.000). On all of the CT scans, most P PS small bowel dose volumes were less than from P BL . V 15 was 170.07 cc vs 178.58 cc ( p =0.000), and they had a significant correlation. The NTCP of chronic and acute side effects from P PS was significantly less than P BL (2.80% vs 3.00%, p =0.018; 57.32% vs 58.64%, p =0.000).

Conclusions

This study indicated that small bowel motion may lead to uncertainties in its dose volume and NTCP evaluation during IMRT for rectal cancer. The BL movements were significantly greater than PS, and the prone position was significantly less than the supine position. Using PS instead of BL can spare the small bowel. V 15 <830 cc is the dose constraint standard.
Levels, Trends and Determinants of Technical Efficiency of General Hospitals in Uganda: Data Envelopment Analysis and Tobit Regression Analysis
Authors: Ayiko Rogers , Mujasi Paschal N. , Abaliwano Joyce , Turyareeba Dickson , Enyaku Rogers , Anguyo Robert , Odoch Walter , Bakibinga Pauline , Aliti Tom
Published: August 2020

Background: General hospitals provide a wide range of primary and secondary healthcare services. They accounted for 38% of government funding to health facilities, 8.8% of outpatient department visits and 28% of admissions in Uganda in the financial year (FY) 2016/17. We assessed the levels, trends and determinants of technical efficiency of general hospitals in Uganda from FY 2012/13 to FY 2016/17. Methods: We undertook input-oriented Data Envelopment Analysis to estimate technical efficiency of 78 general hospitals using data abstracted from the Annual Health Sector Performance Reports for FYs 2012/13, 2014/15 and 2016/17. Trends in technical efficiency was analysed using Excel while determinants of technical efficiency were analysed using Tobit Regression Model in STATA 15.1. Results: Average Constant Returns to Scale, Variable Returns to Scale and Scale Efficiency of general hospitals for FY 2016/17 were 49% (95% CI, 44% - 54%), 69% (95% CI, 65% - 74%) and 70% (95% CI, 65% - 75%) respectively. There was no statistically significant difference in the efficiency scores of public and private hospitals. Technical efficiency generally increased from FY 2012/13 to 2014/15, and dropped by FY 2016/17. Some hospitals were persistently efficient while others were inefficient over this period. Hospital size, geographical location, training status and average length of stay were statistically significant determinants of efficiency at 5% level of significance.Conclusion: The 69% average variable returns to scale technical efficiency indicates that the hospitals could generate the same volume of outputs using 31% (3,439) less staff and 31% (3,539) less beds. Benchmarking performance of the efficient hospitals would help to guide performance improvement in the inefficient ones. There is need to incorporate hospital size, geographical location, training status and average length of stay in the resource allocation formula and adopt annual hospital efficiency assessments.
Nationwide population-based cohort study of adverse obstetric outcomes in pregnancies with myoma or following myomectomy: Retrospective cohort study
Authors: Lee Se Jin , Ko Hyun Sun , Na Sunghun , Bae Jin Young , Seong Won Joon , Kim Jong Woon , Shin Jaeeun , Cho Hae Joong , Choi Gyu Yeon , Kim Jinsil , Cho Geum Joon , Park In Yang
Published: August 2020

Background: Our objective was to evaluate risks of adverse obstetric outcomes in pregnancies with myoma(s) or in pregnancies following myomectomy.Methods: We analyzed the national health insurance database, which covers almost the entire Korean population, between 2004 and 2015. The risks of adverse pregnancy outcomes in pregnancies with myoma(s) or in pregnancies following myomectomy, compared to those in women without a diagnosed myoma, were analyzed in multivariate logistic regression analysis.Results: During the study period, 38,402 women with diagnosed myoma(s), 9,890 women with a history of myomectomy, and 740,675 women without a diagnosed myoma gave birth. Women with a history of diagnosed myoma(s) and women with a history of myomectomy had significantly higher risks of cesarean section (aOR 1.13, 95% CI 1.1-1.16 and aOR 7.46, 95% CI 6.97-7.98, respectively) and placenta previa (aOR 1.41, 95% CI 1.29-1.54 and aOR 1.58, 95% CI 1.35-1.83, respectively), compared to women without a diagnosed myoma. And the risk of uterine rupture was significantly higher in women with previous myomectomy (aOR 12.78, 95% CI 6.5-25.13), compared to women without a diagnosed myoma, which was much increased (aOR 41.35, 95% CI 16.18-105.69) in nulliparous women. The incidence of uterine rupture was the highest at delivery within one year after myomectomy and decreased over time after myomectomy. Conclusions: Women with a history of myomectomy had significantly higher risks of cesarean section and placenta previa compared to women without a diagnosed myoma.
Analysis across diverse fish species highlights no conserved transcriptome signature for proactive behaviour.
Authors: Planellas Sonia Rey , Jin Xingkun , Damsgard Borge , Begout Marie-Laure , Mackenzie Simon
Published: August 2020

BackgroundConsistent individual differences in behaviour, known as animal personalities, have been demonstrated within and across species. In fish, studies applying an animal personality approach have been used to resolve variation in physiological and molecular data suggesting a linkage, genotype-phenotype, between behaviour and transcriptome regulation. In this study, using three fish species (zebrafish; Danio rerio, Atlantic salmon; Salmo salar and European sea bass; Dicentrarchus labrax), we firstly address whether personality-specific mRNA transcript abundances are transferrable across distantly-related fish species and secondly whether a proactive transcriptome signature is conserved across all three species.ResultsPrevious zebrafish transcriptome data was used as a foundation to produce a curated list of mRNA transcripts related to animal personality across all three species. mRNA transcript copy numbers for selected gene targets show that differential mRNA transcript abundance in the brain appears to be partially conserved across species relative to personality type. Secondly, we performed RNA-Seq using whole brains from S. salar and D. labrax scoring positively for both behavioural and molecular assays for proactive behaviour. We further enriched this dataset by incorporating a zebrafish brain transcriptome dataset specific to the proactive phenotype. Our results indicate that cross-species molecular signatures related to proactive behaviour are functionally conserved where shared functional pathways suggest that evolutionary convergence may be more important than individual mRNAs.ConclusionsOur data supports the proposition that highly polygenic clusters of genes, with small additive effects, likely support the underpinning molecular variation related to the animal personalities in the fish used in this study. The polygenic nature of the proactive brain transcriptome across all three species questions the existence of specific molecular signatures for proactive behaviour, at least at the granularity of specific regulatory gene modules, level of genes, gene networks and molecular functions.
Circular DNA intermediates in the generation of large human segmental duplications.
Authors: Chicote Javier Ugarte , López-Sánchez Marcos , Marquès-Bonet Tomàs , Callizo José , Pérez-Jurado Luis Alberto , Garcia-España Antonio
Published: August 2020

Background

Duplications of large genomic segments provide genetic diversity in genome evolution. Despite their importance, how these duplications are generated remains uncertain, particularly for distant duplicated genomic segments.

Results

Here we provide evidence of the participation of circular DNA intermediates in the single generation of some large human segmental duplications. A specific reversion of sequence order from A-B / C-D to B-A / D-C between duplicated segments and the presence of only microhomologies and short indels at the evolutionary breakpoints suggest a circularization of the donor ancestral locus and an accidental replicative interaction with the acceptor locus.

Conclusions

This novel mechanism of random genomic mutation could explain several distant genomic duplications including some of the ones that took place during recent human evolution.
Cluster analysis in 975 patients with current cough identifies a phenotype with several cough triggers, many background disorders, and low quality of life
Authors: Koskela Heikki Olavi , Selander Tuomas A , Lätti Anne M
Published: August 2020

Background

Recognition of disorder phenotypes may help to estimate prognosis and to guide the clinical management. Current cough management guidelines classify patients according to the duration of the cough episode. However, this classification is not based on phenotype analyses. The present study aimed to identify cough phenotypes by clustering.

Methods

An email survey among employed, working-age subjects identified 975 patients with current cough. All filled in a comprehensive 80-item questionnaire including the Leicester Cough Questionnaire. Phenotypes were identified utilizing K-means partitional clustering. A subgroup filled in a follow-up questionnaire 12 months later to investigate the possible differences in the prognosis between the phenotypes.

Results

Two clusters were found. The cluster A included 608 patients (62.4% of the population) and the cluster B 367 patients (37.6%). The three most important variables to separate the clusters were the number of the triggers of cough (mean 2.63 (SD 2.22) vs . 6.95 (2.30), respectively, p<0.001), the number of the cough background disorders (chronic rhinosinusitis, current asthma, gastroesophageal reflux disease, 0.29 (0.50) vs . 1.28 (0.75), respectively, p<0.001), and the Leicester Cough Questionnaire physical domain (5.33 (0.76) vs . 4.25 (0.84), respectively, p<0.001). There were significant interrelationships between these three variables (each p<0.001). Duration of the episode was not among the most important variables to separate the clusters. At 12 months, 27.0% of the patients of the cluster A and 46.1% of the patients of the cluster B suffered from cough that had continued without interruptions from the first survey (p<0.001).

Conclusions

Two cough phenotypes could be identified. Cluster A represents phenotype A, which includes the majority of patients and has a tendency to heal by itself. The authors propose that cluster B represents phenotype TBQ (Triggers, Background disorders, Quality of life impairment). Given the poor prognosis of this phenotype, it urges a prompt and comprehensive clinical evaluation regardless of the duration of the cough episode.
The Treatment of Microbubble Disease of 20th Century Cellulose Acetate Microfilm: Application of Ethyecellulose and Microrepair Method 
Authors: Jia Zhihui , Li Jing , Li Yuhu , Qi Yunpeng , Hu Daodao , Xing Huiping , Chao Xiaolian
Published: August 2020

Microbubble disease observed in cellulose acetate microfilm was accompanied by the production of vinegar syndrome, which has a negative influence on the integrity of image. In the present study, cellulose acetate microfilm with microbubble disease from the Republic of China (AD 1912-1949) collected in the Second Historical Archives of China was chosen as a prototype to investigate its treatment methods. A combination of optical microscopy and a stainless-steel needle was used to remove plasticizer exudation within microbubbles. The plasticizer was effectively removed by infiltrating butan-1-ol into the microbubble from a small hole made by the stainless-steel needle. The SEM and laser confocal microscopy were used to study the morphology and roughness of the internal surface of microbubble. It was found that the blurry image could be attributed to the light scattering from the rough surface. Based on the advantages of ethyl cellulose in conservation science, the optimal concentration of ethyl cellulose was selected and used to fill the interior of the microbubble to obtain a clearer image. To determine the protective potential of this filling material, the chemical and mechanical properties of coated film after dry heat, hygrothermal and UV accelerated ageing were measured. Based on the above-mentioned results, it is encouraging that a new microrepair method and its corresponding method are offered in film treatment work.
Comparative evaluation of two commercial real-time PCR kits (QuantiFast™ and abTES™) for the detection of Plasmodium knowlesi and other Plasmodium species in Sabah, Malaysia
Authors: Nuin Nor Afizah , Tan Angelica Fiona , Lew Yao Long , Piera Kim A , William Timothy , Rajahram Giri Shan , Jelip Jenarun , Dony Jiloris F , Mohammad Rashidah , Cooper Daniel J , Barber Bridget E , Anstey Nicholas M , Chua Tock H , Grigg Matthew J
Published: August 2020

Background : The monkey parasite Plasmodium knowlesi is an emerging public health issue in Southeast Asia. In Sabah, Malaysia, P. knowlesi is now the dominant cause of human malaria. Molecular detection methods for P. knowlesi are essential for accurate diagnosis and in monitoring progress towards malaria elimination of other Plasmodium species. However, recent commercially available PCR malaria kits have unpublished P. knowlesi gene targets or have not been evaluated against clinical samples. Methods : Two real-time PCR methods currently used in Sabah for confirmatory malaria diagnosis and surveillance reporting were evaluated: the QuantiFast™ Multiplex PCR kit (Qiagen, Germany) targeting the P. knowlesi 18S SSU rRNA; and the abTES™ Malaria 5 qPCR II kit (AITbiotech, Singapore), with an undisclosed P. knowlesi gene target. Diagnostic accuracy was evaluated using 52 P. knowlesi, 25 P. vivax , 21 P. falciparum , and 10 P. malariae clinical isolates, and 26 malaria negative controls, and compared against a validated reference nested PCR assay. The limit of detection (LOD) for each PCR method and Plasmodium species was also evaluated. Results : The sensitivity of the QuantiFast™ and abTES™ assays for detecting P. knowlesi was comparable at 98.1% (95%CI 89.7-100) and 100% (95%CI 93.2-100) respectively. Specificity of the QuantiFast™ and abTES™ for P. knowlesi was high at 98.8% (95%CI 93.4-100) for both assays. The QuantiFast™ assay demonstrated falsely-positive mixed Plasmodium species at low parasitaemias in both the primary and LOD analysis. Diagnostic accuracy of both PCR kits for detecting P. vivax , P. falciparum , and P. malariae was comparable to P. knowlesi . The abTES™ assay demonstrated a lower LOD for P. knowlesi of ≤0.125 parasites/µL compared to QuantiFast™ with a LOD of 20 parasites/µL. Hospital microscopy demonstrated a sensitivity of 78.8% (95%CI 65.3-88.9) and specificity of 80.4% (95%CI 67.6-89.8) compared to reference PCR for detecting P. knowlesi . Conclusion : The QuantiFast™ and abTES™ commercial PCR kits performed well for the accurate detection of P. knowlesi infections. Although the QuantiFast™ kit is cheaper, the abTES™ kit demonstrated a lower LOD, supporting its use as a second-line referral-laboratory diagnostic tool in Sabah, Malaysia.
Individual Pain Sensitivity Is Associated With Resting-State Cortical Activities in Healthy Individuals but Not in Patients With Migraine: A Magnetoencephalography Study
Authors: Hsiao Fu-Jung , Chen Wei-Ta , Liu Hung-Yu , Wang Yen-Feng , Chen Shih-Pin , Lai Kuan-Lin , Pan Li-Ling Hope , Wang Shuu-Jiun
Published: August 2020

Background

Pain sensitivity may determine the risk, severity, prognosis, and efficacy of treatment of clinical pain. Magnetic resonance imaging studies have linked thermal pain sensitivity to changes in brain structure. However, the neural correlates of mechanical pain sensitivity remain to be clarified through investigation of direct neural activities on the resting-state cortical oscillation and synchrony.

Methods

We recorded the resting-state magnetoencephalographic (MEG) activities of 27 healthy individuals and 30 patients with episodic migraine (EM) and analyzed the source-based oscillatory powers and functional connectivity at 2 to 59 Hz in pain-related cortical regions, which are the bilateral anterior cingulate cortex (ACC), medial orbitofrontal (MOF) cortex, lateral orbitofrontal (LOF) cortex, insula cortex, primary somatosensory cortex (SI), primary motor cortex (MI), and posterior cingulate cortex (PCC). The mechanical punctate pain threshold (MPPT) was obtained at the supraorbital area (the first branch of the trigeminal nerve dermatome, V1) and the forearm (the first thoracic nerve dermatome, T1) and further correlated with MEG measures.

Results

The MPPT is inversely correlated with the resting-state relative powers of gamma oscillation in healthy individuals (all corrected P < 0.05). Specifically, inverse correlation was noted between the MPPT at V1 and gamma powers in the bilateral insula (r = −0.592 [left] and −0.529 [right]), PCC (r = −0.619 and −0.541) and MI (r = −0.497 and −0.549) and between the MPPT at T1 and powers in the left PCC ( r = −0.561) and bilateral MI ( r = −0.509 and −0.520). Furthermore, resting-state functional connectivity at the delta to beta bands, especially between frontal (MOF, ACC, LOF, and MI), parietal (PCC), and sensorimotor (bilateral SI and MI) regions, showed a positive correlation with the MPPT at V1 and T1 (all corrected P < 0.05). By contrast, in patients with EM, the MPPT was not associated with resting-state cortical activities.

Conclusions

Pain sensitivity in healthy individuals is associated with the resting-state gamma oscillation and functional connectivity in pain-related cortical regions. Further studies must be conducted in a large population to confirm whether resting-state cortical activities can be an objective measurement of pain sensitivity in individuals without clinical pain.