Free Fluids Research Articles

Accurate Rock Mineral Characterization With Nuclear Magnetic Resonance

Nuclear magnetic resonance (NMR) logging is a powerful formation evaluation technology that provides mineralogy-independent porosity and helps distinguish clay-bound water, capillary-bound water, and free fluids. NMR logging tool generally operates at 1H NMR frequency of 2 MHz (magnetic field, B0 ~ 470 Gauss) or lower. At this magnetic field, it is only feasible to detect 1H signal from fluids in pores and rely on the relaxation time variation to characterize fluid and pore types. As magnetic field strength increases, NMR sensitivity increases very dramatically, and NMR signals from solid matrix become easier to be detected in high field. For example, NMR at 600 MHz is about 5,000 times more sensitive than the NMR at 2 MHz. Meanwhile, the spectral resolution of high-field NMR is also greatly increased, and high-field NMR spectrum can resolve the detailed differences between molecule types. Therefore, the high sensitivity and spectral resolution of high-field NMR open a totally new horizon for the characterization of geological samples, especially in organic shale reservoirs, in which organic matter and complex mineralogy remain challenging to be accurately characterized. In this work, we report high-field NMR applications for mineral characterization using a 600-MHz NMR spectrometer equipped with a multichannel and Magic-Angle Spinning (MAS) probe. Compared to X-ray diffraction (XRD), which is the primary tool for identifying and quantifying the mineralogy of crystalline compounds in geological samples based on Bragg’s diffraction, NMR can provide more compositional and structural information for noncrystalline compounds due to its sensitivity to local electronic binding structures. Here we demonstrate such an application of high-resolution 27Al NMR to determine the composition and bonding chemistry of 27Al as a fingerprint for a wide range of minerals. The ratio of 27Al at tetrahedral and octahedral binding sites is quantitative and essential to differentiate the dioctahedral and trioctahedral phases. 27Al NMR can also distinguish plagioclase series members ranging from albite to anorthite end members, where Na and Ca atoms can substitute for each other. 27Al NMR can be further combined with 1H, 13C, 29Si, 25Mg, 23Na, and 31P for more detailed mineral determination and clay typing. Our results show that, combined with XRD, this group of high-field NMR spectroscopic methods can greatly improve the accuracy of rock mineral and formation clay characterization in tight-rock and unconventional reservoirs.

A Case of Rupture Ectopic Pregnancy Diagnosed 10 Days After Hospital Stay In A 22-Year-Old Girl Presented With Symptoms of Anemia Without Abdominal Pain and Amenorrhea: Lessons Learned

A 22-year-old unmarried Myanmar girl presented with symptoms of anemia: fatigue, exertional dyspnea and fainting attack. There was no abdominal pain or amenorrhea. The hemodynamic status was stable except sinus tachycardia. Anemia was refractory to blood transfusion; thus, the differential diagnosis were autoimmune hemolytic anemia and occult blood loss. Blood film, bone marrow examination, Comb tests, Anti-nuclear antibody profile and PNH screen tests excluded autoimmune hemolytic anemia. Presence of fibrous strands in free fluids of abdominal cavity with normal uterus and ovary mislead the diagnosis of tuberculosis. Blood tap in ascitic fluid aspiration made all the answer- rupture ectopic pregnancy. The symptoms resolved after right salpingectomy and blood transfusion. The clerking on sexual exposure to Myanmar single is not acceptable in our culture; it is regarded as “social insult”. Atypical presentation and not asking sexual history caused delay in diagnosis; diagnosed 10 days after hospital stay. She recovered uneventfully.

Angioembolization of Renal Artery Pseudoaneurysm in Blunt Trauma Abdomen

Pseudoaneurysm of the renal artery is a presentation of blunt abdominal injury. We present the case of a 40-year-old male with a history of road traffic accident with a complaint of severe abdominal pain and distention of the abdomen. Contrast-enhanced computed tomography (CECT) shows large perinephric hematoma with free fluid in the abdomen. He was treated conservatively for 48 h but having persistence hypotension with increase free fluids in the abdomen, so mesenteric injury and bowel ischemia was suspected and laparotomy performed and found retroperitoneal hematoma and rest are normal. After that he had persistent hematuria with shock. Repeat CECT showed large pseudoaneurysm of the right renal artery with extravasation of contrast with clot in the bladder. In view this condition, renal artery angioembolization was done.

Constraints on fluids in the continental crust from laboratory-based electrical conductivity measurements of plagioclase

Aqueous fluids are regarded as the crucial origin of high conductivity and low velocity anomalies observed by magnetotelluric and seismic surveys in the middle to lower continental crust. Integration of field geophysical methods with experimental conductivity data is essential to accurately constrain the fluid fraction and salinity. Studies of fluid content and salinity in the crust from the experimental or theoretically calculated conductivity of fluid–minerals systems and saline-bearing fluid have demonstrated that crustal constituent minerals play a prominent role in the conductivity of fluid–mineral systems. We performed systematic measurements on electrical conductivity of dry and hydrous plagioclase solid solutions at high temperature and pressure. A positive dependence of electrical conductivity on Na contents is observed in dry samples, and discontinuous variation in conductivity is associated with the degree of Al/Si order–disorder. For hydrous samples, trace amounts of water considerably enhance the electrical conductivity. The dominant charge carriers in dry and hydrous plagioclase are Na ions and hydrogen, respectively, both of which migrate via the Frenkel mechanism. If there are no free fluids present in minerals, the crustal major constituent minerals containing structure water cannot account for the high-conductivity anomalies in the middle to lower crust based on our model of the rock conductivity–depth profiles in the continental crust. The calculated bulk conductivities of fluid–rock systems further suggest that at least 1 vol% of fluid with seawater salinity (3.5 wt%) is necessary in the middle to lower crust to interpret the high conductivity anomalies.

Perioperative clinical management in relation to emergency surgery for perforated peptic ulcer: A nationwide questionnaire survey.

Perforation is a severe complication of peptic ulcer disease. Evidence regarding perioperative management of patients undergoing surgery for perforated peptic ulcer is scarce without any clear guidelines. This study aimed to investigate the clinical practice and possible differences in the perioperative management of patients undergoing emergency surgery for perforated peptic ulcers in Denmark. The study was an anonymous, nationwide questionnaire survey. All doctors working at general surgical departments in Denmark were included. The questionnaire consisted of four parts; 1) demographic details including job position, subspecialty, geographic location, and surgical experience, 2) pre- and postoperative use of nasoenteral tubes, 3) routine use of nil-by-mouth (NBM) regime, 4) questions regarding postoperative nutrition.Subgroup analyses were performed according to job position and subspecialty. In total, the questionnaire was answered by 287 surgeons, of which 74% were experienced surgeons being able to perform surgery for perforated peptic ulcers independently.Pre- and postoperative nasoenteral tubes were used routinely by the majority of the respondents. One of five surgeons routinely practiced a postoperative NBM regime. Generally, the respondents allowed clear fluids postoperatively without restrictions but were reluctant to allow free fluids or solid foods. Two of three surgeons routinely used tube- or parental nutrition. The results varied depending on job position and subspecialty. After emergency surgery, the postoperative management of patients with perforated peptic ulcers varies considerably among general surgeons in Denmark. Evidence-based national or international guidelines are needed to standardize and optimize the clinical practice.

Comparative Effectiveness of Enhanced Recovery After Surgery Program Combined With Single-Incision Laparoscopic Surgery in Colorectal Cancer Surgery: A Retrospective Analysis.

BackgroundRecently, enhanced recovery after surgery (ERAS) has been widely used in the perioperative management of colorectal cancer (CRC). This study aimed to evaluate the safety and feasibility of ERAS combined with single-incision laparoscopic surgery (SILS) in CRC surgery.MethodsThis was a retrospective study of patients with CRC who underwent surgery between April 2018 and April 2020 in Ruijin Hospital(North), Shanghai Jiaotong University School of Medicine. The patients were divided into three groups: group A (n=138), patients who underwent traditional multiport laparoscopic colectomy with conventional perioperative management; group B (n=63), patients who underwent SILS; and group C (n=51), patients who underwent SILS with ERAS.ResultsOverall, 252 participants were included in the retrospective study. The median operation time (min) in group B and group C was shorter than that in group A (group A 134.0 ± 42.5; group B 117 ± 38.9; group C 111.7 ± 35.4, p=0.004). The estimated surgical blood loss (ml) was lower in groups B and C than in group A (group A 165.1 ± 142.2; group B 122.0 ± 79.4; group C 105.2 ± 55.8, p=0.011). The length of surgical incision (cm) was shorter in groups B and C than in group A (group A 7.34 ± 1.05; group B 5.60 ± 0.80; group C 5.28 ± 0.52, p<0.001). The time before first flatus (hours) in group C was shorter than in groups A and B (group A 61.85 ± 21.14; group B 58.30 ± 20.08; group C 42.06 ± 23.72; p<0.001). The days prior to the administration of free oral fluids in group C was shorter than in groups A and B (group A 4.79 ± 1.28; group B 4.67 ± 1.11; group C 2.62 ± 0.64; p<0.001). The days of prior solid diet was less in group C than in groups A and B (group A 7.22 ± 3.87; group B 7.08 ± 3.18; group C 5.75 ± 1.70; p=0.027). The postoperative length of stay (LOS) was less in group C compared with that in groups A and B (group A 9.46 ± 4.84 days; group B 9.52 ± 7.45 days; group C 7.20 ± 2.37 days; p=0.023). The visual analog scale (VAS) scores on day 0, 1, and 2 in groups B and C were lower than those in group A (day 0, p<0.001; day 1, p<0.001; day 2, p=0.002), while the VAS score on day 3 showed no differences in the three groups (group A 1.29 ± 1.38; group B 0.98 ± 1.24; group C 0.75 ± 0.64, p=0.018).ConclusionThe findings suggest that SILS combined with ERAS may be a feasible and safe procedure for CRC surgery because it provides favorable cosmetic results, early dietary resumption, shorter hospital stays, and appropriate control of postoperative pain without increases in complications or readmission rates compared to conventional perioperative care with SILS or conventional laparoscopic surgery(CLS) of CRC. Further prospective randomized controlled studies are needed to enhance evidence-based medical evidence.

A rare case of persistent fetal intestinal hyperechogenicity – Answer

In our case, the hyperechogenicity of the fetal intestine was observed for the first time during the 12th week sonography and was not resolved later. At the ultrasound checkup at 27 weeks, there was intestinal and gastric dilation; during the following one, at 29 weeks, a peritoneal effusion was also evident. The conditions of the fetus worsened rapidly, and the cardiotocographic trace showed a very reduced cardiac variability that required an urgent cesarean section. The abdominal ultrasound per­formed immedi­ately after birth revealed corpuscolar abdominal free fluids. The bowel loops were dilated, with very thick walls, filled with corpuscle material. The child’s clinical condition worsened rapidly. The oxygen saturation was at the lower limit even after the administration of Curosurf®. For this reason, it was not possible to transfer the patient to the Pediatric Surgery Department. So the surgeon performed a paracentesis in the Neonatal Intensive Care Unit (NICU), subtracting about 100 cc of hemorrhagic fluid. After a transitory improvement, the little girl died. The autopsy confirmed the presence of an intestinal volvulus with extensive hemorrhagic necrosis of the whole ileum, with dilated loops filled with hemorrhagic fluid, in the absence of intestinal malrotation.

Rapid Marcasite to Pyrite Transformation in Acidic Low-Temperature Hydrothermal Fluids and Saturation Index Control on FeS2 Precipitation Dynamics and Phase Selection

Pyrite is the most abundant metal sulfide in the Earth’s crust and is also found on Mars. It can form by direct hydrothermal precipitation or by polymorphic phase transformation from marcasite. However, the control on the dynamics of hydrothermal pyrite precipitation is poorly understood, and the kinetics of the hydrothermal transformation from marcasite to pyrite is unknown. To address these issues, we quantified pyrite and marcasite formation in hydrothermal fluids at pH 1, using pyrrhotite as a precursor mineral to produce supersaturated solutions. In situ powder X-ray diffraction experiments at 190 °C showed that hydrothermal fluids rich in ΣS(-II) (0.2 molal) favored the precipitation of nanocrystal pyrite (∼20 nm) due to a high saturation index (>105), while ΣS(-II)-free fluids produced a mixture of marcasite and pyrite nanocrystals (21–46 nm) due to a low saturation index (<104). The fluid/rock ratio (70 and 120 g/g at 210 °C) can also affect the saturation indices of these fluids, influencing nucleation and crystal growth dynamics of pyrite and marcasite and resulting in complex evolution of crystallite size, phase abundance, and the pyrite/marcasite ratio. Ex situ hydrothermal experiments at 210 °C showed rapid transformation from marcasite to pyrite, with around 95% marcasite being transformed to pyrite in 20 weeks, compared to more than 6.3 million years at 210 °C under dry conditions based on extrapolation from previous kinetic studies. These results suggest that saturation index influences hydrothermal precipitation dynamics and controls phase selection between pyrite and marcasite and that marcasite may not survive over geological time in low-temperature (<200 °C), water-saturated environments.

Confidence and use of physical examination and point-of-care ultrasonography for detection of abdominal or pleural free fluid. A cross-sectional survey

Physical examination (PE) has always been a corner stone of medical practice. The recent advances in imaging and fading of doctors’ ability in performing it, however, raised doubts on PE usefulness. Point-of-care ultrasonography (POCUS) is gaining ground in medicine with the detection of free fluids being one of its main applications. To estimate physicians’ confidence and use of PE and POCUS for the detection of abdominal or pleural free fluid, we conducted a cross-sectional survey. In all, 246 internal and emergency medicine physicians answered to the survey (197 in-hospital physicians and 49 general practitioners; response rate 28.5%). Almost all declared to perform PE in case of suspected ascites or pleural effusion (88% and 90%, respectively). The highest rates of confidence were observed in conventional PE signs (91% for diminished breath sounds, 80% for dullness to thorax percussion, and 66% for abdominal flank dullness). For the remaining signs, rates of confidence were less than 53%. Physicians with > 15 years of experience and POCUS-naïve doctors reported higher confidence in PE. Most of emergency and almost half of internal medicine physicians (78% and 44%, respectively) attended a structured POCUS course. POCUS use was higher among trained physicians for both ascites (84% vs 50%, p < 0.001) and pleural effusion (80% vs 34%, p < 0.001). Similarly, higher POCUS use was observed in younger physicians. In conclusion, PE is frequently performed and rates of confidence are low for most PE signs, especially among young doctors and POCUS users. This detailed inventory suggests an ongoing shift towards POCUS integration in clinical practice.

Assessment of an integrated knowledge translation intervention to improve nutrition intakes among patients undergoing elective bowel surgery: a mixed-method process evaluation

BackgroundA large evidence-practice gap exists regarding provision of nutrition to patients following surgery. The aim of this study was to evaluate the processes supporting the implementation of an intervention designed to improve the timing and adequacy of nutrition following bowel surgery.MethodsA mixed-method pilot study, using an integrated knowledge translation (iKT) approach, was undertaken at a tertiary teaching hospital in Australia. A tailored, multifaceted intervention including ten strategies targeted at staff or patients were co-developed with knowledge users at the hospital and implemented in practice. Process evaluation outcomes included reach, intervention delivery and staffs’ responses to the intervention. Quantitative data, including patient demographics and surgical characteristics, intervention reach, and intervention delivery were collected via chart review and direct observation. Qualitative data (responses to the intervention) were sequentially collected from staff during one-on-one, semi-structured interviews. Quantitative data were summarized using median (IQR), mean (SD) or frequency(%), while qualitative data were analysed using content analysis.ResultsThe intervention reached 34 patients. Eighty-four percent of nursing staff received an awareness and education session, while 0% of medical staff received a formal orientation or awareness and education session, despite the original intention to deliver these sessions. Several strategies targeted at patients had high fidelity, including delivery of nutrition education (92%); and prescription of oral nutrition supplements (100%) and free fluids immediately post-surgery (79%). Prescription of a high energy high protein diet on postoperative day one (0%) and oral nutrition supplements on postoperative day zero (62%); and delivery of preoperative nutrition handout (74%) and meal ordering education (50%) were not as well implemented. Interview data indicated that staff regard nutrition-related messages as important, however, their acceptance, awareness and perceptions of the intervention were mixed.ConclusionsApproximately half the patient-related strategies were implemented well, which is likely attributed to the medical and nursing staff involved in intervention design championing these strategies. However, some strategies had low delivery, which was likely due to the varied awareness and acceptance of the intervention among staff on the ward. These findings suggest the importance of having buy-in from all staff when using an iKT approach to design and implement interventions.

Early enteral feeding is beneficial for patients after pelvic exenteration surgery: A randomized controlled trial.

Postoperative feeding practices vary after pelvic exenteration surgery because of the lack of nutrition research in this specific surgical area. Postoperative ileus (POI) is common after pelvic exenteration surgery, and early enteral feeding is often avoided because of the lack of evidence and the belief that this may induce POI in this patient cohort. The aim of this study was to determine the effects of early enteral feeding after pelvic exenteration surgery on return of bowel movement and POI. A randomized controlled trial was conducted with patients undergoing pelvic exenteration surgery from November 2018 to June 2020. Forty participants received standard nutrition care (parenteral nutrition) and 47 participants received trophic enteral feeding (20 ml/h) via a nasogastric tube, in addition to standard care, until participants were upgraded to free fluids. Time to first bowel movement and rates of POI were the main outcome measures. There was no significant difference between arms for time to first bowel movement; however, POI rates were significantly less in participants who were enterally fed (P = .036) in the per-protocol analysis. Regressions showed that the longer patients were restricted from an oral diet after surgery, the greater the time was to first bowel movement and the greater the postoperative complication rates (P < .0005). Early enteral feeding can be commenced safely to improve gastrointestinal function after pelvic exenteration surgery.

Operational Limitations of Heat Pipes with MgO-Water Nanofluid: An Experimental Investigation

This paper presents the study of functional limits of heat pipes with MgO deionized (DI) water nano fluid as working fluid. The nano fluid is made with the help of two step method and it is surfactant free. The output has been analyzed with the increase in concentrations of MgO / DI water nano fluid (0.005%, 0.025% and 0.05 %) and at power input of (10 W, 30 W & 60 W), for covering operational range temperature of the electronic instruments. (<600C). On the basis of the thermo physical properties of the MgO/DI water nano fluid, the functional limits of heat pipe are determined. The changed of working fluids shows an improvement in boiling, pick up(entrainment), viscous and sonic limit except the capillary limit of heat pipe. The surfactant free nano fluids give good safety margin to the boiling limit of the heat pipe, with elimination of chances of locking due to vapor. The capillary limit reduces by the application of nano fluids due to increase in the vapor and liquid flow path resistance rather than capillary pressure in the evaporator section of heatpipe.

Conservative Management of Isolated Proximal Traumatic Pancreatic Injury: A Case Report

Background: Blunt traumatic pancreatic injuries are rare conditions in case of motor vehicle collision (MVC) and isolated injuries even rarer. Surgical approach is usually preferred in case of advanced pancreatic injuries. In this study we try to shed the light on the role of completely conservative approach in the management of a proximal pancreatic injury. &#x0D; Case Summary: A 19-year-old male patient presented to the ER three days following MVC with upper abdominal pain. Abdominal US showed free intraperitoneal fluids and laboratory results showed elevated total leukocyte count, serum amylase and lipase. CT showed transection at pancreatic head which was grade 5 with free intrabdominal fluids; hence isolated pancreatic injury was diagnosed. At that point, the patient was hemodynamically stable and conservative management was implemented. He was admitted in the ICU for three days followed by 28 days in the ward where patient condition was closely monitored on daily bases. Serial interval imaging showed spontaneous resolution of the intraperitoneal collection together with improvement of the injury, respectively. After completing his course, the patient was discharged and monitored as an outpatient.&#x0D; Conclusion: Conservative treatment can be adopted in patients with proximal pancreatic injuries with complete duct disruption in otherwise hemodynamically stable patients.

The use of noble gas isotopes to trace subsurface boiling temperatures in Icelandic geothermal systems

Geothermal systems are complex environments where geochemical signatures are controlled by the influx of deep mantle fluids as well as near-surface processes that result from the high temperatures. Noble gas isotope ratios (e.g. 3He/4He, 20Ne/22Ne) are well-established tracers of deep mantle fluid provenance, and elemental fractionation of atmosphere-derived isotopes is widely used for tracing shallow processes such as solubility-dependent phase partitioning in groundwater and hydrocarbon fluids. Utilisation of these tracers for the latter purpose has been limited in geothermal systems, where they could be further extended to consider boiling and/or steam condensation. Here we report new noble gas isotope and abundance data for 21 vapour phase geothermal fluid samples collected from geothermal boreholes and naturally degassing fumaroles in Iceland. The samples were collected from active parts of the neovolcanic rift zone and include several key high-temperature geothermal localities of the Northern Rift Zone (NRZ), the Western Rift Zone (WRZ) and the Mid-Iceland Belt (MIB). Helium isotope ratios are MORB-like in the NRZ, whilst samples from the WRZ show values in excess of MORB, up to 15.9 Ra. Neon isotopes plot close to the air value, but may show a small plume mantle contribution. Argon isotopes show distinct mantle-derived 40Ar excesses (40Ar/36Ar up to 361.2), which to our knowledge are the largest measured anomalies in free geothermal fluids from Iceland. The atmosphere-derived noble gas signatures (20Ne, 36Ar, 84Kr) are consistent with high-temperature vapour-liquid phase partitioning. Atmosphere-derived xenon (130Xe) on the other hand is not consistent with the observations from the other atmosphere-derived noble gases, suggesting an additional complexity that likely relates to its unique sorption and bonding behaviour. We show that the abundance of 20Ne, 36Ar, 84Kr in the vapour phase is temperature-dependent, presenting a promising technique that can be used to estimate the temperature at which partitioning occurs in the subsurface. Using multiple noble gas species allows the effects of secondary atmospheric contamination to be corrected when using this method. We predict partitioning temperatures of 229 to 345°C for the samples measured here, consistent with temperatures predicted using conventional geothermometers. The inert nature of the noble gases means that the technique presented here is not reliant on many of the assumptions that underpin conventional geothermometers. We suggest that this technique represents a novel and powerful geochemical tool to investigate the thermal properties of geothermal systems.

The Rayleigh\u2013Taylor instability in a porous medium

The classical Rayleigh–Taylor instability occurs when a heavy fluid overlies a lighter one, and the two fluids are separated by a horizontal interface. The configuration is unstable, and a small perturbation to the interface grows with time. Here, we consider such an arrangement for planar flow, but in a porous medium governed by Darcy’s law. First, the fully saturated situation is considered, where the two horizontal fluids are separated by a sharp interface. A classical linearized theory is reviewed, and the nonlinear model is solved numerically. It is shown that the solution is ultimately limited in time by the formation of a curvature singularity at the interface. A partially saturated Boussinesq theory is then presented, and its linearized approximation predicts a stable interface that merely diffuses. Nonlinear Boussinesq theory, however, allows the growth of drips and bubbles at the interface. These structures develop with no apparent overturning at their heads, unlike the corresponding flow for two free fluids.

Well-posedness of free boundary hard phase fluids in Minkowski background and their Newtonian limit

Well-posedness of free boundary hard phase fluids in Minkowski background and their Newtonian limit

A general numerical procedure for solidification and melting in porous media and free fluids

A numerical model of the solid/liquid phase change problem in porous media and free fluids is presented in this paper for the first time by employing a modified version of the generalized porous medium model, in 2D and 3D, solved by means of the Characteristic-Based-Split (CBS) scheme. The proposed procedure is based on the solution of one set of equations to describe different phenomena: natural convection in porous media, solidification and melting both in porous media and in free fluids. The generalized model has been modified to incorporate the apparent heat capacity, source term and pseudo-viscosity methods in order to reproduce phase change phenomena.Two versions of the algorithm, the Semi-Implicit (SI) and the Quasi-Implicit (QI) schemes, have been developed to solve the governing equations, and validated against numerical and experimental data available in the literature. The two schemes have been compared in terms of accuracy and efficiency for the solution of the benchmark problems.

Pre-operative carbohydrate loading prior to elective caesarean delivery: a randomised controlled trial

IntroductionWomen undergoing elective caesarean deliveries are fasted for long periods prior to surgery and can become catabolic. The use of pre-operative carbohydrate drinks to optimise patients ahead of major surgery is now well established. However, evidence to support this in women undergoing elective caesarean delivery is limited. MethodsWe conducted a single-blind randomised control trial to study the effect of carbohydrate preloading on the presence of urinary ketones in mothers undergoing elective caesarean deliveries compared with standard care, fasting from midnight the night before surgery with free clear fluids until two hours prior to surgery. ResultsTwo-hundred-and-nine patients were allocated to either standard care (n=104) or pre-operative carbohydrate drinks (n=105) prior to elective caesarean section. Twenty-five were excluded from the analysis, leaving 184 (n=90; n=94). The incidence of urinary ketones immediately prior to surgery was lower in the carbohydrate group, 18.1% compared with 61.1% in the standard care group (P<0.001). Relative risk (95% CI) 3.33 (2.12 to 5.26), with a number needed-to-treat of three to prevent urinary ketosis in one woman. There were no major adverse events. ConclusionThe results of this study support the introduction of carbohydrate drinks ahead of caesarean delivery to offset the effects of pre-operative fasting. However, the results may not be generalisable to all maternity units due to differences in fasting protocols.

Nefrectomía asociada con renomegalia derecha en un perro afectado por hidronefrosis

Hydronephrosis results from a total or partial obstruction of the lower urinary Hydronephrosis results from total or partial obstruction of the lower urinary tract, which promotes progressive dilation of the renal pelvis, and consequently, compression and atrophy of the parenchyma. Although its casuistry is low, its diagnosis is favored by clinical, laboratory and imaging exams. The aim of this study was to report the case of an adult mixed breed (SRD) dog with severe hydronephrosis that culminated in unilateral right nephrectomy. The animal had a distended abdomen with no painful response and a flank wound through which it drained blood and purulent secretion. Laboratory tests indicated normochromic normocytic anemia, leukocytosis with deviation to the left and increased plasma proteins. During the surgery, the right kidney was attached to the peritoneum, spleen, pancreas, omentum, liver and stomach. There were no free abdominal fluids or signs of peritoneal and / or retroperitoneal inflammation. Loss of renal parenchyma with replacement by intense fibrous connective tissue was verified microscopically. This report describes the evolution of this case from its initial consultation to the ninety days after the postoperative period. The underlying cause of the disease has not been clarified.

Pore-Type Partitioning in Unconventional Tight Reservoirs: Impact on Formation Damage and Long-Term Production

SummaryWettability is an important petrophysical property, which governs irreducible fluid saturations, relative permeability, and fluid invasion in rocks. Unlike conventional reservoirs, which have relatively uniform pore surface properties, the concept of wettability is not clear in organic-rich tight reservoirs. These rocks do not only have a nanoporous system but also possess multiple pore types with different interfacial affinities. Previous studies have shown that the unconventional reservoirs consist of three major pore types: inorganic pores (assumed to be water-wet), organic pores (assumed to be oil-wet, controlled by organic matter and thermal maturity), and mixed-wet pores (controlled by organic-inorganic distribution) (Curtis et al. 2012).This study revisits the concept of pore-type partitioning in tight rocks. We propose and demonstrate a new workflow to evaluate pore partitioning. First, all the specimens were vacuum dried at 100°C for 6 days to remove the free fluids until the weight stabilized. Total porosity was estimated as the sum of residual liquid volume [using nuclear magnetic resonance (NMR)] and gas-filled volume [using helium high-pressure pycnometer (HPP)]. The companion specimens from two formations (Eagle Ford and Wolfcamp B) were subjected to multiple injection cycles: starting with imbibition, then counter imbibition, and finally step pressurization with the replacing phase. During this process, we used brine-then-dodecane and dodecane-then-brine as the injection fluid sequences. The companion samples were continuously monitored by both gravimetric and NMR measurements until equilibration. Relative fractions of both replaced and replacing phases were calculated from sample weights and pore-fluidvolumes.The new approach not only classifies the connected pore network into three categories—oil-wet,water-wet, and mixed-wet—but also quantifies their respective proportions. The mixed-wet pore is defined as the pore fraction, in which both oil and water can replace air under capillary suction. We observe that the behavior of mixed-wet pores is different among formations: they prefer brine over oil in Wolfcamp B shale, while they prefer oil over brine in the Eagle Ford Formation. Unlike conventional wettability assessments, from which an overall wettability is provided, the novelty of this method is to clearly classify different pore types and their distributions. The concept of fractional wettability is highlighted for organic-rich tight rocks, and the contribution of mixed-wet pores in relative flow is emphasized.Hydraulic fracturing is a necessary stimulation process for tight reservoirs, in which the usage of fracturing fluid can affect formation performance. During well completion, water blockage is more likely to happen in the Wolfcamp B Formation than Eagle Ford Formation. Due to the capillary preference of mixed-wet pores, the water blockage might aid the Wolfcamp Formation to boost initial production, however, at a later stage, damage the formation. The workflow thus is promising to fully describe the pore network in tight formations, in which pore-type partitioning is a more reasonable concept than wettability.