Entrapment Conditions Research Articles

Ultrasound Assessment of the Median Nerve Does Not Adequately Discriminate the Carpal Tunnel Syndrome among Patients Diagnosed with Diabetes

Background: Carpal tunnel syndrome is the most prevalent peripheral nerve entrapment condition of the upper limb. Among metabolic risk factors, diabetes is considered the most relevant. Although wrist ultrasound assessment of the median nerve has demonstrated a good correlation with the gold standard for the diagnosis of this syndrome, neurophysiological study, its usefulness in patients with diabetes is questionable because the compressive phenomenon is not the predominant one. Method: We conducted a retrospective study to compare the clinical and median nerve ultrasound features of patients with carpal tunnel syndrome previously diagnosed or not diagnosed with diabetes. Additionally, a linear multivariate regression analysis was performed to determine to what extent the cross-sectional area of the median nerve was dependent on the condition of diabetes by fixing other variables such as sex, age, or time of evolution. Results: We included 303 records of patients (mean age 44.3 ± 11.7 years old, 57.89% female, mean of time of evolution 13.6 ± 8.3 months) from 2012 to 2020. The cross-sectional area of the median nerve was 10.46 ± 1.44 mm2 in non-diabetic patients and 8.92 ± 0.9 mm2 in diabetic patients (p < 0.001). Additionally, diabetic patients had a shorter time of evolution (7.91 ± 8.28 months vs. 14.36 ± 0.526 months, p < 0.001). In the multivariate analysis, the resultant model (fixed R-square = 0.659, p = 0.003) included a constant of the following four variables: the evolution time (Beta coeff. = 0.108, p < 0.001 95% CI 0.091 to 0.126, standardized coeff. = 0.611), the condition of diabetes (Beta coeff. = −0.623, p < 0.001 95% CI −0.907 to −0.339, standardized coeff. = −0.152), the severity (Beta coeff. = 0.359, p = 0.001 95% CI 0.147 to 0.571, standardized coeff. = 0.169), and the masculine sex (Beta coeff. = 0.309, p = 0.003, 95% CI 0.109 to 0.509, standardized coeff. = 0.103). Conclusions: Ultrasound assessment of the median nerve in patients with diabetes is not a useful tool to confirm whether carpal tunnel syndrome should be diagnosed or not diagnosed.

Fluid circulation in the South Tibetan Detachment System: Evidence from fluid inclusions and oxygen isotope data of quartz veins in the Ramba Dome, North Himalayan Gneiss Domes

Detachment faults are sites of intensive fluid–rock interactions. Here, we report fluid inclusion and oxygen isotope data for quartz veins in the Ramba Dome in the North Himalayan Gneiss Domes, with an aim to constrain the origin and circulation of crustal fluids associated with the South Tibetan Detachment System (STDS). Microthermometric data for fluid inclusions in quartz indicate that the fluids were aqueous and CO2 − H2O ± CH4 ± N2‐bearing with low to moderate salinities (0.60–11.80 wt% eq. NaCl). The entrapment conditions are 295–410°C and 98–135 Mpa, indicating a forming‐depth of 8–10 km. Oxygen isotopic compositions (δ18O) of quartz measured in situ by secondary ion mass spectrometry and bulk by the BrF5 method show limited variations in individual quartz veins, but δ18Oquartz values vary from 12.07 to 18.16‰ (V‐SMOW) among veins. The corresponding δ18Ofluid values range from 7.71 to 13.80‰, based on equilibrium temperatures obtained from fluid inclusions. From the footwall to the detachment zone, δ18Ofluid values exhibit a broadly decreasing trend and indicate that the STDS dominated the fluid flux pathway in the crust, with more contributions of meteoric water in the detachment zone. We further quantified the contribution of meteoric fluids to 8–27% using a binary end‐member mixing model. These data imply that the fluids were predominantly metamorphic/magmatic in origin, and were mixed with infiltrating, isotopically light, meteoric water during extensional detachment shearing of the STDS. The meteoric water can infiltrate from the surface to 8–10 km depth.

Bubble entrapment condition in Bingham materials

We investigate the entrapment condition of initially spherical and ellipsoidal Newtonian bubbles in viscoplastic materials using direct numerical simulations. For a spherical bubble, the entrapment condition depends on the balance between the buoyancy force and the force exerted by the yield stress of the viscoplastic material. For non-spherical bubbles, surface tension may yield the surrounding material to minimize the surface energy of the bubble. The yielding of the surrounding material by surface tension force facilitates the rising motion of bubbles. Although surface tension may yield the surrounding material and start the rising motion, the bubble may get entrapped later if the stress exerted by buoyancy force is less than the yield stress of the material. We evaluate the yield-stress parameter for different bubble shapes over a range of non-dimensional parameters to predict the critical yield-stress parameter for the entrapment of a bubble. • The critical yield stress parameter decreases at very high viscosity ratios. • The yield stress parameter is a constant at low viscosity ratios. • Yield stress resistive force depends on the maximum cross-sectional area normal to the buoyancy. • The critical yield stress parameter is independent of the initial shape of the bubble. • Non-spherical bubbles may be momentarily mobile due to surface tension effects.

The contribution of elastic geothermobarometry to the debate on HP versus UHP metamorphism.

Characterizing the pressure and temperature (P–T) histories of eclogite facies rocks is of key importance for unravelling subduction zone processes at all scales. Accurate P–T estimates provide constraints on tectonic and geochemical processes affecting subduction dynamics and help in interpreting the geophysical images of present‐day converging plates. Conventional equilibrium geothermobarometers are challenged in ultra high pressure (UHP) metamorphic terranes, as minerals may undergo re‐equilibration along their exhumation path. Elastic geobarometry applied to host‐inclusion systems is a complementary method to determine P–T conditions of metamorphism independent from chemical equilibrium. Because only a single measurement, the inclusion strain, is made, only a line in P–T space of possible entrapment conditions, the entrapment isomeke, can be determined. Thus, the entrapment pressure along an isomeke can only be determined if the entrapment temperature is known. An alternative is to calculate entrapment conditions for two types of inclusions that are believed, from petrological evidence such as being in the same garnet growth zone, to have been entrapped at the same time. The intersection between the two sets of isomeke calculated on multiple quartz and zircon inclusions demonstrates that measuring different inclusion phases trapped inside a single host allows unique P–T conditions for the host rock to be determined. Here, we combine Zr‐in‐Rutile thermometry and thermodynamic modelling with micro‐Raman measurements on quartz and zircon inclusions trapped in garnet to obtain pressures and temperatures of equilibration of a quartz–garnet vein from the Proterozoic Ulla gneiss basement and of garnet–kyanite gneiss from the Caledonian Blåhø nappe, both in the Fjørtoft UHP terrane, Norway. We find that the quartz–garnet vein formed at high pressure (1.5–2.5 GPa and 750–800°C) and recrystallized at ~1.2 GPa and 880°C. In contrast, the garnet–kyanite gneiss followed an anticlockwise path with peak P–T at 1.2 GPa and 880°C: these estimates are consistent with previous thermodynamic modelling and suggest that the Ulla gneiss and the Blåhø nappe came into contact at these last conditions. We also discuss a new method to detect hydrostatic versus Non‐hydrostatic stresses near quartz and zircon inclusions in garnet.

The concealed morbidity of buried penis: a narrative review of our progress in understanding adult-acquired buried penis as a surgical condition.

Adult acquired buried penis (AABP) is a condition of entrapment of the phallus resulting most commonly from morbid obesity and formation of cicatrix with other etiologies including genital lymphedema, hidradenitis and trauma. The incidence of this syndrome is invariably connected to the increasing prevalence of obesity. The purpose of this review is to examine the current literature in AABP with a focus on the morbidity of AABP and perioperative management. The discussion and literature surrounding buried penis reconstruction started with the goal of correcting a cosmetic problem and has recently become fairly successful in this aim with an over 85% rate of successful reconstruction in many series with a more uniform surgical approach. The most recent trends have examined the significant burden of morbidity and even mortality that AABP can place on patients as it contributes to risk of penile cancer, urethral strictures and mood disorders. Studies in this space have shown that surgical repair can be successful in improving quality of life for patients with AABP and the removal of the offending pathophysiology suggests its success in correcting the physical morbidities. New directions for research and management of this condition should include a focus on educating providers and patients to make reconstruction more accessible to patients in need as AABP continues to journey toward mainstream acceptance as a surgical condition.

EntraPT: An online platform for elastic geothermobarometry

Abstract EntraPT is a web-based application for elastic geobarometry freely accessible at the “Fiorenzo Mazzi” experimental mineralogy lab website (http://www.mineralogylab.com/software/). It provides an easy-to-use tool to calculate the entrapment conditions of inclusions, with error propagation, from the residual strain measured in mineral inclusions. EntraPT establishes a method and a workflow to import and analyze the measured residual strains, correctly calculates the mean stress in the inclusions, computes the entrapment isomekes with uncertainty estimation, and visualizes all the results in relevant graphs. It enables the user to avoid the many possible errors that can arise from manual handling of the data and from the numerous steps required in geobarometry calculations. All of the data, parameters, and settings are stored in a consistent format and can be exported as project files and spreadsheets, and imported back to EntraPT for further analysis. This allows researchers to store and/or share their data easily, making the checking and the comparison of data and results reliable. EntraPT is an online tool that does not require any download and/or installation, and it will be updated in the future with new functionalities made available from advances in the development of elastic geobarometry.

Using the elastic properties of zircon-garnet host-inclusion pairs for thermobarometry of the ultrahigh-pressure Dora-Maira whiteschists: problems and perspectives

The ultrahigh-pressure (UHP) whiteschists of the Brossasco-Isasca unit (Dora-Maira Massif, Western Alps) provide a natural laboratory in which to compare results from classical pressure (P)–temperature (T) determinations through thermodynamic modelling with the emerging field of elastic thermobarometry. Phase equilibria and chemical composition of three garnet megablasts coupled with Zr-in-rutile thermometry of inclusions constrain garnet growth within a narrow P–T range at 3–3.5 GPa and 675–720 °C. On the other hand, the zircon-in-garnet host-inclusion system combined with Zr-in-rutile thermometry would suggest inclusion entrapment conditions below 1.5 GPa and 650 °C that are inconsistent with the thermodynamic modelling and the occurrence of coesite as inclusion in the garnet rims. The observed distribution of inclusion pressures cannot be explained by either zircon metamictization, or by the presence of fluids in the inclusions. Comparison of the measured inclusion strains with numerical simulations shows that post-entrapment plastic relaxation of garnet from metamorphic peak conditions down to 0.5 GPa and 600–650 °C, on the retrograde path, best explains the measured inclusion pressures and their disagreement with the results of phase equilibria modelling. This study suggests that the zircon-garnet couple is more reliable at relatively low temperatures (< 600 °C), where entrapment conditions are well preserved but chemical equilibration might be sluggish. On the other hand, thermodynamic modelling appears to be better suited for higher temperatures where rock-scale equilibrium can be achieved more easily but the local plasticity of the host-inclusion system might prevent the preservation of the signal of peak metamorphic conditions in the stress state of inclusions. Currently, we cannot define a precise threshold temperature for resetting of inclusion pressures. However, the application of both chemical and elastic thermobarometry allows a more detailed interpretation of metamorphic P–T paths.

Quantitative evaluation of geological fluid evolution and accumulated mechanism: in case of tight sandstone gas field in central Sichuan Basin

Tight gas exploration plays an important part in China’s unconventional energy strategy. The tight gas reservoirs in the Jurassic Shaximiao Formation in the Qiulin and Jinhua Gas Fields of central Sichuan Basin are characterized by shallow burial depths and large reserves. The evolution of the fluid phases is a key element in understanding the accumulation of hydrocarbons in tight gas reservoirs. This study investigates the fluid accumulation mechanisms and the indicators of reservoir properties preservation and degradation in a tight gas reservoir. Based on petrographic observations and micro-Raman spectroscopy, pure CH4 inclusions, pure CO2 inclusions, hybrid CH4–CO2 gas inclusions, and N2-rich gas inclusions were studied in quartz grains. The pressure–volume–temperature–composition properties (PVT-x) of the CH4 and CO2 bearing inclusions were determined using quantitative Raman analysis and thermodynamic models, while the density of pure CO2 inclusions was calculated based on the separation of Fermi diad. Two stages of CO2 fluid accumulation were observed: primary CO2 inclusions, characterized by higher densities (0.874–1.020 g/cm3) and higher homogenization temperatures (> 210 °C) and secondary CO2 inclusions, characterized by lower densities (0.514–0.715 g/cm3) and lower homogenization temperatures: ~ 180–200 °C). CO2 inclusions with abnormally high homogenization temperatures are thought to be the result of deep hydrothermal fluid activity. The pore fluid pressure (44.0–58.5 MPa) calculated from the Raman shift of C–H symmetric stretching (v1) band of methane inclusions is key to understanding the development of overpressure. PT entrapment conditions and simulation of burial history can be used to constrain the timing of paleo-fluid emplacement. Methane accumulated in the late Cretaceous (~ 75–65 Ma), close to the maximum burial depth during the early stages of the Himalayan tectonic event while maximum overpressure occurred at ~ 70 Ma, just before uplift. Later, hydrocarbon gas migrated through the faults and gradually displaced the early emplaced CO2 in the reservoirs accompanied by a continuous decrease in overpressure during and after the Himalayan event, which has led to a decrease in the reservoir sealing capabilities. The continuous release of overpressure to present-day conditions indicates that the tectonic movement after the Himalayan period has led to a decline in reservoir conditions and sealing properties.

Pressure–temperature–time–composition (P–T–t–x) of paleo–fluid in Permian organic–rich shale of Lower Yangtze Platform, China: Insights from fluid inclusions in fracture cements

Recently, much attention has been paid to Permian shale from the Yangtze Platform because of the high–quality hydrocarbon source rock. This research investigates fracture veins derived from conventional cores of the Permian Leping Formation in the Pingle Depression, Lower Yangtze Platform. Based on petrographic observations, micro–Raman spectroscopy, and fluorescent spectrometry, hybrid CH4–C2H6 gas inclusions, pure CH4 inclusions, dissolved CH4 aqueous inclusions, and different abundant blue-green fluorescence petroleum inclusions were discovered in quartz and calcite. The pressure–temperature–time–composition properties of the CH4–bearing inclusions were obtained by quantitative Raman analysis and thermodynamic models. The pore fluid pressure (59.05–87.78 MPa) calculated from Raman shift of C–H symmetric stretching (v1) band of methane indicates inclusions trapped at close to lithostatic pressures, which can provide a key evidence for understanding the formation and evolution of overpressure. PT entrapment conditions, reconstruction of hydrocarbon generation and simulation of burial history permit to constrain accumulation time sequence of paleo-fluid in shale veins. Blue-green fluorescence with high-mature petroleum fluid trapped in late Cretaceous (~81–71 Ma); hybrid CH4–C2H6 fluid trapped in early Paleogene (~68–61 Ma); and CH4 fluid trapped in Paleogene (~62–51 Ma). Dry gas generation period close to the age of maximum burial depth at early Himalayan uplift period.

Meralgia Paraesthetica after Prone Position Ventilation in a Patient with COVID-19.

Background and objectivesOne of the most feared complications of COVID-19 is respiratory failure caused by acute respiratory distress syndrome. In order to improve oxygenation and survival, patients admitted to intensive care units and intubated may undergo prone position mechanical ventilation. Prolonged prone positioning may cause meralgia paraesthetica due to lateral femoral cutaneous nerve entrapment between the inguinal ligament and the anterior superior iliac spine. Reports of the first two cases have been recently published.Case presentationWe describe the case of a 52-year-old man with respiratory failure during COVID-19 infection, who underwent prone position ventilation for 16 hours a day over 19 days and developed persistent burning pain and dysaesthesia on the lateral surface of the thigh bilaterally, diagnosed as meralgia paraesthetica.ConclusionThis is the second report describing meralgia paraesthetica following prone position ventilation in COVID-19. Given the ongoing pandemic and the inevitability of more patients with severe respiratory distress requiring prone position ventilation, this disabling entrapment condition should be considered and possibly prevented.LEARNING POINTSCOVID-19 may require intubation and mechanical ventilation because of respiratory distress.Prone position ventilation improves oxygenation, but may cause lateral femoral cutaneous nerve entrapment and meralgia paraesthetica.Medical personnel should be aware of the risk of meralgia paraesthetica as a disabling condition potentially affecting more patients as the COVID-19 pandemic persists.

Calculating pressure with elastic geobarometry: A comparison of different elastic solutions with application to a calc-silicate gneiss from the Rhodope Metamorphic Province

Raman elastic geobarometry has increasingly been used complementary to metamorphic phase equilibria to estimate the conditions of recrystallization in metamorphic rocks. The procedure of applying Raman elastic barometry to host-inclusion mineral systems requires several steps that involve various assumptions. One of the most essential assumptions is that the mineral host-inclusion system behaves in an elastic and reversible manner. We discuss the discrepant results obtained by different authors employing different analytical solutions for elasticity and explore the assumptions lying behind each method. Furthermore, we evaluate numerically linear and non-linear elastic solutions and show their discrepancies. Both formulations are tested against recently published experiments on quartz inclusions in garnet (QuiG) at pressures up to 3 GPa, and we find a very good agreement between calculated and experimental pressure values (within 10% relative error). We subsequently apply our new elastic geobarometer to a calc-silicate gneiss from the Rhodope Metamorphic Province (N. Greece). The results of Raman elastic barometry combined with garnet-clinopyroxene geothermometry yield eclogite-facies conditions (~720 ± 40 °C, ~1.5 ± 0.2 GPa). These results are comparable to a high-temperature metamorphic overprint deduced from phase equilibria modeling in surrounding lithologies (730 ± 40 °C, ~1.2 ± 0.1 GPa). Our findings indicate that the estimated pressure from Raman elastic barometry is consistent with a significant viscous relaxation at high temperatures. We conclude that although Raman elastic barometry is a powerful tool for pressure estimation in metamorphic rocks, its pressure estimates do not necessarily correspond to entrapment conditions. Our results are consequential for the estimates of reaction overstepping in high-grade metamorphic rocks.

Co-immobilized spore laccase/TiO2 nanoparticles in the alginate beads enhance dye removal by two-step decolorization.

Combinatorial application of different dye removal methods with specific features can lead to a novel and robust decolorizing system. In this study the bacterial spore laccase and TiO2 nanoparticles were co-entrapped to enhance dye degradation. The optimum entrapment conditions were achieved in the presence of alginate 2% (w/v) and Ca2+ (0.2M), Cu2+ (0.05M) and Zn2+ (0.25M) as matric polymer and counterions, respectively. Immobilized laccase showed a wide range of pH and temperature stability in comparison to the free spores. The entrapped degradation systems include single laccase, single TiO2, laccase + TiO2 (one-step remediation), TiO2/laccase (two-step remediation), and laccase/TiO2 (two-step remediation) that result to the 22%, 26% 45.6%, 47.6%, and 69.3% indigo carmine decolorization in 60 min. In the kinetic studies, the half-life of indigo carmine (25 mg/l) in the remediation processes containing laccase, TiO2, laccase + TiO2, TiO2/laccase, and laccase/TiO2 was calculated as 173, 138, 161, 115, and 57 min, respectively. The degradation products by co-entrapped system were not toxic against Sorghum vulgare. The results showed two-step decolorization by co-entrapped spore laccase and TiO2 nanoparticles, including the pretreatment of dye by laccase, and then, treatment by TiO2 has potential for degradation of indigo carmine.

Applications and Limitations of Elastic Thermobarometry: Insights From Elastic Modeling of Inclusion‐Host Pairs and Example Case Studies

AbstractElastic thermobarometry can be used to constrain the pressure and temperature conditions of mineral crystallization by exploiting the difference in the elastic evolution of a mineral inclusion and its host during cooling and decompression. In this work we examine the pressure‐temperature sensitivity of &gt;5,000 untested inclusion‐host pairs. Hosts such as diamond and zircon are ideal host minerals because their low compressibility makes them rigid containment vessels. Highly compressible inclusions such as albite, graphite, and quartz serve as the most reliable barometers. We provide three case studies of inclusion‐host pairs from different geologic settings to demonstrate the advantages and challenges associated with these mineral pairs. Apatite inclusions in olivine from Yellowstone caldera mostly record negative residual pressures (tension) and suggest magmatic crystallization at ~0.4 GPa. Rutile inclusions in garnet from Verpeneset eclogites record near ambient conditions and do not recover reasonable metamorphic conditions of rutile entrapment. These results suggest that stiff inclusions may have a tensile strain limit, a possible limitation of elastic thermobarometry. Albite inclusions in epidote from a blueschist (Syros, Greece) record geologically reasonable entrapment pressures, but a large range of residual pressures that may be caused by the complex anisotropy of both phases. Our theoretical and applied results indicate that elastic thermobarometry has the potential to be used to understand petrologic processes in diverse geologic environments, including mantle, metamorphic, and magmatic settings but that each elastic thermobarometer requires careful evaluation.

Melt inclusions at MT. Edixon (Antarctica): Chemistry, petrology and implications for the evolution of the Lanterman range

The recovery of melt inclusions (MI) in peritectic phases of metamorphic rocks demonstrates their anatectic origin even in the absence of other textural or field evidences, and gives the opportunity to retrieve the chemical composition of primary melts and infer melt entrapment conditions. Here we report the first recovery of such inclusions in a medium-grade schist from the Edixon Metamorphic Complex (EMC) of the Lanterman Range in northern Victoria Land, Antarctica. This is the first study of melt inclusions from an Al2SiO5-free, graywacke-type protolith. Inclusions are hosted in garnet. They are both polycrystalline nanogranitoids, i.e., crystallized former MI, and fluid inclusions (FI) coexisting in the same clusters and displaying frequent negative crystal shape and textures indicative of a primary origin. The MI contain albite, K-feldspar, quartz, muscovite, biotite ± calcite ± siderite ± H2O, while the FI are composed by CO2 + H2O + N2 + CH4 ± H2S and contain step-daughter calcite.The schist hosting the garnets with melt inclusions contains muscovite, biotite, garnet, plagioclase, K-feldspar, and quartz. Extensive resorption of garnet and replacement by biotite, along with composition of micas that suggest medium-temperature, subsolidus conditions, indicate that after anatexis the schist was thoroughly recrystallized under retrograde conditions. The MI were remelted in a piston cylinder apparatus at conditions of 740–900 °C at 0.8–1.0 GPa with complete remelting taking place at 760–780 °C. The remelted glass is sub-alkaline, peraluminous (ASI ≈ 1.3–1.5) with CaO ≈ 1.2–2.1 wt% and K2O ≈ 3.4–4.1 wt% and contains ≈ 4.3–5.3 wt% of H2O and 400–1150 ppm of CO2. The P-T conditions of melt entrapment were retrieved combining results of experimental remelting with calculated phase equilibria in the MnCNKFMASHT model system, and are between 740 and 780 °C and 0.7 to 0.9 GPa. The new and different P-T conditions for a high grade rock of the EMC with respect to other published data, confirm that this metamorphic complex is not homogeneous, and that anatexis may have taken place at different crustal levels during the evolution of the Cambro-Ordovician Ross Orogen.

Analysis of critical slag entrapment speed at the steel–slag interface

ABSTRACT Based on particle image velocimetry (PIV) technology, the process and flow field characteristics of slag entrapment under the condition of critical slag entrapment are investigated by water model. The change of interface flow field at the slag entrapment process from the occurrence to end of critical slag entrapment is analysed, and the influence of kinematic viscosity of slag on critical slag entrapment velocity is quantitatively analysed. The results show that the kinematic viscosity of slag has an important influence on slag entrapment. The critical blowing flow and critical speed increase with the increasing of the viscosity. Based on the law of conservation of energy and the traditional theoretical calculation models, an improved formula for critical slag entrapment speed is proposed in this study, which further considers the thickness and viscosity of the slag.

Exploring sub-basalt reservoirs using object-oriented imaging: A case study from Kutch–Saurashtra area, India

The hydrocarbon strike has been reported above and below basalt (Mesozoic sequences) in shallow water of Kutch–Saurashtra basin of Indian west coast. The evaluation of entrapment conditions within Mesozoic (below basalt) is extremely problematic because of poor quality images, of available data which are not amenable for subsurface mapping. The precise sub-basalt imaging in Kutch–Saurashtra basin is crucial for successful exploration activities in Mesozoic. The challenges for imaging the streamer data are two folds: first, poor data quality, due to poor signal penetration through basalt section and second, masking of signals with multiples and converted waves (PSPP and PSSP). Modelling using Norsar software, reveals that PSSP waves (noise), generate from an offset of about 3000 m from basalt top. We followed a new imaging strategy for achieving good sub-basalt images by proper multiple attenuation, elimination of converted waves, and adequate noise cleaning in different domains with correct estimation of velocity and signal boosting, below basalt. The new images clearly exhibit the sub-basalt horizons like Base of Basalt, Bhuj Formation and Mundra Formation, etc., which are amenable for mapping and pre-stack inversion, a powerful tool for reservoir characterization. The acoustic impedance of gas pay, drastically drops to 8000 unit from background value or 14000 units, delineated lateral extension of pay sand in present study. The new imaging exhibits presence of Graben, half Graben and anticlinal structures formed during Mesozoic and some reverse faults which are key components to unravel the basin tectonics and to aid derive Mesozoic petroleum system.

Comparative Study on Enzyme Immobilization Using Natural Hydrogel Matrices—Experimental Studies Supported by Molecular Models Analysis

Currently, great attention is focused on conducting manufacture processes using clean and eco-friendly technologies. This research trend also relates to the production of immobilized biocatalysts of industrial importance using matrices and methods that fulfill specified operational and environmental requirements. For that reason, hydrogels of natural origin and the entrapment method become increasingly popular in terms of enzyme immobilization. The presented work is the comparative research on invertase immobilization using two natural hydrogel matrices—alginate and gelatin. During the study, we provided the molecular insight into the structural characteristics of both materials regarding their applicability as effective enzyme carriers. In order to confirm our predictions of using these hydrogels for invertase immobilization, we performed the typical experimental studies. In this case, the appropriate conditions of enzyme entrapment were selected for both types of carrier. Next, the characterization of received invertase preparations was made. As a final experimental result, the gelatin-based hydrogel was selected as an effective carrier for invertase immobilization. Hereby, using mild conditions and a pro-ecological, biodegradable matrix, it was possible to obtain very stable and reactive biocatalyst. The choice of gelatin-immobilized invertase preparation was compatible with our predictions based on the molecular models of hydrogel matrices and enzyme used.

Entrapment of glutaraldehyde‐crosslinked cells from Aspergillus oryzaeIPT‐301 in calcium alginate for high transfructosylation activity

AbstractBACKGROUNDFructooligosaccharides (FOS) are sweeteners produced through the use of enzymes called fructosyltransferases (FTases) (EC 2.4.1.9). However, FTase reuse is meagre and the cost of the enzyme production is high, making FOS production economically unfeasible. In order to address these issues, this study aims to immobilize cells from Aspergillus oryzae IPT‐301, containing FTase enzyme previously glutaraldehyde‐crosslinked, by means of entrapment in calcium alginate beads. The conditions to obtain the particles, such as alginate type, mycelium mechanical dispersion, degree of crosslinking, size of the beads, and their reflections on transfructosylation activity (AT) were evaluated previously.RESULTSThe highest AT used low‐viscosity alginate solution (4.0% w/w) crosslinked with calcium chloride (0.2 mol L−1) and beads of mean diameter 2.15 mm. The entrapment conditions were complemented by conducting the reaction under different temperatures, pH values, substrate concentrations and by reusing the beads. The highest transfructosylation activities were obtained under reaction conditions of 50 °C, pH 5.5 and substrate concentration 400 g L−1.CONCLUSIONThe AT levels found with the glutaraldehyde‐crosslinked and entrapped cells in calcium alginate were ≈70% higher than the ones obtained with free cells, not glutaraldehyde‐crosslinked. Moreover, the immobilized cells (crosslinked+entrapped) retained their AT up to the third cycle of total sucrose depletion in the reaction medium, attesting to the potential use of the beads in continuous FOS production. © 2020 Society of Chemical Industry

Optimization and Immobilization of alpha-amylase from &lt;i&gt;Bacillus subtilis&lt;/i&gt; in calcium alginate and calcium alginate – cellulosic residue beads

In this study, Alpha amylase from Bacillus subtilis was immobilized by entrapment in Calcium Alginate beads (CA). To improve the properties of these beads, alginate was blended with Cellulosic Residue (CR) obtained from sorghumstarch extraction. The conditions of entrapment were optimized for a maximum immobilization yield (Y%) by mathematical statistics, where the 23-full factorial design of experiments was used. The properties of calcium alginate beads were improved by comparing the activity of immobilized enzymes in the hydrolysis of starch. The activity of the immobilized enzyme by Calcium Alginate /Cellulosic Residue (CA/CR) was found to be higher than the Calcium Alginate method. Zn2+ and Cu2+ have inhibitory effects on both immobilized enzymes. The Bacillus subtilis immobilized in alginate can be reused for 7 cycles with 12.7 μmol of reduced sugars and 6 cycles for the entrapped enzyme in CA/CR with 30 μmol of reduced sugars.

CH4 accumulation characteristics and relationship with deep CO2 fluid in Lishui sag, East China Sea Basin

Co-accumulation of carbon dioxide and hydrocarbon gas is common and widely existing in oil and gas basins. Such two natural pools are located in Lishui sag (East China Sea Shelf Basin), as a favorable prospecting area for exploration. CO2 gas derived from inorganic mantle sources and CO2 accumulation times have been investigated. In this study, petrographic observation shows pure CH4, CH4-rich, H2O-rich and hybrid CH4-CO2 fluid inclusions exist in healed micro-fractures and overgrowths of quartz mineral in Palaeocene reservoirs of Lishui sag. The pressure–temperature–time–composition (PVT–x) properties of CH4-bearing inclusions were obtained by Raman quantitative analysis and thermodynamic models. These results provide important constraints on the P-T entrapment conditions and predict relative accumulation time of CH4 fluid. Combination of carbon isotope analyses, inclusion petrography, microthermometry, PT entrapment conditions of CH4-bearing inclusions, hydrocarbon generation and simulation of burial history permit to assign periods of CH4 fluid activity and its sequence with CO2 fluid. Methane charging time occurs during two stages in LS-A: low density CH4 fluid (~0.10 g/cm3 or lower) were trapped during late Oligocene (30-20 Ma) and high density (>0.115 g/cm3) during a Pliocene (8-1 Ma) CH4 accumulation event. CO2 fluid accumulation (Miocene, 21-4 Ma) displaced the methane gas trapped in the early stage. Pliocene CH4 fluid partial displaced Miocene CO2 fluid. In well B, only high density (0.144–0.153 g/cm3) recorded a late Oligocene to early Miocene (36-19 Ma) CH4 accumulation event, Pliocene (5-3 Ma) CO2 fluid displaced early CH4 fluid. Micro-thermometry, composition of fluid inclusion, features of reservoir, thermal maturity reflect hydrothermal fluid vertical migration and the existence of Supercritical CO2 extraction.