Applied Natural Sciences

Unconventional shale gas is vital for clean energy and energy security. However, its ultralow permeability leads to low primary recovery. This study investigates CO2-enhanced shale gas recovery (ESGR) in the Yanchang shale reservoir by using a CMG-GEM compositional simulator with a dual porosity/permeability model, evaluating well placements and both continuous and huff-and-puff injection methods. Findings show that continuous CO2 injection increases CH4 recovery by 7.59% over no injection. For huff-and-puff, a shorter 1 year injection period yielded the highest CH4 recovery; extending injection to 2 and 3 years caused declines of 1.93 and 3.89%, respectively. Conversely, using five injection cycles resulted in the highest cumulative CH4 recovery. Starting CO2 injection later in the production lifecycle also optimized recovery, with a 1.15% increase observed after 10 years of initial CH4 production, as it utilizes more favorable reservoir pressure conditions. Moreover, for CO2 storage, the reservoir exhibited 99.565% efficiency during continuous injection. In huff-and-puff, longer injection durations improved storage, with a 3 year period achieving 98.35% efficiency. Similarly, five injection cycles yielded the highest storage efficiency, at 99.12%. Delaying the injection start time also significantly enhanced CO2 storage, with efficiency improving from 96.38% after 1 year to 98.35% after 10 years, leveraging improved pressure dynamics over time. In addition, a sensitivity analysis confirmed that key reservoir parameters, such as matrix porosity, permeability, and pressure, significantly influence both gas recovery and storage capacity. Critical hydraulic fracture parameters, including half-length, spacing, conductivity, and bottom-hole pressure, are essential for optimizing gas flow and CO2 injection efficiency. This study applies to tight shale gas formations worldwide, offering insights into optimizing hydraulic design and injection strategies to enhance shale gas production and CO2 sequestration, supporting global carbon management and climate change mitigation.

Herein, we introducea powerful alkene difunctionalizationprocesswhere anomeric amides (i.e., N-halogenated-O-activated hydroxylamines) react directly with olefins,without the use of catalysts or additives, to yield the corresponding N-haloalkyl-O-activated hydroxylamines.These multifunctional hydroxylamines (MFHAs), containing both alkylhalide and O-activated hydroxylamine moieties, areconvenient building blocks/electrophilic aminating reagents for thesynthesis of structurally complex N-unprotected secondaryamines and various N-heterocycles (i.e., N-alkyl/N-aryl aziridines, pyrrolidines,oxazolidinones and tetrahydroquinolines). Both activated and unactivatedalkenes (including cyclic and acyclic olefins, dienes, and enynes)are effectively converted to the corresponding difunctionalized hydroxylaminederivatives with excellent atom economy. The versatility of MFHAswas demonstrated through the synthesis of various nitrogen-containingmolecules. Density functional theory (DFT) calculations and moleculardynamics simulations, together with mechanistic experiments, indicatethat the reaction proceeds through a radical chain addition mechanisminitiated by a polar-to-radical crossover step.

The effect of production inputs on product properties in the production of polyethylene terephthalate (PET) material by additive manufacturing method was investigated and optimum production parameters were tried to be determined. The degradation of PET material in different filling patterns, mechanical and physical properties of the samples produced at different print speeds, layer thicknesses and filling patterns were investigated. In the study, it was determined that the most effective input on the mechanical properties of the samples was the filling pattern, followed by the print speed and the least effective input was the layer thickness. However, it was determined that the most effective inputs on the surface roughness and dimensional accuracy of the produced samples were layer thickness and filling pattern, respectively. Since the degree of influence of the filling pattern on mechanical and physical properties is higher than other production inputs, hydrolytic degradation properties of 9 different filling patterns were investigated.

Allostery refers to the activity regulation of biological macromolecules originating from the binding of an effector molecule at the allosteric site that is distant from the active site. The few existing allosteric data sets have not been updated with recent discoveries of allosteric proteins and are challenging to use for data-intensive tasks. Instead of providing another data set bound to become outdated, we present the AlloBench pipeline to create high-quality data sets of biomolecules with allosteric and active site information suitable for computational and data-driven studies of protein allostery. The pipeline produces a data set of 2141 allosteric sites from 2034 protein structures with 418 unique protein chains by integrating information from AlloSteric Database, UniProt, Mechanism and Catalytic Site Atlas, and Protein Data Bank. Furthermore, we use a subset of 100 proteins from the AlloBench data set to quantitatively compare the performance of currently available allosteric site prediction tools: APOP, PASSer, Ohm, ALLO, Allosite, STRESS, and AlloPred. Such a large-scale benchmarking of these programs has not been undertaken on a common test set. The results show a significant need for improvement, as the accuracy for all programs is well below 60%, with PASSer (Ensemble) outperforming the rest. The AlloBench pipeline will not only promote the development of improved allosteric site prediction tools but also serve as a reference for studying allostery in general.

Virus-like particles (VLPs) are a promising platform as carriers for vaccination and general treatments against many pathogens. While there are long development timelines and challenges in the production of clinical-grade VLPs, this study introduces a platform process for the production and purification of those particles, aided by process analytical technology (PAT). Fed-batch cultivation and consecutive purification, including novel membrane technology and anion-exchange chromatography, showed robust process performance with design and control spaces defined in previous studies. A novel, stable HEK293F cell line generated using the highly efficient Sleeping Beauty transposon vector technology showed a 3.6-fold increase in productivity compared to a reference cell line established using PiggyBac vector components. The in situ microscope from SOPAT GmbH successfully predicted the viable cell density of a mammalian cell culture, which had been demonstrated for the first time with this type of ISM. Furthermore, Raman, FTIR, and DAD spectroscopies were able to predict the main metabolites and impurities when implemented in the upstream process. FTIR spectra also depicted changes in the buffer composition, therefore enabling robust process control for the prediction of the buffer exchange rate during diafiltration. The applied PAT strategy can deliver real-time data, which is crucial when predictive control is realized with a digital twin. Combined with a robust platform process, the stated control strategy can pave the way toward the autonomous production of VLPs.

SummaryGuanylate kinase-associated protein (GKAP) is a large postsynaptic scaffold protein bearing two closely spaced noncanonical binding sites for the bivalent dynein light chain LC8 hub protein. This might allow the formation of heterogeneous complexes with different sizes and topologies. Here, we show that a well-defined hexameric complex is formed, composed of 2 GKAP molecules and 2 LC8 dimers. Using NMR spectroscopy, we demonstrate that the LC8-binding segment of GKAP is intrinsically disordered and the flexibility of the linker region is largely retained even in the complex form. Molecular dynamics calculations suggest that besides the tightly bound residues, the hexamer also exhibits several dynamically interchanging interactions. The flanking regions of the two binding sites on GKAP exhibit different interaction patterns, hinting at additional contacts that might explain the fixed stoichiometry of the assembly. Our results demonstrate that constrained stoichiometry can coexist with substantial flexibility in a multivalent system.

Abstract The genusFarlowellahas been historically challenging, in part due to the difficulty in defining diagnostic characters which allow to clearly set apart and identify the species.Farlowella colombiensisRetzer & Page 1997 is one of such examples, whose diagnostic characters were based on caudal-fin colour pattern, body cover ventral pattern, and details of the head. We herein reassess the taxonomic status of this species against congeners of theF. acusspecies group (F. acus,F. martini,F. mitoupibo,F. venezuelensis, andF. vittata). We found no significant differences betweenF. colombiensisandF. acusin morphometric, meristic, and discrete characters, therefore renderingFarlowella colombiensisa junior synonym ofFarlowella acus. We provide remarks on different species of theF. acusgroup in Colombia, as well as description of sexual dimorphism in the genital papilla for the first time in the subfamily. We also provide a key to the species of theF. acusspecies group in Colombia.

This study investigates doped CdZnS thin films synthesized through the ultrasonic spray pyrolysis technique, followed by annealing at temperatures of 400 and 500 °C. X-ray diffraction analysis demonstrated that both undoped CdZnS and Cu-doped CdZnS thin films exhibit cubic crystal structures, with a preferred orientation along the (111) plane. Scanning electron microscopy (SEM) measurements indicated that the CdZnS thin film has a smooth surface, whereas the Cu-doped CdZnS film shows clustered particles, attributed to the effect of copper doping acting as an activator metal ion. Electron dispersive scanning (EDS) analysis confirmed that the Cd, Zn, and S elements are present in acceptable chemical stoichiometry (Cd + Zn/S = 1:1), with a ratio of 3:1, consistent with the molar amounts used in the precursor solutions. The band gap of the CdZnS thin film decreased from 3.12 to 2.56 eV after annealing at 500 °C, attributed to an increase in crystal size. In contrast, the band gap of the Cu-doped CdZnS thin film decreased from 2.51 to 2.22 eV, lower than that of pure CdZnS, due to the formation of additional phases such as zinc oxide and copper oxide within the CdZnS host structure during annealing.

In this study, we use discrete Appell convolution to define the sequence of Laguerre type twice-iterated Appell polynomials. We obtain explicit representation, recurrence relation, determinantal representation, lowering operator, integro-partial raising operator and integro-partial differential equation. In addition, the special cases of this new family are investigated using Euler and Bernoulli numbers. We also state their corresponding characteristic properties.

The Strongylophthalmyia ustulata group (Diptera: Brachycera: Strongylophthalmyiidae) from China is revised. Five species are recognized, including three new species (S. elongata sp. nov., S. flavimarginata sp. nov., and S. sivelli sp. nov.) and one new record species [S. ustulata (Zetterstedt, 1847)]. Strongylophthalmyia yaoshana Yang & Wang, 1998, previously placed in the S. ustulata group, is herein transferred to the S. fascipennis group based on its bare antennal arista and patterned wing. A key to the Chinese species of the S. ustulata group is provided.