bluuebunny/crossref_metadata_2025_split huggingface dataset:
Engineering better catalytic activity and acidic adaptation into Kluyveromyces marxianus exoinulinase using site‐directed mutagenesis
Authors: Wang Cheng‐Hua , Xiong Wu‐Ping , Huang Cheng , Li Xiao‐Ming , Wang Qing‐Yan , Huang Ri‐Bo 
Published: October 2020

AbstractBACKGROUNDExoinulinase catalyzes the successive removal of individual fructose moiety from the non‐reducing end of the inulin molecule, which is useful for biotechnological applications like producing fructan‐based non‐grain biomass energy and high‐fructose syrup. In this study, an exoinulinase (KmINU) from Kluyveromyces marxianus DSM 5418 was tailored for increased catalytic activity and acidic adaptation for inulin hydrolysis processes by rational site‐directed mutagenesis.RESULTSThree mutations, S124Y, N158S and Q215V distal to the catalytic residues of KmINU were designed and heterologously expressed in Pichia pastoris GS115. Compared to the wild‐type, S124Y shifted the pH‐activity profile towards acidic pH values and increased the catalytic activity and catalytic efficiency by 59% and 99% to 688.4 ± 17.03 s−1 and 568.93 L mmol−1 s−1, respectively. N158S improved the catalytic activity under acidic pH conditions, giving a maximum value of 464.06 ± 14.06 s−1 on inulin at pH 4.5. Q215V markedly improved the substrate preference for inulin over sucrose by 5.56‐fold, and showed catalytic efficiencies of 208.82 and 6.88 L mmol−1 s−1 towards inulin and sucrose, respectively. Molecular modeling and computational docking indicated that structural reorientation may underlie the increased catalytic activity, acidic adaptation and substrate preference.CONCLUSIONSThe KmINU mutants may serve as industrially promising candidates for inulin hydrolysis. Protein engineering of exoinulinase here provides a successful example of the extent to which mutating non‐conserved substrate recognition and binding residues distal to the active site can be used for industrial enzyme improvements. © 2020 Society of Chemical Industry
Advanced materials on sample preparation for safety analysis of aquatic products
Authors: Lai Huasheng , Li Gongke , Zhang Zhuomin 
Published: October 2020

AbstractSafety analysis of aquatic products has been a challenge in recent years due to the serious matrix interference, complex characteristics, and ultra‐low content of analytes. Introducing advanced materials to sample preparation technique can greatly improve the extraction, enrichment, and separation for further qualification and quantification of target analytes by coupling with consequent analytical technologies. Based on this scope, this review is mainly introducing advanced materials on the sample preparation for safety analysis of aquatic products in the past decade. After introducing the importance of the corresponding advanced materials, advanced materials are used for the sample preparation and in the improvement of safety analysis result of aquatic products. Advanced materials for sample preparation of aquatic products were reviewed including carbon materials, metal organic frameworks, covalent organic frameworks, molecularly/ions imprinted polymers, etc. Then, applications of the advanced materials for the analysis of specific fishery analytes (antibiotics, anesthetic, preservatives, etc.) were briefly introduced. Conclusions and perspectives on advanced materials for sample preparation and safety analysis of aquatic products were also presented.
Assessing land use changes and livelihood outcomes of rural people in the Chittagong Hill Tracts region, Bangladesh
Authors: Ahammad Ronju , Stacey Natasha , Sunderland Terry 
Published: October 2020

AbstractLand use change is a pressing concern for the livelihoods of people in tropical developing countries. Changes in land use from swidden (shifting cultivation) agriculture to smallholder tree‐dominated areas producing timber, fruits and cash crops can result in changing livelihood outcomes for rural communities. This paper examines land use patterns of rural households and the association with food production and income across three different zones of various forest proximity across a landscape gradient (remote, intermediate and on‐road) in the Chittagong Hill Tracts region of Bangladesh. We conducted in‐depth semi‐structured surveys of households (175–300) and farm owners (30) to collect information on people's perceptions of land use change, present land use patterns and contributions to food production and income. Our research found that more than half of the surveyed households experienced a decline in the land available for food production over the past 30 years. The land use patterns revealed decreasing crop lands (mainly swidden shifting cultivation/land rotation farms) and an increase in areas of planted trees within this landscape. However, household use of the reduced crop land has not affected food production in the on‐road zone, whereas the diversity of food sources has declined. People living in more remote areas engaged in swidden farming and used larger areas of crop and fallow lands, fruit orchard and accessed natural forest lands that provide a diverse reservoir of food sources. The current land uses contribute to variations in annual household income across zones, with remote dwelling people earning less to those living closer to urban areas in the intermediate and on‐road zones. In summary, this transition of land uses over three decades and changes in income and food availability cannot be generalised across the region because of zone specific differences. We recommend a broader and context‐reliant landscape management approach in consideration of the diversity of forest and tree benefits for the livelihoods of people in the region.
Dynamic change of the gastrointestinal bacterial ecology in cows from birth to adulthood
Authors: Guo Chun Y. , Ji Shou K. , Yan Hui , Wang Ya J. , Liu Jing J. , Cao Zhi J. , Yang Hong J. , Zhang Wen J. , Li Sheng L. 
Published: October 2020

AbstractThe gut microbiota plays multiple critical roles in maintaining the health of the host, especially in ruminants. However, our understanding of the establishment of gut microbiota from birth to adulthood is still limited. To address this, the bacterial ecology of the rumen, abomasum, duodenum, and rectum in Holstein cows ranging in age from 1 week to 5 years old was investigated using 16S rRNA gene sequencing in this study. A major change in the composition, diversity, and abundance of bacteria was observed with increased age (p < 0.05). Microbiota gradually matured in each gut segment and followed the Gompertz model when the Chao1, Shannon, and maturity indexes (p < 0.05, r > 0.94) were applied. Importantly, the Gompertz model parameter differed between the gut segments, with the highest microbiota growth rate found in the rectum, followed by the rumen, abomasum, and duodenum. Compared to older animals, greater microbiota similarities were found in the adjacent gut segments of younger animals (p < 0.05). Our findings indicate that gut microbiotas are established quickly when cows are young and then slow with age and that early in life, hindgut microbiota may be more easily affected by the foregut microbiota.
Effects of contrast agents on relaxation properties of 31P metabolites
Authors: Valkovič Ladislav , Lau Justin Y. C. , Abdesselam Ines , Rider Oliver J. , Frollo Ivan , Tyler Damian J. , Rodgers Christopher T. , Miller Jack J. J. 
Published: October 2020

PurposePhosphorous MR spectroscopy (31P‐MRS) forms a powerful, non‐invasive research tool to quantify the energetics of the heart in diverse patient populations. 31P‐MRS is frequently applied alongside other radiological examinations, many of which use various contrast agents that shorten relaxation times of water in conventional proton MR, for a better characterisation of cardiac function, or following prior computed tomography (CT). It is, however, unknown whether these agents confound 31P‐MRS signals, for example, 2,3‐diphosphoglycerate (2,3‐DPG).MethodsIn this work, we quantitatively assess the impact of non‐ionic, low osmolar iodinated CT contrast agent (iopamidol/Niopam), gadolinium chelates (linear gadopentetic acid dimeglumine/Magnevist and macrocyclic gadoterate meglumine/Dotarem) and superparamagnetic iron oxide nanoparticles (ferumoxytol/Feraheme) on the nuclear T1 and T2 of 31P metabolites (ie, 2,3‐DPG), and 1H in water in live human blood and saline phantoms at 11.7 T.ResultsAddition of all contrast agents led to significant shortening of all relaxation times in both 1H and 31P saline phantoms. On the contrary, the T1 relaxation time of 2,3‐DPG in blood was significantly shortened only by Magnevist (P = .03). Similarly, the only contrast agent that influenced the T2 relaxation times of 2,3‐DPG in blood samples was ferumoxytol (P = .02).ConclusionOur results show that, unlike conventional proton MR, phosphorus MRS is unconfounded in patients who have had prior CT with contrast, not all gadolinium‐based contrast agents influence 31P‐MRS data in vivo, and that ferumoxytol is a promising contrast agent for the reduction in 31P‐MRS blood‐pool signal.
Primary caregiver decision‐making in hematopoietic cell transplantation and gene therapy for sickle cell disease
Authors: Sinha Cynthia B. , Bakshi Nitya , Ross Diana , Loewenstein George , Krishnamurti Lakshmanan 
Published: October 2020

AbstractBackgroundImproved outcomes and the availability of clinical trials of hematopoietic cell transplantation (HCT) from alternate donors and genetically modified autologous hematopoietic progenitor cells have expanded the applicability of HCT for sickle cell disease (SCD). To understand the perspective of primary caregivers exploring HCT in the current milieu, we asked the research question “What motivates primary caregivers to decide to consider HCT and to seek, and to attend, an HCT consultation?”ProceduresWe conducted qualitative interviews with primary caregivers within one week after a consultation for HCT for SCD. Data were analyzed using open and axial coding stages of grounded theory methodology.ResultsWe interviewed 29 primary caregivers (26 females, age 29 to 64 [median 42] years). Primary caregivers report of SCD complications in their child included at least one in the last year by 23 (82%), few or none by 8 (28%), and pain on ≥3 days a week by 13 (46%) primary caregivers. Qualitative analysis revealed that primary caregivers, (i) learn about curative options through social networks, social media, and the news media; (ii) seek consultation because of their child's diminished quality of life, recent complications, an imminent major medical decision, or anxiety about future severe complications; and (iii) see gene therapy as a new, less invasive, and more acceptable treatment.ConclusionPrimary caregivers of children with SCD learn about HCT through social networks, social and news media, and explore HCT as a means to prevent SCD complications and help their child live a normal life.
Epidemiology and survival of childhood cancer in Turkey
Authors: Kebudi Rejin , Alkaya Dilek Uludag 
Published: October 2020

AbstractIntroductionThe aim of this study is to evaluate demographics, clinical data, and survival rates of children with cancer over 22 years, and to compare the outcomes, before and after a national health reform was performed.Material and MethodsFiles of patients, aged 0‐19 years, diagnosed with cancer at the Istanbul University Oncology Institute during 1990‐2012 were evaluated retrospectively.ResultsThe mean age at diagnosis of 2413 patients was 7.5 ± 5.1 years (range 3 days to 19 years). Male/female ratio was 1.26. After 2002, the number of patients diagnosed at a localized/low‐risk stage compared to advanced stage significantly increased (60.7% vs 65.1%, P = .03). Comparing the period before 2002 to after 2002, a lower percentage of patients were diagnosed with advanced stage non‐Hodgkin lymphoma (62.1% vs 45.1%, P = .03), retinoblastoma (9.5% vs 1.4%, P = .005), soft tissue sarcomas (52.1% vs 38.3%, P = .01), neuroblastoma (82.4% vs 56.2%, P = .005), and carcinomas (72.9% vs 65.4%, P = .04) after 2002. The 5‐year survival rate of all patients during the entire period was 74.4%. The survival rate significantly increased for non‐Hodgkin lymphoma (63.7% vs 91.8%, P < .0001), neuroblastoma (46.8% vs 70.5%, P = .025), and renal tumors (70% vs 92.3%, P = .013) after 2002.ConclusionsThe increase in patients diagnosed at a localized/low‐risk stage and the increase in survival of some types of cancer over years is promising. The national health care reform, enabling patients to easily access free health services, increased awareness, improvement in oncological treatment, and supportive care may have contributed to the progress achieved, and may be a model for other developing countries.
Profiling of phenolic compounds in desiccation‐tolerant and non‐desiccation‐tolerant Linderniaceae
Authors: Passon Maike , Weber Fabian , Jung Niklas Udo , Bartels Dorothea 
Published: October 2020

AbstractIntroductionCraterostigma plantagineum and Lindernia brevidens are resurrection plants, so these plants can tolerate desiccation of their vegetative tissues. Different components and mechanisms contribute to desiccation tolerance and secondary plant metabolites, like phenolic compounds, may play a role during these processes.ObjectivesSecondary plant metabolites of the two resurrection plants, C. plantagineum and L. brevidens as well as the closely related desiccation sensitive species, L. subracemosa, were investigated regarding the polyphenol profile.Material and methodsSecondary plant compounds were extracted with acidified methanol and analysed with ultra‐high‐performance liquid chromatography electrospray ionisation mass spectrometry (UHPLC‐ESI‐MS). Phenolic compounds were identified by comparing of ultraviolet (UV) and MSn‐spectra with published data. All compounds were quantified as verbascoside equivalents by external calibration at the compound specific wavelength.ResultsIn total, eight compounds that belong to the subclass of phenylethanoid glycosides and one flavone, luteolin hexoside pentoside, were identified. Two of these compounds exhibited a fragmentation pattern, which is closely related to phenylethanoid glycosides. The predominantly synthesised phenylethanoid in all of the three plant species and in every stage of hydration was verbascoside. The total content of phenolic compounds during the three stages of hydration, untreated, desiccated, and rehydrated revealed differences especially between C. plantagineum and L. brevidens as the latter one lost almost all phenolic compounds during rehydration.ConclusionThe amount of verbascoside correlates with the degree of desiccation tolerance and verbascoside might play a role in the protective system in acting as an antioxidant.
Unitarity Entropy Bound: Solitons and Instantons
Authors: Dvali Gia 
Published: October 2020

AbstractWe show that non‐perturbative entities such as solitons and instantons saturate bounds on entropy when the theory saturates unitarity. Simultaneously, the entropy becomes equal to the area of the soliton/instanton. This is strikingly similar to black hole entropy despite absence of gravity. We explain why this similarity is not an accident. We present a formulation that allows to apply the entropy bound to instantons. The new formulation also eliminates apparent violations of the Bekenstein entropy bound by some otherwise‐consistent unitary systems. We observe that in QCD, an isolated instanton of fixed size and position violates the entropy bound for strong 't Hooft coupling. At critical 't Hooft coupling the instanton entropy is equal to its area.
A systematic benchmarking of 31P and 19F NMR chemical shift predictions using different DFT/GIAO methods and applying linear regression to improve the prediction accuracy
Authors: Gao Peng , Zhang Jie , Chen Hongming 
Published: October 2020

AbstractA systematic benchmark study of phosphorus and fluorine nuclear magnetic resonance chemical shift predictions using six different density functional theory (DFT)/the gauge‐including atomic orbital (GIAO) methods was conducted. Two databases were compiled: one consists of 35 phosphorus‐containing molecules, which cover the most common intramolecular bonding environments of trivalent and pentavalent phosphorus atoms; the other is composed of 46 fluorine‐containing molecules. The characteristics of each DFT/GIAO method with different solvent models were demonstrated in detail. The application of linear regression between the calculated isotropic shielding constants and experimental chemical shifts was applicable to improving the prediction accuracy. The best methods with the solvation model based on density (SMD) and conductor‐like polarizable continuum model (CPCM) implicit solvent models for 31P chemical shifts predictions are able to yield a root‐mean‐square deviation of 5.58 and 5.42 ppm, respectively; for 19F, the corresponding lowest prediction errors with these two applied solvent models are 4.43 and 4.12 ppm, respectively. The developed scaling factors fitted from linear regression are applicable to enhancing the chance of successful structural elucidations of phosphorus or fluorine‐containing compounds as an efficient complement to 13C, 1H, 11B, and 15N chemical shift predictions.
Visualizing NMR‐shielding effect in fullerene‐ZnPc aggregates: Characteristic patterns of ZnP‐based hosts and encapsulation nature from DFT calculations
Authors: MacLeod Carey Desmond , Rodríguez‐Kessler Peter L. , Muñoz‐Castro Alvaro 
Published: October 2020

AbstractThe formation of supramolecular aggregates incorporating C60 fullerenes can be followed and characterized by nuclear magnetic resonance (NMR) measurements. Here, we unravel the particular patterns provided by zinc‐porphyrin (ZnP)‐bridged dimers, where the aromatic character of each ZnP unit leads to an enhanced shielding region for the closest fullerene atoms, denoting a slight shielding effect for the equatorial atoms. The nature of the stabilization is discussed and compared to a single ZnPC60 aggregate and a ZnP‐dimer (ZnP2C60) model, with a significant contribution from noncovalent ππ interactions, allowing us to address the role of bridging chains. The experimental 13C‐NMR spectrum of C60 in a bridged ZnP dimer shows a single peak owing to the constant tumbling inside the host, which averages the different groups of carbon atoms. The calculations in a static scenario reveal information concerning the local chemical environment underlying the observed shift in relation to isolated C60. We expect that the current approach can be useful to rationalize and predict the origin of the NMR shift upon the formation of host‐guest aggregates involving small and large host species.
Robust exponential quasi‐passivity and global stabilization for uncertain switched nonlinear systems
Authors: Pang Hongbo , Liu Shuo 
Published: October 2020

SummaryIn this article, a concept of robust exponential quasi‐passivity for uncertain switched nonlinear systems is first proposed to describe the overall exponential quasi‐passivity property in the absence of the exponential quasi‐passivity property of the subsystems. Compared to passive systems, quasi‐passive system that may contain sources of energy can produce energy itself. On this basis, several issues including robust exponential quasi‐passivity conditions, feedback robust exponential quasi‐passification, and globally practical stabilization for switched nonlinear systems with structural uncertainties are investigated. First, a more general switching law is designed to render uncertain switched nonlinear systems robust exponentially quasi‐passive. This result is generalization of robust KYP Lemma. Second, the feedback robust exponential quasi‐passification problem for uncertain switched nonlinear systems is solved by the co‐design of a state‐dependent switching law and state feedback controllers. Third, an robust exponentially quasi‐passive switched nonlinear system under a given switching signal is shown to be practically stabilized by a set of output feedback controllers. Furthermore, the obtained results are applicated to solve globally practical stabilization problem for uncertain switched nonlinear systems whose subsystems have any same relative degree by combining the proposed robust exponential quasi‐passification method with backstepping technique. Moreover, a set of feedback controllers and a state‐dependent switching law are designed constructively. Finally, the proposed methods are applied to the investigation of a switched continuous stirred tank reactor system.
Stability analysis for switched stochastic delayed systems under asynchronous switching: A relaxed switching signal
Authors: Zhang Meng , Zhu Quanxin 
Published: October 2020

SummaryThis article deals with the stochastic input‐to‐state stability (SISS) for a class of switched stochastic systems under asynchronous switching. Asynchronous switching refers to that the switching of the candidate controllers does not coincide with the switching of system modes. In addition, the time delays appear in the state. Unlike the existing works, we not only allow the coefficients of the estimated upper bound for the diffusion operator of a Lyapunov function to be increasing during the matched time interval, but also in the unmatched time interval. Meanwhile, by using the switching signals which prevail over the traditional average dwell time scheme and the Razumikhin theorem, the SISS property is obtained. Especially our results improve some existing ones regarding asynchronous switching in the literature. Two examples are used to demonstrate the applicability of the results.
Thermally Responsive Anti‐Protein Adsorption Coated Capillary for Electrophoretic Analysis of Proteins
Authors: Cong Hailin , Wang Fang , Chen Yao , Hu Hao , Chen Xin , Shen Youqing , Yu Bing 
Published: October 2020

AbstractA thermal responsive and reusable capillary column coated with poly (ethylene glycol) diacrylate dithiothreitols (PEGDA‐DTT‐dithiols) was prepared using photosensitive diazo resin (DR) as a coupling agent. DR and PEGDA‐DTT‐dithiols film were self‐assembled on the inner surface of silica capillary with hydrogen bonding. Due to the photo‐sensitive effect of DR, the coating will be covalently cross‐linked under ultraviolet light irradiation, the application of photosensitive DR can provide a simple and environmentally friendly strategy for preparing covalently coated capillaries. PEGDA‐DTT‐dithiols coated column, which not only separates the baseline of the four mixed model proteins, but also has good separation effect on real samples, showing excellent anti‐protein adsorption performance. The thermal responsive capillary coating can be cleaned up and regenerated facilely with a heating treatment after the column was contaminated by proteins and reused without reducing efficiency. The thermal responsive PEGDA‐DTT‐dithiols coated capillary has the advantages of environmental friendliness and recycling.