bluuebunny/crossref_metadata_2025 huggingface dataset:
Röntgenstrukturuntersuchung des flüssigen Acetonitrils
Authors: Kratochwill Alwin , Weidner Jörg U. , Zimmermann Herbert
Published: October 2023

Aus der experimentellen Intensitätsverteilung der Röntgenstreustrahlung wurden die radiale Elektronendichteverteilung und die reduzierte Intensität des flüssigen Acetonitrils bei 20 °C ermittelt. Letztere läßt sich unter Verwendung eines genäherten Molekülmodells in einen intra‐und intermolekularen Anteil zerlegen. Durch Optimierungsrechnungen wurden daraus die Struktur des Moleküls und die Nahordnung in flüssiger Phase ermittelt.

Für das Molekül ergaben sich: C ‐ C = 1,465 Å, C ‐ N = 1,153 Å. Die mittleren Schwingungsamplituden waren etwas größer als solche, die aus IR‐Daten mit Normalkoordinaten berechnet wurden.

Die Nahordnung der Moleküle in flüssiger Phase haben wir an Hand verschiedener, schrittweise verfeinerter Strukturmodelle untersucht. Beste Übereinstimmung mit dem Experiment ergab sich bei einem Flüssigkeitsmodell mit Korrelationsclustern. Innerhalb der Cluster liegt eine Struktur vor, die durch ein Korrelationsgitter beschrieben wird. Die Einheitszelle ist rhombisch und enthält acht Moleküle, deren Dipolachsen entweder parallel oder antiparallel zur a‐Achse liegen. Die Besetzung der Gitterplätze beträgt 95%. Die Abnahme der Lage‐ und Orientierungskorrelation mit steigendem Molekülabstand wurde berücksichtigt.

Der Einfluß der räumlichen Begrenzung der Cluster auf die Radialverteilung läßt sich durch eine Gewichtsfunktion H(r) beschreiben. H(r) charakterisiert die Größe des Clusters und die Korrelation der Moleküle innerhalb desselben. Wie die Optimierungsrechnungen ergaben, besteht vollständige Lage‐ und Orientierungskorrelation für die vier Moleküle der ersten Koordinationssphäre um ein Zentralmolekül. Der mittlere Zentrenabstand zum Zentralmolekül beträgt 3,8 Å. Der Clusterdurchmesser ergibt sich zu ca. 11 Å. Dieser Wert entspricht gut einem Clusterdurchmesser von ca. 13 Å, der sich aus der Dipol‐Dipol‐Wechselwirkung abschätzen läßt.

Der R‐Faktor für das Strukturmodell beträgt R = 0,077.
Reactions in the Formation of Interstellar Radicals and Molecules
Authors: Harteck P. , Reeves R. R.
Published: October 2023

In this paper the authors have tried to develop a series of reaction mechanisms which seems to explain the occurrence of the observed interstellar molecules in the dark clouds. Special emphasis is given in this paper to the dominant role of H3+ which acts as a proton donor for the formation of ion molecules like COH+, CH+, NH2+, which are very reactive and lead over a series of intermediates to observed species such as: OH, H2CO, NH3, CH, and HCN. As will be seen, there exists a large variety of possible mechanisms for the formation of certain species and it is premature in many cases to decide which of these mechanisms is dominant. We like to emphasize that the formation of these molecules occurs in the gas phase, a fact which does not exclude the formation of molecules on the surface of grains or in ion‐clusters.
Die Dehydratisierung des t‐Butanols an HY‐Zeolith. Untersuchungen mit Hilfe der Feldionenmassenspektrometrie
Authors: Zei M. S.
Published: October 2023

In den Feldionenspektren des t‐Butanols wurden an Au‐ und Pt‐Emittern hauptsächlich die lonen (M‐15)+, d. h. (m/n = 59) und (M‐16)+ beobachtet. Die Intensität der restlichen lonen, wie z. B. (M‐18)+ und (M‐17)+ war vernachlässigbar klein. Alle diese lonenspektren sind praktisch von Temperaturänderungen des Emitters unbeeinflußt. Die lonenspektren beim HY‐Zeolith/Pt‐Emitter unterscheiden sich deutlich von denen der reinen Metallemitter. Neben (M‐15)+ treten hier auch merklich (M‐18)+‐und (M‐17)+‐Ionen auf. Mit abnehmender Feldstärke nimmt die Intensität der lonen (M‐15)+ stark, die der anderen dagegen nur wenig ab, weil nur erstere typische Feldionen sind. Letztere dagegen sind, wie die Temperaturabhängigkeit beweist, durch katalytische Aktivierung gebildet worden. Denn sie können bei genügend hoher Temperatur ( > 300 °C) und kleiner Einsatzfeldstärke sogar intensiver als (M‐15)+ auftreten.
Fall‐off Curves of Unimolecular Reactions
Authors: Troe J.
Published: October 2023

Fall‐off curves of thermal unimolecular reactions in the strong collision limit and in the general weak collision case are discussed. The fall‐off curves are represented in (k0, k∞)‐reduced form interpolating between both the limiting low pressure and the limiting high pressure rate constants k0 and k∞. In this reduced form fall‐off curves are very insensitive to details of the theory and simplified models can be used. Reduced fall‐off curves are represented in terms of tabulated Kassel integrals; the two Kassel parameters Sk and Bk are expressed in terms of experimental observables like the apparent activation energies in the low and high pressure limit and the collision efficiency. By this procedure some uncertain parts of the theory of unimolecular reactions can be eliminated from the calculation of fall‐off curves.
Nuclear Magnetic Relaxation of Alkali Metal Ions in Aqueous Solutions
Authors: Hertz H. G. , Holz M. , Keller G. , Versmold H. , Yoon C.
Published: October 2023

The paper is introduced by an analysis of the interrelation between the nuclear magnetic relaxation rates of the cations and anions in the same solution when the nuclear quadrupole interaction is the relaxation mechanism. The treatment is based on an electrostatic model. Higher ion‐ion and ion‐water correlations may cause mutual quenching or reinforcement of the relaxation effect at higher ion concentrations. Experimental results for the relaxation rates of Rb85, Rb87, Cs133, Li7, and Na23 in the ionic state are reported Most of the solutions are alkali halide solutions, partly the results regard mixed electrolyte solutions. An interpretation of the results in terms of higher ion‐ion and ion‐water correlations is discussed. A brief consideration of possible “electronic” contributions to the relaxation is also given.
Nahordnung in Flüssigkeiten I. Ein statistisch‐thermodynamisches Flüssigkeitsmodell auf der Basis von Kontaktwahrscheinlichkeiten
Authors: Schröer Wolffram
Published: October 2023

Ein statistisches Modell der Nahordnung in flüssigen organischen Mischphasen, das einen systematischen Rahmen zur Beschreibung sowohl von thermodynamischen Funktionen als auch von NMR‐Lösungsmittelverschiebungen darstellt, wird vorgestellt. Das Modell ermöglicht es, auf der Basis von Kontaktstellenzahlen, die verschiedenen Atomen und funktionellen Gruppen in Molekülen zugeordnet werden, sowie von den Wechselwirkungsenergien für die Kontakte zwischen den verschiedenen Gruppen die thermodynamischen Funktionen der reinen Stoffe und der Mischungen zu berechnen.
Nahordnung in Flüssigkeiten II. 1H‐ und 13C‐NMR‐Spektroskopische Untersuchungen der Heteroassoziation von Trichloräthylen mit einer starken Base
Authors: Schröer W. , Lippert E.
Published: October 2023

Ein statistisches Modell [1], das die Nahordnung in Flüssigkeiten mit Hilfe von Kontaktwahrscheinlichkeiten beschreibt, wird zur Analyse von NMR‐Lösungsmittelverschiebungen weiter entwickelt, für die Auswertung von 1H‐ und 13C‐Messungen am ternären System Trichloräthylen/Hexamethyl‐Phosphorsäure‐triamid (HMPT)/Cyclohexan verwendet und mit dem Modell der Assoziationsgleichgewichte in idealen Lösungen verglichen. Für die spezifische Wechselwirkung zwischen dem C2Cl3H‐Wasserstoff und dem PO‐Sauerstoff wird ein Enthalpieinkrement von ΔH = ‐(2,58 ± 0,25) kcal/mol erhalten. Die Assoziatverschiebungen der Kerne der CH‐Bindung betragen δH = 2,07 ppm und δ = 5,11 ppm, und zwar beide nach kleinem Feld.
Estimated Distributions of Electronic Redox Levels in aq/eaq−, Haq+/Haq and Some Other Systems
Authors: Henglein A.
Published: October 2023

A crude estimate of the distributions of occupied and unoccupied electronic levels of the redox systems aq/eaq− (aq: water traps) and Haq−/Haq is made using known optical and thermodynamic data of the species involved. The distribution of unoccupied levels in Haq−/Haq is thought to be rather narrow, while that of the occupied levels is wide. Under these circumstances, the hydrated electron may be expected to react with Haq− via tunneling with a nearly diffusion controlled rate. The reaction of the mobile electron with Haq− is expected to be rather slow because of the low density of unoccupied states of the system Haq−/Haq at the energy level of emobile−. Similar considerations were applied to the redox systems Haq/Haq− and OHaq/OHaq−. In both cases, the distribution of unoccupied levels is very broad. The polarograms of H and OH which have recently been measured in the 10−5 s range may be understood in terms of these estimated distribution functions. Ions of high negative redox potentials such as Mgaq2+ are expected to be more reactive towards mobile than towards hydrated electrons.
Research award: Interactive information retrieval
Authors: Kelly Diane
Published: October 2023

EDITOR'S SUMMARY

Diane Kelly progressed from having no idea of information science as a field of inquiry to receiving the 2014 ASIS&T Research Award for her outstanding contributions to the field. Through an early library science course, Kelly met information science scholars and soon started her journey researching interactive information retrieval, search behavior, search interfaces and research methods. She became one of the “user study people” when few in the information retrieval community thought about the search process. Kelly appreciates starting her studies before Google's search box and blinking cursor became pervasive and realizing the wealth of ideas predating Google that are worthy of renewed investigation. She expressed concern that information seeking may become passive receipt of preformed information. In her further research, Kelly hopes to shed more light on the process of search and success metrics.
Passive Drag Reduction Technologies
Authors: Kouser Taiba , Zulfiqar Hina , Misbah Misbah , Alhems Luai Muhammad
Published: October 2023

The developments and involved factors of mature passive drag reduction technologies, i.e., compliant coating, superhydrophobic surfaces, and epoxy coating, are reviewed. Alterations in critical Reynolds number are observed in the presence of passive drag reduction technologies. With the advancement in technology, numerical approaches are introduced to lower the cost and achieve better understanding of physical phenomena such as lowering energy, flow control, designing the surfaces of materials, and so on. Experimental results as well as numerical results are stated. The effects of factors like wetting, contact angle, contact angle hysteresis, roughness, pot life, and coating aging responsible for drag reduction are also briefly presented with numerical and experimental perspective analyses.
Regioselectivity for the Rh(I)‐catalyzed Annulation of 1,2,3‐Thiadiazoles with Alkynes: Experimental and Computational Analysis Reveal the Surprising Role of the Alkyne Substituent
Authors: Reza Tasiana , Tokareva Marina A. , Dobson Natalie K. , Shanahan Alexandra L. , Sheather Kyle , Richardson Christopher , Keaveney Sinead T.
Published: October 2023

The Rh(I)‐catalyzed denitrogenative annulation reactions of 1,2,3‐thiadiazoles are a new direct approach to synthesizing densely functionalized heterocycles. The synthesis of multisubstituted thiophenes is possible using this methodology, however the difficulty to predict which regioisomer will form is a current limitation. In this current work, systematic computational and experimental studies were performed addressing how the terminal alkyne substituent effects regioselectivity. The data revealed that the electronic and steric properties of the alkyne substituent effects regioselectivity, including whether the group is aryl or alkyl. The insight gained from this study has allowed the development of a framework for predicting regioselectivity for the Rh(I)‐catalyzed denitrogenative transannulation of 1,2,3‐thiadiazoles with terminal alkynes.
Differential diagnosis between urticarial vasculitis and chronic spontaneous urticaria: An international Delphi survey
Authors: Krause Karoline , Bonnekoh Hanna , Jelden‐Thurm Jannis , Asero Riccardo , Gimenez‐Arnau Ana Maria , Cardoso José C. , Grattan Clive , Kocatürk Emek , Lippert Undine , Maurer Marcus , Metz Martin , Staubach Petra , Goncalo Margarida , Kolkhir Pavel
Published: October 2023

Background

Urticarial vasculitis (UV) should be differentiated from chronic spontaneous urticaria (CSU) in patients initially presenting with recurrent wheals, although criteria for differential diagnosis remain ill‐defined.

Objectives

To set the goals, define criteria and unmet needs in UV diagnosis and differential diagnosis with CSU, and explore the possibility of coexistence of both diseases.

Methods

Thirteen experts experienced in UV research participated in a Delphi survey of European Academy of Allergy and Clinical Immunology taskforce. This Delphi survey involved three rounds of anonymous responses ton = 32 questions with the aim to aggregate the experts' opinions and to achieve consensus. Urticaria specialists (n = 130, most from Urticaria Centers of Reference and Excellence) evaluated the consensus statements and recommendations in the fourth and final round.

Results

The panel agreed that essential criteria to guide a skin biopsy in patients with recurrent wheals should include at least one of the following features: wheal duration >24 h, bruising/postinflammatory hyperpigmentation, and systemic symptoms. Leukocytoclasia and fibrin deposits were identified as a minimum set of UV histological criteria. As agreed by the panel members, CSU and normocomplementemic UV (NUV) may coexist in some patients.

Conclusions

The use of established criteria for the diagnosis and differential diagnosis of UV in patients with recurrent wheals can help guide the diagnostic approach and prompt earlier treatment. Further studies should investigate whether CSU and NUV are different entities or part of a disease spectrum.
Variation in biomass of cassava genotypes grown under different irrigation levels during the early growth phase
Authors: Ruangyos Chanissara , Banterng Poramate , Vorasoot Nimitr , Jogloy Sanun , Theerakulpisut Piyada , Vongcharoen Kochaphan , Hoogenboom Gerrit
Published: October 2023

Understanding the performance of cassava under different irrigation levels during the early growth phase could support better decision‐making to improve yield. This study aimed to determine the performance of cassava genotypes grown under three different water regimes during the early growth phase. A strip‐plot design with four replications was used for two experimental years (2019/2020 and 2020/2021). Three irrigation levels were applied from 30 to 180 days after planting (DAP) and were assigned as factor A (W1, W2, and W3 denote 100%, 60%, and 20% crop water requirement [ETcrop], respectively), 30 cassava genotypes were assigned as factor B. Crop data were obtained at 180 and 330 DAP. The irrigation at W1 gave the highest biomass at 180 DAP as compared to W2 and W3. Well irrigation for all plots after 180 DAP did not show a difference in storage root dry weight at 330 DAP among the irrigation treatments. The genotype CMR38‐125‐77 had the highest biomass at 180 DAP for all three irrigation levels. For biomass at 330 DAP, CMR36‐31‐381 tended to produce high biomass under different irrigation levels. The genotype CMR34‐40‐43 was also identified as an ideal genotype in terms of biomass for water shortage conditions during the early growth phase of cassava. These genotypes can serve as parental sources for breeders as they have the potential to grow under different water regimes.
Cooperative Chiral Lewis Base/Palladium‐Catalyzed Asymmetric Syntheses of Methylene‐Containing δ‐Lactams
Authors: Zebrowski Paul , Monkowius Uwe , Waser Mario
Published: October 2023

We herein report a two‐step approach for the enantioselective synthesis of novel chiral δ‐lactams. By using a cooperative chiral ITU/achiral Pd‐catalyst system, this protocol proceeds via an asymmetric α‐allylation of activated aryl esters first, followed by an acid‐mediated lactam formation. A variety of differently substituted products could be obtained with usually high levels of enantioselectivities and in reasonable yields (16 examples, up to 98 : 2 er and 73 % yield over two steps). In addition, further utilizations of the products via transformations of the exocyclic double bond were successfully carried out as well.
Assessment of biogas and syngas production from sugarcane vinasse: A sustainable alternative for the production of renewable fuels
Authors: Tonial Gabrielly Mylena Benedetti , Paraiso Paulo Roberto , de Matos Jorge Luiz Mario
Published: October 2023

The increasing demand for renewable energy sources as a substitute for fossil fuels has driven researchers to develop sustainable processes for biomass energy reuse in biofuel production. Based on this premise, the present study aimed to simulate the production process of synthesis gas (syngas) from vinasse, a by‐product of the sugar and alcohol industry, highlighting the applicability of this gas in transitioning toward a more renewable and sustainable energy future. The simulation was conducted in four distinct stages using the Aspen HYSYS® software. The first stage involved obtaining hydrated ethanol from sugarcane juice, followed by anaerobic digestion of vinasse to produce biogas. The third stage involved purifying the biogas to obtain biomethane. Finally, the simulation of steam methane reforming was performed to generate syngas. The modeling and simulation results demonstrated the feasibility of the process, as it generated 20.68 Nm3 of biogas (~55% vol CH4 and 45% vol CO2) per 1 Nm3 of vinasse, corresponding to 11.66 Nm3 of biomethane (~96.5% mol CH4), which aligns with national regulatory standards and the literature presented. Regarding syngas, both evaluated configurations yielded satisfactory results. The first configuration resulted in syngas with an H2/CO molar ratio of three, making it a viable source of pure hydrogen and a raw material for biofuel production, such as dimethyl ether and methanol. The second configuration, with an H2/CO molar ratio of two, holds great potential for its application in the synthesis of liquid fuels (Fischer‐Tropsch), serving as a direct substitute for gasoline, diesel, and jet fuel.
Natural resistance to cancer: A window of hope
Authors: Masoudi Mohammad , Torabi Parisa , Judson‐Torres Robert L. , Khodarahmi Reza , Moradi Sharif
Published: October 2023

As healthcare systems are improving and thereby the life expectancy of human populations is increasing, cancer is representing itself as the second leading cause of death. Although cancer biologists have put enormous effort on cancer research so far, we still have a long way to go before being able to treat cancers efficiently. One interesting approach in cancer biology is to learn from natural resistance and/or predisposition to cancer. Cancer‐resistant species and tissues are thought‐provoking models whose study shed light on the inherent cancer resistance mechanisms that arose during the course of evolution. On the other hand, there are some syndromes and factors that increase the risk of cancer development, and revealing their underlying mechanisms will increase our knowledge about the process of cancer formation. Here, we review natural resistance and predisposition to cancer and the known mechanisms at play. Further insights from these natural phenomena will help design future cancer research and could ultimately lead to the development of novel cancer therapeutic strategies.
Elucidating the role of blood metabolites on pancreatic cancer risk using two‐sample Mendelian randomization analysis
Authors: Zhong Hua , Liu Shuai , Zhu Jingjing , Xu Teddy H. , Yu Herbert , Wu Lang
Published: October 2023

Pancreatic ductal adenocarcinoma (PDAC) is an uncommon but highly fatal malignancy. Identifying causal metabolite biomarkers offers an opportunity to facilitate effective risk assessment strategies for PDAC. In this study, we performed a two‐sample Mendelian randomization (MR) study to characterize the potential causal effects of metabolites in plasma on PDAC risk. Genetic instruments were determined for a total of 506 metabolites from one set of comprehensive genome‐wide association studies (GWAS) involving 913 individuals of European ancestry from the INTERVAL/EPIC‐Norfolk cohorts. Another set of genetic instruments was developed for 483 metabolites from an independent GWAS conducted with 8299 individuals of European ancestry from the Canadian Longitudinal Study on Aging (CLSA) cohort. We analyzed GWAS data of the Pancreatic Cancer Cohort Consortium (PanScan) and the Pancreatic Cancer Case‐Control Consortium (PanC4), comprising 8275 PDAC cases and 6723 controls of European ancestry. The association of metabolites with PDAC risk was assessed using the inverse‐variance weighted (IVW) method, and complemented with sensitivity analyses of MR‐Egger and MR‐PRESSO tests. Potential side effects of targeting the identified metabolites for PDAC intervention were further evaluated by a phenome‐wide MR (Phe‐MR) analysis. Forty‐four unique metabolites were identified to be significantly associated with PDAC risk, of which four top‐ranking metabolites (X: 12798, X: 11787, X: 11308 and X: 19141) showed replication evidence when using instruments developed from both two cohorts. Our results highlight novel blood metabolites related to PDAC risk, which may help prioritize metabolic features for PDAC mechanistic research and further evaluation of their potential role in PDAC risk assessment.
Particle profiling of EV‐lipoprotein mixtures by AFM nanomechanical imaging
Authors: Ridolfi Andrea , Conti Laura , Brucale Marco , Frigerio Roberto , Cardellini Jacopo , Musicò Angelo , Romano Miriam , Zendrini Andrea , Polito Laura , Bergamaschi Greta , Gori Alessandro , Montis Costanza , Panella Stefano , Barile Lucio , Berti Debora , Radeghieri Annalisa , Bergese Paolo , Cretich Marina , Valle Francesco
Published: October 2023

The widely overlapping physicochemical properties of lipoproteins (LPs) and extracellular vesicles (EVs) represents one of the main obstacles for the isolation and characterization of these pervasive biogenic lipid nanoparticles. We herein present the application of an atomic force microscopy (AFM)‐based quantitative morphometry assay to the rapid nanomechanical screening of mixed LPs and EVs samples. The method can determine the diameter and the mechanical stiffness of hundreds of individual nanometric objects within few hours. The obtained diameters are in quantitative accord with those measured via cryo‐electron microscopy (cryo‐EM); the assignment of specific nanomechanical readout to each object enables the simultaneous discrimination of co‐isolated EVs and LPs even if they have overlapping size distributions. EVs and all classes of LPs are shown to be characterised by specific combinations of diameter and stiffness, thus making it possible to estimate their relative abundance in EV/LP mixed samples in terms of stoichiometric ratio, surface area and volume. As a side finding, we show how the mechanical behaviour of specific LP classes is correlated to distinctive structural features revealed by cryo‐EM. The described approach is label‐free, single‐step and relatively quick to perform. Importantly, it can be used to analyse samples which prove very challenging to assess with several established techniques due to ensemble‐averaging, low sensibility to small particles, or both, thus providing a very useful tool for quickly assessing the purity of EV/LP isolates including plasma‐ and serum‐derived preparations.
Prostate Age Gap: An MRI Surrogate Marker of Aging for Prostate Cancer Detection
Authors: Fernandez‐Quilez Alvaro , Nordström Tobias , Jäderling Fredrik , Kjosavik Svein Reidar , Eklund Martin
Published: October 2023

Background

Aging is the most important risk factor for prostate cancer (PC). Imaging techniques can be useful to measure age‐related changes associated with the transition to diverse pathological states. However, biomarkers of aging from prostate magnetic resonance imaging (MRI) remain to be explored.

Purpose

To develop an aging biomarker from prostate MRI and to examine its relationship with clinically significant PC (csPC, Gleason score ≥7) risk occurrence.

Study Type

Retrospective.

Population

Four hundred and sixty‐eight (65.97 ± 6.91 years) biopsied males, contributing 7243 prostate MRI slices. A deep learning (DL) model was trained on 3223 MRI slices from 81 low‐grade PC (Gleason score ≤6) and 131 negative patients, defined as non‐csPC. The model was tested on 90 negative, 52 low‐grade (142 non‐csPC), and 114 csPC patients.

Field Strength/Sequence

3‐T, axial T2‐weighted spin sequence.

Assessment

Chronological age was defined as the age of the participant at the time of the visit. Prostate‐specific antigen (PSA), prostate volume, Gleason, and Prostate Imaging‐Reporting and Data System (PI‐RADS) scores were also obtained. Manually annotated prostate masks were used to crop the MRI slices, and a DL model was trained with those from non‐csPC patients to estimate the age of the patients. Following, we obtained the prostate age gap (PAG) on previously unseen csPC and non‐csPC cropped MRI exams. PAG was defined as the estimated model age minus the patient's age. Finally, the relationship between PAG and csPC risk occurrence was assessed through an adjusted multivariate logistic regression by PSA levels, age, prostate volume, and PI‐RADS ≥ 3 score.

Statistical Tests

T‐test, Mann–Whitney U test, permutation test, receiver operating characteristics (ROC), area under the curve (AUC), and odds ratio (OR). A P value <0.05 was considered statistically significant.

Results

After adjusting, there was a significant difference in the odds of csPC (OR = 3.78, 95% confidence interval [CI]: 2.32–6.16). Further, PAG showed a significantly larger bootstrapped AUC to discriminate between csPC and non‐csPC than that of adjusted PI‐RADS ≥ 3 (AUC = 0.981, 95% CI: 0.975–0.987).

Data Conclusion

PAG may be associated with the risk of csPC and could outperform other PC risk factors.

Level of Evidence

3

Technical Efficacy

Stage 3
Ultrasound‐Induced Tumor Perfusion Changes and Doxorubicin Delivery
Authors: Bai Luhua , Luo Tingting , Tang Jiawei , Zhang Jing , Tan Xi , Tang Junhui , Huang Leidan , Dong Xiaoxiao , Li Ningshan , Li Peijing , Liu Zheng
Published: October 2023

Objectives

To investigate the appropriate combination of pulse length (PL) and pulse repetition frequency (PRF) when performing ultrasound stimulated microbubble (USMB) to enhance doxorubicin (DOX) delivery to tumors.

Methods

A total of 48 tumor‐bearing mice were divided into four groups, namely groups A–D. The mice in groups B–D were treated with chemotherapy and USMB treatment with different combinations of PL and PRF, and group A was control. Contrast‐enhanced ultrasound imaging was conducted to analyze tumor blood perfusion. Fluorescence microscopy and high‐performance liquid chromatography were used to qualitatively and quantitatively analyse DOX release. The structural changes of tumors were observed under light microscope and transmission electron microscope. Furthermore, another 24 tumor‐bearing mice were treated with sonochemotherapy and some related inflammatory factors were measured to explore the underlying mechanism.

Results

With PL of three cycles and PRF of 2 kHz, the tumor perfusion area ratio increased by 26.67%, and the DOX concentration was 4.69 times higher than the control (P < .001). With PL of 34.5 cycles and PRF of 200 Hz, the tumor perfusion area ratio decreased by 12.7% and DOX did not exhibit increased extravasation compared with the control. Microvascular rupture and hemorrhage were observed after long PL and low PRF treatment. While vasodilation and higher levels of some vasodilator inflammatory factors were found after treatment with short PL and high PRF.

Conclusions

USMB treatment using short PL and high PRF could enhance tumor blood perfusion and increase DOX delivery, whereas long PL and low PRF could not serve the same purpose.
Richardson extrapolation method for solving the Riesz space fractional diffusion problem
Authors: Qi Ren‐jun , Sun Zhi‐zhong
Published: October 2023

The Richardson extrapolation is widely utilized in numerically solving the differential equations since it enjoys both high accuracy and ease of implementation. For the Riesz space fractional diffusion equation, the fractional centered difference operator is employed to approximate the fractional derivative, then the Richardson extrapolation methods for two difference schemes are constructed with the help of the asymptotic expansions of the discrete solutions. Specifically, for the Crank–Nicolson difference scheme, the extrapolation method contains two extrapolation formulae that achieve the fourth order and the sixth order both in the temporal and spatial directions, respectively. The extrapolation method for the compact difference scheme involves one extrapolation formula by which the sixth order can be obtained when the time step size is proportional to the squares of the space step size. The maximum norm error estimates of the extrapolation solutions are proved by the discrete fractional Sobolev embedding inequalities. The extension to the high dimensional and nonlinear cases is also demonstrated. Numerical results verify the theoretical convergence orders and efficiency of our methods.
Remaining useful life prediction for degradation processes based on the Wiener process considering parameter dependence
Authors: Guan Qingluan , Wei Xiukun , Zhang Huixian , Jia Limin
Published: October 2023

Remaining useful life prediction (RUL) is a critical procedure in the application of prognostics and health management for devices or systems. It is difficult to predict the RUL in a time‐varying external environment. Specifically, many mechanical systems typically experience various operating conditions, which have impacts on the degradation process and degradation rate. In particular, the linear degradation modeling of the Wiener process‐based RUL prediction method has attracted considerable attention recently. However, the dependency of degradation rate and operating conditions is generally ignored in the current degradation modeling, which leads to inaccurate issues in the RUL prediction. Therefore, to solve the above issues, a novel RUL prediction method based on the Wiener process considering parameter dependence is proposed in this paper. At first, a linear Wiener process degradation model considering parameter dependence is constructed to describe the dependency of the drift coefficient and operating conditions. Secondly, the probability density function of RUL is derived under the concept of first hit time. After that, the collaboration between the Bayesian update and expectation maximization algorithm is introduced to update and estimate the model parameters. Finally, the validity and applicability of the proposed method are verified by a numerical simulation and three case studies of bearings.
Understand role of retention in enrollment management
Authors: Dennis Marguerite J.
Published: October 2023

Several years ago, I wrote the book A Practical Guide to Enrollment and Retention Management in Higher Education. I believed then, as I do now, that retention management is as important as enrollment management and is essential for any enrollment management program to succeed.
Reversible MnO to Mn3O4 Oxidation in Manganese Oxide Nanoparticles
Authors: de Boer Roos M. , van Huis Marijn A. , Mendes Rafael G.
Published: October 2023

Manganese is an attractive element for sustainable solutions. It is largely available in the earth's crust, making it ideal for cost‐effective and large‐scale applications. Especially MnO nanoparticles have recently received attention for applications in battery technology. However, manganese has many oxidation states that are energetically very similar, indicating that they may easily transform from one to the other. Herein, the reversible oxidation of MnO nanoparticles to Mn3O4 studied with in situ transmission electron microscopy is shown. The oxygen sublattices of MnO and Mn3O4 are found to be perfectly aligned, and an atomic mechanism where the transformation is facilitated by the migration of Mn cations on the shared O sublattice is proposed. Even when protected with an amorphous carbon layer, MnO particles are highly unstable and oxidize to Mn3O4 in ethanol. The poor stability of MnO lacks discussion in many battery‐related works, and strategies aimed at avoiding this should be developed.
Dynamics of thermal radiation and Lorentz force on the hybrid nanofluid (Ethylene Glycol + Graphene + Copper) flow via an exponentially stretching sheet with chemical reaction: An irreversibility analysis
Authors: Kathyayani Gandrakota , Gowd Poojari Prakash
Published: October 2023

An exciting new class of heat transmission fluids, nanofluids, has been developed as an alternative to traditional fluids in manufacturing. Fuel cells, heat exchangers and pharmaceutical processes are just a few of the many uses for them. When compared to monofluids, the heat transmission properties of hybrid fluids are superior. These are findings used in an extensive diversity of fields, from solar energy to air conditioning. The objective of this paper is to examine how Lorentz force and chemical reaction parameters affect the characteristics of a couple stress hybrid nanofluid (Ethylene Glycol + Graphene + Copper) flow via an exponentially stretching surface. The heat transport phenomenon is studied using viscous dissipation, exponential heat source and thermal radiation parameters. Furthermore, irreversibility analysis is provided in this paper. Governing equations are transformed into a set of nonlinear ordinary differential equations using suitable similarity transformations. The bvp4c solver in MATLAB is used to solve the transformed system. Engineering parameters of interest, including skin friction coefficient, are described using bar diagrams. It has been noted that the magnetic field and volume fraction of graphene nanoparticles (ϕ1) reduce the skin friction coefficient. At , the skin friction coefficient decreases at a rate of 4.68187. It is observed that there is an increment in the fluid temperature with the rise in the exponential heat source parameter, and the velocity profile increases with the increase in the mixed convection parameter. It is detected that, while Eckert number () was set to , Nusselt number was reduced by 6.29239. It is noticed that, while the chemical reaction () is set to , the mass transfer rate rises at a Rate of 0.349644. It has been observed that as the Brinkmann number and magnetic field parameters increase, so does the rate of entropy production. It is also detected that as the porosity parameter increases, the fluid momentum decreases. Furthermore, increasing the couple stress parameter decreases the fluid velocity.
Effect of global and regional SST biases on the East Asian Summer Monsoon in the MetUM GA7 and GC3 configurations
Authors: Franco-Díaz Armenia , Klingaman Nicholas P. , Turner Andrew G. , Dong Buwen , Guo Liang
Published: October 2023

Climate-length experiments of the Met Office Unified Model Global Atmosphere 7.0 (GA7) and Global Coupled 3.0 (GC3) configurations are evaluated against observations and reanalyses for the simulation of the East Asian summer monsoon (EASM). The results show systematic model biases, such as overestimated rainfall over southern China and underestimated rainfall over northern China, suggesting a monsoon that does not penetrate northward enough. We evaluate the effects on the EASM of regional errors in sea-surface temperature (SST) conditions in three regions: the Pacific, the Indian, and the Atlantic Oceans. The global SST biases in GC3 configuration substantially shift the EASM seasonal cycle: a late northward progression of the EASM in the early/mid-monsoon season, and an early retreat of the monsoon that also reduces rainfall over most of northern China. The EASM seasonal rainfall bias in the EASM region is linked to changes in the locations and strength of the western North Pacific subtropical high, which is associated with biases in local evaporation and moisture transport towards South China. GC3 biases in the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) teleconnection pathways also influence the EASM biases. GC3 biases weaken the ENSO teleconnection to the EASM and cause a strong dry bias in southeast China during developing El Niño.
Optimization over the Pareto front of nonconvex multi-objective optimal control problems
Authors: Kaya C. Yalçın , Maurer Helmut
Published: October 2023

Simultaneous optimization of multiple objective functions results in a set of trade-off, or Pareto, solutions. Choosing a, in some sense, best solution in this set is in general a challenging task: In the case of three or more objectives the Pareto front is usually difficult to view, if not impossible, and even in the case of just two objectives constructing the whole Pareto front so as to visually inspect it might be very costly. Therefore, optimization over the Pareto (or efficient) set has been an active area of research. Although there is a wealth of literature involving finite dimensional optimization problems in this area, there is a lack of problem formulation and numerical methods for optimal control problems, except for the convex case. In this paper, we formulate the problem of optimizing over the Pareto front of nonconvex constrained and time-delayed optimal control problems as a bi-level optimization problem. Motivated by existing solution differentiability results, we propose an algorithm incorporating (i) the Chebyshev scalarization, (ii) a concept of the essential interval of weights, and (iii) the simple but effective bisection method, for optimal control problems with two objectives. We illustrate the working of the algorithm on two example problems involving an electric circuit and treatment of tuberculosis and discuss future lines of research for new computational methods.
Potential ecotoxicological effects of silver nanoparticles and silver sulphide on the endogeic earthworm Aporrectodea caliginosa (Savigny 1826)
Authors: Kister Jeannette M. , Lowe Christopher N. , Butt Kevin R.
Published: October 2023

Silver nanoparticles (AgNPs) are increasingly used in consumer products and subsequently arrive in wastewater systems, accumulating as silver sulphide (Ag2S) in the resulting biosolids, which are commonly spread onto agricultural fields as a fertiliser. Experiments were performed to investigate the effect of AgNPs, using the endogeic earthworm Aporrectodea caliginosa as a test organism. In an acute toxicity experiment, A. caliginosa were exposed to soil containing different concentrations of AgNPs (0, 1, 5, 10, 50, 100, 250, 500, 750, and 1000 mg kg−1 dry soil) and Ag2S (0, 10, 50, 100, 500, and 1000 mg kg−1 dry soil). Earthworm biomass and mortality were monitored. Earthworms exposed to 500, 750 and 1000 mg kg−1 fresh AgNPs had mortality rates of 20%, 60% and 70%, respectively. Changes in biomass were directly related to AgNP concentration. Exposure to Ag2S did not affect biomass or mortality. Further experiments used 0, 10, 50, 100 and 250 mg kg−1 AgNPs and 0, 50, 100, 500, and 1000 mg kg−1 Ag2S to evaluate sublethal effects on A. caliginosa. Avoidance behaviour in a linear gradient was evaluated after 14 days. Earthworms significantly preferred soil that was free of either AgNPs or Ag2S. The same concentrations were used to assess effects on cocoon production of A. caliginosa exposed to AgNPs and Ag2S. In the first 3 months of AgNP exposure, higher concentrations had a negative effect on cocoon production, but this effect diminished thereafter. Ag2S had no discernible effect on reproduction. Overall, introduction of AgNPs into the soil through the application of biosolids appears to be of low concern to the tested endogeic earthworm.
Digital Facilitation of Group Work to Gain Predictable Performance
Authors: Gimpel Henner , Lahmer Stefanie , Wöhl Moritz , Graf-Drasch Valerie
Published: October 2023

Group work is a commonly used method of working, and the performance of a group can vary depending on the type and structure of the task at hand. Research suggests that groups can exhibit "collective intelligence"—the ability to perform well across tasks—under certain conditions, making group performance somewhat predictable. However, predictability of task performance becomes difficult when a task relies heavily on coordination among group members or is ill-defined. To address this issue, we propose a technical solution in the form of a chatbot providing advice to facilitate group work for more predictable performance. Specifically, we target well-defined, high-coordination tasks. Through experiments with 64 virtual groups performing various tasks and communicating via text-based chat, we found a relationship between the average intelligence of group members and their group performance in such tasks, making performance more predictable. The practical implications of this research are significant, as the assembly of consistently performing groups is an important organizational activity.
Retail Markups and Discount-Store Entry
Authors: Chenarides Lauren , Gómez Miguel I. , Richards Timothy J. , Yonezawa Koichi
Published: October 2023

“Hard discounters” are retail formats that set retail food prices even lower than existing discount formats, such as Walmart and Target. Offering limited assortments and focusing on store-brands, these formats promise to change the competitive landscape of food retailing. In this paper, we study the effect of entry of one hard-discount format on markups earned by existing retail stores, focusing on several important grocery markets across the Eastern U.S. Focusing on establishment-level profitability, we estimate store-level markups using the production-side approach of De Loecker and Warzynski (Am Econ Rev 102(6):2437–2471). We find that hard-discounter entry reduced markups for incumbment retailers by 7.3% relative to markups in non-entry markets. These results indicate that the net effect of hard-discounter entry reduces the overall level of store profitability—despite the somewhat higher sales realized by incumbent retailers.
Weighted directed graph-based automatic seizure detection with effective brain connectivity for EEG signals
Authors: Sun Qi , Liu Yuanjian , Li Shuangde
Published: October 2023

Epileptic seizure is one of the most common neurological disorders characterized by sudden abnormal discharge of neurons in the brain. Automated seizure detection using electroencephalograph (EEG) recordings would improve the quality of treatment and reduce medical overhead. The purpose of this paper is to design an automated seizure detection framework that can effectively identify seizure and non-seizure events by discovering connectivity between brain regions. In this work, a weighted directed graph-based method with effective brain connectivity (EBC) is proposed for seizure detection. The weighted directed graph is built by analyzing the correlation among the different regions of the brain. Then, graph theory-based measures are used to extract features for classification. Furthermore, we illustrate the ability of the proposed method to achieve seizure detection for the patient-specific model and the cross-patient model. The results show that the proposed method achieves accuracy values of 99.97% and 98.29% for the patient-specific model and the cross-patient model in the CHB-MIT dataset, respectively. These results demonstrate that the proposed method achieves an effective classification performance and can be used to provide assistance for automatic seizure detection and clinical diagnosis.
Pseudomonas taiwanensis VLB120 als Plattform für die Biotechnologie
Authors: Wynands Benedikt , Wierckx Nick , Heipieper Hermann J. , Eberlein Christian
Published: October 2023

The microbial production of fine chemicals that can be used as pharmaceuticals or chemical building blocks is an important cornerstone of the sustainable bio-based economy. However, the efficient production of many chemicals is often hampered by limited tolerance of the bacterial hosts towards the substrates, products, or process conditions. Robust platform organisms are needed for economically viable biotechnological applications as an alternative to classical chemical synthesis.
Zelluläre Lichtschalter für die Biotechnologie
Authors: Hochrein Lena
Published: October 2023

De

Optogenetics is an efficient method for controlling cellular processes in living organisms by light and a promising tool for biotechnology. Optogenetic switches can regulate the production of recombinant proteins or entire biosynthetic pathways in a reversible, time- and dose-dependent manner without influencing the cultivation condition. By combining light-driven regulation of native and heterologous genes, the growth and production phases of cells can be decoupled, maximizing product yield.
Big Business and the Crisis of German Democracy
Authors: Bisno Adam
Published: October 2023

Through the colorful world of Berlin's grand hotels, this book charts a new history of German liberalism and explores the changing relationships among big business, society, and politics. Behind imposing facades, managers and workers were often the picture of orderly and harmonious service, despite living in sometimes uncomfortable proximity. Then, during World War I, class tensions rose to the surface and failed to resolve in the following years. Doubting the ability of the Weimar Republic to contain these conflicts, a group of hotel owners, some of the most prominent Jewish industrialists and financiers in the country, chose to let Adolf Hitler use their hotel, the Kaiserhof, as his Berlin headquarters in 1932. From a splendid suite opposite the chancellery, Hitler and his henchmen engineered the assumption of power, the death of the Weimar Republic, and the ruin of their hosts, the Kaiserhof's owners: Jewish liberals now fleeing for their lives. Big Business and the Crisis of German Democracy asks how this came about and explores the decision-making processes that produced such catastrophic consequences. This title is also available as open access on Cambridge Core.
The Behavioral Economics and Politics of Global Warming
Authors: Shefrin Hersh
Published: October 2023

The main goal of this Element is to provide a psychological explanation for why actual global climate policy is so much at odds with the prescriptions of most neoclassical economists. To be sure, the behavioral approach does focus on why neoclassical models are often psychologically unrealistic. However, in this Element the author argues that the unrealistic elements are minor compared to the psychological pitfalls driving politically determined climate policy. Why this is the case is what the author describes as 'the big behavioral question.' More precisely, the big behavioral question asks why there is a huge gap between actual policy and even the weakest of the prescriptions in the range of plausible prescriptions coming from neoclassical economists' integrated assessment models. This title is also available as Open Access on Cambridge Core.