bluuebunny/crossref_metadata_2025 huggingface dataset:
Zum Lösungsmitteleinfluß bei der Bildung von Polystyrolperoxyd
Authors: Kerber Robert
Published: October 2023

Die Kinetik der Polystyrolperoxydbildung wird unter Verwendung verschiedener Lösungsmittel unter‐sucht. Dabei zeigt sich eine Abhängigkeit der Bruttoreaktionsgeschwindigkeit von der Dielektrizitätskonstante des Lösungsmittels. Eine Erhöhung der DK im Reaktionssystem ist ganz allgemein auch mit einer Erhöhung der Sauerstoffaufnahmegeschwindigkeit verbunden, während Lösungsmittel mit einer DK, die kleiner ist als die des monomeren Styrols, eine ganz ausgeprägte Verlangsamung der Reaktion bewirken. Es werden verschiedene Möglichkeiten für die Beeinflussung der einzelnen Teilreaktionen durch die DK des Lösungsmittels diskutiert. Die erhaltenen experimentellen Ergebnisse lassen sich zumindest qualitativ deuten, wenn man die Ansätze von Alfrey und Price, die für die Behandlung von Kopolymerisationssystemen aufgestellt wurden, anwendet. Dabei wird lediglich die Wechselwirkung effektiver Ladungen im Übergangszustand als durch die DK des Lösungsmittels beeinflußbar angenommen. Andere Effekte, die durch die Verschiedenheit der Lösungsmittel hervorgerufen werden können, scheinen nur von sekundärer Bedeutung für die Geschwindigkeit der Bruttoreaktion zu sein.
Thermodynamische Eigenschaften und Moleküldimensionen in Lösungen
Authors: Schulz G. V. , Craubner H.
Published: October 2023

Es wird untersucht, ob die Knäuelgestalt eines unverzweigten Fadenmoleküls in Lösung von zwei trennbaren Faktoren abhängt: Der die Drehbehinderung erfassenden „inneren”︁ Konstante η und dem Expansionsfaktor α, der die Wechselwirkung mit dem Lösungsmittel berücksichtigt und vom 2. Virialkoeffizienten (VK) A2 abhängt.

Durch Lichtstreuungsmessungen an vier fraktionierten Polymethylmethacrylaten in drei Lösungsmitteln werden Molekulargewicht M, mittlerer Fadenendenabstand hs und A2 gemessen und daraus durch Extrapolation nach A2 = 0 die Expansionskoeffizienten bestimmt.

Es wird gezeigt, daß für diese Lösungen die statistisch‐thermodynamische Gleichung von Isihara und Koyama zutrifft. Sie liefert die experimentell richtigen Werte für die Bindungslänge α und sinnvolle Werte für das ausgeschlossene Volumen. Diese Gleichung ist jedoch nicht allgemeingültig. Die exothermen Lösungen von Nitrocellulose in Aceton und Polystyrol in Toluol werden besser durch eine Gleichung von Münster erfaßt.

Bei Polymethacrylaten können die Faktoren η und α getrennt werden. Es ergibt sich, daß für die Drehbarkeit um die Valenzrichtung im Mittel etwa der halbe Bogen gesperrt ist.
Untersuchung von Adsorptionserscheinungen an Rhodium, Iridium, Palladium und Gold mit der potentiostatischen Dreieckmethode
Authors: Will F. G. , Knorr C. A.
Published: October 2023

Mit der kürzlich beschriebenen Methode der potentiostatischen Vorgabe von Dreieckspannungen1) werden Versuchsergebnisse hauptsächlich über die Größe der Wasserstoff‐ und Sauerstoffadsorptionsschichten an den Edelmetallen Rhodium, Iridium, Palladium und Gold in Abhängigkeit von der Bezugsspannung mitgeteilt. An Rhodium wurde die maximale Wasserstoffbedeckung der aufgerauhten Oberfläche zu 62% gefunden, an Iridium zu 45% und an Gold zu nur 3%. Sie erwies sich als abhängig von der Spannungsgeschwindigkeit und der Vorbehandlung. Die Sauerstoffbelegung beginnt, wie auch die Sauerstorfentwicklung, bei den einzelnen Metallen bei etwas verschiedenen Spannungswerten und nimmt in dem gesamten untersuchten Bereich bis 2,2 V außer an Iridium stetig zu. An Iridium wurde bei einer Spannungsgeschwindigkeit von 1 V/sec oberhalb 1,6 V über eine einatomare Schicht hinaus kein Anwachsen der Sauerstoffschicht mehr festgestellt. Einige charakteristische Meßwerte, die mit der Dreieckmethode erhalten wurden, sind zum Vergleich zwischen den untersuchten Edelmetallen abschließend in einer Tabelle zusammengestellt.
Der Vergleich der Spannungsreihen in verschiedenen Solventien. II
Authors: Koepp H.‐M. , Wendt H. , Stkehlow H.
Published: October 2023

Die bisher vorgeschlagenen McThoden [1] für einen brauchbaren Anschluß der Spannungsreihen in nichtwäßrigen Lösungsmitteln an diejenige des Wassers (E0H(H2O) = 0) werden um ein weiteres Verfahren vermehrt. Das Redoxnormalpotential geeignet ausgewählter Redoxsysteme kann näherungsweise als unabhängig von der Art des Lösungsmittels angenommen werden. Damit ist dann eine Möglichkeit gegeben, die Spannungsreihen aneinander anzuschließen. Die verschiedenen Anforderungen, die an ein hierzu geeignetes Redoxsystem gestellt werden müssen, werden von den untersuchten Systemen am besten von Ferrocen/Ferrociniumion (Cyclopentadienyl‐Eisen‐II bzw. ‐Eisen‐III) erfüllt. Als gleich brauchbar erweist sich das Kobaltanaloge des Ferrocens. Einige weitere Eisen‐ und Osmiumkomplexe sind wenigstens in einigen Lösungsmitteln anwendbar. Die Redoxnormalpotentiale wurden in den Lösungsmitteln Wasser, Methanol, Acetonitril und Formamid bestimmt. Die erhaltenen Ergebnisse stimmen befriedigend mit der verbesserten, von Plesskow [2] vorgeschlagenen Rubidiummethode überein. Ferner wurde der Gang der freien Solvatationsenergie des Silberions mit dem Molenbruch des Lösungsmittelgemisches Wasser‐Acetonitril bestimmt.
Über NMR‐spektroskopische Untersuchungen zur Eigenassoziation von 2‐t‐Butylphenol und Mischassoziation von 2‐t‐Butylphenol mit Dioxan in CCI4
Authors: Strohbusch Frank , Zimmermann Herbert
Published: October 2023

Die chemische Verschiebung des OH‐Signals von 2‐t‐Butylphenol (TBP) wurde in CCl4 und Dioxan/CCl4‐Gemischen als Funktion des Molenbruchs gemessen. Die Konstanten für die Gleichgewichte zwischen Monomeren und Assoziaten wurden bestimmt. Im System TBP/CCl4 stehen TBP‐Moleküle nur mit Dimeren im Gleichgewicht. Die Assoziationskonstante beträgt Kd = 0,53 Molenbruch−1.

Im System TBP/Dioxan/CCl4 erfolgt Eigen‐ und Mischassoziation. In den Mischassoziaten gehen beide Sauerstoffatome des Dioxans nahezu unabhängig voneinander Wasserstoffbrückenbindungen mit TBP ein. In den Lösungen liegen demnach nebeneinander Assoziate im Molverhältnis TBP: Dioxan = 1:1 und 2:1 vor. Die mittlere Assoziationskonstante zwischen einem Molekül TBP und einem Sauerstoffatom des Dioxans beträgt Kx = 13,4 Molenbruch−1.

Einige einschränkende Bedingungen für die Berechnung von Assoziationskonstanten aus NMR‐Daten werden diskutiert.
Akkommodation der Edelgase an reinen Wolfram‐ und Molybdänoberflächen bei Zimmertemperatur
Authors: Kouptsidis Johannes , Menzel Dietrich
Published: October 2023

Die thermischen Akkommodationskoeffizienten (A.K.) der Edelgase an polykristallinen Drähten aus Wolfram und Molybdän wurden in einem Ultravakuumsystem mit der bekannten Hitzdrahtmethode gemessen. Die Sauberkeit des Systems wurde mit Hilfe eines Feldelektronenmikroskops kontrolliert; Einflüsse von Verunreinigungen konnten dadurch vollständig ausgeschlossen werden, so daß die Meßergebnisse für die reinen Metalloberflächen repräsentativ sind. Der Einfluß der Veränderung der Temperaturdifferenz zwischen Oberfläche und Gas auf die A.K. wurde geprüft; in den hier berichteten Fällen ist dieser gering, so daß eine Extrapolation auf verschwindende Temperaturdifferenz leicht möglich ist. Die gemessenen Werte stimmen mit den besten bisher zugänglichen Werten gut überein. Die sich für jeweils das gleiche Gas ergebenden A.K. an Wolfram und Molybdän unterscheiden sich nur sehr wenig; daraus läßt sich folgern, daß die elastischen Konstanten der Metalle von sehr viel größerer Bedeutung für die Energieübertragung beim Stoß sind als die Massen der Metallatome. Dieses Ergebnis wird mit den Aussagen der für den Energieaustausch vorgeschlagenen Theorien verglichen.
Zur Reaktionsfähigkeit der tritiummarkierten Hydroxylgruppe von o‐ und p‐Nitrophenol bei der Umsetzung mit Methylradikalen in flüssiger Phase. Rolle der intramolekularen Wasserstoffbrückenbindung
Authors: Kohler W. , Kasanskaja N. F. , Nagler L. G. , Beresin I. W.
Published: October 2023

Die relativen Geschwindigkeitskonstanten der Ablösung von Tritium aus OH‐markierten o‐ und p‐Nitrophenol durch Methylradikale wurden in n‐Heptan bei 80 ± 0,1°C zu 1,23 ± 0,05 und 4 ± 0,8 bestimmt. Das in der intramolekularen Wasserstoffbrückenbindung fixierte Tritium besitzt eine größere Reaktionsfähigkeit bei der Umsetzung mit Methylradikalen als das in der intermolekularen Wasserstoffbrückenbindung. Aus der Konzentrationsabhängigkeit der spezifischen Radioaktivität des gebildeten Methans konnte für o‐Nitrophenol nach dem Assoziationsmodell von Coggenshall und Saier [1, 2] die Dissoziationskonstanten des Dimeren und der weiteren Assoziate bei 80 ± 0,1 °C zu 2,0 und 0,11 mol · 1−1 bestimmt werden.
A systematic review on cellular responses of Escherichia coli to nonthermal electromagnetic irradiation
Authors: Askaripour Khadijeh , Żak Arkadiusz
Published: October 2023

Investigation of Escherichia coli under electromagnetic fields is of significance in human studies owing to its short doubling time and human‐like DNA mechanisms. The present review aims to systematically evaluate the literature to conclude causality between 0 and 300 GHz electromagnetic fields and biological effects in E. coli. To that end, the OHAT methodology and risk of bias tool were employed. Exponentially growing cells exposed for over 30 min at temperatures up to with fluctuations below were included from the Web‐of‐Knowledge, PubMed, or EMF‐Portal databases. Out of 904 records identified, 25 articles satisfied the selection criteria, with four excluded during internal validation. These articles examined cell growth (11 studies), morphology (three studies), and gene regulation (11 studies). Most experiments (85%) in the included studies focused on the extremely low‐frequency (ELF) range, with 60% specifically at 50 Hz. Changes in growth rate were observed in 74% of ELF experiments and 71% of radio frequency (RF) experiments. Additionally, 80% of ELF experiments showed morphology changes, while gene expression changes were seen in 33% (ELF) and 50% (RF) experiments. Due to the limited number of studies, especially in the intermediate frequency and RF ranges, establishing correlations between EMF exposure and biological effects on E. coli is not possible.
Partial IGF‐1 deficiency induces brain oxidative damage and edema, which are ameliorated by replacement therapy
Authors: Puche Juan E. , Muñoz Úrsula , García‐Magariño Mariano , Sádaba María C. , Castilla‐Cortázar Inma
Published: October 2023

Insulin‐like growth factor 1 (IGF‐1) induces multiple cytoprotective effects on every tissue, including the brain. Since the mechanisms by which IGF‐1 produces neuroprotection are not fully understood, the aim of this work was to delve into the underlying mechanisms. IGF‐1 deficient mice (Hz) were compared with wild type (WT) and Hz mice treated with low doses of IGF‐1 (2 µg/100 g body weight/day) for 10 days (Hz + IGF). Gene expression, quantitative PCR, histology, and magnetic resonance imaging were performed in the three groups. IGF‐1 deficiency induced increased oxidative damage determined by markers of lipid peroxidation and hypoxia, as well as gene expression of heat shock proteins, antioxidant enzymes, and molecules involved in inflammation, apoptosis, and mitochondrial protection. These changes correlated with edema and learning impairment in Hz mice. IGF‐1 therapy improved all these alterations. In conclusion, IGF‐1 deficiency is responsible for increased brain oxidative damage, edema, and impaired learning and memory capabilities which are rescued by IGF‐1 replacement therapy. © 2016 BioFactors, 42(1):60–79, 2016
Quantification of age‐related changes of α‐tocopherol in lysosomal membranes in murine tissues and human fibroblasts
Authors: König Jeannette , Besoke Fabian , Stuetz Wolfgang , Malarski Angelika , Jahreis Gerhard , Grune Tilman , Höhn Annika
Published: October 2023

Considering the biological function of α‐tocopherol (α‐Toc) as a potent protective factor against oxidative stress, this antioxidant is in the focus of aging research. To understand the role of α‐Toc during aging we investigated α‐Toc concentrations in young and aged primary human fibroblasts after supplementation with RRR‐α‐Toc. Additionally, α‐Toc contents were determined in brain, kidney, and liver tissue of 10 week‐, 18 month‐, and 24 month‐old mice, which were fed a standard diet containing 100 mg/kg dl‐α‐tocopheryl acetate. α‐Toc concentrations in isolated lysosomes and the expression of the α‐Toc transport proteins Niemann Pick C1 (NPC1), Niemann Pick C2 (NPC2), and lipoprotein lipase were also analyzed. Obtained data show a significant age‐related increase of α‐Toc in murine liver, kidney, and brain tissue as well as in human dermal fibroblasts. Also liver and kidney lysosomes are marked by elevated α‐Toc contents with aging. NPC1 and NPC2 protein amounts are significantly decreased in adult and aged murine kidney tissue. Also aged human dermal fibroblasts show decreased NPC1 amounts. Supplementation of young and aged fibroblasts led also to decreased NPC1 amounts, suggesting a direct role of this protein in α‐Toc distribution. Our results indicate an age‐dependent increase of α‐Toc in different murine tissues as well as in human fibroblasts. Furthermore saturation and intracellular distribution of α‐Toc seem to be strongly dependent on the availability of this vitamin as well as on the presence of the lysosomal protein NPC1. © 2016 BioFactors, 42(3):307–315, 2016
Neuroprotective effects of vitamin D in an Alzheimer's disease rat model: Improvement of mitochondrial dysfunction via calcium/calmodulin‐dependent protein kinase kinase 2 activation of Sirtuin1 phosphorylation
Authors: Mohanad Marwa , Mohamed Shimaa K. , Aboulhoda Basma E. , Ahmed Maha A. E.
Published: October 2023

Mitochondrial dysfunction is an early event in Alzheimer's disease (AD) pathogenesis. To assess the impact of vitamin D3 (Vit.D) on neurogenesis, we investigated its role in mitigating cognitive impairment and mitochondrial dysfunction through calcium/calmodulin‐dependent protein kinase kinase 2 (CAMKK2)‐mediated phosphorylation of Sirtuin1 (SIRT1) in an aluminum‐chloride‐D‐galactose (AlCl3‐D‐gal)‐induced AD rat model. Rats were distributed into four groups: control, AlCl3 + D‐gal (10 + 60 mg/kg, ip), Vit.D (500 IU/kg, po), and AlCl3 + D‐gal+Vit.D. Novel object recognition (NOR), Morris Water Maze, and passive avoidance (PA) tests were used to measure memory abilities. The hippocampal tissue was used to assess vitamin D3 receptor (VDR) and peroxisome‐proliferator‐activated‐receptor‐γ‐coactivator‐1α (PGC‐1α) expression by quantitative real‐time polymerase chain reaction (qRT‐PCR), CAMKK2, p‐SIRT1, phosphorylated‐AMP‐activated protein kinase (p‐AMPK), dynamin‐related‐protein‐1 (Drp1), and mitofusin‐1 (Mnf1) proteins by western blot and Ca2+ levels, endothelial nitic oxide synthase (eNOS), superoxide dismutase (SOD), amyloid beta (Aβ), and phospho tau (p‐Tau) via enzyme‐linked immunosorbent assay(ELISA) in addition to histological and ultrastructural examination of rat's brain tissue. Vit.D‐attenuated hippocampal injury reversed the cognitive decline and Aβ aggregation, and elevated p‐Tau levels in the AlCl3 + D‐gal‐induced AD rat model. In AlCl3 + D‐gal‐exposed rats, Vit.D induced VDR expression, normalized Ca2+ levels, elevated CAMKK2, p‐AMPK, p‐SIRT1, and PGC‐1α expression. Vit.D reduced Drp1, induced Mnf1, increased mitochondrial membrane potential, preserved mitochondrial structure, restored normal mitochondrial function, and retained normal eNOS level and SOD activity in AlCl3 + D‐gal rats. In conclusion, our findings proved that Vit.D may ameliorate cognitive deficits in AlCl3 + D‐gal‐induced AD by restoring normal mitochondrial function and reducing inflammatory and oxidative stress via CAMKK2‐AMPK/SIRT1 pathway upregulation.
3D Printing in Libraries: A View from Within the American Library Association: Privacy, Intellectual Freedom and Ethical Policy Framework
Authors: Jones Barbara M.
Published: October 2023

EDITOR'S SUMMARY

Two fundamental purposes of libraries are to provide access to information and enable freedom of expression. Digital technologies have spurred the American Library Association to examine patron use of 3D printing technology in light of intellectual freedom policy. Libraries are strongly encouraged to proactively formulate and implement acceptable use policies regarding their 3D printers. The policy statement should address the library's mission to nurture creative expression; express policies in a straightforward, positive tone without repeating existing laws; outline the process for creating, submitting and retrieving a work; and define terminology. The ALA's own policy and advocacy documents support statements on the ethics of access for all, intellectual freedom regarding content, avoidance of anything illegal, patron privacy, and libraries as public forums promoting user interaction with information where any restrictions are content neutral.
Methods used to achieve different levels of the neuronal differentiation process in SH‐SY5Y and Neuro2a cell lines: An integrative review
Authors: dos Santos Mônica G. , Gomes José R. , Costa Michele D. M.
Published: October 2023

To study the process of neuronal differentiation, the human neuroblastoma (SH‐SY5Y) and the murine neuroblastoma (Neuro2a) cell lines have proven to be effective models. For this approach, different protocols involving known neurotrophic factors and other molecules, such as retinoic acid (RA), have been assessed to better understand the neuronal differentiation process. Thus, the goal of this manuscript was to provide a brief overview of recent studies that have used protocols to promote neurodifferentiation in SH‐SY5Y and Neuro2a cell lines and used acquired morphology and neuronal markers to validate whether differentiation was effective. The published results supply some guidance regarding the relationship between RA and neurotrophins for SH‐SY5Y, as well a serum concentrations for both cell lines. Furthermore, they demonstrate the potential application of Neuro2a, which is critical for future research on neuronal differentiation.
Transient aphonia following spinal anesthesia during emergency cesarean section: Case report and review of literature
Authors: Adhikari Gauri , Ghimire Suson , Adhikari Gopal , Aryal Krishnaraj , Kandel Narayan
Published: October 2023

Key Clinical Message

Subarachnoid block with local anesthetic agents is a well‐established anesthesia technique among pregnant females for labor analgesia and cesarian delivery. Although it is considered a reliable and safe technique for both mothers and fetuses, unexpected high or low levels of block may occur due to accidental injection of these agents into different meningeal spaces other than intended. Hypotension, bradycardia, headache, and failed anesthesia are common complications of spinal anesthesia. Though rare, neurological complications like aphonia, dysphagia, and tingling sensation have also been reported. The article reports a case of a 22‐year‐old primigravida who sustained transient aphonia following intrathecal administration of bupivacaine for an emergency cesarian section for meconium‐stained liquor with fetal distress. There were no other neurological manifestations or features suggestive of high spinal block. The sensory level of the block was fixed to T6 with hemodynamic stability throughout aphasia with an episode of hypotension preceding aphonia. Aphonia commenced 9 min after the spinal anesthesia continued for a total duration of 15 min. Neurological examination, relevant investigations, and consultations were done to make a diagnosis. Thus, it is important to be aware of the possible neurological complications associated with spinal anesthesia.
Real‐time microbial growth monitoring by combining microbial fuel cell‐based device with modified Nernst equation
Authors: Shen Siyang , Lin Yen‐Han , Liu Chenguang
Published: October 2023

In this work, we demonstrate a novel design that integrates a modified Nernst equation and readings from a microbial fuel cell (MFC)‐based device, facilitating real‐time monitoring of microbial growth. The MFC‐based device is comprised of an H‐shaped double‐chamber MFC, specifically designed to incorporate an oxidation–reduction potential (ORP) sensor, allowing for simultaneous measurements of both parameters. The Nernst equation was adjusted to assimilate readings from both the ORP sensor and the MFC device, ultimately deriving a unitless curve that represents the online dynamics of microbial growth. This curve exhibits two distinct peaks: the first peak indicates the initiation of the exponential phase, while the second peak signals its termination. The proposed design can be seamlessly integrated into fermentation processes to continually monitor progress, boost productivity, develop tailored control strategies that meet specific objectives, and so on.
The Influence of Large Pendent Groups on Chain Anisotropy and Electrical Energy Loss of Polyimides at High Frequency through All‐Atomic Molecular Simulation
Authors: Lin Tzu‐Jen
Published: October 2023

Polyimide is a potential material for high‐performance printed circuit boards because of its chemical stability and excellent thermal and mechanical properties. Flexible printed circuit boards must have a low static dielectric constant and dielectric loss to reduce signal loss in high‐speed communication devices. Engineering the molecular structure of polyimides with large pendant groups is a strategy to reduce their dielectric constant. However, there is no systematic study on how the large pendant groups influence electrical energy loss. We integrated all‐atomic molecular dynamics and semi‐empirical quantum mechanical calculations to examine the influence of pendant groups on polymer chain anisotropy and electrical energy loss at high frequencies. We analyzed the radius of gyration, relative shape anisotropy, dipole moment, and degree of polarization of the selected polyimides (TPAHF, TmBPHF, TpBPHF, MPDA, TriPMPDA, m‐PDA, and m‐TFPDA). The simulation results show that anisotropy perpendicular to chain direction and local chain rigidity correlate to electrical energy loss rather than dipole moment magnitudes. Polyimides with anisotropic pendant groups and significant local chain rigidity reduce electrical energy loss. The degree of polarization correlated well with the dielectric loss with a moderate computational cost, and difficulties in directly calculating the dielectric loss were circumvented.
Interaction of planting system with radiation‐use efficiency in wheat lines
Authors: Moroyoqui‐Parra Marcela A. , Molero Gemma , Reynolds Matthew P. , Gaju Oorbessy , Murchie Erik H. , Foulkes Michael John
Published: October 2023

Radiation‐use efficiency (RUE) is an important trait for raising biomass and yield potential in plant breeding. However, the effect of the planting system (PS) on genetic variation in RUE has not been previously investigated. Our objectives were to quantify genetic variation in RUE, biomass and grain yield in raised‐bed and flat‐basin planting systems, and associations with canopy‐architecture traits (flag‐leaf angle and curvature). Twelve spring wheat (Triticum aestivum L.) cultivars were evaluated under irrigated conditions for 3 years in North West Mexico using raised‐bed and flat‐basin planting systems. Canopy architecture traits were measured at booting and anthesis + 7 days. Grain yield (10.6%), biomass (7.6%), and pre‐grain‐filling RUE (9.7%) were higher in raised beds than flat basins, while a significant planting system × genotype interaction was found for grain yield. Genetic variation in pre‐grain‐filling RUE was associated with biomass and grain yield in beds and basins. In flat basins, higher pre‐grain‐filling RUE was correlated with a more upright flag‐leaf angle but not in raised beds. In raised beds, cultivars with less upright flag‐leaf angle had greater fractional light interception pre‐anthesis. Taller semi‐dwarf cultivars intercepted relatively more radiation in the beds than the flats before anthesis, consistent with the taller cultivars showing relatively greater increases in yield in beds compared to flats. Our results indicated that the evaluation of genotypes for RUE and biomass in wheat breeding should take into account planting systems to capture genotype × PS effects. In addition, the results demonstrate how flag‐leaf angle has a different effect depending on the planting system.
Epithelial–immune cell interactions in allergic diseases
Authors: Albrecht Melanie , Garn Holger , Buhl Timo
Published: October 2023

Epithelial/immune interactions are characterized by the different properties of the various epithelial tissues, the mediators involved, and the varying immune cells that initiate, sustain, or abrogate allergic diseases on the surface. The intestinal mucosa, respiratory mucosa, and regular skin feature structural differences according to their primary function and surroundings. In the context of these specialized functions, the active role of the epithelium in shaping immune responses is increasingly recognizable. Crosstalk between epithelial and immune cells plays an important role in maintaining homeostatic conditions. While cells of the myeloid cell lineage, mainly macrophages, are the dominating immune cell population in the skin and the respiratory tract, lymphocytes comprise most intraepithelial immune cells in the intestine under healthy conditions. Common to all surface epithelia is the fact that innate immune cells represent the first line of immunosurveillance that either directly defeats invading pathogens or initiates and coordinates more effective successive immune responses involving adaptive immune cells and effector cells. Pharmacological approaches for the treatment of allergic and chronic inflammatory diseases involving epithelial barriers target immunological mediators downstream of the epithelium (such as IL‐4, IL‐5, IL‐13, and IgE). The next generation of therapeutics involves upstream events of the inflammatory cascade, such as epithelial‐derived alarmins and related mediators.
Mechanisms of shear band formation in heterogeneous materials under compression: The role of pre-existing mechanical flaws
Authors: Mukhopadhyay Manaska , Roy Arnab , Mandal Nibir
Published: October 2023

Shear bands critically govern the shear failure processes and associated
many geophysical phenomena, e.g., faulting, in Earth’s crust. Earlier
investigations on homogeneous materials recognized temperature and
strain rate as the principal factors controlling the band growth.
However, how inherent mechanical heterogeneities can influence their
growth mechanism and internal structures remained unexplored. From
plane-strain compression experiments on rock analogue models the present
article addresses this issue. It is demonstrated from these experiments
that mechanical heterogeneities dictate the failure to develop wide
bands, localized preferentially in their neighborhood, unlike uniformly
distributed, conjugate sets of closely spaced narrow bands in
homogeneous models. The wide bands eventually attain a composite
structure with a core of densely packed band-parallel sharp secondary
bands, flanked by a linear zone of closely spaced, narrow bands. This
study also reveals the effects of global strain-rate on the band
evolution in heterogeneous systems. Decreasing strain rates replace the
composite bands by well-defined homogeneous shear bands, containing a
core of uniform shear, bordered by narrow zones of weak shear, grading
into completely unstrained walls. Numerical modelling in a
visco-elasto-plastic rheological framework under geological strain-rates
is used to quantify the strain partitioning patterns in the
heterogeneity-controlled transformation of spatially distributed narrow
to localized, wide composite shear bands. The model simulations also
reveal that increasing strain rates facilitates the bands to form
clusters, instead of single wide bands. The article finally provides a
set of field observations to demonstrate the importance of
heterogeneity-driven band mechanics in interpreting macro-scale shear
zones in geological terrains.
Clinical outcomes of oral epithelial dysplasia managed by observation versus excision
Authors: Bernard Christopher , Zhang Jasper Zhongyuan , Klieb Hagen , Blanas Nick , Xu Wei , Magalhaes Marco
Published: October 2023

Importance

Oral potentially malignant disorders, including oral epithelial dysplasia (OED), are a group of conditions with an increased risk of progression to oral cancer. Clinical management of OED is challenging and usually involves monitoring with repeated incisional biopsies or complete surgical excision.

Objective

To determine if complete surgical excision of OED impacts malignant transformation or improves survival outcomes in lesions that progress to malignancy.

Design

A retrospective review of all patients diagnosed with OED between 2009 and 2016 was completed, and patients were followed until January 2022 for disease course and outcomes.

Results

Hundred and fifty‐five cases of OED met the inclusion criteria. Among the 61 lesions managed by observation, 15 progressed to cancer. Among the 94 lesions managed by surgical excision, 27 progressed to cancer. The overall malignant transformation rate was 27%, with an annual rate of 6.4%. Surgical excision with or without histologically negative margins did not decrease malignant transformation but was associated with lower oncologic staging at the time of diagnosis and improved survival.

Conclusions and relevance

Surgical excision of OED with or without negative margins did not reduce the rate of transformation to oral cancer but resulted in lower oncologic staging at diagnosis, leading to improved patient outcomes. Our results support the implementation of more extensive tissue sampling to improve cancer diagnosis and patient outcomes.
FIGO good practice recommendations for preterm labor and preterm prelabor rupture of membranes: Prep‐for‐Labor triage to minimize risks and maximize favorable outcomes
Authors: Ubom Akaninyene Eseme , Vatish Manu , Barnea Eytan R. ,   the FIGO Childbirth and Postpartum Hemorrhage Committee
Published: October 2023

Preterm labor occurs in around 10% of pregnancies worldwide. Once diagnosed, significant efforts must be made to reduce the likelihood of morbidity and mortality associated with preterm birth. In high‐resource settings, access to hospitals with a neonatal intensive care unit (NICU) is readily available, whereas access to NICU care is limited in low‐ and middle‐income countries (LMICs) and many rural settings. Use of FIGO's Prep‐for‐Labor triage method rapidly identifies low‐ and high‐risk patients with preterm labor to enable clinicians to decide whether the patient can be managed on site or if transfer to a level II–IV facility is needed. The management steps described in this paper aim to minimize the morbidity and mortality associated with preterm labor and in the setting of preterm labor with preterm premature rupture of membranes (PPROM). The methods for accurate diagnosis of PPROM and chorioamnionitis are described. When the risk of preterm birth is high, antenatal corticosteroids should be administered for lung maturation combined with limited tocolysis for 48 hours to permit the corticosteroid course to be completed. Magnesium sulfate is also administered for fetal neuroprotection. Implementation of FIGO's Prep‐for‐Labor triage method in an LMIC setting will help improve maternal and neonatal outcomes.
A unique case of Schistosoma‐related ureteral stricture: Diagnosis and surgical reconstruction
Authors: Seaman Jonathan A , Bracamonte Erika , Kim Sunchin
Published: October 2023

Background

Chronic infection with Schistosoma haematobium can lead to pathology of the upper and lower urinary tracts. While well known as a cause of squamous cell carcinoma of the bladder, relatively little research exists on ureteral involvement. Here, we present a unique case of bilateral ureteral obstruction from schistosomiasis with concomitant ureteral stone disease.

Case presentation

A 43‐year‐old male Somalian immigrant was diagnosed with a right proximal ureteral stone and bilateral multifocal ureteral narrowing causing obstruction with preserved renal function. He underwent a staged repair with right robotic pyelolithotomy and non‐transecting ureteroureterostomy, followed by left robotic ureteroureterostomy with stricture excision. Pathology revealed Schistosoma ova.

Conclusion

Ureteral stricture from schistosomiasis represents a rare diagnosis for urologists in non‐endemic countries. Bilateral ureteral narrowing and concomitant ureteral stone burden presented both diagnostic and reconstructive challenges, requiring a staged repair. Minimally invasive reconstruction was achieved using robotic assistance with good functional outcome.
Usefulness of the Hypo‐Osmotic Swelling Test in Predicting Pregnancy Rate and Outcome in Couples Undergoing Intrauterine Insemination
Authors: TARTAGNI MASSIMO , SCHONAUER MATTEO MARIA , CICINELLI ETTORE , SELMAN HELMY , de ZIEGLER DOMINIQUE , PETRUZZELLI FILOMENA , D'ADDARIO VINCENZO
Published: October 2023

This study was designed to evaluate the usefulness of the hypo‐osmotic swelling (HOS) test in predicting successful conception and the pregnancy outcome in couples in whom men are affected by mild infertility and fertile women are treated with ovulation induction and intrauterine insemination (IUI). We retrospectively analyzed the results obtained from 120 couples who underwent not more than 3 consecutive cycles of gonadotropin‐induced mono‐ovulation followed by IUI. Semen was analyzed by classical parameters, and the HOS test was performed using a hypo‐osmotic solution. Using HOS, at least 50% swollen spermatozoa was considered normal. The pregnancy rate obtained in couples with an HOS less than 50% was significantly lower (P > .05) than that achieved in couples with HOS values at least 50%. Furthermore, the miscarriage rate was higher when HOS was less than 50%. For prediction of successful pregnancy, the sensitivity and specificity of the HOS test was 64% and 75%, respectively; the predictive value of an abnormal test was 94%, and that of a normal test was 24%. The HOS test may detect subtle damage in spermatozoan structure, which is responsible for the reduced capacity of spermatozoa to induce a viable embryo, with a low rate of pregnancy and a high rate of miscarriage. The results suggest that the HOS test may help in recognizing men who have a poor chance of fertilizing their partners and to have viable pregnancies using IUI.
Development of a Cryopreservation Protocol for Type A Spermatogonia
Authors: IZADYAR FARIBORZ , MATTHIJS‐RIJSENBILT J. J. , DEN OUDEN KRISTA , CREEMERS LAURA B. , WOELDERS HENRI , de ROOIJ DIRK G.
Published: October 2023

The aim of this study was to develop a cryopreservation protocol for type A spermatogonia. Testes from 5‐ to 7‐month‐old calves were collected, and type A spermatogonia were isolated using two‐step enzymatic digestion and Percoll separation. Cells were resuspended in minimum essential medium (MEM) supplemented with 1% bovine serum albumin (BSA) in a final concentration of 6 × 106 per mL, and the effects of different cryoprotectants and freezing protocols were tested. Cells frozen/thawed in medium containing 10% fetal calf serum (FCS) and 1.4 M glycerol or dimethyl sulfoxide (DMSO) had a significantly (P < .05) higher percentage of living cells compared to medium with only FCS, whereas DMSO gave a significantly better cell survival rate than glycerol did. An increase in the concentration of FCS in the DMSO‐based medium to 20% had no effect on survival after freezing and thawing. Furthermore, inclusion of 0.07, 0.14, or 0.21 M sucrose in DMSO‐based medium resulted in a significant improvement of cell survival, cell proliferation in culture, and colonization efficiency in recipient testes. A controlled slow‐freezing rate (1 °C/min) resulted in significantly (P < .05) more viable cells than fast (5°C/min) freezing. However, noncontrolled‐rate freezing, with a comparably low cooling rate, gave even better results than the controlled‐rate slow freezing. Cryopreservation in MEM‐based medium containing 10% FCS, 10% DMSO, and 0.07 M sucrose using a non‐controlled‐rate freezing protocol appeared to be a simple and effective way to preserve type A spermatogonia, with a high yield of almost 70% living cells after thawing. Frozen/thawed spermatogonia survived in culture and retained the ability to proliferate as determined by colorimetric and bromodeoxyuridine incorporation assays. To test whether the stem cells among the A spermatogonia retained their ability to colonize the testis of a recipient mouse, bovine spermatogonia were transplanted. This resulted in colonization 2–3 months after transplantation. In conclusion, for the first time, a method specific for cryopreservation of type A spermatogonia, including spermatogonial stem cells was developed, which allows long‐term preservation of these cells without apparent harmful effects to their function.
Environmental Agents and Erectile Dysfunction: A Study in a Consulting Population
Authors: OLIVA ALEJANDRO , GIAMI ALAIN , MULTIGNER LUC
Published: October 2023

We evaluated chemical and physical environmental agents as risk factors for erectile dysfunction among a consulting population. We studied 199 men who sought medical help for erectile disorders between 1996 and 1998 in 3 andrology units in the Litoral Sur region of Argentina. Patients were evaluated by monitoring nocturnal penile tumescence and rigidity, and were classified as having normal (n = 26), irregular (dissociation, short episode or low amplitude, n = 146), or flat erectile pattern (n = 26). Exposure to environmental agents was assessed by a detailed interview, and 4 groups were constituted: nonexposed, pesticide‐exposed, solventexposed, and heat‐exposed. A multivariate polytomous logistic regression model was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for association between quality of nocturnal erections and exposure groups adjusted for confounding factors. Exposure to environmental agents was a risk factor for a flat erectile pattern (OR 7.1, 95% CI 1.5–33.0 for pesticides; OR 12.2, 95% CI 1.2–124.8 for solvents; and OR 1.7, 95% CI 0.3–9.4 for heat). Associations were much weaker for an irregular erectile pattern (OR 1.8, 95% CI 0.5–6.7 for pesticides; OR 2.1, 95% CI 0.3–17.9 for solvents; and OR 1.2, 95% CI 0.4‐4.0 for heat). Our results suggest that environmental agents constitute a risk factor for erectile dysfunction by interfering with erectile ability.
Cytofluorographic Identification of Activated T‐cell Subpopulations in the Semen of Men With Spinal Cord Injuries
Authors: BASU SARMISTHA , LYNNE CHARLES M. , RUIZ PHILLIP , ABALLA TEODORO C. , FERRELL SEAN M. , BRACKETT NANCY L.
Published: October 2023

The semen of most men with spinal cord injury (SCI) contains an abundance of leukocytes. It is not known if this leukocytospermia contributes to the abnormally low sperm motility observed in many of these men. Our study used flow cytometry to identify the leukocyte population in the semen of 12 men with SCI compared to 8 healthy age‐matched control subjects. The results showed that, compared to control subjects, the semen of men with SCI had increased numbers of mature granulocytes and lymphocytes. The largest proportion of the leukocytes consisted of lymphocytes, and immunophenotypic analysis showed that the greater fraction were T cells, many of which coexpressed human leukocyte antigen HLA‐DR and CD25, suggesting they were in an “activated” state. No significant B‐cell population was evident. Our finding of immunologically active leukocytes is a significant step in understanding the relationship of leukocytospermia and decreased sperm motility in the semen of men with SCI.
Effects of Sildenafil on Nocturnal Penile Tumescence and Rigidity in Normal Men: Randomized, Placebo‐Controlled, Cross‐over Study
Authors: ROCHIRA VINCENZO , GRANATA ANTONIO R. M. , BALESTRIERI ANTONIO , MADEO BRUNO , CARANI CESARE
Published: October 2023

We studied the effects of sildenafil on sleep‐related erections in 44 adult healthy men not affected by erectile dysfunction (mean age ± SD: 39.3 ± 10.5 years). No subjects were administered any medication the first night, but all were randomly administered sildenafil 50 mg or placebo the second night and vice versa the third night. Sildenafil and placebo were administered 1 hour before bedtime. The following parameters of sleep‐related erections, after taking sildenafil or placebo, were analyzed: total number of valid erections, total duration of rigidity more than or equal to 70% of a tightening force of 2.8 N applied by the recording device, total duration of increase in penile circumference more than or equal to 30 mm, maximum rigidity, mean of maximum rigidity, and maximum increase of tumescence. Apart from the maximum increase of tumescence, all the parameters analyzed were significantly higher after sildenafil than after placebo administration during the first 4 hours of monitoring in all subjects (n = 44) (study 1). All the parameters were significantly higher after sildenafil than after placebo administration during the whole 8 hours of monitoring in 25 of 44 subjects (study 2A) who slept at least 8 hours. Comparing both the first and the second 4 hours in the 25 of 44 subjects who slept at least 8 hours (study 2B), all the parameters were significantly higher after sildenafil than after placebo administration, apart from maximum rigidity and mean of maximum rigidity during the first 4 hours. Our data suggest that sildenafil, administered at bedtime, is efficacious in improving sleep‐related erections in normal men, indirectly confirming that the nitric oxide pathway is crucial in the physiology of erections during sleep. The effect of sildenafil is prolonged up to 8–9 hours after its administration.
Investigation of the Differences in the Pharmacokinetics of CYP2D6 Substrates, Desipramine, and Dextromethorphan in Healthy African Subjects Carrying the Allelic Variants CYP2D6*17 and CYP2D6*29, When Compared with Normal Metabolizers
Authors: Marasanapalle Venugopal P. , Masimirembwa Collen , Sivasubramanian Rama , Sayyed Sarfaraz , Weinzierl‐Hinum Armin , Mehta Dheeraj , Kapungu Nyasha Nicole , Kanji Comfort , Thelingwani Roslyn , Zack Julia
Published: October 2023

This study investigated the differences in the pharmacokinetics (PK) of dextromethorphan and desipramine in healthy African volunteers to understand the effect of allelic variants of the human cytochrome P450 2D6 (CYP2D6) enzyme, namely the diplotypes of CYP2D6*1/*2 (*1*1, *1*2, *2*2) and the genotypes of CYP2D6*17*17 and CYP2D6*29*29. Overall, 28 adults were included and split into 3 cohorts after genotype screening: CYP2D6*1/*2 (n = 12), CYP2D6*17*17 (n = 12), and CYP2D6*29*29 (n = 4). Each subject received a single oral dose of dextromethorphan 30 mg syrup on day 1 and desipramine 50 mg tablet on day 8. The PK parameters of area under the plasma concentration‐time curve from time of dosing to time of last quantifiable concentration (AUClast), and extrapolated to infinity (AUCinf), and the maximum plasma concentration (Cmax) were determined. For both dextromethorphan and desipramine, AUCinf and Cmax were higher in subjects of the CYP2D6*29*29 and CYP2D6*17*17 cohorts, as compared with subjects in the CYP2D6*1/*2 diplotype cohort and with normal metabolizers from the literature. All PK parameters, including AUCinf, Cmax, and the elimination half‐life, followed a similar trend: CYP2D6*17*17 > CYP2D6*29*29 > CYP2D6*1/*2. The plasma and urinary drug/metabolite exposure ratios of both drugs were higher in subjects of the CYP2D6*17*17 and CYP2D6*29*29 cohorts, when compared with subjects in the CYP2D6*1/*2 diplotype cohort. All adverse events were mild, except in 1 subject with CYP2D6*17*17 who had moderately severe headache with desipramine. These results indicate that subjects with CYP2D6*17*17 and CYP2D6*29*29 genotypes were 5‐10 times slower metabolizers than those with CYP2D6*1/*2 diplotypes. These findings suggest that dose optimization may be required when administering CYP2D6 substrate drugs in African patients. Larger studies can further validate these findings.
Systematic compositional analysis of exosomal extracellular vesicles produced by cells undergoing apoptosis, necroptosis and ferroptosis
Authors: Cappe Benjamin , Vadi Mike , Sack Eliza , Wacheul Ludivine , Verstraeten Bruno , Dufour Sara , Franck Julien , Xie Wei , Impens Francis , Hendrix An , Lafontaine Denis L. J. , Vandenabeele Peter , Riquet Franck B.
Published: October 2023

Formation of extracellular vesicles (EVs) has emerged as a novel paradigm in cell‐to‐cell communication in health and disease. EVs are notably produced during cell death but it had remained unclear whether different modalities of regulated cell death (RCD) influence the biogenesis and composition of EVs. To this end, we performed a comparative analysis of steady‐state (ssEVs) and cell death‐associated EVs (cdEVs) following TNF‐induced necroptosis (necEVs), anti‐Fas‐induced apoptosis (apoEVs), and ML162‐induced ferroptosis (ferEVs) using the same cell line. For each RCD condition, we determined the biophysical and biochemical characteristics of the cell death‐associated EVs (cdEVs), the protein cargo, and the presence of methylated ribosomal RNA. We found that the global protein content of all cdEVs was increased compared to steady‐state EVs. Qualitatively, the isolated exosomal ssEVs and cdEVs, contained a largely overlapping protein cargo including some quantitative differences in particular proteins. All cdEVs were enriched for proteins involved in RNA splicing and nuclear export, and showed distinctive rRNA methylation patterns compared to ssEVs. Interestingly, necEVs and apoEVs, but strikingly not ferEVs, showed enrichment of proteins involved in ribosome biogenesis. Altogether, our work documents quantitative and qualitative differences between ssEVs and cdEVs.
Validation of a surgical difficulty grading system in laparoscopic cholecystectomy for acute cholecystitis
Authors: Asai Koji , Ohyama Tetsuji , Watanabe Manabu , Moriyama Hodaka , Kujiraoka Manabu , Watanabe Ryutaro , Shigeta Kenta , Kakizaki Nanako , Hagiwara Osahiko , Saida Yoshihisa
Published: October 2023

Background

The surgical difficulty of laparoscopic cholecystectomy (LC) for acute cholecystitis varies from case to case, and appropriate intraoperative evaluation would help prevent bile duct injury (BDI).

Methods

We analyzed 178 patients who underwent LC for acute cholecystitis. Expert surgeons and trainees individually evaluated the surgical difficulty. The inter‐rater agreement was analyzed using Conger's κ and Gwet's agreement coefficient (AC). Furthermore, we analyzed the predictive surgical difficulty item for performing subtotal cholecystectomy (STC).

Results

Regarding the inter‐rater agreement between expert surgeons and trainees, 15 of the 17 surgical difficulty items had a Gwet's AC of 0.5 or higher, indicating “moderate” agreement or higher. Furthermore, the highest and total surgical difficulty scores were deemed “substantial” agreement. Scarring and dense fibrotic changes around the Calot's triangle area with easy bleeding with/without necrotic changes were predictive of whether STC should be performed.

Conclusions

This surgical difficulty grading system is expected to be a tool that can be used by any surgeon with LC experience. STC should be performed to prevent BDI according to the changes around the Calot's triangle area.