bluuebunny/crossref_metadata_2025 huggingface dataset:
AFM force measurements on microtubule‐associated proteins: the projection domain exerts a long‐range repulsive force
Authors: Mukhopadhyay Rajendrani , Hoh Jan H.
Published: July 2002

Microtubule‐associated proteins (MAPs) are thought to control spacing between microtubules. We propose that the projection domain is largely unstructured and exerts a long‐range repulsive force that is predominantly entropic in origin, providing a physical mechanism for maintaining spacing. To test this hypothesis, we developed an experimental system where MAPs are electrostatically end‐attached to a flat surface, such that the projection domains extend away from the surface. Atomic force microscopy force measurements on this system show that projection domains exert a long‐range (>100 nm) repulsive force. This force depends on the ionic strength of the solution in a way that is consistent with a polyelectrolyte polymer brush.
A ligand that Trypanosoma cruzi uses to bind to mammalian cells to initiate infection
Authors: Villalta Fernando , Smith Cassandra M , Ruiz-Ruano Antonio , Lima Maria F
Published: July 2002

We purified a soluble gp83 trans‐sialidase (gp83‐TSA), from phospholipase C‐treated Trypanosoma cruzi trypomastigote membranes, which binds to myoblasts, fibroblasts and macrophages to mediate trypanosome entry. Myoblasts display a single class of receptors for the gp83‐TSA present at 4×104 per myoblast with a K
d of 8 nM. Monovalent Fab fragments of the monoclonal antibody 4A4 specific for gp83‐TSA inhibit gp83‐TSA binding to myoblasts, fibroblasts and macrophages, block the trypanosomes from attaching to and entering these cells and neutralize T. cruzi infection in BALB/c mice. This is the first demonstration that gp83‐TSA is a ligand that T. cruzi uses to attach to cells.
Direct observation of membrane retrieval in chromaffin cells by capacitance measurements
Authors: Henkel Andreas W , Horstmann Heinz , Henkel M.Kerstin
Published: July 2002

This study was focussed on the identification of the endocytic organelles in chromaffin cells which retrieve large, dense core vesicle (LDCV)‐membrane components from the plasma membrane. For this purpose, ‘on‐cell’ capacitance measurements and electron microscopy were employed. We found capacitance steps and capacitance flickers, corresponding to single exo‐ and endocytic events. The analysis revealed that the total membrane surface of completely fused LDCVs is recycled by large endocytic vesicles and smaller, most likely clathrin‐coated vesicles, at approximately the same ratio. These results were confirmed by rapid‐freeze immuno‐electron microscopy, where an extracellular marker was rapidly internalized into endocytic vesicles that morphologically resembled LDCVs.
The C‐terminal domain of yeast Ero1p mediates membrane localization and is essential for function
Authors: Pagani Massimiliano , Pilati Stefania , Bertoli Gloria , Valsasina Barbara , Sitia Roberto
Published: July 2002

In eukaryotes, members of the Ero1 family control oxidative protein folding in the endoplasmic reticulum (ER). Yeast Ero1p is tightly associated with the ER membrane, despite cleavage of the leader peptide, the only hydrophobic sequence that could mediate lipid insertion. In contrast, human Ero1‐Lα and a yeast mutant (Ero1pΔC) lacking the 127 C‐terminal amino acids are soluble when expressed in yeast. Neither Ero1‐Lα nor Ero1pΔC complements an ERO1 disrupted strain. Appending the yeast C‐terminal tail to human Ero1‐Lα restores membrane association and allows growth of ERO1 disrupted cells. Therefore, the tail of Ero1p mediates membrane association and is crucial for function.
Interaction of ADP‐ribosylated actin with actin binding proteins
Authors: Ballweber Edda , Galla Marco , Aktories Klaus , Yeoh Sharon , Weeds Alan G. , Mannherz Hans Georg
Published: July 2002

Actin ADP‐ribosylated at Arg177 was previously shown not to polymerise after increasing the ionic strength, but to cap the barbed ends of filaments. Here we confirm that the polymerisation of ADP‐ribosylated actin is inhibited, however, under specific conditions the modified actin copolymerises with native actin, indicating that its ability to take part in normal subunit interactions within filaments is not fully eliminated. We also show that ADP‐ribosylated actin forms antiparallel but not parallel dimers: the former are not able to form filaments. ADP‐ribosylated actin interacts with deoxyribonuclease I, vitamin D binding protein, thymosin β4, cofilin and gelsolin segment 1 like native actin. Interaction with myosin subfragment 1 revealed that the potential of the modified actin to aggregate into oligomers or short filaments is not fully eliminated.
A PKCβ isoform mediates phorbol ester‐induced activation of Erk1/2 and expression of neuronal differentiation genes in neuroblastoma cells
Authors: Trollér Ulrika , Zeidman Ruth , Svensson Karin , Larsson Christer
Published: July 2002

Protein kinase C (PKC) activation induces neuronal differentiation of SH‐SY5Y neuroblastoma cells. This study examines the role of PKCβ isoforms in this process. The PKCβ‐specific inhibitor LY379196 had no effect on 12‐O‐tetradecanoylphorbol 13‐acetate (TPA)‐induced neurite outgrowth from SH‐SY5Y neuroblastoma cells. On the other hand, PKCβ inhibition suppressed the TPA‐stimulated increase in neuropeptide Y mRNA, activation of neuropeptide Y gene promoter elements, and phosphorylation of Erk1/2. The TPA‐induced increase in neuropeptide Y expression was also inhibited by the MEK inhibitor PD98059. These data indicate that activation of a PKCβ isoform, through a pathway involving Erk1/2, leads to increased expression of neuronal differentiation genes in neuroblastoma cells.
Saposins (sap) A and C activate the degradation of galactosylsphingosine
Authors: Harzer Klaus , Hiraiwa Masao , Paton Barbara C
Published: July 2002

As previously shown for [3H‐galactosyl]ceramide, the breakdown of [3H‐galactosyl]sphingosine was reduced in prosaposin‐deficient skin fibroblast homogenates. Galactosylsphingosine hydrolysis was also deficient in cell homogenates from Krabbe's disease (β‐galactocerebrosidase‐deficient) patients, but not acid β‐galactosidase‐deficient patients. Moreover, hydrolysis of galactosylsphingosine in the prosaposin‐deficient cell homogenates could be partially restored by adding pure saposin A or C, thereby identifying these saposins as essential facilitators of galactosylsphingosine hydrolysis. By contrast, saposins B and D had little effect on galactosylsphingosine hydrolysis in the prosaposin‐deficient cells. The reduced galactosylsphingosine turnover in prosaposin‐deficiency suggests that there could be a pathogenetic cerebral accumulation of galactosylsphingosine in this disorder.
The allograft inflammatory factor‐1 family of proteins
Authors: Deininger Martin H , Meyermann Richard , Schluesener Hermann J
Published: July 2002

The allograft inflammatory factor‐1 (AIF‐1) is a 17 kDa interferon‐γ‐inducible Ca2+‐binding EF‐hand protein that is encoded within the HLA class III genomic region. Three proteins are probably identical with AIF‐1 termed Iba1 (ionized Ca2+‐binding adapter), MRF‐1 (microglia response factor) and daintain. Considerable but not complete sequence identity with AIF‐1 has been described for IRT‐1 (interferon‐responsive transcript), BART‐1 (balloon angioplasty‐responsive transcript), and other, yet unassigned alternatively spliced variants. In this review, genomic and functional characteristics of AIF‐1‐related proteins are summarized and a common nomenclature is proposed.
Action pattern and subsite mapping of Bacillus licheniformis α‐amylase (BLA) with modified maltooligosaccharide substrates
Authors: Kandra Lili , Gyémánt Gyöngyi , Remenyik Judit , Hovánszki György , Lipták András
Published: July 2002

This study represents the first characterisation of the substrate‐binding site of Bacillus licheniformis α‐amylase (BLA). It describes the first subsite map, namely, number of subsites, apparent subsite energies and the dual product specificity of BLA. The product pattern and cleavage frequencies were determined by high‐performance liquid chromatography, utilising a homologous series of chromophore‐substituted maltooligosaccharides of degree of polymerisation 4–10 as model substrates. The binding region of BLA is composed of five glycone, three aglycone‐binding sites and a ‘barrier’ subsite. Comparison of the binding energies of subsites, which were calculated with a computer program, shows that BLA has similarity to the closely related Bacillus amyloliquefaciens α‐amylase.
Isolation of up‐ or down‐regulated genes in PPARγ‐expressing NIH‐3T3 cells during differentiation into adipocytes
Authors: Okuno Masaaki , Arimoto Emi , Nishizuka Makoto , Nishihara Tsutomu , Imagawa Masayoshi
Published: July 2002

Adipocyte differentiation is a complex process in which the expression of many transcription factors and adipocyte‐specific genes is regulated under a strict program. The peroxisome proliferator‐activated receptor γ (PPARγ), a member of the steroid/thyroid nuclear hormone receptor superfamily of ligand‐activated transcription factors, is an important regulator of adipocyte gene expression and differentiation. In this study, we tried to identify downstream target genes of PPARγ, by using PPARγ‐expressing cells and a subtractive cloning strategy, and isolated cDNA clones which were up‐regulated or down‐regulated by PPARγ. Northern blot analyses revealed that the expression levels of the aldehyde dehydrogenase‐2‐like, type VI collagen alpha 3 subunit, cellular retinoic acid binding protein 1 and thrombospondin 1 are changed during the differentiation of mouse 3T3‐L1 preadipocyte cells, indicating that these genes might be downstream targets of PPARγ in adipocyte differentiation.
Triabodies: single chain Fv fragments without a linker form trivalent trimers
Authors: Iliades Peter , Kortt Alexander A , Hudson Peter J
Published: July 2002

A single chain Fv fragment (scFv) of the murine monoclonal antibody 11‐1G10 was constructed by directly joining the C‐terminal residue of the VH domain to the N‐terminal residue of VL. 11‐1G10 is an anti‐idiotype and competes with the antigen, influenza virus neuraminidase (NA), for binding to the NC41 antibody. The scFv formed stable trimers with three active antigen combining sites for NC41 Fab fragments. We propose that trimeric scFvs may be the preferred conformation for directly linked VH‐VL molecules, which contrasts the formation of scFv dimers (diabodies) when the VH and VL domains are joined by short flexible linkers of between 5–10 residues. BIAcore biosensor binding experiments showed that the trimeric scFv showed an expected increase in binding affinity, due to avidity, compared to the monomeric 15‐residue linked scFv. The increase in avidity of scFv trimers offers advantages for imaging and immunotherapy.
Constitutively active mutants of the β1‐adrenergic receptor
Authors: Lattion Anne-Laure , Abuin Liliane , Nenniger-Tosato Monique , Cotecchia Susanna
Published: July 2002

We provide the first evidence that point mutations can constitutively activate the β1‐adrenergic receptor (AR). Leucine 322 of the β1‐AR in the C‐terminal portion of its third intracellular loop was replaced with seven amino acids (I, T, E, F, C, A and K) differing in their physico‐chemical properties. The β1‐AR mutants expressed in HEK‐293 cells displayed various levels of constitutive activity which could be partially inhibited by some beta‐blockers. The results of this study might have interesting implications for future studies aiming at elucidating the activation process of the β1‐AR as well as the mechanism of action of beta‐blockers.
NAADP‐induced calcium release in sea urchin eggs
Authors: Galione Antony , Patel Sandip , Churchill Grant C.
Published: July 2002

Nicotinic acid adenine dinucleotide phosphate (NAADP) is the most potent activator of Ca2+ release from intracellular stores described. It acts on a mechanism distinct from inositol trisphosphate and ryanodine receptors, the two major Ca2+ release channels characterised. NAADP‐gated Ca2+ release channels do not appear to be regulated by Ca2+ and may be better suited for triggering Ca2+ signals rather than propagating them. They exhibit a remarkable pharmacology for a putative intracellular Ca2+ release channel in that they are selectively blocked by potassium and L‐type Ca2+ channel antagonists. Furthermore, in contrast to microsomal Ca2+ stores expressing IP2+Rs and RyRs, those sensitive to NAADP are thapsigargin‐insensitive, suggesting that they may be expressed on a different part of the endoplasmic reticulum. Perhaps the most unusual feature of the NAADP‐gated Ca2+ release mechanisms is its inactivation properties. Unlike the mechanisms regulated by IP2+ and cADPR in sea urchin eggs which after induction of Ca2+ release appear to become refractory to subsequent activation, very low concentrations of NAADP are able to inactivate NAADP‐induced Ca2+ release fully at concentrations well below those required to activate Ca2+ release. The mechanism and physiological significance of this most unusual desensitisation phenomenon are unclear. More recently, NAADP has been shown to mobilise Ca2+ in ascidian oocytes, brain microsomes and pancreatic acinar cells suggesting a more widespread role in Ca2+ signalling. A possible role for this novel Ca2+ release mechanism in sea urchin egg fertilisation is discussed.
The Raf/MEK/ERK pathway: new concepts of activation
Authors: Peyssonnaux Carole , Eychène Alain
Published: July 2002

Summry— The Raf/MEK/ERK signaling was the first MAP kinase cascade to be characterized. It is probably one of the most well known signal transduction pathways among biologists because of its implication in a wide variety of cellular functions as diverse ‐and occasionally contradictory‐ as cell proliferation, cell‐cycle arrest, terminal differentiation and apoptosis. Discovery and understanding of this pathway have benefited from the combination of both genetic studies in worms and flies and biochemical studies in mammalian cells. However, ten years after, this field is still under debate and new molecular partners in the cascade continue to increase the complexity of its regulation. This review deals with the emergence of new concepts in the activation and regulation of the Raf/MEK/ERK module. In particular, the preponderant role of B‐Raf is underlined, and the role of novel regulators such as KSR is discussed.
The National Strategy for Suicide Prevention
Authors: Krulewitch Cara J.
Published: July 2002

The suffering of the suicidal is private and inexpressible, leaving family members, friends and colleagues to deal with an almost unfathomable kind of loss, as well as guilt. Suicide carries in its aftermath a level of confusion and devastation that is, for the most part beyond description.

Kay Redfield Jamison ()
Multifunctional and Stimuli‐Responsive Polydopamine Nanoparticle‐Based Platform for Targeted Antimicrobial Applications
Authors: Andoy Nesha May O. , Jeon Keuna , Kreis Christian Titus , Sullan Ruby May A.
Published: August 2020

The rising threat of antimicrobial resistance is a crisis of a global scale. If not addressed, it can lead to health care system problems worldwide. This warrants alternative therapeutic approaches whose mechanism of action starkly differs from conventional antibiotic‐based therapies. Here, a multifunctional and stimuli‐responsive (NIR laser‐activated) antimicrobial platform is engineered by combining the intrinsic photothermal capability and excellent biocompatibility of polydopamine nanoparticles (PdNPs), with the membrane targeting and lytic activities of an antimicrobial peptide (AMP). The resulting PdNP‐AMP nanosystem can specifically target and destabilize the mechanical integrity of the outer membrane of Escherichia coli, as measured using the atomic force microscope. Furthermore, the laser‐induced nano‐localized heating of PdNP—in close proximity to the already compromised bacterial envelope—induces further membrane damage. This results in a more efficient, laser‐activated, bacterial killing action of PdNP‐AMP. The antimicrobial platform developed in this work is shown to be effective against a drug‐resistant E. coli. Overall, this work highlights the advantage and strength of combining multiple and coordinated biocidal mechanisms, into one nanomaterial‐based system and its promise in treating drug‐resistant pathogens.
Hyaluronic Acid‐Based Bioink Composition Enabling 3D Bioprinting and Improving Quality of Deposited Cartilaginous Extracellular Matrix
Authors: Hauptstein Julia , Böck Thomas , Bartolf‐Kopp Michael , Forster Leonard , Stahlhut Philipp , Nadernezhad Ali , Blahetek Gina , Zernecke‐Madsen Alma , Detsch Rainer , Jüngst Tomasz , Groll Jürgen , Teßmar Jörg , Blunk Torsten
Published: August 2020

In 3D bioprinting, bioinks with high concentrations of polymeric materials are frequently used to enable fabrication of 3D cell‐hydrogel constructs with sufficient stability. However, this is often associated with restricted cell bioactivity and an inhomogeneous distribution of newly produced extracellular matrix (ECM). Therefore, this study investigates bioink compositions based on hyaluronic acid (HA), an attractive material for cartilage regeneration, which allow for reduction of polymer content. Thiolated HA and allyl‐modified poly(glycidol) in varying concentrations are UV‐crosslinked. To adapt bioinks to poly(ε‐caprolactone) (PCL)‐supported 3D bioprinting, the gels are further supplemented with 1 wt% unmodified high molecular weight HA (hmHA) and chondrogenic differentiation of incorporated human mesenchymal stromal cells is assessed. Strikingly, addition of hmHA to gels with a low polymer content (3 wt%) results in distinct increase of construct quality with a homogeneous ECM distribution throughout the constructs, independent of the printing process. Improved ECM distribution in those constructs is associated with increased construct stiffness after chondrogenic differentiation, as compared to higher concentrated constructs (10 wt%), which only show pericellular matrix deposition. The study contributes to effective bioink development, demonstrating dual function of a supplement enabling PCL‐supported bioprinting and at the same time improving biological properties of the resulting constructs.
Negative Magnetoresistance Behavior in Polymer Spin Valves Based on Donor−Acceptor Conjugated Molecules
Authors: Zheng Naihang , Wang Xiang , Zheng Yuanhui , Li Dong , Lin Zuzhang , Zhang Weifeng , Jin Kui‐juan , Yu Gui
Published: August 2020

Organic spin valves (OSVs) have become an essential building block of next‐generation memory devices which focus on spin degree of transporting carriers. Meanwhile, negative magnetoresistance (MR) effect in the OSV devices is increasingly observed which deserves further exploration for the rich spin physics behind. In this work, the negative MR response in ferromagnetic (FM) metal‐based OSVs using donor−acceptor (D−A) conjugated polymer based on the naphthalenediimide units as a spacer material is observed. The negative MR effect does not result from negative polarization at spin injection and detection interface as well as tunneling anisotropic magnetoresistance effect, but from the spin transport inside the D−A polymer spacer. Even the stacking sequence of the spin injection and detection electrodes is reversed or changed the polymer coating solvents, the D−A polymer contributed negative MR response still can be observed. For further identifying negative MR origin, the bottom FM metal polarizer is replaced into high‐polarization La0.7Sr0.3MnO3 thin film, negative MR feature is well reproduced. Based on these points, it is deduced that the spin‐orientation reversal inside D−A polymer spacer is the ultimate reason for such negative MR response. The filtering‐like spin reversal activity is also in positive proportion to intermolecular interaction.
A One‐Step Biofunctionalization Strategy of Electrospun Scaffolds Enables Spatially Selective Presentation of Biological Cues
Authors: Wieringa Paul , Girao Andre , Ahmed Maqsood , TruckenmÜller Roman , Welle Alexander , Micera Silvestro , van Wezel Richard , Moroni Lorenzo
Published: August 2020

To recapitulate the heterogeneous complexity of tissues in the human body with synthetic mimics of the extracellular matrix (ECM), it is important to develop methods that can easily allow the selective functionalization of defined spatial domains. Here, a facile method is introduced to functionalize microfibrillar meshes with different reactive groups able to bind biological moieties in a one‐step reaction. The resulting scaffolds prove to selectively support a differential neurite growth after being seeded with dorsal root ganglia. Considering the general principles behind the method developed, this is a promising strategy to realize enhanced biomimicry of native ECM for different regenerative medicine applications.
Denatured M13 Bacteriophage‐Templated Perovskite Solar Cells Exhibiting High Efficiency
Authors: Lin Hao‐Sheng , Lee Jong‐Min , Han Jiye , Lee Changsoo , Seo Seungju , Tan Shaun , Lee Hyuck Mo , Choi Eun Jung , Strano Michael S. , Yang Yang , Maruyama Shigeo , Jeon Il , Matsuo Yutaka , Oh Jin‐Woo
Published: August 2020

The M13 bacteriophage, a nature‐inspired environmentally friendly biomaterial, is used as a perovskite crystal growth template and a grain boundary passivator in perovskite solar cells. The amino groups and carboxyl groups of amino acids on the M13 bacteriophage surface function as Lewis bases, interacting with the perovskite materials. The M13 bacteriophage‐added perovskite films show a larger grain size and reduced trap‐sites compared with the reference perovskite films. In addition, the existence of the M13 bacteriophage induces light scattering effect, which enhances the light absorption particularly in the long‐wavelength region around 825 nm. Both the passivation effect of the M13 bacteriophage coordinating to the perovskite defect sites and the light scattering effect intensify when the M13 virus‐added perovskite precursor solution is heated at 90 °C prior to the film formation. Heating the solution denatures the M13 bacteriophage by breaking their inter‐ and intra‐molecular bondings. The denatured M13 bacteriophage‐added perovskite solar cells exhibit an efficiency of 20.1% while the reference devices give an efficiency of 17.8%. The great improvement in efficiency comes from all of the three photovoltaic parameters, namely short‐circuit current, open‐circuit voltage, and fill factor, which correspond to the perovskite grain size, trap‐site passivation, and charge transport, respectively.
Vertically Aligned Sn4+ Preintercalated Ti2CTX MXene Sphere with Enhanced Zn Ion Transportation and Superior Cycle Lifespan
Authors: Li Xinliang , Li Mian , Yang Qi , Wang Donghong , Ma Longtao , Liang Guojin , Huang Zhaodong , Dong Binbin , Huang Qing , Zhi Chunyi
Published: August 2020

While 2D MXenes have been widely used in energy storage systems, surface barriers induced by restacking of nanosheets and the limited kinetics resulting from insufficient interlayer spacing are two unresolved issues. Here an Sn4+ preintercalated Ti2CTX with effectively enlarged interlayer spacing is synthesized. The preintercalated Ti2CTX is aligned on a carbon sphere to further enhance ion transportation by shortening the ion diffusion path and enhancing the reaction kinetics. As a result, when paired with a Zn anode, 12 500 cycles, which equals 2 800 h cycle time, and 5% capacity fluctuation are obtained, surpassing all reported MXene‐based aqueous electrodes. At 0.1 A g‐1, the capacity reaches 138 mAh g‐1, and 92 mAh g‐1 remains even at 5 A g‐1. In addition, the low anti‐self‐discharge rate of 0.989 mV h‐1 associated with a high capacity retention of 80.5% over 548 h is obtained. Moreover, the fabricated quasi‐solid capacitor based on a hydrogel film electrolyte exhibits good mechanical deformation and weather resistance. This work employs both preintercalation and alignment to MXene and achieves enhanced ion diffusion kinetics in an aqueous zinc ion capacitors (ZICs) system, which may be applied to other MXene batteries for enhanced performance.
Structured Ni@NaA zeolite supported on silicon carbide foam catalysts for catalytic carbon dioxide methanation
Authors: Zhang Rongxin , Chen Huanhao , Mu Yibing , Chansai Sarayute , Ou Xiaoxia , Hardacre Christopher , Jiao Yilai , Fan Xiaolei
Published: August 2020

Carbon dioxide (CO2) conversion is an important yet challenging topic, which helps to address climate change challenge. Catalytic CO2 methanation is one of the methods to convert CO2, however, it is limited by kinetics. This work developed a structured Ni@NaA zeolite supported on silicon carbide (SiC) foam catalyst (i.e., Ni@NaA‐SiC), which demonstrated an excellent performance with a CO2 conversion of ~82%, being comparable to the corresponding equilibrium conversion, and CH4 selectivity of ~95% at 400°C. The activation energy for CO2 conversion over the 15Ni@NaA‐SiC catalyst is about 31 kJ mol−1, being significantly lower than that of the 15Ni@NaA pelletized catalyst (i.e., ~84 kJ mol−1). Additionally, the structured catalyst was highly stable with sustained CO2 conversion at 78.7 ± 1.4% and selectivity to CH4 at 97.7 ± 0.2% over an 80 hr longevity test. In situ diffuse reflectance infrared Fourier transform spectroscopy‐mass spectroscopy characterization revealed that catalysis over the structured catalyst proceeded primarily via the CO free mechanism.
Anatomical and hydraulic responses to desiccation in emergent conifer seedlings
Authors: Miller Megan L. , Roddy Adam B. , Brodersen Craig R. , McElrone Andrew J. , Johnson Daniel M.
Published: August 2020

Premise

The young seedling life stage is critical for reforestation after disturbance and for species migration under climate change, yet little is known regarding their basic hydraulic function or vulnerability to drought. Here, we sought to characterize responses to desiccation including hydraulic vulnerability, xylem anatomical traits, and impacts on other stem tissues that contribute to hydraulic functioning.

Methods

Larix occidentalis, Pseudotsuga menziesii, and Pinus ponderosa (all ≤6 weeks old) were imaged using x‐ray computed microtomography during desiccation to assess seedling biomechanical responses with concurrently measured hydraulic conductivity (ks) and water potential (Ψ) to assess vulnerability to xylem embolism formation and other tissue damage.

Results

In non‐stressed samples for all species, pith and cortical cells appeared circular and well hydrated, but they started to empty and deform with decreasing Ψ which resulted in cell tearing and eventual collapse. Despite the severity of this structural damage, the vascular cambium remained well hydrated even under the most severe drought. There were significant differences among species in vulnerability to xylem embolism formation, with 78% xylem embolism in L. occidentalis by Ψ of −2.1 MPa, but only 47.7% and 62.1% in P. ponderosa and P. menziesii at −4.27 and −6.73 MPa, respectively.

Conclusions

Larix occidentalis seedlings appeared to be more susceptible to secondary xylem embolism compared to the other two species, but all three maintained hydration of the vascular cambium under severe stress, which could facilitate hydraulic recovery by regrowth of xylem when stress is relieved.
Genome‐wide transcriptome analysis identifies novel dysregulated genes implicated in Alzheimer's pathology
Authors: Nho Kwangsik , Nudelman Kelly , Allen Mariet , Hodges Angela , Kim Sungeun , Risacher Shannon L. , Apostolova Liana G. , Lin Kuang , Lunnon Katie , Wang Xue , Burgess Jeremy D. , Ertekin‐Taner Nilüfer , Petersen Ronald C. , Wang Lisu , Qi Zhenhao , He Aiqing , Neuhaus Isaac , Patel Vishal , Foroud Tatiana , Faber Kelley M. , Lovestone Simon , Simmons Andrew , Weiner Michael W. , Saykin Andrew J. ,   for the Alzheimer's Disease Neuroimaging Initiative
Published: August 2020

Introduction

Abnormal gene expression patterns may contribute to the onset and progression of late‐onset Alzheimer's disease (LOAD).

Methods

We performed transcriptome‐wide meta‐analysis (N = 1440) of blood‐based microarray gene expression profiles as well as neuroimaging and cerebrospinal fluid (CSF) endophenotype analysis.

Results

We identified and replicated five genes (CREB5, CD46, TMBIM6, IRAK3, and RPAIN) as significantly dysregulated in LOAD. The most significantly altered gene, CREB5, was also associated with brain atrophy and increased amyloid beta (Aβ) accumulation, especially in the entorhinal cortex region. cis‐expression quantitative trait loci mapping analysis of CREB5 detected five significant associations (P < 5 × 10−8), where rs56388170 (most significant) was also significantly associated with global cortical Aβ deposition measured by [18F]Florbetapir positron emission tomography and CSF Aβ1‐42.

Discussion

RNA from peripheral blood indicated a differential gene expression pattern in LOAD. Genes identified have been implicated in biological processes relevant to Alzheimer's disease. CREB, in particular, plays a key role in nervous system development, cell survival, plasticity, and learning and memory.
Enantioselective Intramolecular [2,3]‐Sigmatropic Rearrangement of Aldehydes via a Sulfonium Enamine Intermediate
Authors: Li Li , Chen Baoli , Chen Jiean , Huang Yong
Published: August 2020

The rearrangement of sulfur‐containing aldehydes by using a sulfonium enamine intermediate as a formylcarbene mimetic is reported. This is an enantioselective, organocatalytic [2,3]‐sigmatropic rearrangement enabling chiral cyclic sulfides bearing an α‐quaternary chiral center to be prepared in high optical purity. The enantioselectivity is controlled with a cooperative organocatalyst pair consisting of a chiral amine and a chiral phosphoric acid (CPA). The synthetic versatility of this method is demonstrated by its rapid access to structurally diverse chiral spiro S‐heterocycles.
Improving adhesion between polyester cord and rubber by using glycidyl‐POSS
Authors: Doganci Erdinc
Published: August 2020

Poly(ethylene terephthalate) (PET) cords are usually coated with epoxy and/or isocyanate solutions (like methylene diphenyl diisocyanate [MDI]) before resorcinol‐formaldehyde‐latex (RFL) to increase the adhesion efficiency of RFL. In this article, the addition of glycidyl polyhedral oligomeric silsesquioxane (GPOSS) as an adhesion promoter to PET cord was investigated for reinforcing PET cord/rubber interfacial adhesion. Therefore, GPOSS treated PET cords (GPOSS + MDI + RFL) were prepared in different process conditions like different GPOSS ratios and oven curing times and then vulcanized with rubber. RFL, GPOSS + RFL, MDI + RFL, and commercial epoxies treated PET cord samples were also prepared for comparison with GPOSS+MDI + RFL treated PET cord. The thermal, mechanical, and morphological properties of the treated PET yarn and their composites with rubber were investigated. It was seen that in the GPOSS coated PET yarns increased the stiffness and no change was observed in the tensile strength of the PET yarns. It was determined that the utilization of GPOSS in the PET cord improved the adhesion of the cord to rubber when compared with other treated PET cords via H‐adhesion and strip peel adhesion tests. Especially, since adhesion values give better results than commercially used epoxies, GPOSS as an adhesion promoter can be recommended in the rubber industry.
Simultaneous impact modified and chain extended glass fiber reinforced poly(lactic acid) composites: Mechanical, thermal, crystallization, and dynamic mechanical performance
Authors: Akindoyo John Olabode , Beg Mohammad Dalour Hossen , Ghazali Suriati , Heim Hans Peter , Feldmann Maik , Mariatti Mustapha
Published: August 2020

Herein, glass fiber (GF) reinforced binary, ternary, and quaternary poly(lactic acid) (PLA) composites were prepared. Toughening, and chain extension of PLA was achieved through the incorporation of impact modifier and chain extender and their concurrent effects on the spectroscopic, crystallization, mechanical, thermal, and thermomechanical properties of the composites were investigated. High mechanical properties of GF influenced the mechanical performance of the composites. However, GF alone could not restrict the chain mobility of PLA due to poor interface and low crystallization activities in the PLA‐GF composite. Incorporation of impact modifier and chain extender produced significantly enhanced interaction between GF and PLA. Significantly, the crystallinity, impact strength, and flexural modulus of PLA in the quaternary composite were increased by 58%, 63%, and 66%, respectively. In addition, damping and effectiveness coefficient of the PLA‐GF composite were notably reduced by the simultaneous impact modification and chain extension of the reinforced composites.
A new model reference adaptive control with the disturbance observer‐based adaptation law for the Nonlinear Servomechanisms: SISO and MIMO Systems
Authors: Chen Kun‐Yung
Published: August 2020

A disturbance observer (DOB) is proposed to replace the external disturbance adaptation law in model reference adaptive control (MRAC) to perform robust tracking control performance for nonlinear servomechanisms. Lyapunov stable theory is implemented to combine the DOB with MRAC to simultaneously converge the estimated states and tracking errors toward null. Then, the disturbance observer‐based MRAC (DOBMRAC) is proposed and realized. The single‐input single‐output (SISO) mass‐spring‐damper system and multi‐input multi‐output (MIMO) two‐link manipulator robot system are both demonstrated as the control examples. However, in comparisons of tracking control performance between MRAC and DOBMRAC, it is found that the proposed controller reveals better robust tracking control performance for SISO and MIMO servomechanisms with unknown time‐varying disturbances. The contributions of this paper are: i) the proposed DOBMRAC is successfully implemented in both the SISO and MIMO systems; ii) the proposed controller performs better tracking control performance than MRAC for unknown time‐varying disturbances; iii) the DOBMRAC cannot only perform robust tracking control performance, but also shows disturbance estimation ability well; and iv) the proposed control methodology can also be widely applied to other MRAC systems with unknown time‐varying disturbance.
Repurposing of quinoline alkaloids identifies their ability to enhance doxorubicin‐induced sub‐G0/G1 phase cell cycle arrest and apoptosis in cervical and hepatocellular carcinoma cells
Authors: El‐Mesery Mohamed , Seher Axel , El‐Shafey Mohamed , El‐Dosoky Mohamed , Badria Farid A
Published: August 2020

The ability of quinoline alkaloids (cinchonine, cinchonidine, quinine, and quinidine) to sensitize different human cancer cell lines to doxorubicin (DOX)‐induced cell death was evaluated. Cell viability was analyzed using 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay and the alkaloids ability to enhance DOX‐induced apoptosis was explored using Western blotting analysis. Also, flow cytometry was applied to analyze cell fractions in the different cell cycle phases. All alkaloids showed a significant enhancement of DOX‐induced cell death in HeLa and HepG2 cell lines. The chemosensitizing activity of the quinoline alkaloids was attributed to the induction of apoptosis as indicated by splitting of caspase‐3 and its substrate poly (ADP‐ribose) polymerase (PARP). In addition, there was an increase in the cell fractions in sub‐G0/G1 phase in case of DOX combination with the alkaloids. This study proves the ability of the quinoline alkaloids to enhance DOX‐induced apoptotic cell death in human cervical and hepatocellular carcinoma cells.
Teratogen update: Amphetamines
Authors: Garey Joan D. , Lusskin Shari I. , Scialli Anthony R.
Published: August 2020

Amphetamines are synthetic noncatecholamine sympathomimetic amines that act as psychostimulants. They have been prescribed for the treatment of attention‐deficit/hyperactivity disorder (ADHD), narcolepsy, and additional health conditions. Amphetamines are also drugs of abuse. Some experimental animal studies suggested adverse developmental effects of amphetamines, including structural malformations. These effects were most often observed in experimental animals at higher dose levels than those used for treatment or abuse and at dose levels that produce maternal toxicity. Controlled studies of amphetamine use for the treatment of ADHD and other indications did not suggest that amphetamines are likely to cause structural malformations, although there are three studies associating medication for ADHD or methamphetamine abuse with gastroschisis. We did not locate studies on the neurobehavioral effects of prenatal exposures to therapeutic amphetamine use. Amphetamine abuse was associated with offspring neurobehavioral abnormalities, but lack of adequate adjustment for confounding interferes with interpretation of the associations. Adverse effects of methamphetamine abuse during pregnancy may be due to factors associated with drug abuse rather than methamphetamine itself. The adverse effects observed in methamphetamine abuse studies may not be extrapolatable to amphetamine medication use.
Exploring copy number variants in deceased fetuses and neonates with abnormal vertebral patterns and cervical ribs
Authors: Schut Pauline C. , Brosens Erwin , Van Dooren Tom J. M. , Galis Frietson , ten Broek Clara M. A. , Baijens Inge M. M. , Dremmen Marjolein H. G. , Tibboel Dick , Schol Martin P. , de Klein Annelies , Eggink Alex J. , Cohen‐Overbeek Titia E.
Published: August 2020

Background

Cervical patterning abnormalities are rare in the general population, but one variant, cervical ribs, is particularly common in deceased fetuses and neonates. The discrepancy between the incidence in the general population and early mortality is likely due to indirect selection against cervical ribs. The cause for the co‐occurrence of cervical ribs and adverse outcome remains unidentified. Copy number variations resulting in gain or loss of specific genes involved in development and patterning could play a causative role.

Methods

Radiographs of 374 deceased fetuses and infants, including terminations of pregnancies, stillbirths and neonatal deaths, were assessed. Copy number profiles of 265 patients were determined using single nucleotide polymorphism array.

Results

274/374 patients (73.3%) had an abnormal vertebral pattern, which was associated with congenital abnormalities. Cervical ribs were present in 188/374 (50.3%) and were more common in stillbirths (69/128 [53.9%]) and terminations of pregnancies (101/188 [53.7%]), compared to live births (18/58, 31.0%). Large (likely) deleterious copy number variants and aneuploidies were prevalent in these patients. None of the rare copy number variants were recurrent or overlapped with candidate genes for vertebral patterning.

Conclusions

The large variety of copy number variants in deceased fetuses and neonates with similar abnormalities of the vertebral pattern probably reflects the etiological heterogeneity of vertebral patterning abnormalities. This genetic heterogeneity corresponds with the hypothesis that cervical ribs can be regarded as a sign of disruption of critical, highly interactive stages of embryogenesis. The vertebral pattern can probably provide valuable information regarding fetal and neonatal outcome.
Silencing and freedom of speech in UK higher education
Authors: Malcolm Finlay
Published: August 2020

Freedom of speech in universities is currently an issue of widespread concern and debate. Recent empirical findings in the UK shed some light on whether speech is unduly restricted in the university, but it suffers from two limitations. First, the results appear contradictory. Some studies show that the issue of free speech is overblown by media reportage, whilst others track serious concerns about free speech arising from certain university policies. Second, the findings exclude important issues concerning restrictions to speech on campus that fall outside the traditional debate around violations to free speech rights. This is particularly the case when certain voices are excluded from important policy conversations, and in issues around diversifying the curriculum. This article overcomes these two limitations by developing a novel conceptual framework within which to situate current debates concerning speech‐related matters in universities. It does so by developing a taxonomy around the concept of ‘silencing’. It then considers the current issue of speech matters in universities within this framework to determine whether, and to what extent, speech is indeed unduly restricted, and where this is a concern for free speech violations, and where it falls outside this issue.
On the finite sample distribution of the likelihood ratio statistic for testing heterogeneity in meta‐analysis
Authors: Kuk Sunghee , Lee Woojoo
Published: August 2020

In meta‐analysis, hypothesis testing is one of the commonly used approaches for assessing whether heterogeneity exists in effects between studies. The literature concluded that the Q‐statistic is clearly the best choice and criticized the performance of the likelihood ratio test in terms of the type I error control and power. However, all the criticism for the likelihood ratio test is based on the use of a mixture of two chi‐square distributions with 0 and 1 degrees of freedom, which is justified only asymptotically. In this study, we develop a novel method to derive the finite sample distribution of the likelihood ratio test and restricted likelihood ratio test statistics for testing the zero variance component in the random effects model for meta‐analysis. We also extend this result to the heterogeneity test when metaregression is applied. A numerical study shows that the proposed statistics have superior performance to the Q‐statistic, especially when the number of studies collected for meta‐analysis is small to moderate.
Reduced thiamine is a predictor for cognitive impairment of cerebral infarction
Authors: Feng Liang , He Weilei , Huang Guiqian , Lin Shasha , Yuan Chengxiang , Cheng Haoran , He Jincai , Liu Yiming
Published: August 2020

Objective

Reduced thiamine (vitamin B1) had been reported to be associated with cognitive impairment caused by Alzheimer disease. Our study is to explore the association between thiamine and cognitive impairment after acute ischemic stroke.

Materials and Methods

One hundred and eighty two patients with acute cerebral infarction were recruited within the first 24 hr after admission. Thiamine and other vitamin Bs of peripheral blood samples were measured. Patients were divided into with poststroke cognitive impairment (PSCI) and non‐PSCI according to the score of MMSE and the degree of education.

Results

Reduced thiamine (<1.0 ng/ml) was independently associated with PSCI (OR: 2.033, 95% CI: 1.017–4.067, p = .045) after adjusting for potential confounding factors. Advanced age, lower education, diabetes mellitus, left hemisphere infarction, and higher National Institute of Health Stroke Scale (NIHSS) were also independent risk factors for PSCI.

Conclusions

Reduced thiamine is one of the predictors for early cognitive impairment in patients with acute cerebral infarction.
Estrogen improved the regeneration of axons after subcortical axon injury via regulation of PI3K/Akt/CDK5/Tau pathway
Authors: Xia Xiaohui , Zhou Changlong , Sun Xiaochuan , He Xuenong , Liu Chang , Wang Guanyu
Published: August 2020

Aim

To investigate the effect of estrogen on axon regeneration and neurological recovery after subcortical axon injury, and further explore its underlying molecular mechanisms.

Method

Subcortical axonal fiber injury model was used in this study. Morris water maze was conducted to detect the learning and memory ability of the rats; modified neurological severity score (mNSS) and beam walking test were performed to evaluate the behavioral; and diffusion tensor imaging (DTI) was used for the determination of recovery after subcortical axonal injury, while Western blotting was performed to detect the expression of p‐Akt, CDK5, p‐Ser262, p‐Ser404, and p‐Thr205.

Results

Compared with the Sham group, the injury of subcortical axonal fiber resulted in higher mNSS, higher beam walking scores, longer time of escape latency, less number, time and shorter distance of crossing the quadrant, and less FA values. After ovariectomy, the mNSS, beam walking scores, and escape latency reached the peak; inversely, the others reached a minimum. High estrogen treatment reduced the mNSS, beam walking score, and escape latency; improved the number, time, and distance of crossing the quadrant; and increased the FA value. Western blotting results showed that estrogen increased the expression of p‐Akt and decreased the expression of CDK5, p‐Ser262, p‐Ser404, and p‐Thr205. All the changes were counteracted to some extent by Akt inhibitor LY294002.

Conclusion

After subcortical axonal injury, estrogen could improve the regeneration of axons and improve their functions via regulating the PI3K/Akt/CDK5/Tau pathway.
Evaluating an online augmented reality puzzle for DC circuits: Students' feedback and conceptual knowledge gain
Authors: Urbano Diana , de Fátima Chouzal Maria , Restivo Maria Teresa
Published: August 2020

Augmented reality (AR) enables users to overlay new information over the real environment, allowing them to get a clear perception of physical systems or even to interact with them. AR is a powerful and promising tool in many areas, including engineering‐related ones. Therefore, it has aroused growing interest in engineering education. The main objectives of this study are to examine engineering students' feedback and conceptual knowledge gain resulting from using an online AR app. The design and development of the app, named “AR DC circuit puzzle,” was driven by the intention to familiarize students with AR, using a tool that addresses direct current circuits' concepts, a subject belonging to almost all undergraduate engineering syllabi. Through structural equation modeling, the analysis of the relationships between several psychological traits related to the use of the AR app revealed that attitude toward the use of AR is very positive and mostly driven by the value students perceived this app to have in the context of their engineering training. The use of a pre‐ and posttest methodology resulted in large average normalized gains and effect sizes, indicating conceptual knowledge gain. The current worldwide situation triggered the massive use of digital tools; hence, it can be anticipated that in the future, there will be a greater need for online learning resources. This study, involving a large sample of engineering students in three consecutive academic years, shows that the used online tool based on AR can engage students and, with the right strategy, can promote knowledge gain.
Who can be nudged? Examining nudging effectiveness in the context of need for cognition and need for uniqueness
Authors: Ingendahl Moritz , Hummel Dennis , Maedche Alexander , Vogel Tobias
Published: August 2020

In the last decade, there has been a growing research focus on the subtle modifications of choice architecture that have strong effects on consumer behavior and are subsumed under the term nudging. There is still little research, however, on how different nudges influence individuals with different personality characteristics. An experimental online shopping scenario is used to test whether a customer's Need for Cognition and Need for Uniqueness moderate the effectiveness of two of the most prominent nudges—defaults and social influence. Two experiments with samples stratified by age, gender, and education (total N = 1,561) reveal that defaults and social influence have the predicted impact on a customer's decision. Across both studies, nudge effectiveness was partially impacted by Need for Cognition and not impacted at all by Need for Uniqueness. These findings imply that both types of nudges are strong and robust techniques to influence consumer decision‐making and are effective across different levels of consumer's Need for Cognition or Need for Uniqueness.