bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies of the reactivity of artificial peroxidase‐like hemoproteins based on antibodies elicited against a specifically designed ortho‐carboxy substituted tetraarylporphyrin
Authors: de Lauzon Solange , Desfosses Bernard , Mansuy Daniel , Mahy Jean-Pierre
Published: July 2002

The temperature and pH dependence as well as the selectivity of the peroxidase activity of a complex associating a monoclonal antibody 13G10 with its iron(III)‐α,α,α,β‐meso‐tetrakis(ortho‐carboxyphenyl) porphyrin (Fe(ToCPP)) hapten have been studied and compared to those of Fe(ToCPP) alone. It first appears that the peroxidase activity of the 13G10‐Fe(ToCPP) complex is remarkably thermostable and remains about 5 times higher than that of Fe(ToCPP) alone until at least 80°C. Secondly, this complex is able to use not only H2O2 as oxidant but also a wide range of hydroperoxides such as alkyl, aralkyl and fatty acid hydroperoxides and catalyze their reduction 2–6‐fold faster than Fe(ToCPP) alone. It is also able to catalyze the oxidation by H2O2 of a variety of reducing cosubstrates such as 2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS), o‐phenylenediamine (OPD), 3,3′,5,5′‐tetramethylbenzidine (TMB) and 3,3′‐dimethoxybenzidine 3–8‐fold faster than Fe(ToCPP) alone, the bicyclic aromatic ABTS and TMB being the best reducing cosubstrates. Finally, a pH dependence study, between pH 4.6 and 7.5, of the oxidation of ABTS by H2O2 in the presence of either 13G10‐Fe(ToCPP) or Fe(ToCPP) shows that K
m(H2O2) values vary very similarly for both catalysts, whereas very different variations are found for the k
cat values. With Fe(ToCPP) as catalyst the k
cat value remains constant around 100 min−1 whereas with the 13G10‐Fe(ToCPP) complex, it increases sharply below pH 5 to reach 540 min−1 at pH 4.6. This could be due to the participation of a carboxylic acid side chain of the antibody protein, as a general acid‐base catalyst, to the heterolytic cleavage of the O‐O bond of H2O2 leading to the highly reactive iron(V)‐oxo intermediate in the peroxidase mechanism. Accordingly, the modification of the carboxylic acid residues of antibody 13G10 by glycinamide leads to a 50% decrease of the peroxidase activity of the 13G10‐Fe(ToCPP) complex.
Hybridization of antisense oligonucleotides with the 3′ part of tRNAPhe
Authors: Petyuk Vladislav A. , Zenkova Marina A. , Giege Richard , Vlassov Valentin V.
Published: July 2002

The interaction of antisense oligodeoxyribonucleotides with yeast tRNAPhe was investigated. 14–15‐mers complementary to the 3′‐terminal sequence including the ACCA end bind to the tRNA under physiological conditions. At low oligonucleotide concentrations the binding occurs at the unique complementary site. At higher oligonucleotide concentrations, the second oligonucleotide molecule binds to the complex due to non‐perfect duplex formation in the T‐loop stabilized by stacking between the two bound oligonucleotides. In these complexes the acceptor stem is open and the 5′‐terminal sequence of the tRNA is accessible for binding of a complementary oligonucleotide. The results prove that the efficient binding of oligonucleotides to the 3′‐terminal sequence of the tRNA occurs through initial binding to the single‐stranded sequence ACCA followed by invasion in the acceptor stem and strand displacement.
Folding and refolding of thermolabile and thermostable bacterial luciferases: the role of DnaKJ heat‐shock proteins
Authors: Manukhov Ilia V , Eroshnikov Gennadii E , Vyssokikh Mikhail Yu , Zavilgelsky Gennadii B
Published: July 2002

Bacterial luciferases are highly suitable test substrates for the analysis of refolding of misfolded proteins, as they are structurally labile and loose activity at 42°C. Heat‐denatured thermolabile Vibrio fischeri luciferase and thermostable Photorhabdus luminescens luciferase were used as substrates. We found that their reactivation requires the activity of the DnaK chaperone system. The DnaKJ chaperones were dispensable in vivo for de novo folding at 30°C of the luciferase, but essential for refolding after a heat‐shock. The rate and yield of DnaKJ refolding of the P. luminescens thermostable luciferase were to a marked degree lower as compared with the V. fischeri thermolabile luciferase. The refolding activity of the DnaKJ chaperones was examined at various temperatures. Between 30 and 37°C, the refolding rates of the V. fischeri luciferase decreased and the reaction reached a complete arrest at temperatures above 40°C. The rate of DnaKJ‐mediated refolding of the thermostable luciferase at first increased between 30 and 37°C and then decreased at the range of 37–44°C. We observed that the rate of DnaKJ‐mediated refolding of the heat‐denatured P. luminescens thermostable luciferase, but not of the thermolabile V. fischeri luciferase, decreased during the prolonged incubation at a high (47°C) temperature. The efficiency and reversibility of protein refolding arrest during and after heat‐shock strongly depended on the stability of the DnaKJ‐denatured luciferase complex. It is supposed that the thermostable luciferase is released during the heat‐shock, whereas the thermolabile luciferase remained bound to the chaperone.
Involvement of cis‐acting repressive element(s) in the 3′‐untranslated region of human connective tissue growth factor gene
Authors: Kubota Satoshi , Hattori Takako , Nakanishi Tohru , Takigawa Masaharu
Published: July 2002

To analyze the regulatory mechanism of connective tissue growth factor expression, the 3′‐untranslated region (3′‐UTR) of CTGF cDNA was amplified from HeLa cell RNA. Direct nucleotide sequencing revealed a single major population in the amplicon, which was nearly identical to other sequences. Subsequently, the effect of the 3′‐UTR on gene expression was evaluated. When it was fused downstream of a firefly luciferase gene, the 3′‐UTR strongly repressed luciferase gene expression. Interestingly, the repressive effect of the antisense 3′‐UTR appeared to be more prominent than that of the sense one. Together with the fact that several consensus sequences for regulatory elements are found in it, these results suggest the involvement of multiple sets of regulatory elements in the CTGF 3′‐UTR.
An early salicylic acid‐, pathogen‐ and elicitor‐inducible tobacco glucosyltransferase: role in compartmentalization of phenolics and H2O2 metabolism
Authors: Chong Julie , Baltz Rachel , Fritig Bernard , Saindrenan Patrick
Published: July 2002

Treatment of tobacco cell suspension cultures with a fungal elicitor of defense responses resulted in an early accumulation of the phenylpropanoid glucosyltransferase TOGT, along with the rapid synthesis and secretion of scopolin, the glucoside of scopoletin. Elicitor‐triggered extracellular accumulation of the aglycone scopoletin and of free caffeic and ferulic acids could only be revealed in the presence of diphenylene iodonium, an inhibitor of extracellular H2O2 production. Our results strongly support a role for TOGT in the elicitor‐stimulated production of transportable phenylpropanoid glucosides, followed by the release of free antioxidant phenolics into the extracellular medium and subsequent H2O2 scavenging.
The photosystem I trimer of cyanobacteria: molecular organization, excitation dynamics and physiological significance
Authors: Karapetyan Navassard V. , Holzwarth Alfred R. , Rögner Matthias
Published: July 2002

The photosystem I complex organized in cyanobacterial membranes preferentially in trimeric form participates in electron transport and is also involved in dissipation of excess energy thus protecting the complex against photodamage. A small number of longwave chlorophylls in the core antenna of photosystem I are not located in the close vicinity of P700, but at the periphery, and increase the absorption cross‐section substantially. The picosecond fluorescence kinetics of trimers resolved the fastest energy transfer components reflecting the equilibration processes in the core antenna at different redox states of P700. Excitation kinetics in the photosystem I bulk antenna is nearly trap‐limited, whereas excitation trapping from longwave chlorophyll pools is diffusion‐limited and occurs via the bulk antenna. Charge separation in the photosystem I reaction center is the fastest of all known reaction centers.
Molybdopterin guanine dinucleotide cofactor in Synechococcus sp. nitrate reductase: identification of mobA and isolation of a putative moeB gene
Authors: Rubio Luis M. , Flores Enrique , Herrero Antonia
Published: July 2002

The narC locus required for assimilatory nitrate reduction in the cyanobacterium Synechococcus sp. strain PCC 7942 was found to carry a mobA gene for molybdopterin guanine dinucleotide biosynthesis. Insertional inactivation of this gene blocked production of nitrate reductase in Synechococcus cells. We have previously described Synechococcus genes encoding homologues to molybdopterin biosynthesis proteins including MoaA, MoaC/MoaB, MoaD, MoaE, and MoeA, but not to MoeB. A cyanobacterial gene putatively encoding a protein composed of an amino‐terminal domain of 260 amino acids homologous to Escherichia coli MoeB and of a carboxy‐terminal extension of 130 amino acids was identified. Synechococcus mutants bearing only inactive versions of this putative moeB gene could not be isolated suggesting that it has function(s) additional to molybdopterin biosynthesis.
Metastatic placental site trophoblastic tumor
Authors: Twiggs L.B. , Hartenbach E. , Saltzman A.K. , King L.A.
Published: July 2002

Since our publication, which first defined the malignant potential of placental site trophoblastic tumor (PSTT), we have had a keen interest in this rare, unique entity. This histologic entity is noted by its monomorphic population of trophoblast‐like cells which are classified as originating in the intermediate trophoblast. These cells contain hymman placental lactogen (HPL). This is in contrast to cytotrophoblastic and syncytiotrophblastic tissues as the histologic, cytologic and immunohistochemical stain characteristics are disparate.

Its rarity and the wide spectrum of clinical behavior combined with the lack of sensitivity of serum levels of beta hCG in predicting disease recurrence and spread have lead to anecdotal reports outlining clinical management.

Most discerning to the clinician is the high mortality of metastatic placental site trophoblastic tumor. At our institution, we have treated two patients with a metastatic disease with a successful conclusion. The durability of responses is 3 and 8 years. This report will present these patients in detail and define the important characteristics of successful treatment.

The use of dose‐intensive, multi‐agent chemotherapy, early intervention when metastatic disease is discovered, imaging techniques to define disease spread, surgery for localized disease and the use of growth factors, most notably granulocyte colony‐stimulating factor (G‐CSF), are the fundamentals of clinical care of placental site trophoblastic tumor in patients with metastatic placental site trophoblastic tumor.
Control of CREB phosphorylation and its role for induction of melatonin synthesis in rat pinealocytes*
Authors: Maronde Erik , Schomerus Christof , Stehle Jörg H. , Korf Horst‐Werner
Published: July 2002

Phosphorylation of the transcription factor CREB appears as an important step in the signal transduction cascade that activates melatonin biosynthesis in the mammalian pineal organ. We have studied the mechanisms causing CREB phosphorylation by immunocytochemical and immunochemical demonstration of phosphorylated CREB (pCREB) in isolated, immunocytochemically identified rat pinealocytes kept in vitro and in the rat pineal organ in situ. Norepinephrine (NE), the most potent stimulator of the melatonin biosynthesis was shown to induce pCREB immunoreaction (ir) in the vast majority of pinealocytes in a time‐ and dose‐dependent manner. This response was elicited by stimulation of β‐adrenergic receptors resulting in an increase in the intracellular cAMP concentration. Activation of α1‐adrenergic receptors that causes a rise in intracellular calcium via stimulation of intracellular stores and subsequent increase in calcium influx did not evoke pCREB ir on its own and did not potentiate the β‐adrenergic response. VIP and PACAP that activate the melatonin biosynthesis to a lesser extent than NE induced pCREB ir in only 50–60% of the pinealocytes. Immunoblotting showed that a protein of 43 kDa corresponding to CREB accounts for the pCREB ir and confirmed that VIP and PACAP are less effective in inducing CREB phosphorylation than NE. The amount of total (phosphorylated and unphosphorylated) CREB was not changed upon stimulation of the cells with NE, VIP or PACAP. In an attempt to identify the protein kinase catalyzing CREB phosphorylation in rat pinealocytes, the cAMP‐dependent protein kinases (cAK) present in the rat pineal were identified with the use of antibodies recognizing different catalytic and regulatory subunits. Application of cAK agonists and antagonists showed that the cAK type II is responsible for CREB phosphorylation. Correlations between the melatonin concentration in the medium and the CREB phosphorylation in pinealocytes revealed a tight connection between these two parameters. Phosphorylation of CREB appears important for the stimulation of melatonin biosynthesis also under natural conditions because our investigations of whole pineal organs taken from rats during different time points of the 24 h light‐dark cycle revealed a strong induction of pCREB ir in the first part of the night.
An empirical investigation of supplier development: reactive and strategic processes
Authors: Krause Daniel R. , Handfield Robert B. , Scannell Thomas V.
Published: July 2002

As firms continue to focus on core competencies and outsource non‐core products and services to external suppliers, supply chain management is increasingly viewed as a source of competitive advantage. However, if the supply chain is to be a source of competitive advantage, suppliers' performance must be managed and developed to meet the needs of the buying firm. In an exploratory study based on data collected from 84 companies, the authors develop a process model for supplier development. Using this process model as a framework, the authors then compare two approaches buying firms use in supplier development: (1) reactive efforts to increase the performance of laggard suppliers, and (2) strategic efforts to increase the capabilities of the supply base to enhance the buying firm's long‐term competitive advantage. Strategic efforts were found to significantly increase the buying company's involvement in suppliers' processes, and required greater dedication of resources, personnel and communication.
Reactive glia support and guide axon growth in the rat thalamus during the first postnatal week. A sharply timed transition from permissive to non‐permissive stage
Authors: Ajtai Béla M. , Kálmán Mihály
Published: July 2002

The present study demonstrates a supportive and guiding effect of the reactive glia on the postlesional axon growth in vivo, and offers a model system to compare permissive and non‐permissive forms of the glial reaction. After stab wounds in early postnatal (P2–P9) rats, the reactive glia and the nerve fibers were detected by the immunohistochemical staining of glial fibrillary acidic protein (GFAP) and neurofilament protein, respectively. In the thalamus of the animals lesioned at P5 or earlier, an extraordinary bundle of fibers immunoreactive to neurofilament protein was found, corresponding to the lesion track marked by reactive glia. This bundle persisted up to 2 months, as shown by electron microscopy. When the animals were lesioned at P7 or later, the lesion track was immunonegative to neurofilament protein. Following P6 lesions, an intermediate situation was found, the strip of immunoreactive neurofilament protein was missing, or short and weak. GFAP immunostaining demonstrated a typical reactive glia in every case. As a result of the same operation, reactive glia plus a deficiency of neurofilament protein immunostaining was found in every animal in the cortex and the corpus callosum, independently from the age at lesion. The results demonstrate that the permissive nature of the glial reaction depends on the lesioned area as well, and changes to a non‐permissive effect in a short time interval.
Myelin proteolipid DM20: evidence for function independent of myelination
Authors: Nadon Nancy L. , Miller Shirley , Draeger Karen , Salvaggio Michelle
Published: July 2002

DM20 is a proteolipid protein that has been extensively studied for its role in central nervous system myelination. We demonstrate that DM20 expression is wide‐spread and independent of myelination. In the Schwann cells and neurons of the peripheral nervous system, DM20 is not incorporated into the membrane as it is in the central nervous system (CNS), but remains cytoplasmic. Mutations that severely reduce the amount of DM20 mRNA in CNS myelinating cells have little effect on DM20 expression in nonmyelinating cells of the peripheral nervous system and embryonic CNS. Most importantly, the combination of wild‐type DM20 from the endogenous X‐linked gene and mutant DM20 expressed from an autosomal transgene results in embryonic lethality. We propose a function for DM20 to explain these diverse findings based on the ability of DM20 to form multimeric complexes, and hypothesize that the DM20 complex participates in intracellular molecular transport.
Correlation between lead‐induced changes in cerebral ornithine decarboxylase and protein kinase C activities during development and in cultured PC 12 CELLS
Authors: Hilliard A. , Ramesh A. , Zawia N.H.
Published: July 2002

Exposure to lead (Pb) interferes with neurodevelopment and disturbs ornithine decarboxylase (ODC) activity. ODC the key regulatory enzyme of the polyamine pathway, is a potential substrate for protein kinase C (PKC). Therefore, we examined developmental changes in PKC activity and its relationship to ODC activity. Male rats were lactationally exposed to 0.2% Pb‐acetate from birth to weaning. PKC and ODC activity were measured on postnatal days (PND) 3, 5, 10, 20 and 30. We found that the basal patterns of ODC and PKC activities resembled each other in both the neocortex and cerebellum and Pb‐exposure attenuated both enzymes in a similar manner. To determine whether any link existed between these enzymes, ODC and PKC activities were induced to increase using nerve growth factor (NGF) in the presence and/or absence of ODC (difluoromethylornithine, DFMO) and PKC (staurosporine) inhibitors, in control and Pb‐exposed Pheochromocytoma (PC‐12) cells. Staurosporine decreased both ODC activity and PKC activity, while DFMO had no effect on PKC activity. These data suggest that ODC may be regulated by PKC and that Pb‐induced developmental alterations in ODC activity may be secondary to changes in the integrity of PKC.
Schizophrenic patients: physical health and access to somatic care
Authors: Casadebaig F , Philippe A , Guillaud-Bataille JM , Gausset MF , Quemada N , Terra JL
Published: July 2002

This study concerns the state of physical health and the availability of somatic care for 3,470 adult patients diagnosed as schizophrenic according to the research criteria established by the International Classification of Diseases (ICD-10 F20) and treated in public institutions. These institutions volunteered to participate in the study, whereas the patients were selected at random. Data concerning demographic characteristics, physical health, and access to somatic care are compared to that of a public health survey of a sample of the French population. The present study allows the estimation of ratios for a large number of diseases and of some risk factors among the target group. Heavy smokers and overweight individuals are more numerous among schizophrenics. Pathologies such as epilepsy, diabetes and AIDS infection are overrepresented. Patients' access to somatic care is more prevalent than that of the general population overall, similar to that of the less qualified workers or unemployed group. In this study, gender does not appear to allow prediction of care use for schizophrenics in contrast to the general population.
Further evidence on optimism and underreaction in analysts' forecasts
Authors: Espahbodi Reza , Dugar Amitabh , Tehranian Hassan
Published: July 2002

In this paper, we argue that the observed optimism in analysts' forecasts of earnings is related to the costs and benefits to analysts of issuing optimistic forecasts — when the costs of issuing an optimistic forecast are high relative to the benefits of doing so, optimism will be less apparent or absent. We also argue that underreaction to past forecast errors and past changes in earnings is most evident when earnings components are viewed as permanent. We test our arguments by examining the properties of analysts' forecasts for two samples of distressed firms: (1) firms that file for bankruptcy and (2) firms that experience financial distress but turnaround. According to our arguments, for bankrupt firms, optimism should become less apparent or absent as bankruptcy approaches. Further, for these (bankrupt) firms, underreaction to past forecast errors and past changes in earnings should persist during the period of financial distress. For turnaround firms, we predict the opposite results. We find that the bias in forecasts for the bankrupt sample declines to insignificant levels by the year prior to bankruptcy filing. Forecast bias for the turnaround sample disappears in the year of recovery and is absent during the first half of the following year. For the bankrupt sample, we find evidence of underreaction to past errors in the 4 years prior to the bankruptcy filing; this underreaction is driven by firms with negative earnings‐to‐price ratios. Underreaction to past errors for the turnaround sample disappears in the year of recovery and is absent in the two subsequent years. Unlike past research, we do not find analysts' forecasts to be correlated with past earnings changes. Overall, our results support our cost–benefit and permanence of earnings arguments.
Differing beta‐blocking effects of carvedilol and metoprolol
Authors: Stoschitzky Kurt , Koshucharova Gergana , Zweiker Robert , Maier Robert , Watzinger Norbert , Fruhwald Friedrich M. , Klein Werner
Published: July 2002

Background:

Metoprolol is a beta1‐selective beta‐adrenergic antagonist while carvedilol is a non‐selective beta‐blocker with additional blockades of alpha1‐adrenoceptors. Administration of metoprolol has been shown to cause up‐regulation of beta‐adrenoceptor density and to decrease nocturnal melatonin release, whereas carvedilol lacks these typical effects of beta‐blocking drugs.

Aims:

To compare beta‐blocking effects of metoprolol and carvedilol when applied orally in healthy subjects.

Methods:

We investigated the effects of single oral doses of clinically recommended amounts of metoprolol (50, 100 and 200 mg) and carvedilol (25, 50 and 100 mg) to those of a placebo in a randomised, double‐blind, cross‐over study in 12 healthy male volunteers. Two hours after oral administration of the drugs heart rate and blood pressure were measured at rest, after 10 min of exercise, and after 15 min of recovery.

Results:

Metoprolol tended to decrease heart rate during exercise (−21%, −25% and −24%) to a greater extent than carvedilol (−16%, −16% and −18%). At rest, increasing doses of metoprolol caused decreasing heart rates (62, 60 and 58 beats/min) whereas increasing doses of carvedilol caused increasing heart rates (62, 66 and 69 beats/min), 50 and 100 mg carvedilol failed to differ significantly from the placebo (71 beats/min).

Conclusions:

We conclude that clinically recommended doses of carvedilol cause a clinically relevant beta‐blockade in humans predominantly during exercise where it appears to be slightly (although not significantly) less effective than metoprolol. On the other hand, the effects of carvedilol on heart rate at rest appear rather weak, particularly in subjects with a low sympathetic tone. This might be caused by a reflex increase on sympathetic drive secondary to peripheral vasodilation resulting from the alpha‐blocking effects of the drug. These results might be helpful in explaining why carvedilol, in contrast to metoprolol, may fail to cause up‐regulation of beta‐adrenoceptor density and does not decrease nocturnal melatonin release. This, in turn, may be a reason for the weak side‐effects of carvedilol resulting from the beta‐blockade. In addition, our data might be of interest in the interpretation of the forthcoming results of the COMET trial, although it has to be emphasised that they were derived from healthy subjects and, therefore, cannot be directly extrapolated to patients with heart failure.
Clinical trials update: Highlights of the Scientific Sessions of Heart Failure 2001, a meeting of the Working Group on Heart Failure of the European Society of Cardiology. CONTAK‐CD, CHRISTMAS, OPTIME‐CHF
Authors: Thackray Simon , Coletta Alison , Jones Peter , Dunn Anita , Clark Andrew L. , Cleland John G.F.
Published: July 2002

This article continues a series of reports summarising recent research developments pertinent to the topic of heart failure. This is a summary of presentations made at Scientific Sessions of Heart Failure 2001, a meeting of the Working Group on Heart Failure of the European Society of Cardiology. Clinical studies of particular interest to people caring for patients with heart failure include CONTAK‐CD, CHRISTMAS and further updates on OPTIME‐CHF. A brief review of the current status of cardiac resynchronisation therapy is included.
Relationship between cardiac metaiodobenzylguanidine uptake and hemodynamic, functional and neurohormonal parameters in patients with heart failure
Authors: de Milliano Paul A.R. , van Eck‐Smit Berthe L.F. , van Zwieten Pieter A. , de Groot Andre C. , Tijssen Jan G.P. , Lie Kong I.
Published: July 2002

Background:

Sympathetic activation plays a pivotal role in heart failure attributing to the disease process and symptoms of the patient. Myocardial sympathetic activity can be visualized using radioiodinated metaiodobenzylguanidine 123I‐MIBG, a structural analogue of norepinephrine (NE).

Aim of the study:

We investigated whether a relation exists between myocardial MIBG uptake and different functional, hemodynamic and neurohormonal parameters in patients with chronic heart failure.

Methods and results:

The study comprised 52 patients with stable congestive heart failure functional class II or III and left ventricular ejection fractions of <35%. The heart/mediastinum ratio (H/M ratio) was calculated to quantify myocardial MIBG uptake. A significant correlation was found between peak oxygen consumption and maximal exercise duration as exercise parameters and H/M ratio of MIBG (R, respectively, 0.36 and 0.4, P<0.05). From all other measured parameters, only plasma NE showed a significant correlation with the H/M ratio of MIBG.

Conclusion:

Cardiac sympathetic activity, as measured by myocardial MIBG uptake, is correlated with peak exercise parameters.
Influence of maximum MLC leaf speed on the quality of volumetric modulated arc therapy plans
Authors: Chen Jiayun , Cui Weijie , Fu Qi , Zhang Haojia , Huang Xiaodong , Han Fei , Xia Wenlong , Liang Bin , Dai Jianrong
Published: October 2020

Purpose

Maximum leaf speed is a configurable parameter of MLC in a treatment‐planning system. This study investigated the influence of MLC on the quality of VMAT plans.

Methods

Seven MLCs with different maximum leaf speeds (1.0, 1.5, 2.25, 3.5, 5.0, 7.5, and 10 cm/s) were configured for an accelerator in treatment‐planning system. Correspondingly, seven treatment plans, with the identical initial optimization parameter, were designed with the mdaccAutoPlan system. Six nasopharyngeal carcinoma (NPC) patients and nine rectal cancer patients were selected, representing complex and simple clinical circumstances. VMAT plan quality was evaluated with PlanIQTM software. The results were statistically analyzed with a one‐way analysis of variance (ANOVA) and pairwise comparison tests.

Results

The relative changes of plan scores achieved by the seven configured accelerators, with specific maximum MLC leaf speed (MMLS) for each patient, were studied. Two apparent trends of MMLS influence on VMAT plan scores were observed: Plan scores increased with MMLS; Plan scores increased rapidly when MMLS increased from 1 to 3.5, thus the relative change of plan score decreased in this MMLS range. The stationary point of maximum MLC speed (MMSSP) is defined, for the specific MMLS when the relative changes of plan scores is first <5%, as MMLS increases from 1.0 to 10. For rectal plans, MMSSPs were 2.25 for six patients and 3.5 for the other three patients. For NPC plans, MMSSPs were 3.5 for five patients and 2.25 for one patient.

Conclusion

This work indicates that MMLS directly influences VMAT plan quality in NPC cases and rectal cancer cases. VMAT plan quality improved conspicuously as MMLS increased from 1 to 3.5, VMAT plan quality with marginal improvement when MMLS is above 3.5.
Robust adaptive passivity‐based PIλD control
Authors: Gallegos Javier A. , Aguila‐Camacho Norelys , Duarte‐Mermoud Manuel A.
Published: October 2020

In this article, we develop proportional, fractional‐integral, and derivative () controllers for the regulation and tracking problems of nonlinear systems. The analytic results are obtained by extending the passivity‐based approach to include fractional operators. Robustness under parametric uncertainty is dealt with by a combination with an adaptive scheme. It is also shown their robustness under additive noise and their robustness under uncertainty in the derivation order. The advantages in the controlled system performance and in the control energy consumption in comparison to classic PI and proportional integral derivative controllers are illustrated for the quadratic boost converter and a benchmark system in the literature.
The Structure–Property Correlations in Dry Gelatin Adhesive Films
Authors: Mosleh Yasmine , de Zeeuw Willem , Nijemeisland Marlies , Bijleveld Johan C. , van Duin Paul , Poulis Johannes A.
Published: October 2020

Gelatins are proteinaceous natural materials that are widely used in areas such as conservation and restoration of artifacts as adhesives and consolidants, in pharmaceutics as drug delivery carriers, and in the food industry as structurants. Herein, type A porcine gelatin adhesive films are prepared via solution casting method and their physical and mechanical properties are investigated using X‐ray diffraction (XRD), differential scanning calorimetry, contact angle measurement, dynamic mechanical analysis, and uniaxial tensile tests. The results demonstrate a linear correlation between microstructure of gelatin films in terms of their triple‐helix content and their macroscopic mechanical properties such as tensile strength and gel (Bloom) strength. Moreover, the findings of this study can help the scientists, in, e.g., art conservation and restoration, to predict the mechanical performance of these adhesives by performing a less material demanding and nondestructive physical measurement such as XRD.
Ultrasonic Assisted Incremental Equal Angular Channel Pressing Process of AA 6063
Authors: Günay Bulutsuz Aslı
Published: October 2020

Industrial usage of ultrafine‐grained materials is not common because of their high manufacturing cost of unconventional processing techniques for serial manufacturing. There is a need to increase process efficiency and decrease manufacturing costs for industrial usage of severe plastic deformation methods to manufacture ultrafine‐grained materials. Previously, ultrasonic systems and incremental feeding of materials are used to increase process efficiency. In this experimental study, the ultrasonic system is adapted to an incremental equal angular channel pressing method, called ultrasonic‐assisted incremental equal channel angular pressing (UI‐ECAP). As a reference material of this new system, AA 6063 is selected. Two passes I‐ECAP are applied to the initial material with and without ultrasonic vibrations. The microstructure and mechanical results are investigated for both specimen groups. According to the observations, grain size differences throughout the microstructure decrease with the application of ultrasonic impulses during the deformation. However, UI‐ECAP results in smaller and more equiaxed grain geometry and finer precipitates observed in transmission electron microscope (TEM) analysis. According to the hardness mapping results, UI‐ECAPed sample shows more homogenous hardness distribution than I‐ECAPed sample. The yield strength and ultimate tensile strength of the specimen after two passes of UI‐ECAP are higher in comparison with the I‐ECAP.
Architectured Lattice Materials with Tunable Anisotropy: Design and Analysis of the Material Property Space with the Aid of Machine Learning
Authors: Kulagin Roman , Beygelzimer Yan , Estrin Yuri , Schumilin Artem , Gumbsch Peter
Published: October 2020

Architectured beam lattice materials whose anisotropy can be tuned by varying the composition of their elementary cell are investigated. As an exemplary prototype of such material architecture, a regular triangular lattice with an elementary cell composed of 12 beams is considered. One out of three possible values of the elastic modulus is assigned to each beam. The structure is fully defined by a vector in the 12D composition‐structure space whose components are given by the elastic modulus values of the beams comprising the elementary cell. The elastic properties of this 2D material are represented by the compliance elasticity tensor with six independent compliance coefficients. Aiming at a specific set of properties thus involves finding the point in the 12D composition‐structure space that corresponds to a given point in the 6D property space. This is a problem of large dimensionality. To solve it, the neural network approach is used. This enables creation of architectured materials with tunable elastic anisotropy. A chiral element combining large twist with additional anisotropy requirements is presented as an example of successful machine‐learning‐based optimization of beam lattices proposed.
Compensation Charge Control and Modeling for Reproducing Negative Capacitance Effect of Hafnia Ferroelectric Thin Films
Authors: Ahn Dante , Jung Moonyoung , Lee Yoseop , Song Sungmun , Ham Woori , Suh Dongseok , Ahn Seung‐Eon
Published: October 2020

To enable continuing development of the performance of highly integrated semiconductor chips, it is necessary to dramatically lower the power consumption of transistors. The discovery of the negative capacitance (NC) effect and the ferroelectric properties of HfO2 thin films have raised the possibility of surpassing the known physical limitations of the 60 mV subthreshold slope of the current MOSFETs. However, for commercial application, stable reproducibility of the voltage drop effect due to the ferroelectric polarization and a model that can fully interpret this phenomenon must be obtained. Despite intense recent efforts, guidance for the design of devices for mass production based on the NC effect is currently unavailable. This study has directly observed the NC effect and confirmed that the NC effect can be controlled through analysis based on the equivalent circuit theory. It is experimentally verified that the NC effect is caused by an imbalance between the amount of polarization switching and the amount of charge supplied to compensate for such switching in the initial stage of the applied voltage pulse. The results suggest that a gate structure or peripheral circuit that can actively respond to polarization switching is necessary to implement a novel MOSFET with breakthrough power consumption.
Supercapacitors in the Light of Solid Waste and Energy Management: A Review
Authors: Dutta Arindam , Mahanta Jiwajyoti , Banerjee Tamal
Published: October 2020

In line with the UN's Sustainable Development Goals (SDGs), the world is witnessing a phenomenal shift toward renewable energy. With this, the demand for energy storage devices has gained immense attention from researchers worldwide over the past decades and so have concerns pertaining to the disposal and management of material and energy wastes from various energy resources. Because of their unique features such as high power density, long cycling stability, and high capacitance, supercapacitors have emerged as a promising technology for storing energy. This review focuses on some of the recent advances in supercapacitors in the wake of solid waste and energy management. First, the utilization of a range of solid waste materials in the fabrication of supercapacitors is summarized. Thereafter, the roles of some of the recently developed “green” electrolytes in curbing the detrimental effects of waste generation from supercapacitors are discussed. Furthermore, different applications of supercapacitors in the field of energy management are highlighted. The strategies for the management of waste generated on account of a supercapacitor's end of life are also reported. The review is concluded by outlining some of the unarticulated challenges as well as the personal outlook of the authors in this area.
Cognitive outcomes in trials of two BACE inhibitors in Alzheimer's disease
Authors: Wessels Alette M. , Lines Christopher , Stern Robert A. , Kost James , Voss Tiffini , Mozley Lyn Harper , Furtek Christine , Mukai Yuki , Aisen Paul S. , Cummings Jeffrey L. , Tariot Pierre N. , Vellas Bruno , Dupre Nicole , Randolph Christopher , Michelson David , Andersen Scott W. , Shering Craig , Sims John R. , Egan Michael F.
Published: October 2020

Introduction

The APECS and AMARANTH trials showed that beta‐secretase (BACE) inhibitors verubecestat and lanabecestat failed to slow cognitive and functional decline in individuals with prodromal or early Alzheimer's disease. Here, the performance on secondary and exploratory cognitive measures in both studies is reported.

Methods

APECS (verubecestat) and AMARANTH (lanabecestat) were randomized, double‐blind, placebo‐controlled, parallel‐group, 104‐week clinical trials conducted by different sponsors. Measures included the 3‐Domain Composite Cognition Score (CCS‐3D), Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), Letter/Category Fluency, and Digit Symbol Coding.

Results

Verubecestat showed worsening on the CCS‐3D Total Score, Episodic Memory, and Attention/Processing Speed domains. Lanabecestat showed worsening on the RBANS Total Score, Immediate Memory, and Visuospatial/Constructional Indexes. Both BACE inhibitors showed worsening on Digit Symbol Coding and improvements on Letter/Category Fluency.

Discussion

In both studies, many measures showed treatment‐associated cognitive worsening, whereas verbal fluency tasks showed improvement.
Prognostic value of transient conduction disturbance in out‐of‐hospital cardiac arrest
Authors: Iiya Munehiro , Shimizu Masato , Kimura Shigeki , Fujii Hiroyuki , Suzuki Makoto , Nishizaki Mitsuhiro
Published: October 2020

Aim

A retrospective observational study to verify the impact of electrocardiograms (ECGs) following out‐of‐hospital cardiac arrest (OHCA) on mortality.

Methods

We retrospectively studied 101 OHCA patients who achieved a return of spontaneous circulation (ROSC) and survived for ≥3 h. Among them, 50 patients (66 ± 17 years; 22 male) were evaluated using 12‐lead ECGs repeatedly and were included in the final analysis: immediately after ROSC (initial ECG) and after the initial evaluation in the emergency department (second ECG). Transient conduction disturbance (transient CD) was defined as a narrowing in QRS duration from the initial to second ECG of ≥18 ms. Multivariate Cox regression analyses were carried out to predict 90‐day mortality following OHCA.

Results

Among 50 OHCA patients, 30 patients survived for 90 days. Thirty patients had initial ventricular fibrillation rhythm. Median emergency medical services response time and low‐flow duration were 8 and 21 min, respectively. Multivariate analysis showed that the transient CD and low‐flow duration were significant predictors of all‐cause mortality (hazard ratio 16.55, 1.06; P = 0.001, 0.022, respectively).

Conclusion

Transient CD is a powerful predictor of 90‐day mortality in patients who survived 3 h after ROSC from OHCA.
Co‐assembled Supramolecular Gel of Dipeptide and Pyridine Derivatives with Controlled Chirality
Authors: Wu Aoli , Guo Yongxian , Li Xianbao , Xue Huimin , Fei Jinbo , Li Junbai
Published: October 2020

It is commonly considered that amyloid‐β (Aβ) fibrils are heavily involved in the neurological diseases. Establishing an external model based on the core recognition motif (diphenylalanine, FF) of Aβ would be of significance in understanding the assembly and disassembly of Aβ fibrils in living system. Herein, supramolecular gels with structure transition from amyloid‐like β‐sheet to different supramolecular helices were obtained through the co‐assembly of a N‐fluorenylmethoxycarbonyl‐protected L‐FF (L‐FmocFF) with achiral pyridine derivatives. It is found that the different stacking modes (H‐ or J‐aggregates) of additives and the microenvironment of chiral carbon play vital roles for the selectively chiral transfer or amplification of L‐FmocFF. The dynamic process of helix formation was also captured. This work provides a convenient co‐assembly way to explore the structure basis of Aβ fibrils with a controlled chirality.
Effect of bone ash fillers on mechanical and thermal properties of biobased epoxy nanocomposites
Authors: Uddin Md‐Jamal , Kodali Deepa , Rangari Vijaya K.
Published: October 2020

In this study, the fabrication and characterization of bone ash filled biobased epoxy resin (Super SAP 100/1000, contains 37% biobased carbon content) nanocomposites are presented. Biosource bone ash was modified by size reduction and surface modification processes using a combination of ball milling and sonochemical techniques and characterized using X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy. The modified bone ash particles were incorporated into biobased epoxy with noncontact mixing process. The as‐fabricated nanocomposites were characterized using various thermal and mechanical analyses. The nanocomposites showed significant improvement in flexural strength (41.25%) and modulus (34.56%) for 2 wt% filler loading. Dynamic mechanical analysis (DMA) results showed improvement in both storage modulus and loss modulus. Additionally, DMA results showed a slight reduction in glass transition temperature which also complies with differential scanning calorimetry results. Thermomechanical analysis results showed a reduction in the coefficient of thermal expansion. Thermogravimetric analysis results showed improved thermal stability at both onset of degradation and the major degradation. These enhanced thermal and mechanical performances of the epoxy nanocomposites allows them to be suitable for lightweight aerospace, automotive, and biomedical applications.
Cl@Ag22Au6(4‐TBBT)28(PPh4): A Chloride‐Centered Ag−Au Bimetallic Cluster for Optics
Authors: Andrew Gaya N. , Wu Haiming , Anumula Rajini , Luo Zhixun
Published: October 2020

We report the single‐crystal synthesis of a chlorine‐centered bimetallic cluster, Cl@Ag22Au6(4‐TBBT)28(PPh4), which bears a quatrefoil‐structured Cl@Ag22(SR)16 core studded by six Au(SR)2 staples showing a quasi Td symmetry. This cluster bears 28 metal atoms and 28 ligands, with a chlorine atom hosted in the center of the metallic Ag22Au6 core. Single‐crystal analysis shows that this cluster possesses essentially a different bonding nature compared with other monolayer‐protected metal clusters (MPCs) or traditional metal‐sulfur complexes. We fully dissect the structure evolution in forming such a chlorine‐centered cluster. Interestingly, this cluster, Cl@Ag22Au6(4‐TBBT)28(PPh4), displays a fluorescence emission at 570 nm and supports the solid emission with a minor red shift at 574 nm. On the other hand, we have tested the nonlinear optical property and observed unambiguous nonlinear optical property with a normal valley‐shaped transmittance curve corresponding to reverse saturated absorption (RSA) of the cluster.
Pyrene‐Tagged Alcoholic Ionic Liquids as Phase Transfer Catalysts for Nucleophilic Fluorination
Authors: Taher Abu , Kim Dong Wook
Published: October 2020

Functional group−activity relationships of pyrene‐tagged ionic liquid (PTIL)‐based organocatalysts for nucleophilic fluorination using alkali metal fluorides (MFs) are described, which demonstrate that the pyrene, oligoether and alcohol moieties on the imidazolium ring are vital for efficient catalysis. Further investigation of these findings led to the discovery of new strategy, which showed superior catalyst separation process, i.e., catalyst is effortlessly separated from the reaction mixture using reduced graphene oxide. The catalytic efficiency of the PTIL as a phase transfer catalyst was demonstrated by the high conversion of the reactants up to 98% fluorinated yield using MFs in CH3CN or t‐amyl alcohol. Importantly, the catalyst not only enhanced the reactivity of bimolecular nucleophilic substitutions (SN2) within a short reaction time and reduces the formation of by‐products but also affords high yield with easy isolation and separation under mild conditions.
Associations between brain‐derived neurotrophic factor and cognitive impairment in panic disorder
Authors: Wang Wenchen , Liu Yuanyuan , Luo Shuqing , Guo Xiaoyun , Luo Xingguang , Zhang Yong
Published: October 2020

Introduction

Our study was designed to examine the relationship between Brain‐Derived Neurotrophic Factor (BDNF) genotypes (rs6265, Val66Met), BDNF plasma levels, and cognitive impairment in Chinese patients with panic disorder (PD).

Methods

Total 85 patients with PD and 91 healthy controls finally completed all assessments. The severity of panic symptoms and whole anxiety of PD was measured by Panic Disorder Severity Scale–Chinese Version (PDSS‐CV) and Hamilton Anxiety Scale (HAMA‐14). Montreal Cognitive Assessment (MoCA) and some neurocognitive measures were conducted to evaluate the cognitive performance. All participants were detected for the plasma BDNF levels and BDNF Val66Met polymorphism before assessment and treatment.

Results

No significant differences were found in the BDNF allele frequencies and the BDNF genotype distributions between healthy controls and PD patients. BDNF Met/Met genotype was associated with lower BDNF plasma levels in PD patients, and PD patients with BDNF Met/Met genotype had the lower scores in the attention and speed of processing domains compared to those with Val/Val and Met/Val genotype (p's < .05). Among PD patients, the BDNF plasma levels showed moderate positive correlations with Stroop interference (r = .60, p < .001). Using the MoCA data, the BDNF plasma levels were correlated with delayed memory (r = .50, p < .001), verbal learning (r = .45, p < .001), and total scores of MoCA (r = .51, p < .001).

Conclusions

The BDNF Met/Met genotype may be associated with lower BDNF plasma levels and cognitive impairments in PD patients.