Long-standing Controversial Issue Research Articles

Complete Universal Scaling in First-Order Phase Transitions

Abstract Phase transitions and critical phenomena are among the most intriguing phenomena in nature and society. They are classified into first-order phase transitions (FOPTs) and continuous ones. While the latter shows marvelous phenomena of scaling and universality, whether the former behaves similarly is a long-standing controversial issue. Here we definitely demonstrate complete universal scaling in field driven FOPTs for Langevin equations in both zero and two spatial dimensions by rescaling all parameters and subtracting nonuniversal contributions with singular dimensions from an effective temperature and a special field according to an effective theory. This offers a perspective different from the usual nucleation and growth but conforming to continuous phase transitions to study FOPTs.

DOSIMETRIC ANALYSIS OF INCIDENTALAXILLARY IRRADIATION IN BREAST CANCER USING TANGENTIAL FIELDS TREATED BY 3DCRT TECHNIQUE

Introduction Radiotherapy is an important aspect of treatment for multimodality approach in cancer breast. Inclusion of axillary nodes in radiotherapy tangential elds remains a long-standing controversial issue. It is considered that axillary nodes receive incidental radiation through tangential beams of chest-wall. The benet of decreasing regional recurrences with axillary nodal irradiation needs to be weighed against the risk of chronic lymphedema and its impact on quality of life. The following study was done to analyze the incidental dose received to axillary region and whether the addition of radiotherapy to axillary region will be useful. Material and methods Twenty post Modied Radical Mastectomy (MRM) patients who had received adjuvant radiotherapy from 2018-2021were retrospectively selected. Planning was a done with Field in Field–Forward planned–3DCRT with mono-isocentric technique. Dose prescribed was 50Gy/25 fractions. Axillary Lymph nodes were contoured according to RTOG guidelines. Various parameters of PTV(V95,D90, D95, Dmax, Dmean, Homogeneity Index(HI), Conformity Index (CI), Volume of PTV), Axillary Lymph nodes I, II, III and SCF (Dmean,V95, V90, Volume) and BMI were evaluated. Correlation was done among these parameters and Statistical analysis was done using Pearson-Correlation coefcient. Results The mean dose to axillary Lymph node level I, II, III were 45.75Gy, 31.80Gy and 25.83Gy respectively. The V90% and V95% of Axillary level–III also received a dose of 32.97Gy and 22.73Gy respectively. The combined volume of I and II received a mean dose of 40.85Gy and all three levels received 39.44.Gy. There is a weak correlation of SCF dosimetry with axillary nodal volumes although PTV volumes and BMI had positive correlation with axillary lymph nodal irradiation. ConclusionAxillary levels I and II received substantial amount of incidental radiation by the tangential eld 3DCRT technique. Our small sample size may have impacted a more detailed analysis of the correlation among variables. However more prospective clinical studies addressing this issue may help in understanding the risks versus benets of axillary lymph nodal irradiation.

Kinetic Monte Carlo Simulation of Clustering in an Al-Mg-Si-Cu Alloy.

The mechanism of the clustering in Al-Mg-Si-Cu alloys has been a long-standing controversial issue. Here, for the first time, the mechanism of the clustering in the alloy was investigated by a Kinetic Monte Carlo (KMC) approach. In addition, reversion aging (RA) was carried out to evaluate the simulation results. The results showed that many small-size clusters formed rapidly in the early stages of aging. With the prolongation of aging time, the clusters merged and grew. The small clusters formed at the beginning of aging in Al-Mg-Si-Cu alloy were caused by initial vacancies (quenching vacancies). The merging and decomposition of the clusters were mainly caused by the capturing of vacancies, and the clusters had a probability to decompose before reaching a stable size. After repeated merging and decomposition, the clusters reach stability. During RA, the complex interaction between the cluster merging and decomposition leaded to the partial irregular change of the hardness reduction and activation energy.

Complexes of humic acid with cationic surfactants support the supramolecular view of extracted humic matter

Environmental context The molecular organisation of humic substances is key to understanding various natural and engineered processes, such as metal speciation and bioavailability. Two main models have been proposed: polymeric organisation and supramolecular organisation. A physicochemical approach, based on the interaction of humic acid with increasing amounts of cationic surfactants, leads to a sequence of molecular structures that provides support to the supramolecular view of humic organisation. Abstract The structural organisation of extracted humic matter, polymeric or supramolecular, has been a long-standing controversial issue. In this paper, we show that the interaction between a reference humic material, the Suwannee River Humic Acid (SRHA), and a homologous series of cationic surfactants (n-alkyl trimethyl ammonium chloride) provides key insights to resolve the controversy. By combining measurements of turbidity, electrophoretic mobility, surface tension and cryogenic transmission electron microscopy, we show that: (i) the binding of cationic surfactant to the anionic humic acid is initially triggered by electrostatic interactions; (ii) the contrasting evolution of turbidity–surfactant concentration curves implies that the surfactant alkyl chain interacts with the hydrophobic moieties of humic matter from very low concentrations of surfactant; (iii) a drastic restructuring of humic matter occurs on surfactant binding, which brings out supplementary anionic humic sites; (iv) in the presence of C12 cationic surfactant, SRHA spontaneously forms stable nanoscale unilamellar vesicles, which, in addition to the high surface activity of complexes, could be of interest in the remediation of oil-contaminated environments; (v) the sequence of molecular structures obtained from SRHA with increasing amounts of C12-cationic surfactant – humic-rich vesicles, aggregates, surfactant-rich vesicles – bears striking similarities with the phase behaviour of aqueous mixtures of anionic and cationic surfactants, thus supporting the supramolecular view of humic structure.

Determination of pH Dependent Structures of Thymol Blue Revealed by Cooperative Analytical Method of Quantum Chemistry and Multivariate Analysis of Electronic Absorption Spectra

Abstract The pH dependent structure of thymol blue (TB) in solution, a long-standing controversial issue, has been determined by quantum chemistry with an aid of multivariate analysis of electronic absorption spectra. It has been revealed that the TB structure varies from the neutral biprotonated form with open-sulton ring showing red to the monovalent anion of the pure quinoid form showing yellow and then to the quinoid-phenolate form showing blue on raising the pH for a solution.

Unraveling the controversy over a catalytic reaction mechanism using a new theoretical methodology: One probe and non-equilibrium surface Green's function

We propose a new methodology called “one probe and non-equilibrium surface Green's function (OPNS)” to elucidate the longstanding controversial issue of a catalytic reaction mechanism, especially iodine reduction reaction (IRR) mechanisms. With aid of OPNS overcoming the limitations of conventional approach based on the free energy diagram and theoretical slab model, we clearly elucidate that the IRR follows a consecutive mechanism where the configurational preference of approaching I2 molecules depending on the external electric field governs the IRR mechanism. Under reductive potential, I2 molecules prefer a vertical configuration (I2V) rather than a parallel configuration (I2P), which leads to the consecutive mechanism where I atoms are sequentially reduced due to asymmetric charge accumulation on a single I atom that is subsequently desorbed. In addition, we provide new convincing descriptors for catalytic activity evaluation, the slope of the linear relation between the reductive process and the electric field strength representing the ability of the partial reduction and the threshold electric field of minimum required potential for the complete reduction.

A thiocarbonate sink on the enzymatic energy landscape of aerobic CO oxidation? Answers from DFT and QM/MM models of Mo[sbnd]Cu CO-dehydrogenases

We present a theoretical investigation providing key insights on a long-standing controversial issue that dominated the debate on carbon monoxide oxidation by MoCu CO-dehydrogenases. Previous investigations gravitate around the possible occurrence of a thiocarbonate intermediate, that was repeatedly reported to behave as a thermodynamic sink on the catalytic energy landscape. By using a hierarchy of quantum mechanical and hybrid quantum/classical models of the enzyme, we show that no such energy sink is present on the catalytic energy profile. Consequent perspectives for the definition of a novel mechanistic proposal for the enzyme-catalyzed CO-oxidation are discussed in light of the recent literature.

Antidepressant Prescription Patterns in Bipolar Disorder: a Nationwide, Register-based Study in Korea.

BackgroundThe role of antidepressants (ADs) in bipolar disorder is long-standing controversial issue in psychiatry. Many clinicians have used ADs as a treatment for bipolar depression, and the selection of therapeutic agents is very diverse and inconsistent. This study aimed to examine recent AD prescription patterns for patients with bipolar disorder in Korea, using the nationwide, population-based data.MethodsThis study utilized the Korean nationwide, whole population-based registry data of the year 2010, 2011, and 2013. All prescription data of the ADs, antipsychotics, and mood stabilizers of the sampled patients diagnosed with bipolar disorder (n = 2,022 [in 2010]; 2,038 [in 2011]; 2,626 [in 2013]) were analyzed for each year.ResultsAnnual prescription rate of ADs was 27.3%–33.6% in bipolar disorder, which was gradually increasing over the 3-year period. The combination pattern of ADs and antipsychotic drugs tended to increase over 3 years. The proportion of females and the prevalence of comorbid anxiety disorder were significantly higher in AD user group in all three years. Among individual ADs, escitalopram was prescribed most frequently, and fluoxetine and bupropion were prescribed to the next many patients. The mean duration of bipolar depressive episodes was 135.90–152.53 days, of which ADs were prescribed for 115.60–121.98 days.ConclusionOur results show prescription rate of ADs in bipolar disorder was maintained at substantial level and increased in recent 3 years. More empirical data and evidence are needed to establish practical treatment consensuses.

On the Choice of Difference Sequence in a Unified Framework for Variance Estimation in Nonparametric Regression

Difference-based methods do not require estimating the mean function in nonparametric regression and are therefore popular in practice. In this paper, we propose a unified framework for variance estimation that combines the linear regression method with the higher-order difference estimators systematically. The unified framework has greatly enriched the existing literature on variance estimation that includes most existing estimators as special cases. More importantly, the unified framework has also provided a smart way to solve the challenging difference sequence selection problem that remains a long-standing controversial issue in nonparametric regression for several decades. Using both theory and simulations, we recommend to use the ordinary difference sequence in the unified framework, no matter if the sample size is small or if the signal-to-noise ratio is large. Finally, to cater for the demands of the application, we have developed a unified R package, named VarED, that integrates the existing difference-based estimators and the unified estimators in nonparametric regression and have made it freely available in the R statistical program http://cran.r-project.org/web/packages/.

Brain-Derived Neurotrophic Factor Gene Val66Met Polymorphism and Risk of Schizophrenia: A Meta-analysis of Case-Control Studies.

According to evidences from previous family and association studies, it has been claimed that genetic factors are involved in the neuropathogenesis of Schizophrenia disorder. Whether the Val66Met variant of brain-derived neurotrophic factor (BDNF) gene plays any roles in the pathogenesis of this syndrome or could be a potential biomarker for prognosis of this disorder has been a long-standing controversial issue. We performed a meta-analysis restricted to case-control studies and searched Pubmed, PsychInfo, and Google scholar using keywords including 'association,' 'Val66Met,' 'BDNF,' and 'schizophrenia' published up to May 1, 2015. A total of 39 studies for schizophrenia were combined by fixed- and random-effects models. The pooled results from the schizophrenia sample indicated no significant evidence for the association of Val/Val and Val/Met genotypes of BDNF gene with schizophrenia, but it was observed that there is an association between Met/Met polymorphism and schizophrenia in Asian, European, and Chinese populations, this means that the risk of schizophrenia in Asian, European, and Chinese populations with Met/Met genotype is, respectively, 9, 26, and 9%. There was a significant association between BDNF Val66Met polymorphism and schizophrenia in our meta-analysis study. We cannot rule out the possibility that other polymorphisms in the BDNF gene are involved in the pathophysiology of schizophrenia. In addition, more studies should be conducted on the polymorphisms in other genes to elucidate their possible roles in schizophrenia.

The plastic yield and flow behavior in metallic glasses

Metallic glasses have vast potential applications as components in microelectronics- and nanoelectronics-type devices. The design of such components through computer simulations requires the input of a faithful set of continuum-based constitutive equations. However, one long-standing controversial issue in modeling the plastic behavior of metallic glasses at the continuum level is the use of the most appropriate plastic yield criterion and flow rule. Guided by a series of molecular dynamics simulations conducted at low-homologous temperatures under homogeneous deformations, we quantitatively prove that the continuum plastic behavior in metallic glasses is most accurately described by a von Mises-type plastic yield criterion and flow rule.

Enzymatic Epoxide-Opening Cascades Catalyzed by a Pair of Epoxide Hydrolases in the Ionophore Polyether Biosynthesis

Our recent findings of the first epoxide hydrolase Lsd19, involved in lasalocid A biosynthesis, led us to investigate a long-standing controversial issue on the mechanism of enzymatic epoxide-opening cascades. The site-directed mutagenesis and domain dissection analysis to reveal the mechanism of the reaction catalyzed by Lsd19 is examined, especially in the role of acidic amino acid pair and catalytic domains.

Correlated versus ferromagnetic state in repulsively interacting two-component Fermi gases

Whether a spin-1/2 Fermi gas will become ferromagnetic as the strength of repulsive interaction increases is a long-standing controversial issue. Recently this problem has been studied experimentally by Jo et al. [Science 325, 1521 (2009)] in which the authors claim a ferromagnetic transition is observed. This work is to point out the results of this experiment cannot distinguish whether the system is in a ferromagnetic state or in a nonmagnetic but strongly short-range correlated state. A conclusive experimental demonstration of ferromagnetism relies on the observation of ferromagnetic domains.

Identification of a Gene Cluster of Polyether Antibiotic Lasalocid fromStreptomyces lasaliensis

Elucidation of enzymatic polyether formation is a long-standing controversial issue in organic chemistry. To address this intriguing issue, identifying the actual substrate for epoxidation and sequential cyclization is essential. We selected the representative polyether ionophore, lasalocid, which has been proposed to undergo no modification at the late stage of biosynthesis. Cloning and a sequence analysis revealed seven polyketide synthase (PKS) genes, epoxidase and epoxide hydrolase genes for sequential ether formation, and several putative genes for supplying ethylmalonyl-CoA. Based on bioinformatic data, we propose the lasalocid biosynthetic pathway which involves characteristic aromatic ring formation and sequential cyclic ether formation. The finding of a thioesterase domain at the C-terminal of the seventh PKS indicates that intriguing oxidative cascade cyclization would occur after cleavage of the polyketide intermediate from PKS. Based on this observation, we have recently reported the enzymatic transformation of a bisepoxide intermediate to lasalocid with the recombinant epoxide hydrolase, Lsd19.

Stacked triangular XY antiferromagnets: End of a controversial issue on the phase transition

In this paper, we show, by using the Wang–Landau flat-histogram Monte Carlo method, that the phase transition in the XY stacked triangular antiferromagnet is clearly of first order, confirming results from latest Monte Carlo simulation and from a nonperturbative renormalization group, putting an end to a long-standing controversial issue.

Voice in Chinese

The present paper revisits a long-standing controversial issue in Chinese grammar — the passive voice — from a systemic functional approach. This study examines how the ba- and bei-constructions control the flow of information in text and shows that they are textually motivated. It argues, by differentiating the bei-construction from the OSV structure, and the ba-construction from the SOV and SVO structures, that the two constructions are not options of THEME, but form a separate level within the grammar. It then describes the system of VOICE in the language. Furthermore, facing the increasing productivity of the ba- and bei-constructions in process types other than transitive material processes, this study examines this trend of increasing productivity.

Adsorption of thiolates to singly coordinated sites on Au111 evidenced by photoelectron diffraction.

The adsorption structure of methylthiolate (CH3S) adsorbed on Au(111), a long-standing controversial issue, has been unambiguously determined by scanned-energy and scanned-angle S 2p photoelectron diffraction. The methylthiolate molecules are found to occupy atop sites with a S-Au distance of 2.42 +/- 0.03 A. The angular distribution of the S 2p photoelectrons due to forward scattering reveals that the S-C bond is inclined by approximately 50 degrees from the surface normal towards both the [211] and [121] (nearest-neighbor thiolate) directions.

The origin and nature of ramified and amoeboid microglia: a historical review and current concepts.

The origin of ramified microglia has been a longstanding controversial issue, with 4 major schools of thought, which state that they are derived (1) from invasion of mesodermal pial elements, (2) from neuroectodermal matrix cells together with the macroglia, (3) from pericytes, and (4) from invasion of monocytes in early development. This paper is in support of the last-mentioned hypothesis. It is known that ramified microglial cells do not divide under normal circumstances, and since our studies in the corpus callosum have shown that these cells do not appear until the fifth postnatal day, it is reasoned that they must be derived from some preexisting mitotically active cells. The putative precursor is the preponderant amoeboid microglia in the same region. Our experimental studies with the carbon labelling technique have demonstrated for the first time that blood monocytes invade into the early postnatal brain to become amoeboid microglia, which then differentiate into ramified microglia. Just like other tissue macrophages, the monocyte-derived amoeboid microglia exhibit features indicative of phagocytic activities. These include the content of hydrolytic enzymes, uptake of carbon, and a characteristic surface morphology, as seen by scanning electron microscopy. The transformation of amoeboid microglia into ramified microglia, which occurs between the second and third postnatal week, is considered to be a regressive phenomenon, as shown by the diminution of their content of hydrolytic enzymes and the downregulation of membrane antigen. Apart from their primary role as active phagocytes, their involvement in Alzheimer's disease (AD) is evidenced recently by the fact that the cells are specifically marked by antibodies present in the cerebrospinal fluid of AD patients. In conclusion, ramified microglial cells are derived from monocytes, but through an intermediate amoeboid microglia stage as active macrophages in the perinatal period.

Effect of ambient temperature storage on potable water coliform population estimations.

The effect of the length of time between sampling potable water and performing coliform analyses has been a long-standing controversial issue in environmental microbiology. The issue is of practical importance since reducing the sample-to-analysis time may substantially increase costs for water analysis programs. Randomly selected samples (from those routinely collected throughout the State of Wisconsin) were analyzed for total coliforms after being held at room temperature (20 +/- 2 degrees C) for 24 and 48 h. Differences in results for the two holding times were compared with differences predicted by probability calculations. The study showed that storage of the potable water for up to 48 h had little effect on the public health significance of most samples containing more than two coliforms per 100 ml.

Contact and Conflict: The Question of Integrated Education

The idea that contact between members of different groups will improve relations between them has a long history. It has provided some of the rationale for such policy decisions as the racial integration of education in the USA. Within the context of the Northern Ireland conflict the question of religiously segregated education is a long-standing controversial issue although there are some well-established integrated schools. The topic is of current interest due both to the Government proposal to integrate the teacher-training colleges and to the opening of an integrated second-level school with explicit social goals. This paper reviews a number of recent investigations in Northern Ireland which have studied Protestant and Catholic children attending the same schools. Of special interest are the children’s positive attitudes to religion and their non-sectarian patterns of social interaction. It is suggested, however, that research in Northern Ireland has not yet adequately tested the contact thesis.