bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Volume Fraction
Effects of Inertial Colliding Particles in Homogeneous Isotropic
Turbulence
Authors: Ernst Martin , Sommerfeld Martin
Published: March 2012

The main objective of the present study is the investigation of volume fraction effects on the collision statistics of nonsettling inertial particles in a granular medium as well as suspended in an unsteady homogeneous isotropic turbulent flow. For this purpose, different studies with mono-disperse Lagrangian point-particles having different Stokes numbers are considered in which the volume fraction of the dispersed phase is varied between 0.001 and 0.01. The fluid behavior is computed using a three-dimensional Lattice-Boltzmann method. The carrier-fluid turbulence is maintained at Taylor microscale Reynolds number 65.26 by applying a spectral forcing scheme. The Lagrangian particle tracking is based on considering the drag force only and a deterministic model is applied for collision detection. The influence of the particle phase on the fluid flow is neglected at this stage. The particle size is maintained at a constant value for all Stokes numbers so that the ratio of particle diameter to Kolmogorov length scale is fixed at 0.58. The variation of the particle Stokes number was realized by modifying the solids density. The observed particle Reynolds and Stokes numbers are in between [1.07, 2.61] and [0.34, 9.79], respectively. In the present simulations, the fluid flow and the particle motion including particle-particle collisions are based on different temporal discretization. Hence, an adaptive time stepping scheme is introduced. The particle motion as well as the occurrence of inter-particle collisions is characterized among others by Lagrangian correlation functions, the velocity angles between colliding particles and the collision frequencies. Initially, a fluid-free particle system is simulated and compared with the principles of the kinetic theory to validate the implemented deterministic collision model. Moreover, a selection of results obtained for homogeneous isotropic turbulence is compared with in literature available DNS and LES results as well. According to the performed simulations, the collision rate of particles with large Stokes numbers strongly depends on the adopted volume fraction, whereas for particles with small Stokes numbers the influence of particle volume fraction is less pronounced.
A Review of External Hydrodynamics With Experimental Data Assessment for Low-Speed Ocean Flows
Authors: Blanco Max , Wilson Philip A.
Published: March 2012

This article describes a literature review focused on published empirical measurements of external flows over bodies of revolution that can be employed for verification and validation of calculations of survey-class autonomous underwater vehicles (AUVs) or other like bodies. The flow regime for a survey-class AUV is defined, and a mathematically optimal velocity results for these energy-limited vehicles. A range-maximal hotel load is one of the inferences. Cavitation is shown not to affect this type of AUV. Environmental and computational problems of turbulence are discussed. A table of vital statistics of contemporary survey-class AUVs is provided.
3D Numerical Study of a Flowing Electrolyte – Direct Methanol Fuel Cell With an Implemented Bi-Layered Membrane Electrode Diaphragm Assembly
Authors: Cornellier P. A. , Matida E. , Cruickshank C. A.
Published: March 2012

In the present work, fluid dynamic simulation and experimental studies are compared to assess the validity of using computational fluid dynamics (CFD) to accurately predict the pressure losses experienced across each of the three fluid channels in a flowing electrolyte direct methanol fuel cell: methanol flow through anodic-serpentine channels; air flow through the cathodic-serpentine channels; dilute sulfuric acid flow through the flowing electrolyte (FE) channel located between two membrane-electrode assemblies (MEAs). The methanol flow rate is varied from 5 to 25 mL/min and the airflow is varied from 0.5 to 5 L/min. The flowing electrolyte flow rate is also varied from 5 to 25 mL/min in order to analyze pressure levels within the FE channel, which, according to this analysis, must be larger than the adjacent serpentine channels. This pressure difference is particularly important to maintain the distance (and flow structure) between the MEAs without affecting performance of the fuel cell. Adequately controlling the pressure of each of three fluids disables the MEAs ability to deform without the use of an electrolyte spacer, effectively creating an inter-dependent bi-layered membrane electrode diaphragm assembly (Bi-MEDA). Through CFD simulation, it was observed that pressure equalization through the Bi-MEDA approach supports the elimination of a flowing electrolyte channel spacer from current FE-DMFC designs. The reduction of the spacer is expected to decrease ohmic losses currently experienced in all FE-DMFC designs. Despite several approximations, simulations predicting pressure losses throughout the two serpentine fuel channels are compared against obtained experimental data, showing relatively good agreement for a single cell arrangement.
Synthesis of Nanosize Ceria by a Combustion Process and Electrical Characterization of HeteroFoaM Porous Ceria Electrodes
Authors: Wright J. , Virkar A. V.
Published: March 2012

Nanosize powders of Sm2O3-doped CeO2 (SDC) containing various dopants (Pr, Rh, Re) were synthesized using respective nitrates and D-gluconic acid (DGA) by a combustion process. The resulting powders were extremely fine (nanosize) and of uniform composition. Porous samples with open porosity were fabricated by sintering. Electrical conductivity was measured by a four probe DC technique over a wide pO2 range and a temperature range between 200°C and 800°C. The pO2 was measured using an oxygen sensor. Samples of SDC and SDC with Pr doping exhibited significant electronic conduction in reducing atmospheres above 400°C. Thus, these materials are suitable candidates for SOFC anodes above 400°C. Sintered and powder samples were subjected to various thermal treatments in several atmospheres (oxidizing to reducing) and were characterized by XRD, SEM, and XPS. The purpose of adding the dopants Pr, Rh and Re was to create mixed ionic electronic conductivity in reducing atmospheres at low (<300°C) temperatures. Such materials are potential candidates as SOFC anodes at temperatures possibly lower than 500°C.
Effect of Porous Electrode Morphology on Broadband Dielectric Characteristics of SOFC and Methodologies for Analytical Predictions
Authors: Majumdar Prasun , Raihan Md. , Reifsnider Kenneth , Rabbi Fazle
Published: March 2012

Heterogeneous dielectric material systems and their interfaces which are engineered at the local level (atomic/nano/micro scale) present special challenges for analysis and interpretation of their macroscopic functional behavior in response to specific operational histories. In addition to the chemical composition of the material, the local morphology plays a definitive role in the determination of the transport, electrochemical, and mechanical functions of the heterogeneous constituents, and especially in their interaction and collective action. The basic science of the effect of morphology on polarization, resulting multi-physics properties, and their evolution processes (which determine durability and life) are less well understood. The present paper will focus on a small part of this broader problem. Specifically, the effect of porous microstructure on the broadband dielectric characteristics of the solid oxide fuel cell (SOFC) will be discussed. Different variations of microstructure (such as porosity, pore connectivity, distribution, geometry etc) of YSZ based SOFC materials will be studied using a broadband dielectric spectroscopy system at different temperatures. A finite element based meso-to-continuum model (mm scale model with micron scale features) will be developed to predict dielectric characteristics (voltage, current, impedance distribution) utilizing actual morphology (captured via a 3D X-ray tomography microscope). The paper will summarize all preliminary results from the ongoing research and provide a pathway towards a robust analysis that will help design better microstructures for SOFC electrodes.
Interactive online optics modules for the college physics course
Authors: Hoeling Barbara M.
Published: March 2012

A new learning tool for geometrical optics is presented which has been developed for an algebra based introductory college physics course for life science majors. The interactive online learning module contains images, videos of problem solutions, short animated videos, and interactive animations, which allow students to actively explore the physics content beyond the pictures in a textbook. These elements are accompanied by narration and a transcript to guide the students while allowing them to navigate freely between the different parts of the module. The results of student learning, a comparison with a control group, and a survey of student attitudes toward this new instruction method are discussed.
The Black Queen Hypothesis: Evolution of Dependencies through Adaptive Gene Loss
Authors: Morris J. Jeffrey , Lenski Richard E. , Zinser Erik R.
Published: March 2012

Reductive genomic evolution, driven by genetic drift, is common in endosymbiotic bacteria. Genome reduction is less common in free-living organisms, but it has occurred in the numerically dominant open-ocean bacterioplankton
Prochlorococcus
and “
Candidatus
Pelagibacter,” and in these cases the reduction appears to be driven by natural selection rather than drift. Gene loss in free-living organisms may leave them dependent on cooccurring microbes for lost metabolic functions. We present the Black Queen Hypothesis (BQH), a novel theory of reductive evolution that explains how selection leads to such dependencies; its name refers to the queen of spades in the game Hearts, where the usual strategy is to avoid taking this card. Gene loss can provide a selective advantage by conserving an organism’s limiting resources, provided the gene’s function is dispensable. Many vital genetic functions are leaky, thereby unavoidably producing public goods that are available to the entire community. Such leaky functions are thus dispensable for individuals, provided they are not lost entirely from the community. The BQH predicts that the loss of a costly, leaky function is selectively favored at the individual level and will proceed until the production of public goods is just sufficient to support the equilibrium community; at that point, the benefit of any further loss would be offset by the cost. Evolution in accordance with the BQH thus generates “beneficiaries” of reduced genomic content that are dependent on leaky “helpers,” and it may explain the observed nonuniversality of prototrophy, stress resistance, and other cellular functions in the microbial world.
Vacuolation in hepatocyte nuclei is a marker of senescence
Authors: Aravinthan Aloysious , Verma Suman , Coleman Nick , Davies Susan , Allison Michael , Alexander Graeme
Published: March 2012

Hepatocyte nuclear vacuolation is considered benign and associated with non-alcohol-related fatty liver disease. Vacuolated hepatocyte nuclei were compared with non-vacuolated hepatocyte nuclei in eight patients with advanced fibrosis and a spectrum of liver disease to explore the hypothesis that such nuclei represent senescence. Age- and sex-matched liver donors served as normal tissue. In normal liver <0.01% hepatocytes showed nuclear vacuolation. In contrast, nuclear vacuolation was present in all patients with liver disease, ranging from 0.1% to 11.7% hepatocytes, irrespective of the aetiology of liver disease and independent of insulin resistance. There was a close association between nuclear vacuolation and increased nuclear area, p21 expression, γH2AX expression and the absence of Mcm-2, consistent with senescence and cell cycle arrest. Nuclear vacuolation in hepatocytes is a marker of senescence and likely to be a consequence of liver injury, unrelated to insulin resistance.
Synaptic Polarity Depends on Phosphatidylinositol Signaling Regulated bymyo-Inositol Monophosphatase inCaenorhabditis elegans
Authors: Kimata Tsubasa , Tanizawa Yoshinori , Can Yoko , Ikeda Shingo , Kuhara Atsushi , Mori Ikue
Published: March 2012

Although neurons are highly polarized, how neuronal polarity is generated remains poorly understood. An evolutionarily conserved inositol-producing enzyme myo-inositol monophosphatase (IMPase) is essential for polarized localization of synaptic molecules in Caenorhabditis elegans and can be inhibited by lithium, a drug for bipolar disorder. The synaptic defect of IMPase mutants causes defects in sensory behaviors including thermotaxis. Here we show that the abnormalities of IMPase mutants can be suppressed by mutations in two enzymes, phospholipase Cβ or synaptojanin, which presumably reduce the level of membrane phosphatidylinositol 4,5-bisphosphate (PIP2). We also found that mutations in phospholipase Cβ conferred resistance to lithium treatment. Our results suggest that reduction of PIP2 on plasma membrane is a major cause of abnormal synaptic polarity in IMPase mutants and provide the first in vivo evidence that lithium impairs neuronal PIP2 synthesis through inhibition of IMPase. We propose that the PIP2 signaling regulated by IMPase plays a novel and fundamental role in the synaptic polarity.
Cultivo in vitro de plântulas de orquídea em meios com diferentes concentrações de fertilizante mineral
Authors: Rodrigues Donizetti Tomaz , Novais Roberto Ferreira , V Víctor Hugo Alvarez , Dias José Maria Moreira , Otoni Wagner Campos , Villani Ecila Mercês de Albuquerque
Published: March 2012

Existem diversos meios nutritivos utilizados no cultivo in vitro de orquídeas, com diferentes composições e concentrações de sais, resultando em respostas distintas entre eles. O objetivo deste trabalho foi avaliar o crescimento in vitro de plântulas de orquídea (Cattleya walkeriana Gardner) sob diferentes doses de fertilizante NPK, adicionado ao meio de cultivo, como fonte de nutrientes. Foi utilizado o fertilizante Peters® na formulação NPK 10-30-20 + Mg + micronutrientes, nas doses de: 0,0; 1,0; 2,0; 3,0; 4,0; 5,0 e 10,0 g L-1 de meio, acrescido de água de coco (150 mL L-1), sacarose (20 g L-1), carvão ativado (2 g L-1) e pH corrigido para 5,6. Foram utilizados frascos de vidro de 320 mL de capacidade, contendo 35 mL de meio onde foram inoculadas dez plântulas com seis meses de idade, previamente germinadas em meio Knudson C. O experimento foi mantido em sala de crescimento a 27 ± 2 ºC, 16/8 h luz/escuro e irradiância de 48 µmol m-2 s-1. A produção máxima de matéria seca da parte aérea das plantas, aos seis meses de idade, foi estimada em 0,255 g/frasco com uso de 5,22 g L-1 do fertilizante adicionado ao meio de cultura. Considerando a possibilidade de salinidade elevada do meio, para algumas espécies de orquídea, estimou-se a dose de fertilizante (3,55 g L-1) necessária para obtenção de 90% da produção máxima. As raízes apresentaram drástica redução do crescimento (menor número e curtas) em condições de alta concentração de fertilizante.
Tratamentos da compactação experimental do cólon maior de equinos com hidratação enteral, intravenosa e sene (Cassia augustifolia Vahl)
Authors: Filho José Dantas Ribeiro , Alves Geraldo Eleno Silveira , Dantas Waleska de Melo Ferreira
Published: March 2012

O objetivo deste estudo foi investigar a ação da hidratação enteral (HET), da hidratação intravenosa (IV) e da sene, associada à hidratação intravenosa (SEN), no tratamento da compactação do cólon maior, em equinos. Foram utilizados 15 animais, divididos em três grupos de cinco, cada. Os animais eram portadores de compactação do cólon maior, induzida experimentalmente. O grupo HET recebeu solução isotônica poliônica enteral (8 mL kg-1 h-1,durante 48 horas); o grupo SEN foi tratado com sene (20 mg kg-1, duas doses de 24/24 h), mais Ringer lactato i.v. (10 mL kg-1 h-1 12h-1, durante dois dias) e ao grupo IV foi administrado Ringer lactato i.v. (16 mL kg-1 h-1 12h-1, durante dois dias). O tratamento HET ocasionou maior amolecimento das fezes e desfez a compactação em menor tempo. Entretanto, foi observada hipomotilidade intestinal mais prolongada. O tratamento SEN normalizou mais rapidamente a motilidade intestinal, porém o tempo necessário para desfazer a compactação foi maior. Além disso, ocasionou o maior aumento na distensão abdominal e no grau da dor, assim como a menor capacidade para reverter a desidratação. O tratamento do grupo IV debelou a compactação, igualmente ao HET, e a hipomotilidade intestinal, em menor tempo, mas foi o que menos amoleceu as fezes. Concluiu-se que os tratamentos IV e HET foram os mais eficientes na terapia da compactação, induzida no cólon maior, em equinos. O grupo SEN foi eficiente, porém, foi o que apresentou os efeitos adversos mais importantes.
Influência da nutrição mineral foliar sobre doenças da parte aérea da cultura do trigo
Authors: Morales Rafael Gustavo Ferreira , Santos Idalmir dos , Tomazeli Vanessa Nataline
Published: March 2012

A utilização de fungicida para o controle de doenças foliares na cultura do trigo é prática comum entre os triticultores. Contudo, devido ao impacto ambiental provocado pelo seu uso generalizado, buscam-se alternativas para controle dos fitopatógenos. Sendo assim, este trabalho teve como objetivo avaliar o efeito da nutrição mineral foliar sobre as doenças foliares do trigo, bem como seu efeito sobre o desenvolvimento da planta. O delineamento experimental foi em blocos casualizados com quatro repetições e quatro tratamentos: 1- testemunha; 2- adubação foliar aos 30 dias após a emergência (DAE) e aos 75 DAE; 3- fungicida aos 30 e 75 DAE; e 4- adubação foliar aos 30 DAE e adubação foliar mais fungicida aos 75 DAE. Foram realizadas nove avaliações da incidência e da severidade do oídio, cujos dados foram utilizados para o cálculo das áreas abaixo das curvas de progresso da doença; três avaliações da severidade da ferrugem e da mancha da gluma; e duas avaliações da mancha amarela. Foram determinadas a massa de matéria fresca e seca da parte aérea e do sistema radicular e a produtividade da cultura. Foi observada redução da incidência e da severidade de oídio em função da adubação foliar, apenas na primeira avaliação de incidência e nas segunda e quinta avaliações de severidade da doença. O efeito complementar dos nutrientes com o fungicida para redução das doenças foi observado apenas para a mancha amarela, com redução de aproximadamente 11,16 % da severidade. Os maiores valores de produtividade foram observados para os tratamentos apenas com fungicida e, com fungicida mais nutrientes. A adubação foliar proporcionou aumento da massa fresca de raízes e massa seca de raízes. Apesar disso, não houve aumento da massa fresca da parte aérea em função da adubação foliar.
Potencial alelopático de plantas de cobertura verde de inverno sobre o crescimento do porta-enxerto VR043-43
Authors: Bettoni Jean Carlos , Gardin João Peterson Pereira , Feldberg Nelson Pires , Dalbó Marco Antonio
Published: March 2012

Nos últimos anos, tem-se verificado aumento no uso da adubação verde de inverno na cultura da videira. Essa adubação proporciona ao vinhedo melhor controle da erosão e manutenção da fertilidade, aumento da macro e microporosidade do solo pela penetração e decomposição das raízes e aumento do teor de matéria orgânica, além da possibilidade de diminuição do uso de herbicidas. Algumas espécies vêm sendo utilizadas, mesmo sem se conhecerem os efeitos secundários para a videira, e poucos trabalhos têm sido realizados para avaliação desses efeitos. O objetivo deste trabalho foi verificar o efeito alelopático de diferentes espécies de plantas de cobertura verde de inverno sobre o desenvolvimento do porta-enxerto VR 043-43. O delineamento utilizado foi inteiramente casualizado, com 19 tratamentos e quatro repetições. Foram preparados extratos das partes aérea e radicular de nove espécies, utilizadas como cobertura verde de inverno. As estacas enraizadas foram colocadas em vasos com areia e, durante 45 dias, duas vezes por semana, foram regadas com solução aquosa de cada extrato e fertilizante. Após esse período, foi avaliado o comprimento das raízes, o número de raízes por estaca, a matéria fresca do sistema radicular e a matéria fresca das brotações. Os resultados obtidos permitiram concluir que, dentre os extratos das espécies estudadas, o que apresentou maior efeito alelopático foi o extrato da parte aérea da gorga (Spergula arvensis), seguido pelo extrato da parte aérea do dente-de-leão (Taraxacum officinale L.). O centeio (Secale cereale L.) e o nabo forrageiro (Raphanus sativus L.) não apresentaram efeito alelopático.
Qualidade da informação sobre mortalidade numa coorte de diabéticos - Estado do Rio de Janeiro, 2000 a 2003
Authors: Cascão Angela Maria , Costa Antônio José Leal , Kale Pauline Lorena
Published: March 2012

OBJETIVO: Avaliar a qualidade do Sistema de Informações sobre Mortalidade (SIM) em uma coorte especial de pacientes hospitalizados pelo Sistema Único de Saúde (SIH-SUS) que sofreram amputação de membros inferiores (AMI) devido ao diabetes mellitus (DM) em 2000, e comparar a mortalidade por causas da coorte com a da base populacional do Estado do Rio de Janeiro (ERJ) de 2000 a 2003. MÉTODOS: Os dados foram gerados a partir do relacionamento entre as bases de dados do SIH-SUS (2000) e do SIM (2000-2003). Foram excluídos os registros de indivíduos com menos de 30 anos e para análise de menção de DM, óbitos por causa básica (CB) não natural. A mortalidade foi analisada segundo causas da coorte especial e da base populacional. Os marcadores de qualidade do SIM na coorte foram a proporção de causas mencionadas de morte por DM e a proporção de CB mal definidas (MD) e, na base populacional, apenas o último. RESULTADOS: 38,0% dos indivíduos da coorte (n = 977) morreram nos quatro anos subsequentes à AMI devido ao DM, sendo que 49,1% desses no primeiro ano. As doenças endócrinas, nutricionais e metabólicas (41,5%), do aparelho circulatório (28,5%) e as causas MD (8,1%) foram as primeiras CB de morte. O DM foi mencionado 41,0% como CB, 1,6% como causa consequencial e 10,0% como contribuinte entre os óbitos pelas demais CB naturais nas declarações de óbito. Na base populacional, a mortalidade proporcional por causas MD foi 11,8% . CONCLUSÃO: O elevado risco de morte, o perfil de causas de morte e a sub-declaração do DM no atestado de óbito dos diabéticos tiveram resultados semelhantes aos de outros estudos de base populacional. A qualidade da certificação das causas de morte preenchidas nas declarações de óbito da coorte especial foi considerada ruim. É necessário um grande investimento para melhorar a qualidade da certificação das causas de mortes com o correto preenchimento do atestado de óbito pelos médicos e da codificação das causas de morte e seleção da CB pelos técnicos dos serviços de saúde. A metodologia desenvolvida neste estudo visando qualificar o SIM (relacionamento de base de dados e causas múltiplas de morte) mostrou-se efetiva e eficiente.
Desnutrição em crianças menores de 60 meses em dois municípios no Estado do Acre: prevalência e fatores associados
Authors: Souza Orivaldo Florencio de , Benício Maria Helena D'Aquino , Castro Teresa Gontijo de , Muniz Pascoal Torres , Cardoso Marly Augusto
Published: March 2012

OBJETIVO: Investigar a prevalência da desnutrição e fatores associados em crianças menores de 60 meses em dois municípios do Estado do Acre. MÉTODOS: Estudo transversal de base populacional realizado com 667 crianças da área urbana dos municípios de Acrelândia e Assis Brasil. A prevalência da desnutrição foi calculada pelo padrão de crescimento da Organização Mundial da Saúde de 2006, com o ponto de corte -2 escores Z. Informações sobre condições socioeconômicas, acesso aos serviços e cuidado da criança, peso ao nascer e morbidade foram obtidas por questionário estruturado. A regressão de Poisson foi utilizada para identificar os fatores associados à desnutrição de crianças. RESULTADOS: A prevalência do déficit estatura para idade e déficit peso para estatura foi de 9,9% e 4,1%, respectivamente. Os fatores associados ao déficit estatura para idade foram o baixo índice de riqueza (razão de prevalência [RP]: 1,74; intervalo de confiança em 95% [IC95%]: 0,95 - 3,18), analfabetismo do pai ou padrasto (RP: 1,82; IC95%: 1,01 - 3,27), ter 2 ou mais irmãos menores (RP: 2,88; IC95%: 1,45 - 5,72), ausência da mãe biológica no domicílio (RP: 2,63; IC95%: 1,32 - 5,24) e exposição ao esgoto a céu aberto no âmbito domiciliar (RP: 2,46; IC95%: 1,51 - 4,00). Somente o baixo peso ao nascer mostrou-se como fator associado ao déficit peso para estatura (RP: 2,91; IC95%: 1,16 - 7,24). CONCLUSÕES: Nos municípios estudados, a desnutrição em crianças menores de 60 meses apresenta-se como um importante problema de saúde pública, associado aos indicadores de iniquidades sociais, acesso aos serviços de saúde e ausência da mãe no domicílio.
Comparison of Microbial Changes in Early Redeveloping Biofilms on Natural Teeth and Dentures
Authors: Teles F.R. , Teles R.P. , Sachdeo A. , Uzel N.G. , Song X.Q. , Torresyap G. , Singh M. , Papas A. , Haffajee A.D. , Socransky S.S.
Published: March 2012

Background: Surfaces and fluids can affect oral bacterial colonization. The aim of this study is to compare redeveloping biofilms on natural teeth and dentures.

Methods: Supragingival plaque samples were taken from 55 dentate individuals and the denture teeth of 62 edentulous individuals before and after professional cleaning. Also, samples from seven “teeth” (samples included dentures) in randomly selected quadrants were collected after 1, 2, 4, and 7 days of no oral hygiene. Samples were analyzed using checkerboard DNA‐DNA hybridization. Counts and proportions of 41 bacterial taxa were determined at each time point, and significant differences were determined using the Mann‐Whitney U test. Ecological succession was determined using a modified moving window analysis.

Results: Mean total DNA probe counts were similar precleaning but were higher in dentate individuals at all post‐cleaning visits (P <0.01). Precleaning edentate biofilms had higher counts and proportions of Streptococcus mitis, Streptococcus oralis, and Streptococcus mutans, whereas dentate individuals had higher proportions of Tannerella forsythia, Selenomonas noxia, and Neisseria mucosa. By day 2, mean counts of all taxa were higher in natural teeth, and most remained higher at day 7 (P <0.01). Succession was more rapid and complex in dentate individuals. Both groups demonstrated increased proportions of S. mitis and S. oralis by day 1. N. mucosa, Veillonella parvula, and Eikenella corrodens increased in both groups, but later in samples from edentate individuals.

Conclusions: “Mature” natural and denture teeth biofilms have similar total numbers of bacteria but different species proportions. Post‐cleaning biofilm redevelopment is more rapid and more complex on natural teeth than on denture teeth.
A Racial Concern: Adrienne Kennedy's Diary of Lights
Authors: Young Harvey , Geigner Megan
Published: March 2012

This article emphasizes the representation of 1950s culture in Diary of Lights. It examines the artistic and cultural references made by the play's major characters, beginning with Billie and followed by Roy, Eddie, Aisha, Mohammed, Margo, Aaron, and Ellen, and chronicles how they expose the tensions inspired by racism and prejudice in an integrationist (or post-segregationist) period. It concludes with a discussion on how the play reimagines aspects of Kennedy's biography in order to more accurately capture the feel of living in the 1950s.
Electronic Cigarettes vs Varenicline for Smoking Cessation in Adults
Authors: Tuisku Anna , Rahkola Mikko , Nieminen Pentti , Toljamo Tuula
Published: June 2024

Importance

Little is known about the relative effectiveness of nicotine-containing electronic cigarettes (ECs) compared with varenicline as smoking cessation aids.

Objective

To determine the relative effectiveness of ECs in smoking cessation.

Design, Setting, and Participants

This randomized placebo-controlled single-center trial was conducted in northern Finland. Participants aged 25 to 75 years who smoked daily and had volunteered to quit smoking were recruited from August 1, 2018, to February 20, 2020, via local media. The trial included 52 weeks of follow-up. All data analyses were conducted from September 1, 2022, to January 15, 2024. The participants, study nurses, and researchers were masked to group assignment.

Intervention

The participants were assigned by block randomization to receive 18 mg/mL of nicotine-containing ECs together with placebo tablets, varenicline with standard dosing together with nicotine-free ECs, or placebo tablets together with nicotine-free ECs, all combined with a motivational interview, with the intervention phase lasting for 12 weeks.

Main Outcome and Measure

The primary outcome was self-reported 7-day conventional cigarette smoking abstinence as confirmed by the exhaled carbon monoxide level on week 26. The analysis followed the intent-to-treat principle.

Results

Of the 561 recruited participants, 458 (81.6%) eligible participants (257 women [56%]; 201 men [44%]; mean [SD] age, 51 [11.6] years) were randomized. The primary outcome occurred in 61 of 152 participants (40.4%) in the EC group, 67 of 153 (43.8%) in the varenicline group, and 30 of 153 (19.7%) in the placebo group (P < .001). In the pairwise comparison, placebo differed statistically significantly from ECs (risk difference [RD], 20.7%; 95% CI, 10.4-30.4; P < .001) and varenicline (RD, 24.1%; 95% CI, 13.7-33.7; P < .001), but the difference was statistically insignificant between ECs and varenicline (RD, 3.4%; 95% CI, −7.6 to 14.3; P = .56). No serious adverse events were reported.

Conclusions

This randomized clinical trial found that varenicline and nicotine-containing ECs were both effective in helping individuals in quitting smoking conventional cigarettes for up to 6 months.

Trial Registration

ClinicalTrials.gov Identifier: NCT03235505
Interfacial Electronic Modification of Nickel Phosphide via Iron Doping: An Efficient Bifunctional Catalyst for Water/Seawater Splitting
Authors: Muthurasu Alagan , Ko Tae Hoon , Kim Tae Woo , Chhetri Kisan , Kim Hak Yong
Published: June 2024

Seawater electrolysis is an innovative technique that can potentially transform hydrogen production and contribute to environmental redemption. However, the lack of good bifunctional electrocatalysts may hinder further development of this technology. Herein, nickel hydroxide nanosheets can be employed as a precursor to producing a 3D Prussian blue analogue (PBA) with a distinct dimensional structure. Nickel hydroxide nanosheets are formed within a nickel foam and undergo a reaction with potassium ferricyanide (K3[Fe(CN)6]). The nickel hydroxide structure is sheets‐like and well‐preserved, containing a multitude of PBA nanocubes. Following phosphidation at 350 °C, the iron‐doped nickel phosphide (Fe‐doped Ni2P (1.0 mM) nanosheets) demonstrates remarkable potential as a bifunctional electrocatalyst for total water/seawater splitting. This electrocatalyst demonstrates exceptional performance in overall water splitting, achieving current densities of 100 and 500 mA cm−2 in 1.0 M KOH at remarkably low voltages of 1.65 and 2.06 V, respectively. Additionally, its improved ability to resist corrosion and its hydrophilic surface makes it suitable for the seawater splitting process. The material can generate current densities of 100 to 500 mA cm−2 in seawater with 1.0 M KOH, resulting in voltages of 1.74 and 2.32 V. These outstanding results, together with its durability, indicate the material's strong potential for practical seawater electrolysis.
Scalable Nanoimprint Manufacturing of Functional Multilayer Metasurface Devices
Authors: Choi Shinhyuk , Zuo Jiawei , Das Nabasindhu , Yao Yu , Wang Chao
Published: June 2024

Optical metasurfaces, consisting of subwavelength‐scale meta‐atom arrays, hold great promise of overcoming the fundamental limitations of conventional optics. Due to their structural complexity, metasurfaces usually require high‐resolution yet slow and expensive fabrication processes. Here, using a metasurface polarimetric imaging device as an example, the photonic structures and the Nanoimprint lithography (NIL) processes are designed, creating two separate NIL molds over a patterning area of > 20 mm2 with designed Moiré alignment markers by electron‐beam writing, and further subsequently integrate silicon and aluminum metasurface structures on a chip. Uniquely, the silicon and aluminum metasurfaces are fabricated by using the nanolithography and 3D pattern‐transfer capabilities of NIL, respectively, achieving nanometer‐scale linewidth uniformity, sub‐200 nm translational overlay accuracy, and <0.017 rotational alignment error while significantly reducing fabrication complexity and surface roughness. The micro‐sized multilayer metasurfaces have high circular polarization extinction ratios as large as ≈20 and ≈80 in blue and red wavelengths. Further, the metasurface chip‐integrated CMOS imager demonstrates high accuracy in broad‐band, full Stokes parameter analysis in the visible wavelength ranges and single‐shot polarimetric imaging. This novel, NIL‐based, multilayered nanomanufacturing approach is applicable to the scalable production of large‐area functional structures for ultra‐compact optic, electronic, and quantum devices.
Electrochemical Leaching of Ni Dopants in IrRu Alloy Electrocatalyst Boosts Overall Water Splitting
Authors: Xie Yuhua , Feng Yumei , Pan Shuyuan , Bao Haifeng , Yu Yingjie , Luo Fang , Yang Zehui
Published: June 2024

The commercialization of water‐splitting technology strongly relies on the stable and high‐performance electrocatalyst for hydrogen and oxygen evolution reactions (HER‐OER). In this work, the nickel dopants in IrRu alloyed electrocatalyst for acidic water splitting activity are investigated. The incorporation of nickel dopants induces more oxygen atoms coordinating with Ir/Ru facilitating the formation of *OOH species via nucleophilic attack by H2O. Additionally, a fast surface reconstruction is achieved due to the electrochemical dissolution of Ni dopants; as a result, more oxygen species are incorporated, evidenced by in situ Raman spectroscopy and electrochemical impedance spectroscopy. Therefore, the mass activity for Ni@IrRu is enhanced by threefold than commercial IrO2 in acidic OER catalysis. Moreover, the nickel dopants balance the hydrogen binding strength; as a result, only 609 mV overpotential is demanded to reach 1 A cm−2 in acidic HER catalysis. The polymer electrolyte membrane water electrolyzer (PEMWE) test indicates only 1.87 V is required to attain 2 A cm−2, 160 mV lower than Pt/C‐IrO2 revealing its potential application in PEMWE.
Insight into the Interface Design for Li Metal Anode: Organic‐Rich or Inorganic‐Rich
Authors: Wang Yijia , Hou Hongyu , Tantratian Karnpiwat , Goncharova Lyudmila V. , Fu Bolin , Jin Enzhong , Pirayesh Parham , Abdolvand Hamid , Pang Xin , Chen Lei , Cao Changhong , Zhao Yang
Published: June 2024

Microcracks and surface heterogeneity in solid‐electrolyte interphase (SEI) induced by repeated plating/stripping of lithium (Li) metal exacerbate SEI fracture propagation and dendrite growth, which lead to unsatisfactory Coulombic efficiency and limited cycle life of Li metal anode. In this study, the hybrid artificial interfaces with controlled organic–inorganic ratios are designed and deep insight into their impacts on the electro‐chemo‐mechanical properties is obtained. The organic–inorganic ratios in the hybrid interfaces influence the mechanical properties, lithiophilicity, and diffusion kinetics of the interfaces, which in turn affect the nucleation, early growth, and repeated deposition/dissolution behavior of Li. It is found that increasing the inorganic ratio in the hybrid interface can realize significantly enhanced electrochemical performances. This work answers a key question for hybrid interfaces: should organic‐rich or inorganic‐rich be preferred in the hybrid interface? It is believed that this work will guide the future design of hybrid interfaces for Li metal anode and open up opportunities for the realization of next‐generation Li metal batteries.
Perspectives on the Practicability of Li‐Rich NMC Layered Oxide Cathodes
Authors: Li Biao , Zhang Kun , Yang Yali , Zuo Yuxuan , Li Xiang , Xia Dingguo
Published: June 2024

Li‐rich NMCs layered oxides, with the general formula of Li[LixNiyMnzCo1−x−y−z]O2, are known for their exceptionally high capacities but remain yet to be practicalized in the real world. They have attracted enormous research attention due to their complex structure and intriguing redox mechanisms, with a particular focus on anionic redox over the past decade. While fundamental understandings are fruitful, the practical considerations are emphasized here by providing perspectives on how Li‐rich NMCs are limited by practical roadblocks and guidelines on how to cope with these limitations. It is also demonstrated that, via a techno‐economic analysis, Li‐rich NMCs have material cost ($/kg) highly dependent on the lithium price, but still preserve the dominance of lower pack cost ($/kWh) than other cathode candidates principally owing to their larger material energy densities. In addition to their pure application in electric‐vehicle batteries, using them as “electrode additive” or “sacrificial agent” can further multiply their practicalities in assortment of scenarios, which is further discussed.
Epitaxial Growth of Large‐Area Monolayers and van der Waals Heterostructures of Transition‐Metal Chalcogenides via Assisted Nucleation
Authors: Rajan Akhil , Buchberger Sebastian , Edwards Brendan , Zivanovic Andela , Kushwaha Naina , Bigi Chiara , Nanao Yoshiko , Saika Bruno K. , Armitage Olivia R. , Wahl Peter , Couture Pierre , King Phil D. C.
Published: June 2024

The transition‐metal chalcogenides include some of the most important and ubiquitous families of 2D materials. They host an exceptional variety of electronic and collective states, which can in principle be readily tuned by combining different compounds in van der Waals heterostructures. Achieving this, however, presents a significant materials challenge. The highest quality heterostructures are usually fabricated by stacking layers exfoliated from bulk crystals, which – while producing excellent prototype devices – is time consuming, cannot be easily scaled, and can lead to significant complications for materials stability and contamination. Growth via the ultra‐high vacuum deposition technique of molecular‐beam epitaxy (MBE) should be a premier route for 2D heterostructure fabrication, but efforts to achieve this are complicated by non‐uniform layer coverage, unfavorable growth morphologies, and the presence of significant rotational disorder of the grown epilayer. This work demonstrates a dramatic enhancement in the quality of MBE grown 2D materials by exploiting simultaneous deposition of a sacrificial species from an electron‐beam evaporator during the growth. This approach dramatically enhances the nucleation of the desired epi‐layer, in turn enabling the synthesis of large‐area, uniform monolayers with enhanced quasiparticle lifetimes, and facilitating the growth of epitaxial van der Waals heterostructures.
Eliminating Hole Extraction Barrier in 1D/3D Perovskite Heterojunction for Efficient and Stable Carbon‐Based CsPbI3 Solar Cells with a Record Efficiency
Authors: Lin Jiage , Huang Rong , Peng Xin , Zhang Jianxin , Zhang Guizhi , Wang Wenran , Pan Zhenxiao , Rao Huashang , Zhong Xinhua
Published: June 2024

Carbon‐based perovskite solar cells (C‐PSCs) have the advantages of low‐cost and high‐stability, but their photovoltaic performance is limited by severe defect‐induced recombination and low hole extraction efficiency. 1D perovskite is proven to effectively passivate the defects on the perovskite surface, therefore reducing non‐radiative recombination loss. However, the unsuitable energy level of most 1D perovskite renders an undesired downward band bending for 3D perovskite, resulting in a high hole extraction barrier and reduced hole extraction efficiency. Therefore, rational design and selection of 1D perovskites as the modifiers are essential in balancing defect passivation and hole extraction. In this work, based on simulation calculations, thiocholine iodide (TchI) is selected to prepare 1D perovskite with high work function and then constructs TchPbI3/CsPbI3 1D/3D perovskite heterojunction. Experimental results show that this strategy eliminates the hole extraction barrier at the perovskite/carbon interface, which improves the hole extraction efficiency of corresponding devices. Meanwhile, the strong interaction between the thiol group and Pb suppresses defect‐induced recombination effectively and improves the stability of CsPbI3. The assembled C‐PSCs exhibit a champion efficiency of 19.08% and a certified efficiency of 18.7%. To the best of the knowledge, this is a new efficiency record for inorganic C‐PSCs.
Robust Deep UV Photodetectors Based on One‐Step‐Grown Polycrystalline Ga2O3 Film via Pulsed Laser Deposition toward Extreme‐Environment Application
Authors: Huang Hong , Yin Haoran , Han Keju , Wang Yilin , Wang Zhiwei , Feng Xiao , Zou Yanni , Zhou Xuanze , Xu Guangwei , Hou Xiaohu , Zhao Xiaolong , Long Shibing
Published: June 2024

Gallium oxide (Ga2O3), with an ultrawide bandgap corresponding to the deep ultraviolet (DUV) range, has attracted significant attention in optical filter‐free photodetectors. In practical terms, DUV photodetectors employed in extreme conditions, for example, flame detection and space exploration, face the challenges of performance degradation caused by high/low‐temperature transformation. Here, DUV photodetectors are tailored with high durability and stability by one‐step‐grown β‐Ga2O3 films via pulsed laser deposition. A high‐oxygen‐pressure scheme effectively addresses the issue of film‐free deposition at specifically high temperatures, facilitating the formation of polycrystalline high‐resistivity β‐Ga2O3 films. As a result, the devices exhibit outstanding performance, including a low dark current (4.4 pA @30 V), high photoresponsivity (147.36 A W−1), and fast response time (3.1/22.6 ms). Additionally, the photoresponse performance shows minimal degradation at high temperatures up to 300 °C and even improves at low temperatures down to −100 °C, ranking it among the most robust DUV photodetectors. The mechanism of photoresponse, involving the exciton formation, bandgap evolution, carrier‐phonon scatter, etc., is also elucidated in a wide temperature range. This work provides an efficient solution for developing robust Ga2O3 DUV photodetectors with excellent performance for extreme‐condition applications.
Plasmon‐Enhanced Optical Control of Magnetism at the Nanoscale via the Inverse Faraday Effect
Authors: Parchenko Sergii , Hofhuis Kevin , Larsson Agne Åberg , Kapaklis Vassilios , Scagnoli Valerio , Heyderman Laura Jane , Kleibert Armin
Published: June 2024

The relationship between magnetization and light has been the subject of intensive research for the past century. Herein, the impact of magnetization on light polarization is well understood. Conversely, the manipulation of magnetism with polarized light is being investigated to achieve all‐optical control of magnetism, driven by potential technological implementation in spintronics. Remarkable discoveries, such as the single‐pulse all‐optical switching of magnetization in thin films and submicrometer structures, have been reported. However, the demonstration of local optical control of magnetism at the nanoscale has remained elusive. Herein, it is demonstrated that exciting gold nanodiscs with circularly polarized femtosecond laser pulses lead to ultrafast, local, and deterministic control of magnetization in an adjacent magnetic film. This control is achieved by exploiting the magnetic moment generated in plasmonic nanodiscs through the inverse Faraday effect. The results pave the way for light‐driven control in nanoscale spintronic devices and provide important insights into the generation of magnetic fields in plasmonic nanostructures.
Electrochemical Surface Plasmon Resonance Sensing using a van der Waals Heterostructure
Authors: Jungnickel Robert , Balasubramanian Kannan
Published: June 2024

Coupling surface plasmon resonance (SPR) sensing with electrochemistry (EC) is a promising analytical strategy to obtain information about interfacial phenomena in heterogeneous reactions. Typical EC‐SPR sensors utilize a metal film both as the plasmonic material and as the working electrode. In this configuration, the eigenmodulation of the plasmonic properties of the metal film under applied potential results in a background signal, which hampers the unambiguous interpretation of the sensor response due to redox reactions. Here, a new strategy is presented to overcome this disadvantage by using a van der Waals heterostructure (vdW‐HS) as the working electrode. The vdW‐HS comprises of a graphene / hexagonal boron nitride (hBN) stack on a gold film of a standard SPR sensor. It is shown here that the background signal is completely suppressed enabling the unambiguous analysis of SPR sensor response due to electrochemical reactions. It is further observed that the potential dependent plasmonic signals are not just a reproduction of the electrochemical current and subtle differences can be traced back to the diffusive nature of the redox active species. Finally, it is demonstrated that EC‐SPR can be used as a complementary method to distinguish if the electrochemical response is mainly surface‐bound or due to diffusion.
Rapid Conductometric Sensing of Chronic Kidney Disease Biomarkers: Specific and Precise Detection of Creatinine and Cystatin C in Artificial Saliva
Authors: Yang Mingjie , Perera Ganganath , Dhanabalan Shanmuga Sundar , Mahasivam Sanje , Dong Dashen , Cheong Ying Zhi , Xu Chenglong , Elango Peter Francis Mathew , Borkhatariya Sagar , Sriram Sharath , Bhaskaran Madhu
Published: June 2024

Chronic kidney disease (CKD) has asymptomatic early stages, whereby early detection is crucial to prevent its complications and progression. Creatinine and cystatin C (cysC) assays are known for assessing kidney function but there are limited point‐of‐care diagnostics which are rapid, precise, and easy to use. Here, high resistivity silicon conductometric sensors for detection of creatinine and cysC with a 10 min sample incubation is introduced. The sensors provide resistance‐based signals that can be quantified and measured wirelessly. The sensors successfully detect creatinine and cysC in both phosphate buffer saline (PBS) and artificial saliva in the nanomolar range, being able to distinguish their critical concentrations at 8.8 and 20 nm, respectively, for diagnosis of early stage of CKD. The detection limit for both creatinine and cysC is determined as 0.01 nm which is more than 500× and 1000× times lower than critical concentrations for the two biomarkers, respectively. Finally, these sensors are incorporated into a battery‐free, miniaturized electronic device for wireless biomarker detection as a proof‐of‐concept demonstration of a point‐of‐care tool for assessing kidney functionality.