bluuebunny/crossref_metadata_2025 huggingface dataset:
Eruption Guidance of Distally Displaced Mandibular Second Premolar by the Hemisection of Primary Second Molar: Two Case Reports
Authors: Shin Yongwook , Park Howon , Lee Juhyun
Published: August 2022

Distal displacement of the tooth germ of the mandibular second premolar (MnP2) leads to its impaction and obturation of the eruption path of the mandibular first molar delaying its eruption. The present case report describes the treatment of 2 cases of eruption guidance for distally displaced developing MnP2 that caused delayed eruption of the mandibular first molar. Intentional extraction of primary predecessor results in the mesial shift of the displaced MnP2. However, unfavorable distal ectopic eruption of the mandibular first premolar after the premature loss of primary second molar has been previously reported. Hemisection and sequential extraction of the mandibular primary second molar were performed to mesially shift the distally displaced MnP2, while preventing unfavorable distal ectopic eruption of the mandibular first premolar.
Clinical Management and Micro-Computed Tomography Analysis of Supernumerary Teeth in Infancy: A Case Report
Authors: Na Chaehyun , Lee Hana , Kim Hansung , Kim Jihun
Published: August 2022

Supernumerary teeth develop from excessive proliferation and development of the dental lamina. Supernumerary teeth can cause several problems, including ectopic eruption, delayed eruption, root resorption of adjacent teeth, and diastema. Supernumerary teeth in infancy are rare and have rarely been reported. Case of a 2-day-old infant with 3 supernumerary teeth is presented here and the patient was followed up for 21 months. The erupted supernumerary tooth in the primary dentition was extracted under moderate sedation at the age of 14 months. Microcomputed tomography analysis of the extracted tooth confirmed microscopic root malformation. After extraction, the midline diastema was reduced and oral hygiene improved. Early diagnosis and prompt treatment can prevent complications of supernumerary teeth.
Tensile properties and damage mechanism of diamondene with boundary cracks
Authors: Zhang Zi-Xu , Wang Lei ,   College of Mechanics and Materials, Hohai University, Nanjing 211100, China
Published: August 2022

Diamondene has received the attention of scientists recently because of its brilliant physical properties. But, owing to the limitations of current technology, defects are indispensable during the production of diamondene. In this work, the effect of boundary cracks on the tensile properties and damage mechanism of diamondene are investigated by using molecular dynamics method. The results show that the crack leads the tensile properties of diamondene to be weakened, and the elastic modulus, cracking strain, and cracking stress of diamondene containing a boundary crack to become less than those of diamondene without cracks. As for the failure mode, the damage of crack-free diamondene starts near the mobile end, while the damage of diamondene with a boundary crack starts at the crack tip. After the cracking strain has been reached, the crack will form a penetration rupture without further loading and the crack-free diamondene completely loses its load-bearing capacity. However, in diamondene with a boundary crack, the load still needs adding, and the crack will form a penetration crack after the cracking strain has been reached through several extensions. Furthermore, the tensile properties of diamondene with a boundary crackare strongly dependent on temperature, and decrease significantly when the temperature increases. Changes in the location, length and direction of cracks can cause the tensile properties and damage mechanism of the crack-containing diamondene to change.
Treatment of Ingrown Toenail with a Minimally Invasive Nail Fixator: Comparative Study with Winograd Technique
Authors: Ergün Tuğrul , Korkmaz Mehmet , Ergün Dilan , Turan Kaya , Muratoğlu Osman Görkem , Cabuk Haluk
Published: August 2022

Background: Many surgical techniques have been reported for treatment of ingrown toenails. Occurrence of infection after matricectomy procedures could cause clinicians to prefer using external braces in the treatment of ingrown toenails. This study compares patients with ingrown toenails who underwent the nail fixation technique and the Winograd technique.

Methods: Patients who underwent ingrown toenail surgery were reviewed retrospectively. The patients’ demographic characteristics (ie, age, gender, body mass index morphology according to Heifetz classification, surgical technique, visual analogue scale values, time to return to daily activities [days], complications, and satisfaction levels) were all recorded.

Results: Seventy patients were included in the study. Of the patients, 33 underwent nail fixation and 37 underwent the Winograd technique. No significant statistical differences were found in terms of patients’ age, gender, body mass index, preoperative clinical features, long-term satisfaction, and ingrown toenail recurrence rates between the two groups, but time to return to daily activities and visual analogue scale values were statistically significantly lower in patients treated using nail fixation compared with the Winograd technique.

Conclusions: Nail fixation can be an effective surgical treatment option for ingrown toenail.
Non-canonical function of an Hif-1α splice variant contributes to the sustained flight of locusts
Authors: Ding Ding , Zhang Jie , Du Baozhen , Wang Xuanzhao , Hou Li , Guo Siyuan , Chen Bing , Kang Le
Published: August 2022

The hypoxia inducible factor (Hif) pathway is functionally conserved across metazoans in modulating cellular adaptations to hypoxia. However, the functions of this pathway under aerobic physiological conditions are rarely investigated. Here, we show that Hif-1α2, a locust Hif-1α isoform, does not induce canonical hypoxic responses but functions as a specific regulator of locust flight, which is a completely aerobic physiological process. Two Hif-1α splice variants were identified in locusts, a ubiquitously expressed Hif-1α1 and a muscle-predominantly expressed Hif-1α2. Hif-1α1 that induces typical hypoxic responses upon hypoxia exposure remains inactive during flight. By contrast, the expression of Hif-1α2, which lacks C-terminal transactivation domain, is less sensitive to oxygen tension but induced extensively by flying. Hif-1α2 regulates physiological processes involved in glucose metabolism and antioxidation during flight and sustains flight endurance by maintaining redox homeostasis through upregulating the production of a reactive oxygen species (ROS) quencher, DJ-1. Overall, this study reveals a novel Hif-mediated mechanism underlying prolonged aerobic physiological activity.
Uncovering natural variation in root system architecture and growth dynamics using a robotics-assisted phenomics platform
Authors: LaRue Therese , Lindner Heike , Srinivas Ankit , Exposito-Alonso Moises , Lobet Guillaume , Dinneny José R
Published: August 2022

The plant kingdom contains a stunning array of complex morphologies easily observed above-ground, but more challenging to visualize below-ground. Understanding the magnitude of diversity in root distribution within the soil, termed root system architecture (RSA), is fundamental in determining how this trait contributes to species adaptation in local environments. Roots are the interface between the soil environment and the shoot system and therefore play a key role in anchorage, resource uptake, and stress resilience. Previously, we presented the GLO-Roots (Growth and Luminescence Observatory for Roots) system to study the RSA of soil-grown Arabidopsis thaliana plants from germination to maturity (Rellán-Álvarez et al., 2015). In this study, we present the automation of GLO-Roots using robotics and the development of image analysis pipelines in order to examine the temporal dynamic regulation of RSA and the broader natural variation of RSA in Arabidopsis, over time. These datasets describe the developmental dynamics of two independent panels of accessions and reveal highly complex and polygenic RSA traits that show significant correlation with climate variables of the accessions’ respective origins.
The scaffolding protein flot2 promotes cytoneme-based transport of wnt3 in gastric cancer
Authors: Routledge Daniel , Rogers Sally , Ono Yosuke , Brunt Lucy , Meniel Valerie , Tornillo Giusy , Ashktorab Hassan , Phesse Toby J , Scholpp Steffen
Published: August 2022

The Wnt/β-catenin signalling pathway regulates multiple cellular processes during development and many diseases, including cell proliferation, migration, and differentiation. Despite their hydrophobic nature, Wnt proteins exert their function over long distances to induce paracrine signalling. Recent studies have identified several factors involved in Wnt secretion; however, our understanding of how Wnt ligands are transported between cells to interact with their cognate receptors is still debated. Here, we demonstrate that gastric cancer cells utilise cytonemes to transport Wnt3 intercellularly to promote proliferation and cell survival. Furthermore, we identify the membrane-bound scaffolding protein Flotillin-2 (Flot2), frequently overexpressed in gastric cancer, as a modulator of these cytonemes. Together with the Wnt co-receptor and cytoneme initiator Ror2, Flot2 determines the number and length of Wnt3 cytonemes in gastric cancer. Finally, we show that Flotillins are also necessary for Wnt8a cytonemes during zebrafish embryogenesis, suggesting a conserved mechanism for Flotillin-mediated Wnt transport on cytonemes in development and disease.
Fast, high-throughput production of improved rabies viral vectors for specific, efficient and versatile transsynaptic retrograde labeling
Authors: Sumser Anton , Joesch Maximilian , Jonas Peter , Ben-Simon Yoav
Published: August 2022

To understand the function of neuronal circuits, it is crucial to disentangle the connectivity patterns within the network. However, most tools currently used to explore connectivity have low throughput, low selectivity, or limited accessibility. Here, we report the development of an improved packaging system for the production of the highly neurotropic RVdGenvA-CVS-N2c rabies viral vectors, yielding titers orders of magnitude higher with no background contamination, at a fraction of the production time, while preserving the efficiency of transsynaptic labeling. Along with the production pipeline, we developed suites of ‘starter’ AAV and bicistronic RVdG-CVS-N2c vectors, enabling retrograde labeling from a wide range of neuronal populations, tailored for diverse experimental requirements. We demonstrate the power and flexibility of the new system by uncovering hidden local and distal inhibitory connections in the mouse hippocampal formation and by imaging the functional properties of a cortical microcircuit across weeks. Our novel production pipeline provides a convenient approach to generate new rabies vectors, while our toolkit flexibly and efficiently expands the current capacity to label, manipulate and image the neuronal activity of interconnected neuronal circuits in vitro and in vivo.
Robust cone-mediated signaling persists late into rod photoreceptor degeneration
Authors: Scalabrino Miranda L , Thapa Mishek , Chew Lindsey A , Zhang Esther , Xu Jason , Sampath Alapakkam P , Chen Jeannie , Field Greg D
Published: August 2022

Rod photoreceptor degeneration causes deterioration in the morphology and physiology of cone photoreceptors along with changes in retinal circuits. These changes could diminish visual signaling at cone-mediated light levels, thereby limiting the efficacy of treatments such as gene therapy for rescuing normal, cone-mediated vision. However, the impact of progressive rod death on cone-mediated signaling remains unclear. To investigate the fidelity of retinal ganglion cell (RGC) signaling throughout disease progression, we used a mouse model of rod degeneration (Cngb1neo/neo). Despite clear deterioration of cone morphology with rod death, cone-mediated signaling among RGCs remained surprisingly robust: spatiotemporal receptive fields changed little and the mutual information between stimuli and spiking responses was relatively constant. This relative stability held until nearly all rods had died and cones had completely lost well-formed outer segments. Interestingly, RGC information rates were higher and more stable for natural movies than checkerboard noise as degeneration progressed. The main change in RGC responses with photoreceptor degeneration was a decrease in response gain. These results suggest that gene therapies for rod degenerative diseases are likely to prolong cone-mediated vision even if there are changes to cone morphology and density.
Hypoxia-inducible factor underlies von Hippel-Lindau disease stigmata
Authors: Ohh Michael , Taber Cassandra C , Ferens Fraser G , Tarade Daniel
Published: August 2022

von Hippel-Lindau (VHL) disease is a rare hereditary cancer syndrome that causes a predisposition to renal clear-cell carcinoma, hemangioblastoma, pheochromocytoma, and autosomal-recessive familial polycythemia. pVHL is the substrate conferring subunit of an E3 ubiquitin ligase complex that binds to the three hypoxia-inducible factor alpha subunits (HIF1-3α) for polyubiquitylation under conditions of normoxia, targeting them for immediate degradation by the proteasome. Certain mutations in pVHL have been determined to be causative of VHL disease through the disruption of HIFα degradation. However, it remains a focus of investigation and debate whether the disruption of HIFα degradation alone is sufficient to explain the complex genotype-phenotype relationship of VHL disease or whether the other lesser or yet characterized substrates and functions of pVHL impact the development of the VHL disease stigmata; the elucidation of which would have a significant ramification to the direction of research efforts and future management and care of VHL patients and for those manifesting sporadic counterparts of VHL disease. Here, we examine the current literature including the other emergent pseudohypoxic diseases and propose that the VHL disease-phenotypic spectrum could be explained solely by the varied disruption of HIFα signaling upon the loss or mutation in pVHL.
Be aware of the allele-specific bias and compositional effects in multi-template PCR
Authors: Korvigo Ilia , Igolkina Anna A. , Kichko Arina A. , Aksenova Tatiana , Andronov Evgeny E.
Published: August 2022

High-throughput sequencing of amplicon libraries is the most widespread and one of the most effective ways to study the taxonomic structure of microbial communities, even despite growing accessibility of whole metagenome sequencing. Due to the targeted amplification, the method provides unparalleled resolution of communities, but at the same time perturbs initial community structure thereby reducing data robustness and compromising downstream analyses. Experimental research of the perturbations is largely limited to comparative studies on different PCR protocols without considering other sources of experimental variation related to characteristics of the initial microbial composition itself. Here we analyse these sources and demonstrate how dramatically they effect the relative abundances of taxa during the PCR cycles. We developed the mathematical model of the PCR amplification assuming the heterogeneity of amplification efficiencies and considering the compositional nature of data. We designed the experiment—five consecutive amplicon cycles (22–26) with 12 replicates for one real human stool microbial sample—and estimated the dynamics of the microbial community in line with the model. We found the high heterogeneity in amplicon efficiencies of taxa that leads to the non-linear and substantial (up to fivefold) changes in relative abundances during PCR. The analysis of possible sources of heterogeneity revealed the significant association between amplicon efficiencies and the energy of secondary structures of the DNA templates. The result of our work highlights non-trivial changes in the dynamics of real-life microbial communities due to their compositional nature. Obtained effects are specific not only for amplicon libraries, but also for any studies of metagenome dynamics.
Academic Integrity for All: Building Better Professionals: Chiropractic Educators Research Forum (CERF), June 25, 2022
Authors:   Chiropractic Educators Research Forum
Published: August 2022

This conference was convened by the Chiropractic Educators Research Forum (CERF) on June 25, 2022. This meeting provided a forum for the presentation of scholarly works in education theory and practice. This conference specifically focused on research related to academic integrity and professionalism. During the June 2022 CERF meeting, presenters and panelists took an in-depth look at how chiropractic programs work to address academic integrity.
Semidefinite perturbations in the subspace perturbation problem
Authors:   Fakultaet fuer Mathematik, Technische Universitaet Dortmund, Dortmund, D-44221, Germany, Seelmann Albrecht
Published: August 2022

The variation of spectral subspaces for linear self-adjoint operators under an additive bounded semidefinite perturbation is considered. A variant of the Davis-Kahan sin2Θ theorem adapted to this situation is proved. Under a certain additional geometric assumption on the separation of the spectrum of the unperturbed operator, this leads to a sharp estimate on the norm of the difference of the spectral projections associated with isolated components of the spectrum of the perturbed and unperturbed operators, respectively. Without this additional geometric assumption on the isolated components of the spectrum of the unperturbed operator, a corresponding estimate is obtained by transferring a known optimization approach for general perturbations to the present situation.
Lp-operator algebras associated with oriented graphs
Authors:   Departamento de Matematica-Instituto Santalo, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires Ciudad Universitaria (1428) Buenos Aires, Argentina, Cortinas Guillermo , Rodriguez Maria Eugenia ,   Departamento de Ciencias Exactas, Ciclo Basico Comun, Universidad de Buenos Aires, Ciudad Universitaria, (1428) Buenos Aires, Argentina
Published: August 2022

For each 1⩽p<∞ and each countable oriented graph Q we introduce an Lp-operator algebra Op(Q), which contains the Leavitt path C-algebra LQ as a dense subalgebra, and is universal for those Lp-representations of LQ which are spatial in the sense of N.C. Phillips. We prove that Op(Q) is simple as an Lp-operator algebra if and only if LQ is simple, in which case it is isometrically isomorphic to ¯¯¯¯¯¯¯¯¯¯¯¯¯¯ρ(LQ) for any nonzero spatial Lp-representation ρ:LQ→L(Lp(X)). If moreover LQ is purely infinite simple and p≠p′, then there is no nonzero continuous homomorphism Op(Q)→Op′(Q).
Realization of rigid C∗-tensor categories via Tomita bimodules
Authors:   Dipartimento di Matematica, Universita di Roma Tor Vergata, Via della Ricerca Scientifica, 1, Roma, I-00133, Italy and Dipartimento di Matematica ``Guido Castelnuovo'', Sapienza Universita di Roma, Piazzale Aldo Moro, 5, Roma, I-00185, Italy, Giorgetti Luca , Yuan Wei ,   Institute of Mathematics, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing, 100190, China \textit{and} School of Mathematical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
Published: August 2022

Starting from a (small) rigid C∗-tensor category C with simple unit, we construct von Neumann algebras. These algebras are factors of type II or IIIλ,λ∈(0,1]. The choice of type is tuned by the choice of Tomita structure (defined in the paper) on certain bimodules we use in the construction. If the spectrum is infinite we realize the whole tensor category as endomorphisms of these algebras. Furthermore, if the Tomita structure is trivial, the algebras that we get are an amplification of the free group factors with infinitely (possibly uncountably) many generators.
Functorial properties of Extu(⋅,B) when B is simple with continuous scale
Authors:   Department of Mathematics, Univ. of Louisiana at Lafayette, P. O. Box 43568, Lafayette, LA, 70504-3568, U.S.A., Ng P.W. , Robin Tracy ,   Department of Mathematics, Prairie View A & M University, P. O. Box 519 -- Mailstop 2225, Prairie View, TX, 77446-0519, U.S.A.
Published: August 2022

In this note we define two functors Ext and Extu which capture unitary equivalence classes of extensions in a manner which is finer than KK1. We prove that for every separable nuclear C∗-algebra A, and for every σ-unital nonunital simple continuous scale C∗-algebra B, Ext(A,B) is an abelian group. We have a similar result for Extu. We study some functorial properties of the covariant functor X↦Extu(C(X),B), where X ranges over the category of compact metric spaces.
Screening, lipA Gene Amplification and Molecular Identification of Lipolytic Fungi from Contaminated Soils
Authors: E. Akinduyite A. , O. Abu G. , K. Agwa O.
Published: August 2022

Lipase is a glycerol ester hydrolase that hydrolyzes esters of triglycerides. This study aimed to isolate, screen and characterize lipolytic fungi with lipA gene from soil environments. Fungi [molds and yeasts] were isolated from contaminated soil samples randomly collected from Palm oil mills, Abattoirs and Automobile servicing workshops in Eleme and Obio Akpor local governments in Rivers State, Nigeria using standard microbiological techniques. Qualitative Lipase screening assay was carried out on the fungal isolates through gel diffusion assay using Tributryin, Tween 80 and Olive oil respectively. Isolates with maximum zones of clearance were selected and screened for Lipase gene for hydrolysis of triacylglyceride [lipA gene] through Lipase gene amplification and were identified by Internal Transcribed Spacer characterization.

A total of 96 fungal isolates were obtained, lipolytic screening showed 57 lipolytic strains in which 21 lipolytic fungal strains were screened from contaminated soil from palm oil mills, 17 lipolytic strains from abattoirs and 19 lipolytic strains from automobile workshops respectively. Seven isolates with maximum zones of clearance showed lipA gene in their genomic DNA and were identified as Candida orthopsilosis PMS3 [Accession No: OL546803], Fusarium proliferatum PMS4 [Accession No: OL546804], Saccharomyces cerevisiae PMS8 [Accession No: OL546805], Penicillium paxilli ABS8 [Accession No: OL546799], Pichia kudriavzevii ENS1 [Accession No: OL546800] Aspergillus niger ENS3 [Accession No: OL546801] and Trichoderma viride ENS5 [Accession No: OL546802].

This study showed that soil fungi are potential producers of biotechnologically important lipase with diverse industrial applications.
A GESTÃO DO TRABALHO NA INDÚSTRIA PETROQUÍMICA (A FORMA GERAL E A VARIANTE PATERNALISTA)
Authors: Guimarães Antônio Sérgio Alfredo
Published: August 2022

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BLOCOS NEGROS EM SALVADOR: reelaboração cultural e símbolos de baianidade
Authors: Morales Anamaria
Published: August 2022

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REPRODUÇÃO SOCIAL E REPRODUÇÃO DA FORÇA DE TRABALHO: REFLEXÕES TEÓRICAS PARA O ESTUDO DO TEMA
Authors: De Oliveira Orlandina , Salles Vânia
Published: August 2022

O texto sistematiza contribuições teóricas recentes sobre os processos de reprodução social a fim de delinear um marco de referência para a formulação de linhas de pesquisa no campo dos estudos da reprodução da força de trabalho. Para tanto revisa, em sua primeira parte, alguns dos elementos constitutivos dos processos de reprodução da sociedade na teoria sociológica contemporânea; na segunda parte, examina a literatura socio-demográfica, retomando aspectos conceituais pertinentes ao estudo da reprodução da população e da força de trabalho; na parte final, propõe linhas de investigação para uma abordagem ao estudo do papel dos indivíduos e das famílias na reprodução da força de trabalho.Publicação Online do Caderno CRH:http://www.cadernocrh.ufba.br
SINDICALISMO METALÚRGICO: MESMAS CENAS EM OUTROS CENÁRIOS ?
Authors: Castro Nadya Araujo
Published: August 2022

Uma curiosa sincronia de tempos e movimentos aproxima o sindicalismo metalúrgico baiano do paulista. Isto parece contrariar certa interpretação corrente sobre os efeitos desmobilizadores de fatores como a precária configuração do mercado de trabalho, a resistência cultural do patronato e a fragilidade histórica da ação sindical nas áreas de expansão da indústria no Brasil. Para discutir essa hipótese o texto analisa o movimento sindical metalúrgico na Bahia, destacando três dimensões principais: (i) as características e transformações do parque produtivo, (ii) a trajetória da ação sindical local e (iii) a natureza da ação patronal. Publicação Online do Caderno CRH:http://www.cadernocrh.ufba.br
TRABALHO E SAÚDE NO PÓLO INDUSTRIAL DE CAMAÇARI
Authors: Franco Tânia
Published: August 2022

O II Pólo Petroquímico brasileiro apresenta um quadro de saúde do trabalhador aparentemente assincrônico com o seu avançado e dinâmico patamar tecnológico. O texto focaliza este fato, reconhecendo a inserção do pólo no processo internacional de transferência de tecnologia e a redefinição dos riscos industriais pelas políticas locais de gestão da produção e do trabalho. The Petrochemical Complex of Camaçari II presents a picture of workers' health conditions apparently incompatible with its advanced and dynamic technological standards. The article focuses on this fact, pointing out the industry's insertion in the internacional process of technology transfer, and the redefinition of industrial risks produced by the local policies of production and work management. Publicação Online do Caderno CRH:http://www.cadernocrh.ufba.br
MARX, INDIVÍDUO E SUBJETIVIDADE
Authors: De Souza José Crisóstomo
Published: August 2022

Apesar de sua suposta ruptura com "toda a filosofia anterior", em 1845, a nova concepção da história de Marx é aqui mostrada como embasando- se numa "tradução" espinozeana de Hegel, numa variedade de monismo materialista. Tal concepção, malgrado suas alegadas premissas puramente empíricas, e não obstante as promessas que a passagem ao "reino da liberdade" abriga, implica numa forte redução das prerrogativas do indivíduo realmente existente, e de sua subjetividade, uma redução selada pela teoria marxiana da consciência, mostrada aqui como potencialmente desqualificadora de toda negatividade subjetiva. Notwithstanding his supposed break with "all the preceding philosophy", in 1845 Marx's new conception of history is showm here to be based upon a spinozean 'translation" of Hegel, a variety of materialist monism. That conception, in spite of its alleged empirical foundation, and of all the promises that the passage to the "kingdom of liberty" entails, implies a strong reduction of the prerogatives of the actually existing individual and of his subjectivity, a reduction sealed by Marx's theory of conciousness, here shown as potentially disqualifying all subjective negativity. Publicação Online do Caderno CRH:http://www.cadernocrh.ufba.br
TRÊS DEBATES EXEMPLARES SOBRE QUESTÕES AGRÁRIAS NA AMÉRICA LATINA
Authors: Rivière d'Arc Hélène
Published: August 2022

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A SOCIEDADE DOS FATOS CONSUMADOS (Ação Direta, Movimentos Sociais e Cidadania)
Authors: De Carvalho Inaiá Maria Moreia , Laniado Ruthy Nadia
Published: August 2022

Identificando uma nova recorrência e um novo significado das ações diretas coletivas no Brasil atual, este texto analisa os seus determinantes e as suas diferentes modalidades. Mostra, também, como tais mobilizações são marcadas por ambivalências e paradoxos e constituem um recurso estratégico para seus participantes, criando fatos consumados que buscam impor suas insatisfações e suas demandas aos sistemas de controle do poder, dos bens e dos símbolos sociais. Today in Brazil a new meaning can be identified in the occurrence of direct collective action. This article discusses their causes and different modalities as well as their ambivalent and paradoxal characteristics. In fact, these mobilizations form a strategy of collective action by creating "faits accomplis" which contest the systems that control power, goods and social symbols. Publicação Online do Caderno CRH:http://www.cadernocrh.ufba.br
Riscos Industriais: de Desafio a Instrumento de Opressão
Authors: Franco Tânia , Rego Marco A. , Aquino Rosana , Franco Angela , Borges Angela , Druck Graça
Published: August 2022

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Protein synthesis in collagen lattice‐cultured fibroblasts is controlled at the ribosomal level
Authors: Gillery Philippe , Georges Nadine , Wegrowski Janusz , Randoux Alain , Borel Jacques-Paul
Published: July 2002

Fibroblasts cultivated in three‐dimensional lattices exhibit a large decrease of protein synthesis, mainly through transcriptional control. However, no previous work was devoted to a potential ribosomal regulation. We evaluated ribosomal ribonucleic acid (RNA) in monolayer‐ and collagen lattice‐cultured fibroblasts. After one week of culture, total RNA was 60% lower in lattice‐cultured fibroblasts than in monolayer‐cultured cells. The decrease was identical for 18 S and 28 S rRNA subfractions. The half‐life of RNA was much shorter in collagen lattice‐cultured fibroblasts than in monolayers. These results suggest that protein synthesis in lattice‐cultured fibroblasts is partly regulated at the ribosomal level.
Cloning and controlled overexpression of the gene encoding the 35 kDa soluble lytic transglycosylase from Escherichia coli
Authors: Dijkstra Arnoud J. , Hermann Francis , Keck Wolfgang
Published: July 2002

The lytic transglycosylases of Escherichia coli are involved in peptidoglycan metabolism and resemble the lysozymes not only in activity, but in the case of the 70 kDa soluble lytic transglycosylase (Slt70), also structurally. Here we report the cloning of the gene that encodes the 35 kDa soluble lytic transglycosylase (Slt35) of E. coli. Based on the sequence of the full‐length gene, Slt35 is very likely to be a proteolytically truncated form of a slightly large protein. The homology between Slt35 and Slt70, albelt poor, indicates that the active site architecture of both proteins may be alike. Using the T‐7 promoter system, Slt35 was overproduced in large quantities and purified to homogeneity for crystallographic purposes.
The presence of a hydroxyl group at the C‐1 atom of the transketolase substrate molecule is necessary for the enzyme to perform the transferase reaction
Authors: Meshalkina L.E , Neef H , Tjaglo M.V , Schellenberger A , Kochetov G.A
Published: July 2002

Transketolase catalyzes the transfer of an aldehyde residue from keto sugars to aldo sugars. The intermediate product is dihydroxyethylthiamine pyrophosphate (DHETPP). In the absence of an acceptor substrate, the reaction is stopped at this stage and DHETPP does not undergo subsequent transformations. Pyruvate decarboxylase catalyses pyruvate decarboxylation to yield free aldehyde. The intermediate product is hydroxyethylthiamine pyrophosphate (HETPP). It differs from DHETPP only in that it has no hydroxyl at the C‐2 atom of the aldehyde residue. We have shown that transketolase can bind HETPP and split the aldehyde residue from it. This fact suggests that the path of the reaction is determined by the absence (in HETPP) or presence (in DHETPP) of a hydroxyl group. In the former case the reaction will yield free aldehyde, in the latter the aldehyde residue will be transferred onto an acceptor substrate.
Identification of the Drosophila melanogaster homologue of the mammalian signal transducer protein, Vav
Authors: Dekel Idit , Russek Niva , Jones Tamara , Mortin Mark A. , Katzav Shulamit
Published: July 2002

Mammalian Vav signal transducer protein couples tyrosine kinase signals with the activation of the Rho/Rac GTPases, thus leading to cell differentiation and/or proliferation. We have isolated and characterized the DroVav gene, the homologue of hVav in Drosophila melanogaster. DroVav encodes a protein (793 residues) whose similarity with hVav is 47% and with hVav2 and hVav3 is 45%. DroVav preserves the unique, complex structure of hVav proteins, including the ‘calponin homology’, dbl homology, pleckstrin homology; SH2 and SH3 domains in addition to regions that are acidic rich, proline rich and cysteine rich. DroVav is located on the X chromosome in polytene interval 18A5;18B and is expressed in all stages of development and in all tissues. In mammalian cells, DroVav is tyrosine‐phosphorylated in response to epidermal growth factor receptor (EGFR) induction; in vitro, the DroVav SH2 region is associated with tyrosine‐phosphorylated EGFR. Thus, DroVav probably plays a pivotal role as a signal transducer protein during fruit fly development.
Spontaneous galactosylation of agalactoglycoproteins in colostrum
Authors: Oubihi Mohamed , Kitajima Ken , Aoki Naohito , Matsuda Tsukasa
Published: July 2002

We have found that spontaneous galactosylation of GlcNAc residues occurs in bovine colostrum, but not in dialyzed colostrum, without adding UDP‐Gal as a donor substrate. UDP‐Gal was shown to be present in bovine colostrum at a level ranging from 200 to 600 μM. When a tracer UDP‐[14C]Gal was added to the dialyzed colostrum together with a Gal β1,4‐specific β‐galactosidase, remarkable incorporation of radioactivity into 24–28 kDa and 33 kDa RCA1‐positive glycoproteins was demonstrated by SDS–PAGE/autoradiography. Some 100–140 kDa agalactoglycoproteins of a CHO mutant cell line were also galactosylated on a blotted membrane by the incubation in the colostrum.
Comparison of Several Periodic Operations of a Continuous Fermentation Process
Authors: Ruan Lier , Chen Xiao Dong
Published: July 2002

A continuous fermentation process is modeled numerically with five periodic input functions of substrate feed rate. The results show that, for the same average feed concentration of substrate, some of the periodic input functions can improve the performance of the process, giving increased productivities. The reduced ramp‐wave function has been found to give the highest productivity.
Zn doping characteristics for InGaAlP grown by low-pressure metalorganic chemical vapor deposition
Authors: Nishikawa Y. , Tsuburai Y. , Nozaki C. , Ohba Y. , Kokubun Y. , Kinoshita H.
Published: July 2002

Zn doping characteristics have been studied for In0.5(Ga1−xAlx)0.5P grown by low-pressure metalorganic chemical vapor deposition, using dimethylzinc (DMZ) as a Zn dopant source. Hole concentration decreased with increasing Al composition x. For low DMZ introduction, the Zn incorporation efficiency decreased with increasing x. For high DMZ introduction, hole concentration saturation occurred as a result of the fall in Zn electrical activity and the Zn electrical activity also decreased with increasing x.
Sound velocity and index of refraction of AlAs measured by picosecond ultrasonics
Authors: Grahn H. T. , Young D. A. , Maris H. J. , Tauc J. , Hong J. M. , Smith T. P.
Published: July 2002

We use picosecond optics techniques to generate and detect acoustic pulses in an epitaxially grown film of AlAs. From the round trip time of the acoustic pulse we find a sound velocity in the [100] direction of 6.4×105 cm s−1. We also show how measurements of this type can be used to determine the refractive index.
Planar waveguide lenses in GaAs by using ion milling
Authors: Vu T. Q. , Norris J. A. , Tsai C. S.
Published: July 2002

We report, for the first time, the fabrication of negative index-change planar waveguide microlenses in GaAs by using ion milling. The waveguide lenses that have been fabricated and tested include single lenses and lens arrays of analog Fresnel, chirp grating, and hybrid analog Fresnel/chirp grating types. We have obtained small focal spot sizes and good efficiencies in such preliminary components. Ion milling has been shown to be a simple and versatile technique for fabrication of waveguide lenses in GaAs and applicable to any other substrate material. Such ion-milled waveguide lenses should facilitate realization of a variety of monolithically integrated optic device modules and circuits in GaAs and other related substrates with applications to communications, signal processing, and computing.
Enrichment depth profiles in polymer blends measured by forward recoil spectrometry
Authors: Sokolov J. , Rafailovich M. H. , Jones R. A. L. , Kramer E. J.
Published: July 2002

A novel time-of-flight detector system for He+ forward recoil spectrometry which improves the depth resolution to better than 35 nm has been used to investigate the form of the surface enrichment profile in a protonated (normal) polystyrene (PS)/deuterated polystyrene (d-PS) blend. The volume fraction φ of d-PS depends on the depth z as φ(z)=φ∞+(φ1−φ∞) exp(−z/ξ), where φ1 and φ∞ are the surface and bulk volume fractions of d-PS, respectively, and ξ is approximately the bulk correlation length, as predicted by theory.
Novel guided-wave acousto-optic frequency shifting scheme using Bragg diffractions in cascade
Authors: Tsai C. S. , Cheng Z. Y.
Published: July 2002

A novel integrated optical frequency shifter that utilizes guided-wave acousto-optic Bragg diffractions in cascade from two tilted and counterpropagating surface acoustic waves is reported. The doubly and frequency-shifted diffracted light propagates in a fixed direction, but spatially resolved from the incident light, irrespective of the magnitude of frequency tuning. A preliminary device fabricated in a Y-cut LiNbO3 planar waveguide has demonstrated a gigahertz frequency shift, a tunable bandwidth of 165 MHz, and other desirable characteristics at the optical wavelength of 0.63 μm. These preliminary results suggest that a compact integrated acousto-optic frequency shifter module may be realized in a common LiNbO3 substrate 0.2×10×1.5 cm3 in size.
Observation of competing arsenic removal channels in the Cl2+GaAs reaction
Authors: Hou Hui-qi , Zhang Zhuangjian , Chen Shanhua , Su Chaochin , Yan Weiring , Vernon Matt
Published: July 2002

A molecular beam study of the Cl2+GaAs(s) reaction has been performed for surface temperatures in the range of 300–550 K. The gas phase neutral reaction products are identified by mass spectroscopy using electron bombardment ionization. Detailed analysis of the surface temperature dependence of the mass spectrum of the observed reaction products indicates that only three neutral reaction products are formed in this temperature range: GaCl3, AsCl3, and As4. At low (high) surface temperatures, only AsCl3 (As4) is observed. The ratio of the etching rates of Ga and As is independent of the surface temperature and within the range expected for stoichiometric etching. The change in the mode of As removal with surface temperature for the incident Cl2 flux implies that surface diffusion is important at surface temperatures above 400 K.
Direct measurements of Cu diffusion into a polyimide below the glass transition temperature
Authors: Faupel F. , Gupta D. , Silverman B. D. , Ho P. S.
Published: July 2002

Diffusion of a metal (Cu) into a fully cured polymer (polyimide) below the glass transition has been systematically investigated for the first time by means of low-energy ion sputtering in combination with a radiotracer technique. The penetration profiles exhibit a steep non-Fickian decay of the tracer concentration over several orders of magnitude followed by a relatively flat Fickian tail. The initial decay is attributed to the formation of Cu clusters and is discussed in terms of a Monte Carlo simulation. The Fickian tail is related to the diffusion of single Cu atoms. Diffusion measured at the lowest temperature deviates from linearity on the Arrhenius plot and seems to be controlled by a free-volume mechanism of diffusion below the glass transition temperature.
Switching effect in organic charge transfer complex crystals
Authors: Iwasa Y. , Koda T. , Tokura Y. , Koshihara S. , Iwasawa N. , Saito G.
Published: July 2002

A reproducible current switching effect has been observed in various mixed-stack organic charge transfer crystals whose ionicities are close to the neutral-ionic phase boundary. This effect appears to be related to the intrinsic nonlinear conductivity, which has recently been reported in these crystals. This switching has a reasonably large delay time and our results indicate that it is a bulk property of the crystals. Discussion is given on the possible mechanism of this effect.
Implant isolation of GaAs-AlGaAs heterojunction bipolar transistor structures
Authors: Ren F. , Pearton S. J. , Hobson W. S. , Fullowan T. R. , Lothian J. , Yanof A. W.
Published: July 2002

The formation of high-resistivity (>107Ω/⧠) regions in GaAs-AlGaAs heterojunction bipolar transistor (HBT) structures by oxygen and hydrogen ion implantation has been investigated as a function of ion dose and subsequent annealing temperature (400–700 °C). Isolation leakage currents as low as 8 μA mm−1 at 6 V can be achieved between 100-μm-wide ohmic contacts separated by a 16 μm spacing. The isolation of these 1.8-μm-thick heterojunctions requires up to six different energy oxygen implants (40–400 keV) and three different energy proton implants (100–200 keV) with doses in the mid 1012 cm−2 range for O+ and 5×1014 cm−2 for H+ ions. Similar results can be achieved by substituting a MeV energy oxygen implant for the proton implants. The optimum post-implant annealing temperature depends on the ion dose but is in the range 500–600 °C. The evolution of the sheet resistance of the implanted GaAs-AlGaAs material with annealing is consistent with a reduction in tunneling probabilities of trapped carriers between deep level states for temperatures up to ∼600 °C, followed by significant annealing of these deep levels. Small geometry (2×9 μm2) HBTs exhibiting current gain of 44 and cutoff frequency fT as high as 45 GHz are demonstrated using implant isolation.
Mid-infrared detectors in the 3–5 μm band using bound to continuum state absorption in InGaAs/InAlAs multiquantum well structures
Authors: Hasnain G. , Levine B. F. , Sivco D. L. , Cho A. Y.
Published: July 2002

Medium wavelength infrared (MWIR) detectors in the 3–5 μm band are demonstrated using bound to continuum state intersubband absorption in lattice-matched InGaAs/InAlAs multiquantum well (MQW) structures. Photodetectors with responsivity peaked at 4 μm wavelength showed low dark current giving a background-limited detectivity D*BL =2.3×1010 cm(Hz)1/2 /W at temperatures up to 120 K.
High index contrast mirrors for optical microcavities
Authors: Ho Seng-Tiong , McCall S. L. , Slusher R. E. , Pfeiffer L. N. , West K. W. , Levi A. F. J. , Blonder G. E. , Jewell J. L.
Published: July 2002

A new technique for constructing multilayer dielectric mirrors is described that results in high reflectivities with only two or three dielectric layer pairs per mirror. These structures are obtained by selectively etching layered AlxGa1−xAs material grown by molecular beam epitaxy and then replacing the etched regions with acrylic resin or air. A thin optical cavity produced by this technique is demonstrated with mirror reflectivities near 96%. These techniques allow the fabrication of lasers, light-emitting diodes, or optical switches with high contrast ratio mirrors on both sides of an optically active region in order to enhance output coupling, lower laser thresholds, and increase modulation rates.
Reduction of boron diffusion in silicon by 1 MeV 29Si+ irradiation
Authors: Raineri V. , Schreutelkamp R. J. , Saris F. W. , Janssen K. T. F. , Kaim R. E.
Published: July 2002

Reduction of the transient diffusion of B, implanted in Si along [100] at 10 keV to a dose of 1×1013/cm2, after annealing at 900 °C for 10 s has been observed in samples irradiated with 1.0 MeV 29Si ions to a dose of 5×1013/cm2 or higher. A lower Si dose did not influence the transient B tail diffusion. Secondary defects formed near the peak of the 1 MeV Si damage distribution, for doses of 5×1013/cm2 and higher, act as efficient sinks for interstitials from shallower depths and thereby reduce the transient tail diffusion.
Growth of high optical and electrical quality GaN layers using low-pressure metalorganic chemical vapor deposition
Authors: Asif Khan M. , Kuznia J. N. , Van Hove J. M. , Olson D. T. , Krishnankutty S. , Kolbas R. M.
Published: July 2002

We report on the low-pressure metalorganic chemical vapor deposition of high quality single-crystal GaN layers over basal plane sapphire substrates. Optimization of growth conditions resulted in material with carrier densities of 1017 /cm3 at room temperature and corresponding mobilities around 350 cm2 /V s. The photoluminescence linewidths improved from 160 meV [full width at half maximum (FWHM)] to 25 meV (FWHM). With improved material quality we were able to observe the polar optical mode and the ionized impurity scattering regimes in the mobility versus temperature data. Good quality Schottky barriers were formed on the as-grown material using a tungsten probe and an alloyed indium contact. Our observations indicate a direct correlation between electrical and optical characteristics of good material and strongly question nitrogen vacancies as the sole explanation for the high carrier densities observed in poor quality GaN growths.
Electric field-dependent conductivity of polycrystalline diamond thin films
Authors: Huang Bohr-ran , Reinhard D. K.
Published: July 2002

The dc electrical conductivity of polycrystalline diamond films with submicron grain sizes has been studied as a function of the applied electric field up to the point of electrical breakdown. For electric fields below approximately 105 V/cm, the films exhibited predominantly ohmic behavior. For higher electric fields, however, the conductivity was field activated according to Poole’s Law. The data is consistent with a Poole–Frenkel reduction of the ionization energy associated with Coulombic potentials surrounding ionizable centers, where the Coulombic potentials overlap. Consequently, the dielectric strength of the films in this study are lower than that reported for single-crystalline diamond.
Diamond synthesis by microwave plasma chemical vapor deposition using graphite as the carbon source
Authors: Salvadori M. C. , Ager J. W. , Brown I. G. , Krishnan K. M.
Published: July 2002

We report on the growth of high-quality diamond using a microwave plasma chemical vapor deposition (CVD) system in which the feed gas contains no hydrocarbons, but instead the source of carbon is a graphite piece which resides within the plasma volume. Results of experiments using this technique by itself and in combination with the normal methane feed gas method are described. The samples were analyzed by Raman spectroscopy and scanning electron microscopy. Diamond grown in this way was found to be particularly pure and of high crystallinity.
Island growth and surface topography of epitaxial Y-Ba-Cu-O thin films on MgO
Authors: Krebs H. U. , Krauns Ch. , Yang Xiaoguang , Geyer Ulrich
Published: July 2002

High-quality epitaxial Y1B2Cu3Ox thin films (Tc,o ≥ (R18) 90 K, jc (77 K)≥ (R18)3 ×106A/cm2) were in situ grown on MgO by KrF excimer laser ablation. The combination of in situ resistance measurements, x-ray diffraction experiments, Tc measurements, scanning electron microscopy and scanning tunneling microscopy gives clear indications for an island growth on these substrates and shows growth steps and spirals at the film surface.
Study of carrier dynamics in InP:Fe using time-resolved infrared reflection and transmission
Authors: Miranda R. S. , Tom H. W. K. , Johnson A. M. , Bridges T. J. , Aumiller G. D.
Published: July 2002

We have studied the dynamics of photogenerated carriers in the semiconductor InP:Fe, using 2 ps time-resolved infrared (IR) reflection and transmission. We analyze the reflection data in a new way: the transient signal is related to the Fourier transform of the injected carrier depth profile. Because of this sensitivity to the depth profile, time-resolved IR reflection is a unique tool for studying carrier dynamics and is potentially better than visible reflection or Raman scattering. We use the sensitivity of the IR reflection here to test the validity of the standard one-dimensional ambipolar diffusion model.