bluuebunny/crossref_metadata_2025 huggingface dataset:
THE ROLE OF KETO ACIDS IN PHOTOSYNTHETIC CARBON DIOXIDE ASSIMILATION
Authors: Towers G. H. N. , Mortimer D. C.
Published: December 2009

Of the keto acids identified in leaves of sugar beet and other plants exposed to C14O2, pyruvic acid was found to be the only one labelled in light periods up to 45 sec. α-Ketoglutaric and glyoxylic acids became radioactive after about 45 sec. Radioactive hydroxypyruvate was not identified under these conditions and labelled oxaloacetate was detected only in trace amounts after 60 sec. in Scenedesmus. In contrast glycine and serine were labelled after 10 sec. under comparable conditions and aspartic acid was appreciably labelled after 30 sec. The effect on the radioactivity of the keto acids of an additional period intracer-free air, with and without light, as well as the dark incorporation of C14O2 was studied. These results are discussed in relation to the role of the ketoacids in photosynthesis. It is concluded that the synthesis of amino acids such as glycine, serine, and aspartic acid may be effected by mechanisms other than transamination in green leaves in the light.
ÉTUDE QUANTITATIVE DE L'ACTIVITÉ CHOLINESTÉRASIQUE DE LA PLAQUE MOTRICE PAR VOIE D'HISTOPHOTOMÉTRIE
Authors: Crevier Par Marc , Bélanger Léonard-F.
Published: December 2009

The cholinesterase activity of the motor end plate has been determined in situ by histophotometry. It has been possible to establish statistically the probable value of the enzymic activity of a single motor end plate morphologically identified. Studying the rate of the enzymic reaction in function of time, temperature, and concentration of substrate, it became evident that the progressive deposition of the precipitate as the reaction proceeds is represented by a proportional and local increase in its concentration and not by its spreading over the fiber. Inhibition experiments with eserine and acetylcholine in excess have proved that with the substrates used, β-naphthylacetate and β-carbonaphthoxycholine, it is possible to identify independently acetylcholinesterase and cholinesterase activity at the level of the motor end plate, the former being in proportion of 90%. The acetylcholinesterase inactivation has been observed after intramuscular injections of eserine, indicating that pharmacological problems can be studied at the microscopic level by histophotometry.
EFFECT OF ASCORBIC ACID ON THE PHOSPHORUS METABOLISM OF THE ADRENAL GLAND
Authors: Nicholls Doris
Published: December 2009

Brief exposure of rats to a cold environment increased the incorporation of inorganic P32 into the inorganic P, 20-min. hydrolyzable P, and total acid-soluble P of the adrenal gland. This increase was abolished by the administration of sodium ascorbate. Similar quantities of sodium succinate were without effect. The effect of ascorbate was largely due to the fact that it increased the phosphorus metabolism of the adrenals of rats maintained at room temperature. ACTH increased the incorporation of P32 into the acid-soluble P fractions of the adrenal of hypophysectomized rats. This effect of ACTH was greatly increased by sodium ascorbate. These results confirm the suggestion of Dugal that sodium ascorbate may potentiate the effect of ACTH.
WATER DISTRIBUTION IN INCUBATED SLICES OF BRAIN AND OTHER TISSUES
Authors: Pappius Hanna M. , Elliott K. A. C.
Published: December 2009

Slices of rat cerebral cortex swell about 40% during one hour's aerobic incubation in bicarbonate-buffered medium. Thiocyanate or sucrose added to the medium equilibrate with part of the tissue fluid leaving a "non-thiocyanate" or "non-sucrose" space equal to about 45% of the total fluid which was present in the fresh unincubated slice. This space does not change with the extent of swelling or the time during which the tracer is present. The swelling thus appears to be extracellular. Inuilin in the medium equilibrates with little more than the water of swelling and docs not appear to enter the rest of the extracellular fluid. The swelling thus seems to involve uptake of fluid which is not continuous with the true tissue fluids. With glutamate or high potassium in the medium, swelling is increased and the non-thiocyanate, non-sucrose, and non-inulin spaces increase correspondingly. This increase is apparently intracellular. Swelling is also increased under anaerobic conditions. Results with sucrose and inulin indicate that this increase is due to intracellular swelling. The space occupied by thiocyanate increases with the time during which the thiocyanate is present in the medium under anaerobic conditions. Swelling can be decreased but not prevented by colloids in the medium. Medium rendered hypertonic with sucrose apparently causes cell shrinkage, as judged by the non-thiocyanate or non-sucrose space, without preventing uptake of "swelling water". Liver and kidney slices swell about 10%. Thiocyanate occupies the whole of the tissue fluid while inulin leaves a constant non-inulin space, equal to about 60% of the total fluid of the fresh unincubated slice. Sectors of diaphragm swell about 15%. Thiocyanate and inulin occupy about equal spaces. The non-thiocyanate and non-inulin spaces are about 49% of the total fluid of the fresh tissues. Diaphragm cut into strips parallel to the circumference swells more and thiocyanate and inulin penetrate most of the fluid. Sciatic nerve swells nearly as much as brain. The swelling is reduced if the ends are tied. Thiocyanate penetrates the tissue progressively with time. Inulin seems to occupy little more than the water of swelling, as in brain.
THE WATER AND ELECTROLYTE METABOLISM OF RAT DIAPHRAGM IN VITRO
Authors: Rixon R. H. , Stevenson J. A. F.
Published: December 2009

The distribution of water and of sodium and potassium between the cell and synthetic environments has been studied in rat diaphragm muscle. It has been found that: (1) the amount of intracellular water is markedly increased at 0 °C. in oxygen and at 37 °C. in nitrogen compared to that of tissue at 37 °C. in oxygen, in media up to 0.75 osmolar; (2) optimal conditions of temperature and oxygen are necessary to prevent or reduce the uptake of water; (3) swelling at reduced temperatures and under hypoxic conditions is related to the oxygen uptake; (4) the loss of tissue solids during incubation does not have any significant effect on the calculation of the total tissue and intracellular water; (5) the concentration of total sodium and potassium in the tissue, in vivo and in vitro at optimal conditions is slightly in excess of that in the plasma water or incubating medium—this is believed not to represent an active hypertonicity; (6) concomitant with the uptake of water there are marked redistributions of sodium and potassium, the gain of sodium being greater than the loss of potassium. It is concluded that the swelling of tissue cells under conditions that inhibit oxidative metabolism is primarily due to the redistribution of electrolytes and that the natural distribution of water in muscle is determined by active maintenance of the concentration gradients of sodium and potassium across the cell membrane.
SEARCHING FOR PERSISTENCE IN ATMOSPHERIC TEMPERATURE TIME SERIES: A RE-VISITATION OF RESULTS FROM DETRENDED FLUCTUATION ANALYSIS
Authors: SIMONIELLO TIZIANA , COPPOLA ROSA , CUOMO VINCENZO , D'EMILIO MARIAGRAZIA , LANFREDI MARIA , LIBERTI MARGHERITA , MACCHIATO MARIA
Published: December 2009

We re-analyze historical daily atmospheric temperature time series for investigating long-range correlation. Such a problem is attracting much attention due to the deep importance of assessing statistical dependence of atmospheric phenomena on climatic scales in the context of Climate modeling. In particular, we adopt Detrended Fluctuation Analysis (DFA), which is one of the most used techniques for detecting scale invariance in stationary signals contaminated by external non-stationary disturbances. A very standard application of this methodology seems to evidence persistence power-law exponents close to 0.65 on time scales greater than the meteorological one (>15 days). Nevertheless, more careful investigations put into evidence the local character of this exponent whose value decays progressively with scale. Our results show that the simple detection of approximately straight lines in a log–log plot cannot be considered as a signature of scale invariance and local scale features have to be explicitly investigated.
OPTIMAL CONTROL OF SINGULARLY PERTURBED ADVECTION-DIFFUSION-REACTION PROBLEMS
Authors: LUBE GERT , TEWS BENJAMIN
Published: December 2009

In this paper, we consider the numerical analysis of quadratic optimal control problems governed by a linear advection-diffusion-reaction equation without control constraints. In the case of dominating advection, the Galerkin discretization is stabilized via the one- or two-level variant of the local projection approach which leads to a symmetric optimality system at the discrete level. The optimal control problem simultaneously covers distributed and Robin boundary control. In the singularly perturbed case, the boundary control at inflow and/or characteristic parts of the boundary can be seen as regularization of a Dirichlet boundary control. Some numerical tests illustrate the analytical results.
ADAPTIVE FINITE ELEMENT COMPUTATIONS OF SHEAR BAND FORMATION
Authors: BAXEVANIS TH. , KATSAOUNIS TH. , TZAVARAS A. E.
Published: December 2009

We study numerically an instability mechanism for the formation of shear bands at high strain-rate deformations of metals. We use a reformulation of the problem that exploits scaling properties of the model, in conjunction with adaptive finite element methods of any order in the spatial discretization and implicit Runge–Kutta methods with variable step in time. The numerical schemes are of implicit–explicit type and provide adequate resolution of shear bands up to full development. We find that from the initial stages, shear band formation is already associated with collapse of stress diffusion across the band and that process intensifies as the band fully forms. For fully developed bands, heat conduction plays an important role in the subsequent evolution by causing a delay or even stopping the development of the band.
NOISY QUANTUM MONTY HALL GAME
Authors: GAWRON PIOTR
Published: December 2009

The influence of spontaneous emission channel and generalized Pauli channel on quantum Monty Hall Game is analyzed. The scheme of Flittney and Abbott is reformulated using the formalism of density matrices. Optimal classical strategies for given quantum strategies are found. The whole presented scheme illustrates how quantum noise may change the odds of a zero-sum game.
AUTOREGRESSIVE MODELING OF CODING SEQUENCE LENGTHS IN BACTERIAL GENOME
Authors: MORARIU VASILE V. , BUIMAGA-IARINCA LUIZA
Published: December 2009

Previous investigation of the length of coding sequence lengths (CDS) in the bacterial circular chromosome revealed short range correlation in the series of these data. We have further analyzed the averaged periodograms of these series and we found that the organization of CDS can be well described by first-order autoregressive processes. This involves interaction between the neighboring terms. The autoregressive analysis may have great potential in modeling various physical and biological processes like light emission of galaxies, protein organization, cell flickering, cognitive processes and perhaps others.
A FRACTIONAL POISSON EQUATION: EXISTENCE, REGULARITY AND APPROXIMATIONS OF THE SOLUTION
Authors: SANZ-SOLÉ MARTA , TORRECILLA IVÁN
Published: December 2009

We consider a stochastic boundary value elliptic problem on a bounded domain D ⊂ ℝk, driven by a fractional Brownian field with Hurst parameter H = (H1,…,Hk) ∈ [½, 1[k. First, we define the stochastic convolution derived from the Green kernel and prove some properties. Using monotonicity methods, we prove the existence and uniqueness of solution along with regularity of the sample paths. Finally, we propose a sequence of lattice approximations and prove its convergence to the solution of the SPDE at a given rate.
Stress Hormone Regulation: Biological Role and Translation into Therapy
Authors: Holsboer Florian , Ising Marcus
Published: December 2009

Stress is defined as a state of perturbed homeostasis following endangerment that evokes manifold adaptive reactions, which are summarized as the stress response. In the case of mental stress, the adaptive response follows the perception of endangerment. Different peptides, steroids, and biogenic amines operate the stress response within the brain and also after they have been released into circulation. We focus in this review on the biological roles of corticosteroids, corticotrophin-releasing hormone (CRH), and arginine vasopressin (AVP), and we evaluate the effects of treatments directed against the actions of these hormones. CRH and AVP are the central drivers of the stress hormone system, but they also act as neuromodulators in the brain, affecting higher mental functions including emotion, cognition, and behavior. When released toward the pituitary, these central neuropeptides elicit corticotrophin into the periphery, which activates corticosteroid release from the adrenal cortex. These stress hormones are essential for the adequate adaptation to stress, but they can also evoke severe clinical conditions once persistently hypersecreted. Depression and anxiety disorders are prominent examples of stress-related disorders associated with an impaired regulation of stress hormones. We summarize the effects of drugs acting at specific targets of the stress hormone axis, and we discuss their potential use as next-generation antidepressant medications. Such treatments require the identification of patients that will optimally benefit from such specific interventions. These could be a first step into personalized medicine using treatments tailored to the specific pathology of the patients.
Speech Perception and Language Acquisition in the First Year of Life
Authors: Gervain Judit , Mehler Jacques
Published: December 2009

During the first year of life, infants pass important milestones in language development. We review some of the experimental evidence concerning these milestones in the domains of speech perception, phonological development, word learning, morphosyntactic acquisition, and bilingualism, emphasizing their interactions. We discuss them in the context of their biological underpinnings, introducing the most recent advances not only in language development, but also in neighboring areas such as genetics and the comparative research on animal communication systems. We argue for a theory of language acquisition that integrates behavioral, cognitive, neural, and evolutionary considerations and proposes to unify previously opposing theoretical stances, such as statistical learning, rule-based nativist accounts, and perceptual learning theories.
Somesthetic Senses
Authors: Hollins Mark
Published: December 2009

This is a review of recent advances in our understanding of the sensory modalities of touch, temperature sensitivity, and pain. Most of the research described is psychophysical or perceptual in nature, but physiological and imaging studies are included when they sharpen issues or reveal underlying mechanisms. Coverage of touch research comprises the subjects of acuity, vibrotaction and texture perception, perception of location and movement, tactile attention, and cross-modal phenomena. For pain, the covered topics are central sensitization, pain-touch and pain-pain interactions, placebo effects, the role of attention and emotion in pain, and the genetics of pain. For touch, the topics are arranged roughly in order of increasing cognitive involvement, but such an ordering is not feasible for pain, where attitudes and expectations can substantially affect even the most “sensory” of judgments.
Negotiation
Authors: Thompson Leigh L. , Wang Jiunwen , Gunia Brian C.
Published: December 2009

Negotiation occurs whenever people cannot achieve their own goals without the cooperation of others. Our review highlights recent empirical research that investigates this ubiquitous social activity. We selectively review descriptive research emerging from social psychology and organizational behavior. This research examines negotiation behavior and outcomes at five levels of analysis: intrapersonal, interpersonal, group, organizational, and virtual. At each level, we review research on negotiation processes and outcomes, and we discuss the implications of various processes and outcomes for the two functions of negotiation: value creation (integrative negotiation) and value claiming (distributive negotiation).
OSMOSIS: A MACROSCOPIC PHENOMENON, A MICROSCOPIC VIEW
Authors: Ben-Sasson S. A. , Grover N. B.
Published: December 2009

At present, physical chemistry employs the tools of thermodynamics to treat osmosis across a semipermeable membrane. We propose a model in terms of momentum transfer, the inherent asymmetry of which leads quantitatively to the van’t Hoff relationship; qualitatively, the solute molecules can be looked upon as micropumps that suck solvent through the pores in the membrane.
SMOOTH MUSCLE CONTRACTION AND RELAXATION
Authors: Webb R. Clinton
Published: December 2009

This brief review serves as a refresher on smooth muscle physiology for those educators who teach in medical and graduate courses of physiology. Additionally, those professionals who are in need of an update on smooth muscle physiology may find this review to be useful. Smooth muscle lacks the striations characteristic of cardiac and skeletal muscle. Layers of smooth muscle cells line the walls of various organs and tubes in the body, and the contractile function of smooth muscle is not under voluntary control. Contractile activity in smooth muscle is initiated by a Ca2+-calmodulin interaction to stimulate phosphorylation of the light chain of myosin. Ca2+sensitization of the contractile proteins is signaled by the RhoA/Rho kinase pathway to inhibit the dephosphorylation of the light chain by myosin phosphatase, thereby maintaining force generation. Removal of Ca2+from the cytosol and stimulation of myosin phosphatase initiate the process of smooth muscle relaxation.
Simple, Inexpensive Classroom Experiments for Understanding Basic Gas Laws and Properties of Gases
Authors: Collins Heidi L. , DiCarlo Stephen E.
Published: December 2009

As educators, we are continually designing new methods and procedures to enhance learning. During this process, good ideas are frequently generated and tested, but the extent of such activities may not be adequate for a full manuscript. Nonetheless, the ideas may be quite beneficial in improving the teaching and learning of physiology. Illuminations is a column designed to facilitate the sharing of these ideas (illuminations). The format of submissions is quite simple: a succinct description of about one or two double-spaced pages (less title and authorship) of something you have used for the classroom, teaching, lab, conference room, etc. You may include one or two simple figures or references. Submit ideas for inclusion in Illuminations directly to the Associate Editor in charge, Stephen DiCarlo (sdicarlo@med.wayne.edu).
STUDENT RETENTION OF COURSE CONTENT IS IMPROVED BY COLLABORATIVE-GROUP TESTING
Authors: Cortright Ronald N. , Collins Heidi L. , Rodenbaugh David W. , DiCarlo Stephen E.
Published: December 2009

We recently reported that collaborative testing (i.e., group test taking) increased student performance on quizzes. It is unknown, however, whether collaborative testing improves student retention of course content. Therefore, this study was designed to test the hypotheses that collaborative-group testing improves student retention of course content. To test this hypothesis, our undergraduate exercise physiology class of 38 students was randomly divided into two groups: group A ( n = 19) and group B ( n = 19). During exam 1, students from both groups answered questions in the traditional format as individuals. Immediately after completing the exam as individuals, students from group A answered a randomly selected subset of questions from exam 1 in groups of two (1 group had 3 students) to test the effectiveness of collaborative-group testing on test performance and level of student retention. On the next exam ( exam 2, 4 wk later), students from both groups answered questions in the traditional format as individuals and responded to the same subset of questions from exam 1. The subset of questions was analyzed to determine the level of retention of the original test material. In addition, immediately after completing the exam as individuals, students from group B answered a randomly selected subset of questions from exam 2 in groups of two (1 group had 3 students). Finally, on the next exam ( exam 3, 4 wk later), students from both groups answered questions in the traditional format as individuals and responded to the same subset of questions from exam 2. This protocol followed a randomized crossover design to control for time and order effects. Student retention of course content was reduced when students completed the original examinations individually. In sharp contrast, student retention was improved ( P < 0.05) when students completed the original examinations in groups. Results suggest that collaborative testing is an effective strategy to enhance learning and increase student retention of course content.
COMPUTER SIMULATION OF INTRODUCTORY NEUROPHYSIOLOGY
Authors: McGrath Paul , Kucera Robert , Smith Wayne
Published: December 2009

A computer-assisted learning (CAL) package, NeuroLab, developed for use by first-year university students undertaking professional programs in the health area, is described and evaluated. NeuroLab is a simulation of a laboratory, in which students are able to impale neurons to measure resting membrane potentials and subsequently undertake experiments including measuring resting membrane potentials, determining threshold potentials, measuring refractory periods, and examining effects on membrane potential through altering the membrane permeability to sodium and potassium ions. Students find the package to be a worthwhile learning experience, with 81 ± 2.2% reporting the package increased their understanding of neuron function, and 78 ± 2.5% expressing a desire for more CAL packages. Exposure to the package resulted in significantly higher mean scores in a multiple-choice question test on measuring neuron membrane potentials compared with those who were not exposed (mean scores out of 4 of 2.42 and 2.02, respectively, P < 0.001).
HOW TO REVIEW A PAPER
Authors: Benos Dale J. , Kirk Kevin L. , Hall John E.
Published: December 2009

Most scientists acquire their training in manuscript review not through instruction but by actually doing it. Formal training in manuscript analysis is rarely, if ever, provided. Editors usually choose reviewers because of expertise in a given subject area and availability. If an individual repeatedly submits bad reviews, it is likely that that person will not be asked to review a manuscript again. Being invited to review a manuscript is an honor, not only because you are being recognized for your eminence in a particular area of research but also because of the responsibility and service you provide to the journal and scientific community. The purpose of this article is to define how best to peer review an article. We will stipulate several principles of peer review and discuss some of the main elements of a good manuscript review, the basic responsibilities of a reviewer, and the rewards and responsibilities that accompany this process. Proper reviewer conduct is essential for making the peer review process valuable and the journal trustworthy.
TECHNOLOGY IN THE TEACHING OF NEUROSCIENCE: ENHANCED STUDENT LEARNING
Authors: Griffin John D.
Published: December 2009

The primary motivation for integrating any form of education technology into a particular course or curriculum should always be to enhance student learning. However, it can be difficult to determine which technologies will be the most appropriate and effective teaching tools. Through the alignment of technology-enhanced learning experiences with a clear set of learning objectives, teaching becomes more efficient and effective and learning is truly enhanced. In this article, I describe how I have made extensive use of technology in two neuroscience courses that differ in structure and content. Course websites function as resource centers and provide a forum for student interaction. PowerPoint presentations enhance formal lectures and provide an organized outline of presented material. Some lectures are also supplemented with interactive CD-ROMs, used in the presentation of difficult physiological concepts. In addition, a computer-based physiological recording system is used in laboratory sessions, improving the hands-on experience of group learning while reinforcing the concepts of the research method. Although technology can provide powerful teaching tools, the enhancement of the learning environment is still dependent on the instructor. It is the skill and enthusiasm of the instructor that determines whether technology will be used effectively.
AGER1 regulates endothelial cell NADPH oxidase-dependent oxidant stress via PKC-δ: implications for vascular disease
Authors: Cai Weijing , Torreggiani Massimo , Zhu Li , Chen Xue , He John Cijiang , Striker Gary E. , Vlassara Helen
Published: December 2009

Advanced glycated end-product receptor 1 (AGER1) protects against vascular disease promoted by oxidants, such as advanced glycated end products (AGEs), via inhibition of reactive oxygen species (ROS). However, the specific AGEs, sources, and pathways involved remain undefined. The mechanism of cellular NADPH oxidase (NOX)-dependent ROS generation by defined AGEs, Nε-carboxymethyl-lysine- and methylglyoxal (MG)-modified BSA, was assessed in AGER1 overexpressing (AGER1+ EC) or knockdown (sh-mRNA-AGER1+ EC) human aortic endothelial (EC) and ECV304 cells, and aortic segments from old (18 mo) C57BL6-F2 mice, propagated on low-AGE diet (LAGE), or LAGE supplemented with MG (LAGE+MG). Wild-type EC and sh-mRNA-AGER1+ EC, but not AGER1+ EC, had high NOX p47 phox and gp91 phox activity, superoxide anions, and NF-κB p65 nuclear translocation in response to MG and Nε-carboxymethyl-lysine. These events involved epidermal growth factor receptor-dependent PKC-δ redox-sensitive Tyr-311 and Tyr-332 phosphorylation and were suppressed in AGER1+ ECs and enhanced in sh-mRNA-AGER1+ ECs. Aortic ROS, PKC-δ Tyr-311, and Tyr-332 phosphorylation, NOX expression, and nuclear p65 in older LAGE+MG mice were significantly increased above that in age-matched LAGE mice, which had higher levels of AGER1. In conclusion, circulating AGEs induce NADPH-dependent ROS generation in vascular aging in both in vitro and in vivo models. Furthermore, AGER1 provides protection against AGE-induced ROS generation via NADPH.
Sirolimus and cyclosporine A alter barrier function in renal proximal tubular cells through stimulation of ERK1/2 signaling and claudin-1 expression
Authors: Martin-Martin Natalia , Ryan Gavin , McMorrow Tara , Ryan Michael P.
Published: December 2009

Alteration of the tight junction complex in renal epithelial cells can affect renal barrier function and perturb normal kidney homeostasis. The immunosuppressant drugs cyclosporine A (CsA) and sirolimus (SRL) used in combination demonstrated beneficial effects in organ transplantation but this combination can also result in increased adverse effects. We previously showed that CsA treatment alone caused an alteration of the tight junction complex, resulting in changes in transepithelial permeability in Madin-Darby canine kidney distal tubular/collecting duct cells. The potential effect of SRL on transepithelial permeability in kidney cells is unknown. In this study, subcytotoxic doses of SRL or CsA were found to decrease the paracellular permeability of the porcine proximal tubular epithelial cells, LLC-PK1cell monolayers, which was detected as an increase in transepithelial electrical resistance (TER). The cotreatment with SRL and CsA was found to increase TER in a synergistic manner. CsA treatment increased total cellular expression and membrane localization of the tight junction protein claudin-1 and this further increased with the combination of SRL/CsA. SRL and CsA treatment alone or in combination stimulated the phosphorylation of ERK1/2. The MEK-ERK1/2 pathway inhibitor, U0126, reduced the SRL, CsA, and CsA/SRL-induced increase in TER. U0126 also reduced the CsA and CsA/SRL-induced increase in the membrane localization of claudin-1. Alterations in claudin-2 and claudin-4 were also detected. However, the results suggest that the modulation in expression and localization of claudin-1 appears to be pivotal in the SRL- and CsA-induced modulation of the epithelial barrier function and that modulation is regulated by ERK1/2 signaling pathway.
Local sensory nerve control of skin blood flow during local warming in type 2 diabetes mellitus
Authors: Strom Nicholas A. , Sawyer Jessica R. , Roberts Shelly K. , Kingsley-Berg Shirley M. , Charkoudian Nisha
Published: December 2009

Cutaneous sensory nerve-mediated vasodilation is an important component of normal microvascular responsiveness to thermal and nonthermal stimuli. Since both neural and microvascular function can be impaired in type 2 diabetes mellitus (T2DM), we tested the hypothesis that local sensory nerve-mediated vasodilation during nonpainful local warming of the skin is less in T2DM compared with healthy controls (C) matched for age and body size. The rapid vasodilation during the first ∼5 min of this local warming (“initial peak”) was previously shown to rely primarily on local sensory nerves. We measured skin blood flow in T2DM and C subjects ( n = 7 in each group) at baseline and during 35 min of local warming of the skin to 42°C at two sites on the ventral forearm. One site was pretreated with 4% lidocaine (LIDO) to block local sensory innervation. During local warming, cutaneous vascular conductance (CVC) during the initial peak was not different between groups, either at the untreated site [T2DM 75 ± 2 vs. C 81 ± 6% of maximum CVC (%maxCVC); P > 0.05] or at the LIDO site (T2DM 63 ± 7 vs. C 64 ± 6%maxCVC; P > 0.05). The difference between untreated and LIDO sites (sensory nerve contribution) was also similar between groups (T2DM 13 ± 5 vs. C 18 ± 5%maxCVC; P > 0.05) and was smaller with LIDO than was previously shown with other local anesthetics. Our results suggest that relatively healthy individuals with T2DM do not exhibit impairments in local sensory nerve vasodilation during thermal stimulation compared with controls of similar age and body size.
Influences of Load Characteristics on Impaired Control of Grip Forces in Patients With Cerebellar Damage
Authors: Brandauer B. , Timmann D. , Häusler A. , Hermsdörfer J.
Published: December 2009

Various studies showed a clear impairment of cerebellar patients to modulate grip force in anticipation of the loads resulting from movements with a grasped object. This failure corroborated the theory of internal feedforward models in the cerebellum. Cerebellar damage also impairs the coordination of multiple-joint movements and this has been related to deficient prediction and compensation of movement-induced torques. To study the effects of disturbed torque control on feedforward grip-force control, two self-generated load conditions with different demands on torque control—one with movement-induced and the other with isometrically generated load changes—were directly compared in patients with cerebellar degeneration. Furthermore the cerebellum is thought to be more involved in grip-force adjustment to self-generated loads than to externally generated loads. Consequently, an additional condition with externally generated loads was introduced to further test this hypothesis. Analysis of 23 patients with degenerative cerebellar damage revealed clear impairments in predictive feedforward mechanisms in the control of both self-generated load types. Besides feedforward control, the cerebellar damage also affected more reactive responses when the externally generated load destabilized the grip, although this impairment may vary with the type of load as suggested by control experiments. The present findings provide further support that the cerebellum plays a major role in predictive control mechanisms. However, this impact of the cerebellum does not strongly depend on the nature of the load and the specific internal forward model. Contributions to reactive (grip force) control are not negligible, but seem to be dependent on the physical characteristics of an externally generated load.
Nanostimulation: Manipulation of Single Neuron Activity by Juxtacellular Current Injection
Authors: Houweling Arthur R. , Doron Guy , Voigt Birgit C. , Herfst Lucas J. , Brecht Michael
Published: December 2009

In the mammalian brain, many thousands of single-neuron recording studies have been performed but less than 10 single-cell stimulation studies. This paucity of single-cell stimulation data reflects a lack of easily applicable single-cell stimulation techniques. We provide a detailed description of the procedures involved in nanostimulation, a single-cell stimulation method derived from the juxtacellular labeling technique. Nanostimulation is easy to apply and can be directed to a wide variety of identifiable neurons in anesthetized and awake animals. We describe the recording approach and the parameters of the electric configuration underlying nanostimulation. We use glass pipettes with a DC resistance of 4–7 MΩ. Obtaining the juxtacellular configuration requires a close contact between pipette tip and neuron and is associated with a several-fold increase in resistance to values ≥20 MΩ. The recorded action potential (AP) amplitude grows to ≥2 mV, and neurons can be activated with currents in the nanoampere range—hence the term nanostimulation. While exact AP timing has not been achieved, AP frequency and AP number can be parametrically controlled. We demonstrate that nanostimulation can also be used to selectively inhibit sensory responses in identifiable neurons. Nanostimulation is biophysically similar to electroporation, and based on this assumption, we argue that nanostimulation operates on membranes in the micrometer area directly below the pipette tip, where membrane pores are induced by high transmembrane voltage. There is strong evidence to suggest that nanostimulation selectively activates single neurons and that the evoked effects are cell-specific. Nanostimulation therefore holds great potential for elucidating how single neurons contribute to behavior.
Coding Characteristics of Spiking Local Interneurons During Imposed Limb Movements in the Locust
Authors: Vidal-Gadea A. G. , Jing X. J. , Simpson D. , Dewhirst O. P. , Kondoh Y. , Allen R. , Newland P. L.
Published: December 2009

The performance of adaptive behavior relies on continuous sensory feedback to produce relevant modifications to central motor patterns. The femoral chordotonal organ (FeCO) of the legs of the desert locust monitors the movements of the tibia about the femoro-tibial joint. A ventral midline population of spiking local interneurons in the metathoracic ganglia integrates inputs from the FeCO. We used a Wiener kernel cross-correlation method combined with a Gaussian white noise stimulation of the FeCO to completely characterize and model the output dynamics of the ventral midline population of interneurons. A wide range of responses were observed, and interneurons could be classified into three broad groups that received excitatory and inhibitory or principally inhibitory or excitatory synaptic inputs from the FeCO. Interneurons that received mixed inputs also had the greatest linear responses but primarily responded to extension of the tibia and were mostly sensitive to stimulus velocity. Interneurons that received principally inhibitory inputs were sensitive to extension and to joint position. A small group of interneurons received purely excitatory synaptic inputs and were also sensitive to tibial extension. In addition to capturing the linear and nonlinear dynamics of this population of interneurons, first- and second-order Wiener kernels revealed that the dynamics of the interneurons in the population were graded and formed a spectrum of responses whereby the activity of many cells appeared to be required to adequately describe a particular stimulus characteristic, typical of population coding.
Doping of TiO2 Polymorphs for Altered Optical and Photocatalytic Properties
Authors: Nie Xiliang , Zhuo Shuping , Maeng Gloria , Sohlberg Karl
Published: December 2009

This paper reviews recent investigations of the influence of dopants on the optical properties of TiO2 polymorphs. The common undoped polymorphs of TiO2 are discussed and compared. The results of recent doping efforts are tabulated, and discussed in the context of doping by elements of the same chemical group. Dopant effects on the band gap and photocatalytic activity are interpreted with reference to a simple qualitative picture of the TiO2 electronic structure, which is supported with first‐principles calculations.
Antibody‐Conjugated Nanoparticles for Biomedical Applications
Authors: Arruebo Manuel , Valladares Mónica , González-Fernández África
Published: December 2009

Nanoscience and Nanotechnology have found their way into the fields of Biotechnology and Medicine. Nanoparticles by themselves offer specific physicochemical properties that they do not exhibit in bulk form, where materials show constant physical properties regardless of size. Antibodies are nanosize biological products that are part of the specific immune system. In addition to their own properties as pathogens or toxin neutralizers, as well as in the recruitment of immune elements (complement, improving phagocytosis, cytotoxicity antibody dependent by natural killer cells, etc.), they could carry several elements (toxins, drugs, fluorochroms, or even nanoparticles, etc.) and be used in several diagnostic procedures, or even in therapy to destroy a specific target. The conjugation of antibodies to nanoparticles can generate a product that combines the properties of both. For example, they can combine the small size of nanoparticles and their special thermal, imaging, drug carrier, or magnetic characteristics with the abilities of antibodies, such as specific and selective recognition. The hybrid product will show versatility and specificity. In this review, we analyse both antibodies and nanoparticles, focusing especially on the recent developments for antibody‐conjugated nanoparticles, offering the researcher an overview of the different applications and possibilities of these hybrid carriers.
Surveillance Methods for Identifying, Characterizing, and Monitoring Tobacco Products: Potential Reduced Exposure Products as an Example
Authors: O'Connor Richard J. , Cummings K. Michael , Rees Vaughan W. , Connolly Gregory N. , Norton Kaila J. , Sweanor David , Parascandola Mark , Hatsukami Dorothy K. , Shields Peter G.
Published: December 2009

Tobacco products are widely sold and marketed, yet integrated data systems for identifying, tracking, and characterizing products are lacking. Tobacco manufacturers recently have developed potential reduced exposure products (PREP) with implied or explicit health claims. Currently, a systematic approach for identifying, defining, and evaluating PREPs sold at the local, state, or national levels in the United States has not been developed. Identifying, characterizing, and monitoring new tobacco products could be greatly enhanced with a responsive surveillance system. This article critically reviews available surveillance data sources for identifying and tracking tobacco products, including PREPs, evaluating strengths and weaknesses of potential data sources in light of their reliability and validity. With the absence of regulations mandating disclosure of product-specific information, it is likely that public health officials will need to rely on a variety of imperfect data sources to help identify, characterize, and monitor tobacco products, including PREPs. (Cancer Epidemiol Biomarkers Prev 2009;18(12):3334–48)
Acculturation Differentially Predicts Smoking Cessation among Latino Men and Women
Authors: Castro Yessenia , Reitzel Lorraine R. , Businelle Michael S. , Kendzor Darla E. , Mazas Carlos A. , Li Yisheng , Cofta-Woerpel Ludmila , Wetter David W.
Published: December 2009

Objectives: The current study examined the influence of gender, acculturation indicators, and their interaction on smoking cessation among Latinos.

Methods: Logistic regression analysis was used to examine the main effects of gender, acculturation indicators, and their interactions on self-reported 7-day abstinence at 12-week follow-up among 271 Latino smokers seeking cessation counseling.

Results: Analyses revealed significant main effects for several acculturation indicators and significant interactions of gender with number of years lived in the United States, proportion of life lived in the United States, and preferred media language (all P values <0.05). Follow-up analyses indicated no significant relationships between abstinence and acculturation indicators among women. Among men, abstinence rates increased with years in the United States, proportion of life in the United States, and preferred media language of English.

Conclusions: Greater acculturation predicted higher abstinence rates, but this relationship was restricted to men. This study is among the first to examine the effects of gender and acculturation on smoking abstinence among Latinos. Findings highlight the need for research focused on mechanisms underlying these relationships. (Cancer Epidemiol Biomarkers Prev 2009;18(12):3468–75)
Chinese “Herbal” Cigarettes Are as Carcinogenic and Addictive as Regular Cigarettes
Authors: Gan Quan , Yang Jie , Yang Gonghuan , Goniewicz Maciej , Benowitz Neal L. , Glantz Stanton A.
Published: December 2009

Objective: To examine the Chinese tobacco industry's claim that herbal cigarettes are less harmful than regular cigarettes.

Methods: The study design was a cross-sectional survey. One hundred thirty-five herbal cigarette smokers and 143 regular smokers from one city in China completed a questionnaire on smoking behavior and provided a urine sample. The main outcome measures were cotinine and trans-3′-hydroxycotinine in all samples, and polycyclic aromatic hydrocarbon metabolites (PAH; 1-hydroxypyrene, naphthols, hydroxyfluorenes, and hydroxyphnanthrenes) and the tobacco specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-butanol (NNAL) and NNAL-glucuronide in randomly selected 98 samples (47 from the herbal smokers' group and 51 from the regular smokers' group). Values were normalized by creatinine to correct for possible variability introduced by dilution or concentration of the urine.

Results: Health concern was among the main reasons that smokers switched to herbal cigarettes from regular cigarettes. Smokers reported increased consumption after switching to herbal cigarettes from regular cigarettes. For all the four markers analyzed (cotinine, trans-3′-hydroxycotinine, total NNAL, and total PAHs), we observed no significant difference in the levels (P = 0.169, P = 0.146, P = 0.171, and P = 0.554, respectively) between smokers of herbal cigarettes and smokers of regular cigarettes. Both total NNAL and total PAHs were significantly correlated with cotinine and trans-3′-hydroxycotinine (P < 0.001 for all four correlations).

Conclusions: Our findings showed that herbal cigarettes did not deliver less carcinogens than regular cigarettes. The public needs to be aware of this fact, and the Chinese tobacco industry should avoid misleading the public when promoting herbal cigarettes as safer products. (Cancer Epidemiol Biomarkers Prev 2009;18(12):3497–501]
Clinical Trials Methods for Evaluation of Potential Reduced Exposure Products
Authors: Hatsukami Dorothy K. , Hanson Karen , Briggs Anna , Parascandola Mark , Genkinger Jeanine M. , O'Connor Richard , Shields Peter G.
Published: December 2009

Potential reduced exposure products (PREPs) to tobacco toxicants may have promise in reducing tobacco-related morbidity or mortality or may promote greater harm to individuals or the population. Critical to determining the risks or benefits from these products are valid human clinical trial PREP assessment methods. Such an assessment involves determining the effects of these products on biomarkers of exposure and effect, which serve as proxies for harm, and assessing the potential for consumer uptake and abuse of the product. This article identifies critical methodologic issues associated with PREP assessments, reviews the methods that have been used to assess PREPs, and describes the strengths and limitations of these methods. Additionally, recommendations are provided for clinical trial PREP assessment methods and future research directions in this area based on this review and on the deliberations from a National Cancer Institute sponsored Clinical Trials PREP Methods Workshop. (Cancer Epidemiol Biomarkers Prev 2009;18(12):3143–95)
Time to First Cigarette after Waking Predicts Cotinine Levels
Authors: Muscat Joshua E. , Stellman Steven D. , Caraballo Ralph S. , Richie John P.
Published: December 2009

There is wide variability in cotinine levels per cigarette smoked. We hypothesized that in addition to smoking frequency, other behavioral measures of nicotine dependence, such as the time to first cigarette after waking, are associated with cotinine levels. To test this hypothesis, we measured plasma and urinary cotinine in a community-based study of 252 black and white daily cigarette smokers. Among one pack per day smokers, plasma cotinine levels varied from 16 to 1,180 ng/mL, a 74-fold difference. Two nicotine dependence phenotypes were discerned by time after waking. Subjects in the “low” dependent phenotype smoked >30 minutes after waking and nearly all smoked ≤20 cigarettes per day. Cotinine levels increased linearly with cigarette consumption in this group. Subjects in the “high” dependent phenotype smoked ≤30 minutes after waking but had a wide range in the frequency of daily cigarettes (6-70). Compared with the low dependent phenotype, there were relatively small differences in cotinine by cigarette frequency with evidence of a plateau effect in heavy smokers (∼30). After adjusting for cigarette frequency, the levels of cotinine by time to first cigarette were as follows: ≤5 minutes, 437 [95% confidence limits (CL), 380-494]; 6 to 30 minutes, 352 (95% CL, 291-413), 31 to 60 minutes, 229 (95% CL, 140-317), and >60 minutes, 215 (95% CL, 110-321). Similar findings were observed for urinary cotinine. These findings suggest that the time to first cigarette is a strong predictor of nicotine uptake and should be considered in the design of smoking interventions. (Cancer Epidemiol Biomarkers Prev 2009;18(12):3415–20)
The Convergence of Lung Cancer Rates between Blacks and Whites under the Age of 40, United States
Authors: Jemal Ahmedin , Center Melissa M. , Ward Elizabeth
Published: December 2009

Lung cancer rates in the United States have been consistently higher in blacks than in whites at all ages in men and at younger ages in women. However, since the 1970s, smoking initiation decreased more rapidly among blacks than whites. We examined trends in lung cancer rates for white and black young adults (ages 20-39) from 1992 to 2006 using joinpoint models and black-to-white rate ratios by sex. Lung cancer death rates in 20- to 39-year-olds significantly decreased in all groups but was much steeper for blacks than for whites. From 1992 to 1994 and 2004 to 2006, the black-to-white mortality rate ratio (95% confidence interval) decreased from 2.16 (1.90-2.44) to 1.28 (1.05-1.55) for men and from 1.47 (1.25-1.71) to 0.97 (0.78-1.19) for women. A similar convergence was observed in the lung cancer incidence rates. These findings suggest that if current smoking trends in the young continue, racial differences in overall lung cancer rates in men will be eliminated in the next 40 to 50 years. (Cancer Epidemiol Biomarkers Prev 2009;18(12):3349–52)