Extrinsic Processes Research Articles

Excitonic homogeneous broadening in single-wall carbon nanotubes

We present a review on the excitonic homogeneous linewidth, with an emphasis on original experiments by means of nonlinear spectral hole-burning. We address three specific aspects of the excitonic homogeneous broadening: (i) the variation of the homogeneous linewidth with the sonication energy, revealing the influence of extrinsic processes such as exciton-defect interactions, (ii) the collision-induced broadening due to exciton–exciton interactions, investigated by power-dependent measurements, and (iii) the phonon-induced dephasing due to exciton–phonon interactions, deduced from temperature-dependent experiments. We discuss the specific properties of one-dimensional excitons in carbon nanotubes in the context of the homogeneous broadening.

High pressure synthesis and in situ Raman spectroscopy of H2 and HD clathrate hydrates

By means of a newly constructed high pressure and low temperature optical apparatus we have measured the Raman spectra of H(2) and HD simple clathrate hydrates, synthesized in situ by the application of more than 2500 bar gas pressure on solid water. High resolution spectra of the molecular vibration have been measured at low temperature (about 20 K). In the case of HD this band is simpler than in the case of H(2), where the presence of the ortho- and para-species complicated the interpretation of the spectrum. We have determined frequency positions of the bands arising from multiple occupancy of the large cages of the sII clathrate, some of which are almost superimposed. The intensity of the bands gives information on the average and distribution of cage occupation, and of the ortho-para (o-p) ratio of H(2) molecules. Hydrogen o-p conversion rate is measured, for molecules in the small cages and in the large cages, and it is observed that these are different. A model considering both intrinsic and extrinsic conversion processes is applied to the measured data. The intrinsic conversion rate so derived is compared favorably to that measured for pure hydrogen in different situations.

Tumor–microenvironment interactions studied by zonal transcriptional profiling of squamous cell lung carcinoma

Invasion is a critical step in lung tumor progression. The interaction between tumor cells and their surroundings may play an important role in tumor invasion and metastasis. To better understand the mechanisms of tumor invasion and tumor-microenvironment interactions in lung tumors, total RNA was isolated from the inner tumor, tumor invasion front, adjacent lung, and distant normal lung tissue from 17 patients with primary squamous cell lung carcinoma using punch-aided laser capture microdissection. Messenger RNA expression profiles were obtained by microarray analysis, and microRNA profiles were generated from eight of these samples using TaqMan Low Density Arrays. Statistical analysis of the expression data showed extensive changes in gene expression in the inner tumor and tumor front compared with the normal lung and adjacent lung tissue. Only a few genes were differentially expressed between tumor front and the inner tumor. Several genes were validated by immunohistochemistry. Evaluation of the microRNA data revealed zonal expression differences in nearly a fourth of the microRNAs analyzed. Validation of selected microRNAs by in situ hybridization demonstrated strong expression of hsa-miR-196a in the inner tumor; moderate expression of hsa-miR-224 in the inner tumor and tumor front, and strong expression of hsa-miR-650 in the adjacent lung tissue. Pathway analysis placed the majority of genes differentially expressed between tumor and nontumor cells in intrinsic processes associated with inflammation and extrinsic processes related to lymphocyte physiology. Genes differentially expressed between the inner tumor and the adjacent lung/normal lung tissue affected pathways of arachidonic acid metabolism and eicosanoid signaling.

Experimental and molecular dynamics study of the growth of crystalline TiO2

Thin films of crystalline TiO2 are of high interest due to their photoactivity and photoinduced hydrophilicity. Previously, preparation of TiO2 has been described in terms of extrinsic process parameters, such as total pressure, oxygen partial pressure, or substrate bias potential. We study the growth of TiO2 phases, rutile and anatase, by atom-by-atom molecular dynamics simulations. We focus on the effect of intrinsic process parameters including particle energy, growth temperature, and growth template. While experiments indicate that the deposition of rutile requires higher temperatures and/or energies compared to anatase, we show that the growth of previously nucleated rutile can take place in a wider range of temperatures and energies compared to anatase. In parallel, we show relationships between crystal growth and the lateral size of a crystal. The results facilitate defining new synthesis pathways for TiO2, and constitute phenomena which may be relevant for other ceramics.

Environmental influences on skin aging and ethnic-specific manifestations

Skin aging does not only occur by passing time alone but also by the exposure to different environmental factors. The skin aging process, which is induced by environmental factors, is named premature or extrinsic skin aging process and can be distinguished from the chronologically (intrinsic) skin aging process by characteristic skin aging signs. Well known environmental factors leading to extrinsic skin aging are sun exposure and smoking. Recently, an epidemiological study could further discover an association between air pollution and skin aging. First of all the skin aging inducing effect of sun exposure was discovered and an own term (photoaging) was given to this special field of extrinsic skin aging. Mechanistic studies have further increased our knowledge about the molecular pathways by which environmental factors contribute to extrinsic skin aging. In this regard, profound knowledge how sun exposure leads to extrinsic skin aging were gained in the last years, and additionally there are also indications how smoking and air pollution might contribute to this process. Moreover it was realized that extrinsic skin aging manifests differently between different populations. Thus, in this review we summarize the influence of the different environmental factors: sun exposure, smoking and air pollution on skin aging and further present ethnic-specific manifestations of extrinsic skin aging.

Role of Relaxation on Cognitive Emotion Regulation of HIV Infected People

AIDS is caused by human immunodeficiency virus (HIV) and it is the most advanced stage of HIV infection. By killing or damaging cells of the body's immune system, HIV progressively destroys the body's ability to fight infections. HIV spread most commonly by having sex with an infected partner. HIV also spread through contact with infected blood, which frequently occurs among injection drug users who share needles or syringes contaminated with blood from someone infected with the virus. Women with HIV can also transmit the virus to their babies during pregnancy, birth, or breast-feeding. In 2009 it was estimated that 2.4 million people were living with HIV in India, which equates to a prevalence of 0.3% (UNAIDS, 2010). 87.1 percent of HIV infections are still occurring through heterosexual routes of transmission. While parent to child transmission accounts for 5.4 percent of HI V cases detected, injecting drug use ( 1.6%), men who have sex with men (1.5%) and contaminated blood and blood products account for 1% percent (NACO, 2010). While this may seem a flow rate, because India's population is so large, it is the world in terms of greatest number of people living with HIV. World Health Organization (2011) estimated a global summary of the AIDS epidemic. The total number of people living with HIV is 34.0 million in which adult rate is 30.1 million, women rate is 16.8 million and children (HIV/AIDS imposes a significant psychological burden. People with HIV often suffer from depression and anxiety as they adjust to the impact of the diagnosis of being infected and face the difficulties of living with a chronic life threatening illness. There is clearly a need for effective coping strategies and stress management programs for individuals with HIV/AIDS. One of the skills that are highly important to learn and implement into daily life is relaxation.Relaxation techniques include behavioral therapeutic approach. Progressive relaxation is a popular technique, in which the individual is taught what it feels like to relax by comparing relaxation with muscle tension. Progressive muscle relaxation (PMR) is said to require several months of practice at least three times per week in order to be able to evoke the relaxation response within seconds.Gross and Thompson (2007) stated that In each moment of our life we are confronted with different kinds of internal or external stimuli that influence our overall functioning, producing modifications in our physiological, cognitive, behavioral, and emotional milieus . A pivotal role in adaptation is played by the subjective perceptions of these changes, namely that result from the multiple evaluations of internal and external stimuli (Denollet, Nykliek, & Vingerhoets, 2008). Emotions have clearly established functions that can both hinder and facilitate the process of adaptation and the maintenance of homeostatic functioning, or propel the development of a dynamic flexibility in emotional experience (Diamond & Aspinwall, 2003). Frijda, (1986) said that through the proper use of our emotions, we can communicate information to others regarding our intentions or internal states. In the same time, the we experience influence our overall intrapersonal functioning. Emotion regulation refers to changes associated with activated emotions (Cole, Martin, & Dennis, 2004), either in their intensity, duration, or related psychological processes. Thompson (1994) defined emotion regulation as all the extrinsic and intrinsic processes responsible for monitoring, evaluating and modifying emotional reactions, especially their intensive and temporal features, to accomplish one's goals. An apparently simplified approach is that of Gross and Thompson (2007), in which emotion regulation is a part of affect regulation, next to coping, mood regulation, and psychological defenses. …

Efficiency of extrinsic and intrinsic charge-carrier photogeneration processes obtained from the steady-state photocurrent action spectra of poly(p-phenylene vinylene) derivatives

The efficiency of the charge-carrier photogeneration processes in poly(2,5-bis(3′,7′-dimethyl-octyloxy)-1,4-phenylene vinylene) (OC1OC10-PPV) has been analyzed by the spectral response of the photocurrent of devices in ITO/polymer/Al structures. The symbatic response of the photocurrent action spectra of the OC1OC10-PPV devices, obtained for light-excitation through the ITO electrode and for forward bias, has been fitted using a phenomenological model which considers that the predominant transport mechanism under external applied electric field is the drift of photogenerated charge-carriers, neglecting charge-carrier diffusion. The proposed model takes into account that charge-carrier photogeneration occurs via intermediate stages of bounded pairs (excitonic states), followed by dissociation processes. Such processes result in two different contributions to the photoconductivity: The first one, associated to direct creation of unbound polaron pairs due to intrinsic photoionization; and the second one is associated to secondary processes like extrinsic photoinjection at the metallic electrodes. The results obtained from the model have shown that the intrinsic component of the photoconductivity at higher excitation energies has a considerably higher efficiency than the extrinsic one, suggesting a dependence on the photon energy for the efficiency of the photogeneration process.

Spatio-temporal patterns of tree establishment are indicative of biotic interactions during early invasion of a montane meadow

Tree invasions of grasslands are occurring globally, with profound consequences for ecosystem structure and function. We explore the spatio-temporal dynamics of tree invasion of a montane meadow in the Cascade Mountains of Oregon, where meadow loss is a conservation concern. We examine the early stages of invasion, where extrinsic and intrinsic processes can be clearly delineated. In a 0.21-ha plot, we mapped and aged 929 trees C0.3-m tall, yielding a detailed record of the spatio-temporal dynamics of invasion. For the primary species, Abies grandis and Pinus contorta ,w e correlated age structures (unimodal in both species) with climate (precipitation, temperature, and snow- pack) and cone production, but found weak or non- significant relationships. Evidence of biotic interac- tions within and between species was obtained by examining the spatial associations of trees to a distance of 5 m and how these changed over time. We used multiple methods including uni- and bivariate forms of the Ripley's K and pair-correlation function (pcf) (corrected for inhomogeneity), the J-function, an evolving nearest-neighbor metric, and a test for directional bias in establishment. Pinus and Abies contributed in contrasting ways to the pace and spatial structure of invasion. Shade-intolerant Pinus tended to establish in the open, initiating clusters. In contrast, shade-tolerant Abies established in association with Pinus or in conspecific clusters. Preferential establish- ment of Abies to the north of older Pinus suggests that facilitation occurs by shading. The factors responsible for initial establishment remain unresolved, but positive interactions are pivotal in accelerating inva- sions, once initiated. Similar processes are likely to occur in other grasslands undergoing rapid conversion to woodland or forest. In combination, analyses of spatial and temporal patterns of establishment provide insight into the processes that structure invasions.

Carpal tunnel syndrome and trigger finger at the wrist caused by an anomalous flexor digitorum superficialis of the index: a case report and review of literature

Carpal tunnel syndrome is usually idiopathic, but many extrinsic or intrinsic processes can cause such a syndrome [1]; anomalies affecting three muscles have been reported to be in relation with carpal tunnel syndrome [2]: hypertrophic or abnormal lumbrical [3–5], palmaris longus and its variants (profundus or reversed) [6–8], and anomalous flexor digitorum superficialis (FDS). In 21 cases of carpal tunnel syndrome, Tanzer described one patient who had FDS which extended completely through the canal [9]. Singer found, in his experience, 147 carpal tunnel release between 1983 and 1993, 74 variations in 60 hands, and introduced a classification of two types for the different anatomic variations [10]. A review of literature revealed that anomalous FDS associated with carpal tunnel syndrome is usually reported, but few cases were described about the association of carpal tunnel and trigger finger at the wrist. A case of a 38-year-old female patient presenting this association secondary to an anomalous FDS muscle belly of the index is described.

Adjusting Phenotypes by Noise Control

Genetically identical cells can show phenotypic variability. This is often caused by stochastic events that originate from randomness in biochemical processes involving in gene expression and other extrinsic cellular processes. From an engineering perspective, there have been efforts focused on theory and experiments to control noise levels by perturbing and replacing gene network components. However, systematic methods for noise control are lacking mainly due to the intractable mathematical structure of noise propagation through reaction networks. Here, we provide a numerical analysis method by quantifying the parametric sensitivity of noise characteristics at the level of the linear noise approximation. Our analysis is readily applicable to various types of noise control and to different types of system; for example, we can orthogonally control the mean and noise levels and can control system dynamics such as noisy oscillations. As an illustration we applied our method to HIV and yeast gene expression systems and metabolic networks. The oscillatory signal control was applied to p53 oscillations from DNA damage. Furthermore, we showed that the efficiency of orthogonal control can be enhanced by applying extrinsic noise and feedback. Our noise control analysis can be applied to any stochastic model belonging to continuous time Markovian systems such as biological and chemical reaction systems, and even computer and social networks. We anticipate the proposed analysis to be a useful tool for designing and controlling synthetic gene networks.

The developing, aging neocortex: how genetics and epigenetics influence early developmental patterning and age-related change.

A hallmark of mammalian development is the generation of functional subdivisions within the nervous system. In humans, this regionalization creates a complex system that regulates behavior, cognition, memory, and emotion. During development, specification of neocortical tissue that leads to functional sensory and motor regions results from an interplay between cortically intrinsic, molecular processes, such as gene expression, and extrinsic processes regulated by sensory input. Cortical specification in mice occurs pre- and perinatally, when gene expression is robust and various anatomical distinctions are observed alongside an emergence of physiological function. After patterning, gene expression continues to shift and axonal connections mature into an adult form. The function of adult cortical gene expression may be to maintain neocortical subdivisions that were established during early patterning. As some changes in neocortical gene expression have been observed past early development into late adulthood, gene expression may also play a role in the altered neocortical function observed in age-related cognitive decline and brain dysfunction. This review provides a discussion of how neocortical gene expression and specific patterns of neocortical sensori-motor axonal connections develop and change throughout the lifespan of the animal. We posit that a role of neocortical gene expression in neocortex is to regulate plasticity mechanisms that impact critical periods for sensory and motor plasticity in aging. We describe results from several studies in aging brain that detail changes in gene expression that may relate to microstructural changes observed in brain anatomy. We discuss the role of altered glucocorticoid signaling in age-related cognitive and functional decline, as well as how aging in the brain may result from immune system activation. We describe how caloric restriction or reduction of oxidative stress may ameliorate effects of aging on the brain.

Emerging concepts in neurogastroenterology and motility

Neurogastroenterology encompasses intrinsic and extrinsic neural processes that regulate gut functions, sensation and related behaviors such as ingestion. In 2011, key advances were made in understanding gut–brain interactions, visceral sensation, serotonin signaling, neurogenesis and neuromuscular transmission.

Raman Spectroscopic Investigation of the Effects of Cosmetic Formulations on the Constituents and Properties of Human Skin

This study aimed to investigate the biochemical alterations in hydration and skin proteins, which are associated with the skin aging process, caused by cosmetic use. Many techniques have been used to assess the effectiveness of cosmetics' hydrating and anti-aging effects on skin. Recently, Raman spectroscopy has been shown to be a powerful, noninvasive tool that can monitor changes in the biomolecules of the skin in real time. Were analyzed human skin in vivo at the beginning of the experiment (T0) and after 30 (T30) and 60 (T60) days of continuous use of a cosmetic product. Fourier-transform and dispersive Raman spectroscopy were the used to examine the periorbicular right lateral eye region of 16 female Brazilian volunteers, aged 60-75 years. Multivariate statistical analysis of principal components analysis (PCA) and linear discriminant analysis were performed on all Raman spectra. Using the cosmetic product for 30 days increased the intensity of the Raman bands for collagen, amide III (1250-1350 cm(-1)) for proteins, and the water (OH) stretching mode at 3250 cm(-1), suggesting that the treatment was effective. The changes observed at T30 were not sustained at the same intensity for 60 days. Intensity variations in other bands may be related to changes in the organization of the epidermis at the dermal matrix. The application of cosmetics with active moisturizing and anti-aging properties helps to maintain the skin's protective barrier and to slow the intrinsic and extrinsic aging processes of the skin.

Generation Separation in Simple Structured Life Cycles: Models and 48 Years of Field Data on a Tea Tortrix Moth

Population cycles have fascinated ecologists since the early nineteenth century, and the dynamics of insect populations have been central to understanding the intrinsic and extrinsic biological processes responsible for these cycles. We analyzed an extraordinary long-term data set (every 5 days for 48 years) of a tea tortrix moth (Adoxophyes honmai) that exhibits two dominant cycles: an annual cycle with a conspicuous pattern of four or five single-generation cycles superimposed on it. General theory offers several candidate mechanisms for generation cycles. To evaluate these, we construct and parameterize a series of temperature-dependent, stage-structured models that include intraspecific competition, parasitism, mate-finding Allee effects, and adult senescence, all in the context of a seasonal environment. By comparing the observed dynamics with predictions from the models, we find that even weak larval competition in the presence of seasonal temperature forcing predicts the two cycles accurately. None of the other mechanisms predicts the dynamics. Detailed dissection of the results shows that a short reproductive life span and differential winter mortality among stages are the additional life-cycle characteristics that permit the sustained cycles. Our general modeling approach is applicable to a wide range of organisms with temperature-dependent life histories and is likely to prove particularly useful in temperate systems where insect pest outbreaks are both density and temperature dependent.

Frequency dependence of spin relaxation in periodic systems

We show that in the presence of a periodic scattering potential the spin relaxation in ultrathin ferromagnets is not a monotonous function of the frequency, as has been usually assumed taking intrinsic Gilbert and extrinsic two-magnon processes into account. The spin relaxation rate is found to substantially increase at characteristic frequencies related to the periodicity of the magnon scattering potential. We propose a theoretical model which is experimentally confirmed in Ni${}_{80}$Fe${}_{20}$ thin films by artificially introducing different scattering periodicities. As a result, the current general approach for determining spin relaxation parameters in thin films has to be reconsidered.

Electromechanical coupling and temperature-dependent polarization reversal in piezoelectric ceramics

Electrostriction plays a central role in describing the electromechanical properties of ferroelectric materials, including widely used piezoelectric ceramics. The piezoelectric properties are closely related to the underlying electrostriction. Small-field piezoelectric properties can be described as electrostriction offset by the remanent polarization which characterizes the ferroelectric state. Indeed, even large-field piezoelectric effects are accurately accounted for by quadratic electrostriction. However, the electromechanical properties deviate from this simple electrostrictive description at electric fields near the coercive field. This is particularly important for actuator applications, for which very high electromechanical coupling can be obtained in this region. This paper presents the results of an experimental study of electromechanical coupling in piezoelectric ceramics at electric field strengths close to the coercive field, and the effects of temperature on electromechanical processes during polarization reversal. The roles of intrinsic ferroelectric strain coupling and extrinsic domain processes and their temperature dependence in determining the electromechanical response are discussed.

Development of a Novel CaP-Containing Mesoporous Silica-Based Xerogels Used as Hemostatic Material with Good Biodegradability and Low Heat Generation

A novel Ca/P-containing mesoporous silica-based xerogels (CaMSX) with good degradability and low heat generation were synthesized for hemorrhage control by a modified sol-gel process and physicochemically characterized. The mesoporous silica-based xerogels without Ca/P (MSX) was also prepared as comparison. The in vitro whole blood coagulation time, activated partial thromboplastin time (APTT) and prothrombin time (PT) of the CaMSX were measured with MSX, Chinese traditional medicin-Yunnan medical powder (YM) and traditional zeolite. In vivo bleeding model was tested with rabbit’ ear side veins. The results illustrated that the CaMSX could remarkably promote the intrinsic and extrinsic blood coagulation processes which greatly depend on the dosage and the content of Ca in the CaMSX. The CaMSX had better efficiency in promoting coagulation process than that of MSX, YM and zeolite.

Embryonic toxicity of sanguinarine through apoptotic processes in mouse blastocysts

In this study, we examined the cytotoxic effects of sanguinarine, a phytoalexin with antimicrobial, anti-oxidant, anti-inflammatory and pro-apoptotic effects, on the blastocyst stage of mouse embryos, subsequent embryonic attachment and outgrowth in vitro and in vivo implantation via embryo transfer. Blastocysts treated with 0.5–2 μM sanguinarine exhibited significantly increased apoptosis and a corresponding decrease in total cell number. Notably, the implantation success rates of blastocysts pretreated with sanguinarine were lower than that of their control counterparts. Moreover, in vitro treatment with 0.5–2 μM sanguinarine was associated with increased resorption of post-implantation embryos and decreased fetal weight. Our results collectively indicate that sanguinarine induces apoptosis and retards early post-implantation development in vitro and in vivo. In addition, sanguinarine induces apoptotic injury effects on mouse blastocysts through intrinsic and extrinsic apoptotic signaling processes to impair sequent embryonic development. However, the extent to which sanguinarine exerts teratogenic effects on early human development is not known at present, and further studies are required to establish effective protection strategies against its cytotoxic effects.

The use of emollient therapy for ageing skin

Skin ageing has intrinsic signs and symptoms, often complicated by extrinsic photo-ageing symptoms and concurrent disease processes. It progresses with age but varies between individuals and its symptoms are numerous. Skin ageing has physical and psychosocial repercussions that can influence coping. Emollient therapy can help to reduce two symptoms--dryness and loss of the skin's barrier function. Better understanding of skin ageing and the usefulness of emollients can be reinforced by education and encouragement from healthcare professionals. Such interventions should encourage self-management and confidence in using emollients. The partnership between healthcare professionals and older people helps to overcome co-existent ageing difficulties, such as cognitive impairment, hearing loss and impairment of manual dexterity and mobility, which enhances self-reliance.

Telomeres as age markers in vertebrate molecular ecology

Chronological age is a fundamental and yet elusive variable in studies of many wild animals. Telomeres are nucleoprotein structures on the ends of chromosomes that change size throughout the life of many animals and because of this property have been advocated as a means to estimate age. In this review, we assess the existing and potential application of using telomeres for age estimation. We argue that there are conceptual and statistical inconsistencies in previous studies and that the basis for telomere change over time is not well understood and affected by several intrinsic and extrinsic process unrelated to chronological time. Furthermore, these processes are likely to vary spatially and temporally for animal populations. We conclude that the current data suggest telomeres should not be used for age estimation. If telomere-based age estimation is to be used, more work in understanding variability in key processes affecting telomere dynamics and rigorous substantiation via blind testing is needed.