153,111 research outputs found
Finger-tapping movements.
No full text(A) A tapping action with the left thumb and index finger is performed. (B) A tapping action with the right thumb and index finger is performed. (C) Tapping with the in-phase task is performed. (D) Tapping with the anti-phase task is performed. The distance between the thumb and index finger is kept between 3 and 4 cm, and movement was performed as fast as possible for 15 s.</p
Zinc finger recombinases with adaptable DNA sequence specificity
No full textSite-specific recombinases have become essential tools in genetics and molecular biology for the precise excision or integration of DNA sequences. However, their utility is currently limited to circumstances where the sites recognized by the recombinase enzyme have been introduced into the DNA being manipulated, or natural 'pseudosites' are already present. Many new applications would become feasible if recombinase activity could be targeted to chosen sequences in natural genomic DNA. Here we demonstrate efficient site-specific recombination at several sequences taken from a 1.9 kilobasepair locus of biotechnological interest (in the bovine beta-casein gene), mediated by zinc finger recombinases (ZFRs), chimaeric enzymes with linked zinc finger (DNA recognition) and recombinase (catalytic) domains. In the "Z-sites" tested here, 22 bp casein gene sequences are flanked by 9 bp motifs recognized by zinc finger domains. Asymmetric Z-sites were recombined by the concomitant action of two ZFRs with different zinc finger DNA-binding specificities, and could be recombined with a heterologous site in the presence of a third recombinase. Our results show that engineered ZFRs may be designed to promote site-specific recombination at many natural DNA sequence
Disruption of the developmental programme of Trypanosoma brucei by genetic ablation of TbZFP1, a differentiation-enriched CCCH protein
No full textThe regulation of differentiation is particularly important in microbial eukaryotes that inhabit multiple environments. The parasite Trypanosoma brucei is an extreme example of this, requiring exquisite gene regulation during transmission from mammals to the tsetse fly vector. Unusually, trypanosomes rely almost exclusively on post-transcriptional mechanisms for regulated gene expression. Hence, RNA binding proteins are potentially of great significance in controlling stage-regulated processes. We have previously identified TbZFP1 as a trypanosome molecule transiently enriched during differentiation to tsetse midgut procyclic forms. This small protein (101 amino acids) contains the unusual CCCH zinc finger, an RNA binding motif. Here, we show that genetic ablation of TbZFP1 compromises repositioning of the mitochondrial genome, a specific event in the strictly regulated differentiation programme. Despite this, other events that occur both before and after this remain intact. Significantly, this phenotype correlates with the TbZFP1 expression profile during differentiation. This is the first genetic disruption of a developmental regulator in T. brucei. It demonstrates that programmed events in parasite development can be uncoupled at the molecular level. It also further supports the importance of CCCH proteins in key aspects of trypanosome cell function
A finger mechanism for adaptive end effectors
No full textThis paper presents design and analysis of a rigid link finger, which may be suitable for a number of adaptive end effectors. The design has evolved from an industrial need for a tele-operated system to be used in nuclear environments. The end effector is designed to assist repair work in nuclear reactors during retrieval operation, particularly for the purpose of grasping objects of various shape, size and mass. The work is based on the University of Southampton's Whole Arm Manipulator, which has a special design consideration for safety and flexibility. The paper discusses kinematic issues associated with the finger design, and to the end of the paper specifies the limits of finger operating parameters for implementing control law
Perceptual distortions of 3-D finger size
No full textOur body is a volumetric, 3-dimensional object in the world, and we experience it as such. Existing methods for measuring the perceptual body image, however, have been based on judgments of 1-dimensional length or 2-dimensional images. We developed a new approach to the 3-D perceptual body image of the fingers by asking people to judge whether each finger would fit through rings of varying diameter. This task requires participants to conceptualize their finger as a volumetric object entering the ring. In two experiments, we used an adaptive staircase procedure to estimate the perceived size of each finger. There were systematic distortions of perceived 3-D finger size, with the size of index finger and (to a lesser extent) the middle finger underestimated. These distortions were unaffected by changes in hand posture. Notably, the pattern of distortions is qualitatively different from that found in previous research investigating 1-D finger length, suggesting that 3-D judgments of the body may differ in fundamental ways from 1-D judgments of individual body dimensions
EXPANDING THE SCOPE OF HETEROGENEOUS BACKBONE DESIGNS TO INCLUDE SINGLE- AND MULTI-DOMAIN ZINC FINGER PROTEINS
No full textPolymers with specific folded conformations — termed “foldamers” — lend themselves to a range of potential applications in therapeutic development and biomedical and material sciences. One promising approach to foldamer design is to incorporate a combination of unnatural building blocks that retain a peptide’s natural side chains while altering the backbone upon which the side chains are displayed. This creates a peptide variant with a heterogenous backbone and native-like folds and functions.
The focus of this dissertation is on recent work towards expanding the scope of heterogeneous backbone design strategies and consists of two main goals. The first goal is to mimic the tertiary structure of a single zinc finger domain (the third finger of Specificity protein 1, Sp1-3). This expands design strategies past simple tertiary structures and presents dynamic challenges such as retaining a precise metal coordination site. Data shown here indicate that appropriately designed alterations can allow for a tertiary structure that is superior to that of the native backbone in the context of folded stability and native ligand binding.
The second goal discussed in this work is two part: 1) to investigate if the increase in folded stability seen with single domain Sp1-3 backbone variants can be generalized to other Cis2His2 zinc finger sequences and 2) to synthesize a multi-domain zinc finger protein through native chemical ligation. Each of these aims attempts to push towards the longer-term goal of gaining a better understanding of how backbone alterations impact DNA binding in multi-domain zinc fingers
Integrated management of Striga hermonthica and cereal stemborers in finger millet (Eleusine coracana (L.) Gaertn.) through intercropping with Desmodium intortum
No full textWe evaluated the potential role of greenleaf desmodium, Desmodium intortum (Mill.) Urb., in the combined management of Striga hermonthica and cereal stemborers in finger millet (Eleusine coracana (L.) Gaertn.) in western Kenya between 2007 and 2008. Treatments comprised finger millet planted either as monocrop stands or intercropped with D. intortum. S. hermonthica counts were significantly lower in the intercrop than in the monocrop plots. Similarly, multi-season analyses showed that the proportions of stemborer-damaged plants were significantly lower in the intercrop than in the monocrop. These differences were associated with significantly higher grain yields in the intercrop than in the monocrop. Total labour and variable costs were significantly higher in the intercrop resulting from the additional seed cost and labour to plant, manage and harvest D. intortum. However, total revenue and gross margins were significantly higher in the intercrop due to the higher finger millet grain yields and additional product, D. intortum forage, part of which is consumed by farmers' own livestock or used for own plot extension, and the remaining amount is sold. Our results demonstrate that intercropping finger millet with D. intortum offers an effective means of control of both pests, leading to higher grain yields and economic returns
Vibration-induced white finger in dockyard employees
No full textVibration-induced white finger (VWF) is a vascular condition associated with occupational exposure to hand-transmitted vibration. The fingers are prone to intermittent blanching attacks which may be triggered by cold conditions and are usually accompanied by numbness and tingling or pain. VWF has been associated with the use of various tools and processes, among which are the percussive and rotary metal-working tools used in ship repair work. This thesis describes a study of dose-effect relationships for VWF in dockyard employees.A review of the literature revealed more than 40 epidemiological studies of VWF in workers using hand-held metal-working tools. Measurements of tool vibration have also been reported, but few researchers have combined epidemiological studies of VWF with measurements of the vibration exposures Involved. Some dose-effect relationships have been suggested and current standards contain tentative dose effect guidance. Some recent authors have suggested that the frequency weighting and time-dependencies assumed In current standards are inadequate.Methods for the measurement of hand-transmitted vibration were assessed. The vibration characteristics of sixteen pneumatic tools commonly used in dockyard work were measured in the laboratory. Repeated measurements were made In three axes at each hand position and analysis included the computation of narrow-band spectra, acceleration magnitudes in octave bands and overall frequency-weighted and unweighted acceleration magnitudes.A survey of vibration-exposed employees in a dockyard was conducted by questionnaire. Information related to symptoms of VWF, and the history of use of vibrating tools was obtained from each individual. The severity of blanching in each affected individual was recorded using a scoring system.The severity and prevalence of symptoms were related to various measures of vibration 'dose' (i.e. combinations of measured vibration magnitudes and reported exposure times) by logistic regression and survival analysis. A highly significant relationship between VWF severity and exposure time was demonstrated. However, the use of frequency-weighted acceleration in dose calculations reduced the goodness of fit, while unweighted acceleration gave a small improvement in some cases. This suggests that higher frequencies in the range 6.3 Hz to 1250 Hz are of greater Importance than current standards imply. The effect of vibration magnitude was found to be small compared with that of exposure time and no clear effect of vibration direction or vibration frequency was demonstrated.No evidence was found for a time-dependency of the form assumed in current standards. It is possible that the risk of VWF may not be directly related to the vibration magnitude, but that a 'threshold' magnitude exists, below which the hazard is small and above which it is proportional to a function of the exposure time. Further Investigation of this hypothesis is recommended
Zinc finger, AN1-type domain 2A--a novel target for lung cancer
No full textArsenic is a commonly toxincant found in the natural environment and from anthropogenic sources. Arsenic exposure can produce multiple adverse effects including chronic lung disease and lung cancer. The Ubiquitin Proteasome System (UPS) is involved in disease development and aging, its dysfunction can cause improper degradation of misfolded and unfolded proteins. UPS is regulated, in part, by zinc finger gene, thus zinc finger gene can mediate protein degradation, disease development and aging. Zinc finger AN1-type domain 2A (ZFAND2A) can be induced by arsenic and heat shock, and it plays an important role in maintaining cellular homeostasis and longevity. Here, we present a short review about arsenic-induced diseases, the UPS protein degradation machinery, and ZFAND2A and a preliminary study addressing ZFAND2A expression in NCI-H441 cell (human lung adenocarcinoma epithelial cell line) following treatment with heat shock or sodium arsenite. H441 cells appear to be resistant to the arsenic cytotoxicity and ZFAND2A increased markedly in these cells in response to heat stress or arsenic exposure. Because ZFAND2A is thought to improve UPS function and thus could be viewed as protective to cancer cells, it has significant public health relevance, future studies targeting ZFAND2A may be useful in the development of novel therapies to lung cancer
Haptic-Motor Transformations for the Control of Finger Position
No full textabstract: Dexterous manipulation relies on modulation of digit forces as a function of digit placement. However, little is known about the sense of position of the vertical distance between finger pads relative to each other. We quantified subjects' ability to match perceived vertical distance between the thumb and index finger pads (d[subscript y]) of the right hand (“reference” hand) using the same or opposite hand (“test” hand) after a 10-second delay without vision of the hands. The reference hand digits were passively placed non-collinearly so that the thumb was higher or lower than the index finger (d[subscript y] = 30 or –30 mm, respectively) or collinearly (d[subscript y] = 0 mm). Subjects reproduced reference hand d[subscript y] by using a congruent or inverse test hand posture while exerting negligible digit forces onto a handle. We hypothesized that matching error (reference hand d[subscript y] minus test hand d[subscript y]) would be greater (a) for collinear than non-collinear d[subscript y]s, (b) when reference and test hand postures were not congruent, and (c) when subjects reproduced dy using the opposite hand. Our results confirmed our hypotheses. Under-estimation errors were produced when the postures of reference and test hand were not congruent, and when test hand was the opposite hand. These findings indicate that perceived finger pad distance is reproduced less accurately (1) with the opposite than the same hand and (2) when higher-level processing of the somatosensory feedback is required for non-congruent hand postures. We propose that erroneous sensing of finger pad distance, if not compensated for during contact and onset of manipulation, might lead to manipulation performance errors as digit forces have to be modulated to perceived digit placement.The article is published at http://journals.plos.org/plosone/article?id=10.1371/journal.pone.006614
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