85,696 research outputs found
Finger-Positional Change in Three Zinc Finger Protein Sp1: Influence of Terminal Finger in DNA Recognition<sup>†</sup>
No full textThe connection of functional modules is effective for the design of DNA binding molecules
with the desired sequence specificity. C2H2-type zinc finger proteins have a tandemly repeated array structure
consisting of independent finger modules and are expected to recognize any DNA sequences by permutation,
multi-connection, and the substitution of various sets of zinc fingers. To investigate the effects of the
replacement of the terminal finger on the DNA recognition by other fingers, we have constructed the
three zinc finger peptides with finger substitution at the N- or C-terminus, Sp1(zf223), Sp1(zf323), and
Sp1(zf321). From the results of gel mobility shift assays, each mutant peptide binds preferentially to the
target sequence that is predicted if the fingers act in a modular fashion. The methylation interference
analyses demonstrate that in the cases of the N-terminal finger substitution mutants, Sp1(zf223) and Sp1(zf323), the N-terminal finger recognizes bases to different extents from that of the wild-type peptide,
Sp1(zf123). Of special interest is the fact that the N-terminal finger of the C-terminal finger substitution
mutant, Sp1(zf321), shows a distinct base recognition from those of Sp1(zf123) and Sp1(zf323). DNase
I footprinting analyses indicate that the C-terminal finger (active finger) induces a conformational change
in the DNA in the region for the binding of the N-terminal finger (passive finger). The present results
strongly suggest that the extent of base recognition of the N-terminal finger is dominated by the binding
of the C-terminal finger. This information provides an important clue for the creation of a zinc finger
peptide with the desired specificity, which is applicable to the design of novel drugs and biological tools
Relation between vibrotactile perception thresholds and reductions in finger blood flow induced by vibration of the hand at frequencies in the range 8–250 Hz
No full textPurpose: this study investigated how the vasoconstriction induced by vibration depends on the frequency of vibration when the vibration magnitude is defined by individual thresholds for perceiving vibration [i.e. sensation levels (SL)].Methods: fourteen healthy subjects attended the laboratory on seven occasions: for six vibration frequencies (8, 16, 31.5, 63, 125, or 250 Hz) and a static control condition. Finger blood flow (FBF) was measured in the middle fingers of both hands at 30-second intervals during five successive periods: (i) no force or vibration, (ii) 2-N force, no vibration, (iii) 2-N force, vibration, (iv) 2-N force, no vibration, (v) no force or vibration. During period (iii), vibration was applied to the right thenar eminence via a 6-mm diameter probe during ten successive 3-min periods as the vibration magnitude increased in ten steps (?10 to +40 dB SL).Results: with vibration at 63, 125, and 250 Hz, there was vasoconstriction on both hands when the vibration magnitude reached 10 dB SL. With vibration at 8, 16, and 31.5 Hz, there was no significant vasoconstriction until the vibration reached 25 dB SL. At all frequencies, there was greater vasoconstriction with greater magnitudes of vibration.Conclusions: it is concluded that at the higher frequencies (63, 125, and 250 Hz), the Pacinian channel mediates vibrotactile sensations near threshold and vasoconstriction occurs when vibration is perceptible. At lower frequencies (8, 16, and 31.5 Hz), the Pacinian channel does not mediate sensations near threshold and vasoconstriction commences at greater magnitudes when the Pacinian channel is activate
seal n ( finger
No full textseal nA scratch or other open wound...made the sealer liable to an occupational hazard known as 'seal-finger' or 'spekk-finger' (Norwegian for 'blubber finger').PRINTED ITEM DNE SupG.M.Story DEC.14 1987WK [ Add to DNE seal n 4, to 1979 cite ]Used I and SupUsed I and Sup4Used Supsile,soil,swale,swile,swoil(e),bay,harbour,harp,hood,old,square flipper,square a,young,bedlamer,dotard,ragged-jacket,saddleback,turner,white-coat,pelt n,sculp n;~bait/bat/cat/catcher/dart/fat/finger/hunt(er)/gun/hand/heaMore collocations:~hunting/shot/skin(er)/soap/twine/vat/bird/penis/worm/frame/oil/pan/pass/patch;~fish/er(y)/ing;dog1;pup;cock,cod worm;snub1;blow hole;bobbing~;sealer1;fish kille
Karate white belt finger
No full textDear Editor-in-chief
Traditional Shotokan Karate training requires hand conditioning using the Okinawan traditional padded punching board, the “makiwara ”(maki -“roll up ”or “wrap”, and wara- to “straw”). Karate practitioners used to work out for hours with this device, to toughen the hands and strengthen the wrists to be able to deliver more powerful hand techniques. However, even though they may not use a makiwara, modern karatekas practice their karate strikes on sandbags. This training may produce different injuries (Adams and Mutasim, 2001; Vayssairat et al., 1984). Crosby (Crosby, 1985) radiographed the hands and wrists of 22 karate instructors, 17 of whom punched regularly the makiwara and performed pushups on the knuckles every day. He concluded that zealous use of the makiwara was a cause of pain and stiffness in the hands and wrists, but neither practice had a consistently deleterious effect on the mobility of the index and middle fingers metacarpo- phalangeal joints which bore the brunt of the impact.
“Karate Kid finger ”(Chiu, 1993) is a traumatic condition of the little finger occurring in karate participants. It may become clinically evident as pain and paraesthesiae along the ulnar border of the little finger and hand. The ulnar dorsal digital nerve of the little finger can be damaged by repetitive contusion when the hand performs karate chop called “tsuki”. The repetitive impact may cause fibrosis within the nerve sheaths and between the nerve fibres. The “Karate Kid finger ”is managed surgically by neurolysis. Overuse and poor technique are considered risk factors. Gichin Funakoshi, the father of modern karate, in the book Karate Jitsu (Funakoshi, 2001), decribes the correct way of performing the karate chop “tsuki”. Precisely, he pointed out that the “seiken ”(the traditional karate “tsuki”) has four point of contact: the first two knuckles and the proximal interphalangeal joint of the index and middle finger. Even though Funaskoshi recommended to practice on makiwara, he was aware of the risks which can be carried out by an uncontrolled and excessive training. Infact, he also wrote: “Then there are those who, having a superficial knowledge of one or two karate techniques, hold their fists in such a way as to call attention to their callused knuckles while pushing their way through crowds as if looking for a fight - foolish beyond words”(Funakoshi, 1995). As proper technique to perform the karate “tsuki ”requires impact to be driven on the first two knuckles and the proximal interphalangeal joint of the index and middle finger, the forearm pronated and the wrist slightly ulnar deviated. The causative factor of the “Karate Kid finger ”is poor technique. The ulnar dorsal digital nerve of the little finger can be damaged only if the “tsuki ”is performed as usually the lower level karatekas (white belt) do, namely with the knuckles of the middle, ring, and little finger as the points of impact. Hence, we suggest that this condition should be more aptly named “karate white belt finger”
Experimental studies of position control of linkage based robotic finger
No full textThe experimental study of position control of a light
weight and small size robotic finger during non-contact motion is presented in this paper. The finger possesses fingertip pinching and self adaptive grasping capabilities, and is made of a seven bar linkage mechanism with a slider in the middle phalanx. The control system is tested under the Proportional Integral Derivative (PID) control algorithm and Recursive Least Square (RLS) based Feedback Error Learning (FEL) control scheme to overcome the uncertainties present in the plant. The experiments conducted in Matlab Simulink and xPC Target environments show that the overall control strategy is efficient
in controlling the finger movement
The Hybrid Finger: Combining Nature with Technology into a 3D Printed Finger for a Hand Prosthesis with Minimized Assembly
No full textAccess to prosthetics is very limited to many potentialusers, while the need is high. There are two main reasonsfor this that both are related to the production of prosthetics: the lack of skilled people and high costs. Minimizedassembly production using 3D printing could be a solution: no training is required, assembly takes only a shortamount of time and cheap materials can be used. Besides,3D printing is a good method for customization. Therefore, this study proposes a 3D-printed finger for a bodypowered hand prosthesis with minimized assembly. Thedesign approach is the following. First, the human fingeranatomy is studied. Then, a stylized version of the humanfinger is made that includes only the functions required forthe prosthesis. Finally, the design principles of the stylizedfinger are evaluated and structurized. Based on the designprinciples, a finger for a prosthetic hand is designed anda prototype is developed. The prototype is produced withan Ultimaker 3 using a rigid and a flexible material in oneprint. The evaluation of the prototype shows promisingresults. The finger is suitable for a hand prosthesis thatcan perform an adaptive power grip and a pinch grip. Themass of the finger is 17 grams, which makes the fingercomfortable to wear. An actuation force of only 16 N isrequired to fully bend the finger. Minimized assembly andcheap production are achieved: only four assembly stepsare required and the material costs are only 1.68 eurosper finger. In conclusion, the prototype shows a promisingstep in the direction of a hand prosthesis that is affordable,functional, body-powered, and has minimized assemblyMechanical Engineerin
PHYSIOLOGICAL FUNCTIONS OF THE HUMAN FINGER
No full textUsing morphological data describing the physiological Curvature morphology of the corresponding articulating surfaces in each finger joint, it is shown that a) the flexion of each finger joint is described by two angles of flexion; b) in each finger joint, a "pump mechanism" for synovial fluid is present whose function is to lubricate and nourish the joint cartilage and c) finger posture has six kinematic degrees of freedom (DOF). Since six muscle forces control Finger posture, the relationship between the muscle forces and finger posture is unambiguously described. The states of flexion of the interphalangeal joints restrict possible flexions in the metacarpophalangeal joint. Since the muscle forces act Simultaneously on all three finger joints, the interdependence of the flexional states in the three finger joints can be attributed to the alignment of the lines of force and their sites of insertion, as a function of the corresponding flexion in the joints
PHYSIOLOGICAL FUNCTIONS OF THE HUMAN FINGER
No full textUsing morphological data describing the physiological Curvature morphology of the corresponding articulating surfaces in each finger joint, it is shown that a) the flexion of each finger joint is described by two angles of flexion; b) in each finger joint, a "pump mechanism" for synovial fluid is present whose function is to lubricate and nourish the joint cartilage and c) finger posture has six kinematic degrees of freedom (DOF). Since six muscle forces control Finger posture, the relationship between the muscle forces and finger posture is unambiguously described. The states of flexion of the interphalangeal joints restrict possible flexions in the metacarpophalangeal joint. Since the muscle forces act Simultaneously on all three finger joints, the interdependence of the flexional states in the three finger joints can be attributed to the alignment of the lines of force and their sites of insertion, as a function of the corresponding flexion in the joints
The Determination of Finger Flexor Critical Force in Rock Climbers
No full textPurpose: To determine if the mathematical model used for the estimation of critical force (CF) and the energy store component W’ is applicable to intermittent isometric muscle actions of the finger flexors of rock climbers, using a multi-session test. As a secondary aim, the agreement of estimates of CF and W’ from a single-session test were also determined. The CF was defined as the slope coefficient and W’ the intercept of the linear relationship between total “isometric work” (Wlim) and time to exhaustion (Tlim). Methods: Subjects performed three (separated by either 20 m or >24 h) tests to failure using intermittent isometric finger flexor contractions at 45, 60 and 80% of their maximum voluntary contraction (MVC). Results: Force plotted against Tlim displayed a hyperbolic relationship, correlation coefficients of the parameter estimates from the work–time CF model were consistently very high (R2 > 0.94). Climbers mean CF was 425.7 ± 82.8 N (41.0 ± 6.2% MVC) and W’ 30882 ± 11820 N·s. Good agreement was found between the single and multi-session protocol for CF (ICC(3,1) = 0.900, 95% Confidence Interval [CI95%] 0.616 – 0.979), but not for W’ (ICC(3,1) = 0.768, CI95% 0.190 – 0.949). Conclusions: The results demonstrated the sensitivity of a simple test for the determination of CF and W’, using equipment readily available in most climbing gyms. While further work is still necessary, the test of CF described is of value for understanding exercise tolerance and determine optimal training prescription to monitor improvements the performance of the finger flexors
Design of a 2-Finger Hand Exoskeleton for Finger Stiffness Measurements
No full textRecent studies of human arm movements have suggested that the control of stiffness may be important both for maintaining stability and for achieving differences in movement accuracy. Several studies in the robotic field demonstrated that grasp stiffness is useful for modelling and controlling manipulators but, even though it is accredited that having models of the human finger impedance would be very desirable for the control of anthropomorphous robot's hands, relatively few studies have focused on finger and hand stiffness. To allow the measurement of such entities at the finger level, an appropriate device capable of applying fast force transients while at the same time be able to monitor the finger movements is required. The work presented in this paper is a very detailed report about the design of a new hand exoskeleton system that will be used in our future works to investigate the finger stiffness range in different grasping postures and conditions
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