76 research outputs found
Touch uses frictional cues to discriminate flat materials
In a forced-choice task, we asked human participants to discriminate by touch alone glass plates from transparent polymethyl methacrylate (PMMA) plastic plates. While the surfaces were flat and did not exhibit geometric features beyond a few tens of nanometres, the materials differed by their molecular structures. They produced similar coefficients of friction and thermal effects were controlled. Most participants performed well above chance and participants with dry fingers discriminated the materials especially well. Current models of tactile surface perception appeal to surface topography and cannot explain our results. A correlation analysis between detailed measurements of the interfacial forces and discrimination performance suggested that the perceptual task depended on the transitory contact phase leading to full slip. This result demonstrates that differences in interfacial mechanics between the finger and a material can be sensed by touch and that the evanescent mechanics that take place before the onset of steady slip have perceptual value
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Gone Rogue: An Analysis of Rogue Security Software Campaigns
In the past few years, Internet miscreants have developed a number of techniques to defraud and make a hefty profit out of their unsuspecting victims. A troubling, recent example of this trend is cyber-criminals distributing rogue security software, that is malicious programs that,by pretending to be legitimate security tools (e.g., anti-virus or anti-spyware), deceive users into paying a substantial amount of money in exchange for little or no protection.While the technical and economical aspects of rogue security software (e.g., its distribution and monetization mechanisms) are relatively well-understood, much less is known about the campaigns through which this type of malware is distributed, that is what are the underlying techniques and coordinated efforts employed by cyber-criminals to spread their malware.In this paper, we present the techniques we used to analyze rogue security software campaigns, with an emphasis on the infrastructure employed in the campaign and the life-cycle of the clients that they infect
Phase I/II Trial of Liver-derived Mesenchymal Stem Cells in Pediatric Liver-based Metabolic Disorders: A Prospective, Open Label, Multicenter, Partially Randomized, Safety Study of One Cycle of Heterologous Human Adult Liver-derived Progenitor Cells (HepaStem) in Urea Cycle Disorders and Crigler-Najjar Syndrome Patients
Background.
Regenerative medicine using stem cell technology is an emerging field that is currently tested for inborn and acquired liver diseases.
Objective.
This phase I/II prospective, open label, multicenter, randomized trial aimed primarily at evaluating the safety of Heterologous Human Adult Liver–derived Progenitor Cells (HepaStem) in pediatric patients with urea cycle disorders (UCDs) or Crigler-Najjar (CN) syndrome 6 months posttransplantation. The secondary objective included the assessment of safety up to 12 months postinfusion and of preliminary efficacy.
Methods.
Fourteen patients with UCDs and 6 with CN syndrome were divided into 3 cohorts by body weight and intraportally infused with 3 doses of HepaStem. Clinical status, portal vein hemodynamics, morphology of the liver, de novo detection of circulating anti–human leukocyte antigen antibodies, and clinically significant adverse events (AEs) and serious adverse events to infusion were evaluated by using an intent-to-treat analysis.
Results.
The overall safety of HepaStem was confirmed. For the entire study period, patient-month incidence rate was 1.76 for the AEs and 0.21 for the serious adverse events, of which 38% occurred within 1 month postinfusion. There was a trend of higher events in UCD as compared with CN patients. Segmental left portal vein thrombosis occurred in 1 patient and intraluminal local transient thrombus in a second patient. The other AEs were in line with expectations for catheter placement, cell infusion, concomitant medications, age, and underlying diseases.
Conclusions.
This study led to European clinical trial authorization for a phase II study in a homogeneous patient cohort, with repeated infusions and intermediate doses
GABA Receptors and the Pharmacology of Sleep
Current GABAergic sleep-promoting medications were developed pragmatically, without making use of the immense diversity of GABAA receptors. Pharmacogenetic experiments are leading to an understanding of the circuit mechanisms in the hypothalamus by which zolpidem and similar compounds induce sleep at α2βγ2-type GABAA receptors. Drugs acting at more selective receptor types, for example, at receptors containing the α2 and/or α3 subunits expressed in hypothalamic and brain stem areas, could in principle be useful as hypnotics/anxiolytics. A highly promising sleep-promoting drug, gaboxadol, which activates αβδ-type receptors failed in clinical trials. Thus, for the time being, drugs such as zolpidem, which work as positive allosteric modulators at GABAA receptors, continue to be some of the most effective compounds to treat primary insomnia
Understanding acute ankle ligamentous sprain injury in sports
This paper summarizes the current understanding on acute ankle sprain injury, which is the most common acute sport trauma, accounting for about 14% of all sport-related injuries. Among, 80% are ligamentous sprains caused by explosive inversion or supination. The injury motion often happens at the subtalar joint and tears the anterior talofibular ligament (ATFL) which possesses the lowest ultimate load among the lateral ligaments at the ankle. For extrinsic risk factors to ankle sprain injury, prescribing orthosis decreases the risk while increased exercise intensity in soccer raises the risk. For intrinsic factors, a foot size with increased width, an increased ankle eversion to inversion strength, plantarflexion strength and ratio between dorsiflexion and plantarflexion strength, and limb dominance could increase the ankle sprain injury risk. Players with a previous sprain history, players wearing shoes with air cells, players who do not stretch before exercising, players with inferior single leg balance, and overweight players are 4.9, 4.3, 2.6, 2.4 and 3.9 times more likely to sustain an ankle sprain injury. The aetiology of most ankle sprain injuries is incorrect foot positioning at landing – a medially-deviated vertical ground reaction force causes an explosive supination or inversion moment at the subtalar joint in a short time (about 50 ms). Another aetiology is the delayed reaction time of the peroneal muscles at the lateral aspect of the ankle (60–90 ms). The failure supination or inversion torque is about 41–45 Nm to cause ligamentous rupture in simulated spraining tests on cadaver. A previous case report revealed that the ankle joint reached 48 degrees inversion and 10 degrees internal rotation during an accidental grade I ankle ligamentous sprain injury during a dynamic cutting trial in laboratory. Diagnosis techniques and grading systems vary, but the management of ankle ligamentous sprain injury is mainly conservative. Immobilization should not be used as it results in joint stiffness, muscle atrophy and loss of proprioception. Traditional Chinese medicine such as herbs, massage and acupuncture were well applied in China in managing sports injuries, and was reported to be effective in relieving pain, reducing swelling and edema, and restoring normal ankle function. Finally, the best practice of sports medicine would be to prevent the injury. Different previous approaches, including designing prophylactice devices, introducing functional interventions, as well as change of games rules were highlighted. This paper allows the readers to catch up with the previous researches on ankle sprain injury, and facilitate the future research idea on sport-related ankle sprain injury
Os impactos da gestão do conhecimento na orientação estratégica, na inovatividade e nos resultados organizacionais: uma survey com empresas instaladas no Brasil
Normal and Tangential Forces Combine to Convey Contact Pressure During Dynamic Tactile Stimulation
Humans need to accurately process the contact forces that arise as they perform everyday haptic interactions such as sliding the fingers along a surface to feel for bumps, sticky regions, or other irregularities. Several different mechanisms are possible for how the forces on the skin could be represented and integrated in such interactions. In this study, we used a force-controlled robotic platform and simultaneous ultrasonic modulation of the finger-surface friction to independently manipulate the normal and tangential forces during passive haptic stimulation by a flat surface. To assess whether the contact pressure on their finger had briefly increased or decreased during individual trials in this broad stimulus set, participants did not rely solely on either the normal force or the tangential force. Instead, they integrated tactile cues induced by both components. Support-vector-machine analysis classified physical trial data with up to 75% accuracy and suggested a linear perceptual mechanism. In addition, the change in the amplitude of the force vector predicted participants’ responses better than the change of the coefficient of dynamic friction, suggesting that intensive tactile cues are meaningful in this task. These results provide novel insights about how normal and tangential forces shape the perception of tactile contact
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Development of laser-based resonance ionization techniques for 81-Kr and 85-Kr measurements in the geosciences, II. December 1, 1994 through December 31, 2000 reporting period. Final technical report for Grant No. DE-FG05-95ER14497
A facility for measurement of rare Kr-81 and Kr-85 isotope concentration in hydrogeologic samples, and isotopic composition of minute quantities of krypton and xenon from extraterrestrial samples, was established, requiring refinement of an emerging mass spectrometric-based analytical technique and securing of laboratory space and equipment. The analytical process consists of (1) collecting a groundwater sample, (2) degassing the water, (3) separating Kr from the recovered gases, (4&5) two isotopic enrichments to reduce interfering isotopes by E9, and (6) detecting the rare krypton isotope in a unique time-of-flight mass spectrometer detecting as few as 100 Kr atoms. All equipment is installed and operating, with only some additional adjustment and testing of the last step (6, above) remaining to be completed. Collaborations have been established with a number of researchers and organizations world wide, and both groundwater and extraterrestrial samples have been collected. Completion of analyses awaits full operation of step 6
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