A wirelessly programmable, skin-integrated thermo-haptic stimulator system for virtual reality.

Sensations of heat and touch produced by receptors in the skin are of essential importance for perceptions of the physical environment, with a particularly powerful role in interpersonal interactions. Advances in technologies for replicating these sensations in a programmable manner have the potential not only to enhance virtual/augmented reality environments but they also hold promise in medical applications for individuals with amputations or impaired sensory function. Engineering challenges are in achieving interfaces with precise spatial resolution, power-efficient operation, wide dynamic range, and fast temporal responses in both thermal and in physical modulation, with forms that can extend over large regions of the body. This paper introduces a wireless, skin-compatible interface for thermo-haptic modulation designed to address some of these challenges, with the ability to deliver programmable patterns of enhanced vibrational displacement and high-speed thermal stimulation. Experimental and computational investigations quantify the thermal and mechanical efficiency of a vertically stacked design layout in the thermo-haptic stimulators that also supports real-time, closed-loop control mechanisms. The platform is effective in conveying thermal and physical information through the skin, as demonstrated in the control of robotic prosthetics and in interactions with pressure/temperature-sensitive touch displays.

Battery-free, wireless soft sensors for continuous multi-site measurements of pressure and temperature from patients at risk for pressure injuries.

Capabilities for continuous monitoring of pressures and temperatures at critical skin interfaces can help to guide care strategies that minimize the potential for pressure injuries in hospitalized patients or in individuals confined to the bed. This paper introduces a soft, skin-mountable class of sensor system for this purpose. The design includes a pressure-responsive element based on membrane deflection and a battery-free, wireless mode of operation capable of multi-site measurements at strategic locations across the body. Such devices yield continuous, simultaneous readings of pressure and temperature in a sequential readout scheme from a pair of primary antennas mounted under the bedding and connected to a wireless reader and a multiplexer located at the bedside. Experimental evaluation of the sensor and the complete system includes benchtop measurements and numerical simulations of the key features. Clinical trials involving two hemiplegic patients and a tetraplegic patient demonstrate the feasibility, functionality and long-term stability of this technology in operating hospital settings.

Characterization of smooth muscle, enteric nerve, interstitial cells of Cajal, and fibroblast-like cells in the gastric musculature of patients with diabetes mellitus.

AIM: To investigate histologic abnormalities in the gastric smooth muscle of patients with diabetes mellitus (DM). METHODS: Full-thickness gastric specimens were obtained from patients undergoing surgery for gastric cancer. H&E stain and Masson's Trichrome stain were performed to assess the degree of fibrosis. Immunohistochemical staining using various antibodies was also performed [antibodies against protein gene product 9.5 (PGP9.5), neuronal nitric oxide synthase (nNOS), vasoactive intestinal peptide (VIP), neurokinin-1 (NK1) receptor, c-Kit, and platelet-derived growth factor receptor-alpha, (PDGFRα)]. Immunofluorescent staining and evaluation with confocal microscopy were also conducted. RESULTS: Twenty-six controls and 35 diabetic patients (21 short-duration patients and 14 long-duration patients) were included. There were no significant differences in basic demographics between the two groups except in mean body mass index (BMI) (higher in the DM group). Proportions of moderate-to-severe intercellular fibrosis in the muscle layer were significantly higher in the DM group than in the control group (P < 0.01). On immunohistochemical staining, c-Kit- and PDGFRα-positive immunoreactivity were significantly decreased in the DM group compared with the control group (P < 0.05). There were no statistically significant differences in PGP9.5, nNOS, VIP, and neurokinin 1 expression. On immunofluorescent staining, cellularity of interstitial cells of Cajal (ICC) was observed to decrease with increasing duration of DM. CONCLUSION: Our study suggests that increased intercellular fibrosis, loss of ICC, and loss of fibroblast-like cells are found in the smooth muscle of DM patients. These abnormalities may contribute to changes in gastric motor activity in patients with DM.

[Comparison of transient elastography and hepatic fibrosis assessed by histology in chronic liver disease].

BACKGROUND/AIMS: Transient elastography (Fibroscan, Echosens, France) is a new, simple, and non-invasive method to assess the degree of hepatic fibrosis by measuring liver stiffness. Recent reports have shown that liver stiffness measurement using Fibroscan allowed accurate prediction of hepatic fibrosis in patient with chronic hepatitis C. The aim of this study was to evaluate accuracy of Fibroscan for the detection of hepatic fibrosis in Korea with various etiologies of chronic liver disease by comparison with fibrosis assessed by histologic examination. METHODS: Fifty-four patients with chronic liver diseases, which were histologically confirmed within recent 6 months were enrolled. Etiologies were HBV, HCV infection, autoimmune hepatitis, and non alcoholic steatohepatitis. Hepatic fibrosis was graded on the basis of standard guideline proposed by the Korean Study Group for the Pathology of Digestive Diseases. RESULTS: Fibroscan values were significantly higher in F3 (16.96 kPa) and F4 (19.86 kPa) than others (p=0.003). Liver stiffness measurement was significantly correlated to the fibrosis stage (r=0.614, p<0.0001). CONCLUSIONS: Liver stiffness measurement by Fibroscan is a promising method for the assessment of hepatic fibrosis in chronic liver disease because it accompanies no complication.

[The factors related to the prognosis of solitary hepatocellular carcinoma after radiofrequency ablation].

BACKGROUND/AIMS: Several risk factors, such as size and location, are related to local recurrence after radiofrequency ablation (RFA) in the treatment of hepatocellular carcinoma (HCC). The objectives of this study were to clarify factors related to prognosis. METHODS: From October 1999 to December 2002, we performed RFA for 107 consecutive patients with solitary HCC. We evaluated spiral computed tomography and serum alpha-fetoprotein level every 3 months after RFA. Seven possible factors for prognosis were analyzed using the Cox proportional hazards regression model: tumor size, tumor location, age, sex, etiology, platelet count, and Child-Pugh classification. Overall survival and disease free survival rate were estimated using the Kaplan-Meier method, and differences between two groups were compared using the log rank test. RESULTS: The Kaplan-Meier estimates of overall survival after radiofrequency ablation were 90.5% at 12 months, 67.4% at 24 months and 46.4% at 36 months and disease free survival were 71.4%, 46.7% and 20.9%, respectively. Using the Cox proportional hazards regression model, it was shown that with regard to overall survival and disease free survival, Child-Pugh classification (P=0.001, P=0.026) and platelet count (P<0.001, P=0.002) were statistically significant factors. The other factors did not have a statistically significant relationship to overall survival and disease free survival. CONCLUSIONS: The size and location known as local recurrence factors were not statistically significant with regard to survival and disease free survival. The Child-Pugh classification and platelet count, that reflect the liver function at the time of RFA, were significant factors for prognosis.