Magnetic Cellular Nonlinear Network with Spin Wave Bus for Image Processing

We describe and analyze a cellular nonlinear network based on magnetic nanostructures for image processing. The network consists of magneto-electric cells integrated onto a common ferromagnetic film - spin wave bus. The magneto-electric cell is an artificial two-phase multiferroic structure comprising piezoelectric and ferromagnetic materials. A bit of information is assigned to the cell's magnetic polarization, which can be controlled by the applied voltage. The information exchange among the cells is via the spin waves propagating in the spin wave bus. Each cell changes its state as a combined effect of two: the magneto-electric coupling and the interaction with the spin waves. The distinct feature of the network with spin wave bus is the ability to control the inter-cell communication by an external global parameter - magnetic field. The latter makes possible to realize different image processing functions on the same template without rewiring or reconfiguration. We present the results of numerical simulations illustrating image filtering, erosion, dilation, horizontal and vertical line detection, inversion and edge detection accomplished on one template by the proper choice of the strength and direction of the external magnetic field. We also present numerical assets on the major network parameters such as cell density, power dissipation and functional throughput, and compare them with the parameters projected for other nano-architectures such as CMOL-CrossNet, Quantum Dot Cellular Automata, and Quantum Dot Image Processor. Potentially, the utilization of spin waves phenomena at the nanometer scale may provide a route to low-power consuming and functional logic circuits for special task data processing

Short- and long-term outcomes of laser haemorrhoidoplasty for grade II-III haemorrhoidal disease.

Laser haemorrhoidoplasty is associated with minimal postoperative pain and good symptom improvement in the short-term. However, less is known about its long-term efficacy. This study aims to determine the short- and long-term outcomes of laser haemorrhoidoplasty. Between October 2010 and May 2012, 50 consecutive patients with grade II-III haemorrhoids were treated with laser haemorrhoidoplasty. Short-term follow-up was assessed on days 1, 30 and 60 and long-term follow-up was at 5 years (haemorrhoidal stage reduction, pain, patient satisfaction, symptom improvement, incapacity for work, continence, complications, recurrence). Short-term follow-up was achieved for all patients and long-term follow-up for 44/50 patients (88%). At short-term follow-up, haemorrhoidal stage reduction was documented in 49 (98%) patients. Complete or good symptom improvement was reported by 36/50 (72%) and 10/50 patients (20%) at 60 days. Postoperative complications occurred in 9/50 patients (18%) with three Clavien-Dindo grade IIIb complications (two fistulas, one incontinence), one grade IIIa (perianal thrombosis) and five grade I (one perianal thrombosis, two perianal eczema, one local bleeding, one anal fissure). Postoperative pain was low (visual analogue scale 0-1) at day 1 in 37/50 (74%), at day 30 in 47/50 (94%) and at day 60 in 50/50 patients (100%). After a mean follow-up of 5.4 years (SD 5.4 months) the recurrence rate was 34% (15/44 patients) with a median time to recurrence of 21 months (range 0.2-6 years). Although laser haemorrhoidoplasty achieves a high short-term success rate with respect to stage reduction and symptom improvement, it is associated with a high rate of minor postoperative complications and long-term recurrence. Therefore, laser haemorrhoidoplasty should be used with caution

Nanofeatured silk fibroin membranes for dermal wound healing applications

As an effort to create the next generation of improved skin graft materials, in this study, we modified the surfaces of a previously investigated material, silk fibroin, using a NaOH alkaline treatment to obtain a biologically inspired nanofeatured surface morphology. Such surfaces were characterized for roughness, energy, and chemistry. In addition, keratinocyte (skin-forming cells) adhesion and proliferation on such nanofeatured silk fibroin wound dressings were studied in an initial attempt to determine the promotion of an epidermal cover on the wound bed to form a new epidermal barrier. Dermal fibroblast adhesion and proliferation were also studied to assess the ability of nanostructured silk fibroin to replace damaged dermal tissue in chronic wounds (i.e., for diabetic foot ulcers). Results demonstrated for the first time that keratinocyte and fibroblast cell density was greater on nanofeatured silk fibroin membranes compared with non-treated silk fibroin surfaces. The enhancement in cellular functions was correlated with an increase in silk surface nanotopography, wettability and change in chemistry after NaOH treatment. Due to the present promising results, the newly developed nanofeatured silk fibroin membranes are exciting alternative skin graft materials which should be further studied for various skin patch and wound dressing applications. (c) 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 135-144, 2015

Nanostructured anti-bacterial poly-lactic-co-glycolic acid films for skin tissue engineering applications

Major issues faced with the use of today's skin grafts are infection, scar tissue formation, insufficient keratinocyte (or skin producing cells) proliferation and high production costs. To overcome these limitations, we propose here for the first time, a nanofeatured poly(lactide-co-glycolide) (PLGA) membrane as a next generation antibacterial skin graft material. An alkaline surface treatment method was used to create random nanofeatures on PLGA membranes where sodium hydroxide (NaOH) concentration and exposure times were altered to control surface morphology. Most significantly, and without the use of antibiotics, results showed a decrease in Staphylococcus aureus (a dangerous pathogen infecting skin grafts) growth for up to approximate to 40% after 2 days of culture on nanofeatured PLGA membranes compared to untreated controls. Results also showed that while bacteria growth was stunted, mammalian cell growth was not. Specifically, cell culture results showed an increase in human epidermal keratinocyte density, while the density of scar tissue forming human dermal fibroblasts, did not change on nanofeatured PLGA surfaces compared to the untreated controls after 3 days of culture. These findings indicate that the alkaline treatment of PLGA membranes is a promising quick and effective manner to limit scar tissue formation and bacterial invasion while increasing skin cell proliferation for improving numerous wound-healing applications. (c) 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 4598-4608, 2014