Reaction control of metal-assisted chemical etching for silicon-based zone plate nanostructures

Metal-assisted chemical etching (MACE) reaction parameters were investigated for the fabrication of specially designed silicon-based X-ray zone plate nanostructures using a gold catalyst pattern and etching solutions composed of HF and H₂O₂. Etching depth, zone verticality and zone roughness were studied as a function of etching solution composition, temperature and processing time. Homogeneous, vertical etching with increasing depth is observed at increasing H₂O₂ concentrations and elevated processing temperatures, implying a balance in the hole injection and silica dissolution kinetics at the gold–silicon interface. The etching depth decreases and zone roughness increases at the highest investigated H₂O₂ concentration and temperature. Possible reasons for these observations are discussed based on reaction chemistry and zone plate design. Optimum MACE conditions are found at HF : H₂O₂ concentrations of 4.7 M : 0.68 M and room temperature with an etching rate of ≈0.7 μm min⁻¹, which is about an order of magnitude higher than previous reports. Moreover, our results show that a grid catalyst design is important for successful fabrication of vertical high aspect ratio silicon nanostructures.

Specially designed X-ray zone plates with high aspect-ratios have been fabricated via metal-assisted chemical etching, by controlling the reaction kinetics.     

A thin I-125 seed eye plaque to treat intraocular tumors using an acrylic insert to precisely position the sources

A thin re-usable stainless steel ophthalmic applicator is described. The radioactive Iodine-125 sources are inserted in an acrylic button which fits neatly into a stainless steel shell 1 mm thick. The applicator can be assembled with the radioactive sources precisely positioned without the use of adhesives or mechanical devices such as clamps or screws in a matter of a few minutes, (under sterile conditions if necessary). The applicator can be dismantled in seconds after which it is ready for cleaning and re-sterilization. The overall thickness of the plaque is 2.6 mm, but this has the potential to be reduced to 2.1 mm. Suture holes are provided on a flange subtending 120 degrees around the circumference of the shell and are exactly matched on a stainless steel template.     

Infection and activation of human peripheral blood monocytes by dengue viruses through the mechanism of antibody-dependent enhancement

Human monocytes are susceptible to dengue virus (DV) infection through an FcR-dependent pathway known as antibody-dependent enhancement (ADE). In this study, infection enhancement was observed when purified monocytes were infected with DV serotypes in the presence of serially diluted immune serum antibodies. Analyzing binding of the DV-antibody immune complexes to monocytes by quantifying the amount of viruses attached to monocytes, we found that binding did not correlate with the input amount of antibodies; rather, it peaked at suboptimal antibody concentrations, correlating with the observed infection enhancement. These results suggested that immune complexes are involved in hindering DV from binding to FcR-bearing cells; when such a protective feature is weakened, enhancement of viral attachment and ADE are observed. Further, increased cytokine production (TNF-alpha and IFN-alpha), and costimulatory marker expression (CD86 and CD40), were found to be associated with infection enhancement, suggesting a pathological role of ADE-affected monocytes in dengue hemorrhagic diseases.     

Comparison of non-surgical methods for the treatment of deep partial thickness skin burns of the hand

This paper describes a randomized, controlled, parallel-group, single-center clinical trial designed to compare non surgical treatment methods of deep partial thickness skin burns of the hand.All patients were scanned with the Laser Doppler Imaging device to determine the depth of the burn wound. Viable keratinocytes sites were determined according to the established Perfusion Units (PU) measurement system. The trial enrolled 87 patients with hand burn wounds in the section of 260–600 PU.Hand burn patients were divided into the following four groups: treated with hydrocolloid dressings; treated with mechanical debridement of monofilament polyester fibers pad and then applying silver sulfadiazine; treated with gauze dressings containing enzymatic collagenase preparation. The fourth group of patients was treated with silver sulfadiazine and gauze dressings. This group was considered as the control group. The wound healing status was assessed after 3, 7, 14 and 21 days. Burn scars and injured extremity function were assessed after six months according to the Vancouver Scar Scale and Disabilities of the Arm, Shoulder and Hand Outcome Measure.The fastest epithelialization of hand burn wounds was observed in the patients group treated with hydrocolloid dressings (15, 7 days, p < 0,05). The patients of this group also had less scars and a better hand function.     

Congenital unilateral facial nerve palsy as an unusual presentation of BOR syndrome

Congenital facial nerve palsy (CFNP) is a rare condition that can be generally categorized as developmental or traumatic. Though trauma during birth is the most common cause, sometimes CFNP is observed in association with genetic syndromes and congenital hearing loss and structural anomalies of the middle and inner ear. CFNP is infrequently reported in association with branchio–oto–renal (BOR) syndrome. We present a case of a 4-day-old infant girl with a familial history of renal disease, who was hospitalized because of congenital unilateral facial palsy, which subsequently appeared to be a part of BOR syndrome and led to the diagnosis of congenital bilateral renal hypoplasia, renal failure, and secondary arterial hypertension. This case proves that sometimes rare manifestations of BOR syndrome may be one of the first signs of an underlying syndrome. Issues regarding patterns of BOR syndrome inheritability and expressivity that we encountered are also discussed. Patients with a familial history of BOR syndrome should be carefully inspected after birth, especially in suspected cases such as newborns with preauricular pits and/or facial nerve palsy.     

Tailoring a Combination Preerythrocytic Malaria Vaccine

The leading malaria vaccine candidate, RTS,S, based on the Plasmodium falciparum circumsporozoite protein (CSP), will likely be the first publicly adopted malaria vaccine. However, this and other subunit vaccines, such as virus-vectored thrombospondin-related adhesive protein (TRAP), provide only intermediate to low levels of protection. In this study, the Plasmodium berghei homologues of antigens CSP and TRAP are combined. TRAP is delivered using adenovirus- and vaccinia virus-based vectors in a prime-boost regime. Initially, CSP is also delivered using these viral vectors; however, a reduction of anti-CSP antibodies is seen when combined with virus-vectored TRAP, and the combination is no more protective than either subunit vaccine alone. Using an adenovirus-CSP prime, protein-CSP boost regime, however, increases anti-CSP antibody titers by an order of magnitude, which is maintained when combined with virus-vectored TRAP. This combination regime using protein CSP provided 100% protection in C57BL/6 mice compared to no protection using virus-vectored TRAP alone and 40% protection using adenovirus-CSP prime and protein-CSP boost alone. This suggests that a combination of CSP and TRAP subunit vaccines could enhance protection against malaria.