Sequence-specific molecular lithography on single DNA molecules

Recent advances in the realization of individual molecular-scale electronic devices emphasize the need for novel tools and concepts capable of assembling such devices into large-scale functional circuits. We demonstrated sequence-specific molecular lithography on substrate DNA molecules by harnessing homologous recombination by RecA protein. In a sequence-specific manner, we patterned the coating of DNA with metal, localized labeled molecular objects and grew metal islands on specific sites along the DNA substrate, and generated molecularly accurate stable DNA junctions for patterning the DNA substrate connectivity. In our molecular lithography, the information encoded in the DNA molecules replaces the masks used in conventional microelectronics, and the RecA protein serves as the resist. The molecular lithography works with high resolution over a broad range of length scales from nanometers to many micrometers.     

Urethral obstruction in cats: predisposing factors, clinical, clinicopathological characteristics and prognosis

Feline lower urinary tract diseases in general, and urethral obstruction (UO) in particular, are common clinical conditions in cats. The aims of this study were to identify risk factors for UO, to characterise clinical and clinicopathological signs, outcome and recurrence, as well as risk factors for mortality and recurrence. Eighty-two cats with UO were compared to 82 sex and time matched controls. The mean age of cats with UO was significantly lower compared to controls, while the mean body weight was higher. The proportion of indoors-outdoors cats was significantly lower in the study group compared to the control group, and the proportion of cats consuming only dry food was higher. Overall mortality was 8.5%. Ionised calcium was significantly higher in survivors compared to non-survivors, and the prevalence of hypocalcaemia was lower. Recurrence in 6 months and 2 years were 22% and 24%, respectively. Cats with recurrence had significantly lower urine pH at presentation.     

Superconducting interfaces between insulating oxides

At interfaces between complex oxides, electronic systems with unusual electronic properties can be generated. We report on superconductivity in the electron gas formed at the interface between two insulating dielectric perovskite oxides, LaAlO3 and SrTiO3. The behavior of the electron gas is that of a two-dimensional superconductor, confined to a thin sheet at the interface. The superconducting transition temperature of congruent with 200 millikelvin provides a strict upper limit to the thickness of the superconducting layer of congruent with 10 nanometers.     

Resolution of renal adenocarcinoma-induced secondary inappropriate polycythaemia after nephrectomy in two cats

Two cases of secondary, inappropriate polycythaemia caused by renal adenocarcinoma in domestic shorthair cats, are described. The cats were 9 and 12 years old and both were presented because of generalised seizures presumably due to hyperviscosity. Both cats had a markedly increased haematocrit (0.770 and 0.632 l/l) and thrombocytosis (744 x 10(9)/l and 926 x 10(9)/l). An abdominal ultrasound revealed a mass in the cranial pole of one kidney in both cats. Serum erythropoietin (EPO) concentration was within the reference interval (RI) in both cats but was inappropriately high considering the markedly increased haematocrit. The cats were initially stabilised and managed by multiple phlebotomies and intravenous fluid therapy and underwent nephrectomy of the affected kidney later on. Both the polycythaemia and thrombocytosis resolved following surgery. Postoperative serum EPO concentration, measured in one cat, decreased markedly. Histopathology of the affected kidneys confirmed a diagnosis of renal adenocarcinoma. Both cats were stable for an 8-month follow-up period; however, one cat had developed a stable chronic kidney disease (CKD), while the other was represented 8 months postoperatively due to dyspnoea, and had radiographic evidence of lung metastasis, presumably because of the spread of the original renal tumour and was euthanased. Initial stabilisation of polycythaemic cats should include multiple phlebotomies. Nephrectomy should be considered in cats with secondary, inappropriate, renal adenocarcinoma-related polycythaemia when only one kidney is affected by the tumour, and provided that the other kidney's function is satisfactory. Nephrectomy should be expected to resolve the polycythaemia and lead to normalisation of serum EPO concentration.