Graphene overcoats for ultra-high storage density magnetic media.

Hard disk drives (HDDs) are used as secondary storage in digital electronic devices owing to low cost and large data storage capacity. Due to the exponentially increasing amount of data, there is a need to increase areal storage densities beyond ~1 Tb/in2. This requires the thickness of carbon overcoats (COCs) to be <2 nm. However, friction, wear, corrosion, and thermal stability are critical concerns below 2 nm, limiting current technology, and restricting COC integration with heat assisted magnetic recording technology (HAMR). Here we show that graphene-based overcoats can overcome all these limitations, and achieve two-fold reduction in friction and provide better corrosion and wear resistance than state-of-the-art COCs, while withstanding HAMR conditions. Thus, we expect that graphene overcoats may enable the development of 4-10 Tb/in2 areal density HDDs when employing suitable recording technologies, such as HAMR and HAMR+bit patterned media.

Raman spectroscopy of graphene under ultrafast laser excitation.

The equilibrium optical phonons of graphene are well characterized in terms of anharmonicity and electron-phonon interactions; however, their non-equilibrium properties in the presence of hot charge carriers are still not fully explored. Here we study the Raman spectrum of graphene under ultrafast laser excitation with 3 ps pulses, which trade off between impulsive stimulation and spectral resolution. We localize energy into hot carriers, generating non-equilibrium temperatures in the ~1700-3100 K range, far exceeding that of the phonon bath, while simultaneously detecting the Raman response. The linewidths of both G and 2D peaks show an increase as function of the electronic temperature. We explain this as a result of the Dirac cones' broadening and electron-phonon scattering in the highly excited transient regime, important for the emerging field of graphene-based photonics and optoelectronics.

p-wave triggered superconductivity in single-layer graphene on an electron-doped oxide superconductor.

Electron pairing in the vast majority of superconductors follows the Bardeen-Cooper-Schrieffer theory of superconductivity, which describes the condensation of electrons into pairs with antiparallel spins in a singlet state with an s-wave symmetry. Unconventional superconductivity was predicted in single-layer graphene (SLG), with the electrons pairing with a p-wave or chiral d-wave symmetry, depending on the position of the Fermi energy with respect to the Dirac point. By placing SLG on an electron-doped (non-chiral) d-wave superconductor and performing local scanning tunnelling microscopy and spectroscopy, here we show evidence for a p-wave triggered superconducting density of states in SLG. The realization of unconventional superconductivity in SLG offers an exciting new route for the development of p-wave superconductivity using two-dimensional materials with transition temperatures above 4.2 K.

Case-controlled review of Clostridium difficile-associated diarrhoea in southern Tasmania.

AIM: While the incidence of Clostridium difficile-associated diarrhoea (CDAD) has increased sharply over the last 15 years, its risk factors are still not well defined. The aim of this study was to review cases of CDAD at the major teaching hospital in Tasmania, Australia, to identify risk factors for CDAD and their association with prognosis. METHODS: A retrospective review of the medical records of adult patients admitted to the hospital between January 1994 and December 1996 was performed. Sixty-four patients who developed CDAD prior to or during their admission, and an additional 120 diarrhoea-free patients (the control group) were studied. An extensive range of demographic and clinical variables were recorded, and the differences between the control group and patients with CDAD were evaluated. RESULTS: The CDAD patients had a median age of 66 years (range 22-95 years), with females accounting for 52% of cases. There were no significant demographic differences from the control group. Identifiable risk factors for developing CDAD were severe underlying disease, renal impairment, exposure to antibiotics or antineoplastic agents, and the use of total parenteral nutrition or nasogastric feeding. Cephalosporins were the most frequently used antibiotics in both CDAD and control patients, with cefotaxime being the only antibiotic which was identified as being significantly associated with an increased risk of CDAD. The median length of diarrhoea episodes was 9 days (range 1-60 days). The mortality rate was 17.2%, and factors associated with a poor prognosis were older age, severe underlying disease, renal impairment and failure to treat with metronidazole or vancomycin. Delay in starting specific treatment and use of codeine were related to prolonged CDAD. CONCLUSION: CDAD is a growing contributor to hospital morbidity and costs. Severely ill patients with compromised immune function are particularly susceptible, with antibiotic use being a major risk factor. Prompt diagnosis and initiation of treatment are important factors in the improvement of prognosis.

An immunodominant antigen of Candida albicans shows homology to the enzyme enolase.

Antibody to an immunodominant antigen of approximately 48 kDa is found in a high proportion of patients with mucocutaneous or systemic infections of the yeast Candida albicans. A cDNA encoding part of the 48 kDa antigen has been isolated. From the deduced amino acid sequence of the cDNA clone, the 48 kDa antigen shows homology to the enzyme enolase.

Modern perspectives on vaginal candidiasis.

Vaginal thrush is not only a medical problem--it also causes significant psychological and emotional distress, particularly if the infections persist or recur. Women who suffer from frequent recurrences often express dissatisfaction with the treatment they receive, and such comments may be provoked by a lack of awareness on the part of the physician of the natural history of the infection, and of the difficulties inherent in its diagnosis and treatment.

Autoimmunity as a factor in recurrent vaginal candidosis and the minor vestibular gland syndrome.

Chronic vaginal candidosis is a significant cause of morbidity in women, but its causes are not yet understood. We propose that in genetically susceptible women a candidal infection elicits responses that cross-react with self-antigens. Control of these deleterious responses may compromise the normal mechanisms of resistance and predispose to recurrent infection. Furthermore, the local inflammation caused by these autoreactive cells may contribute to other forms of vaginitis.

Prenatal screening for markers of hepatitis B in aboriginal mothers resident in non-metropolitan Western Australia.

Of 1947 Aboriginal women who resided in non-metropolitan regions of Western Australia and gave birth during January 1983 to February 1985, 42% of women were screened prenatally for the presence of hepatitis B surface antigen (HBsAg). The proportions of Aboriginal women who were screened varied from 17% in the southern divisions to 72% in the Kimberley region. The screening programme identified 29 Aboriginal women with a positive result of the test. On this basis, the estimated prevalence of HBsAg among non-metropolitan Aboriginal women was 3.6% (95% confidence interval, 2.5%-5.1%). According to the geographical location of the mother's residence, the observed prevalence of HBsAg varied from 0 in the southern divisions to around 4%-5% in the central and eastern divisions.

Tungiasis: imported disease.

A case of importation of the sandflea Tunga penetrans is reported. If this species were to become established in Australia, there could be medical and socioeconomic repercussions.