Derivation and validation of cutoffs for clinical use of cell cycle arrest biomarkers

Background Acute kidney injury (AKI) remains a deadly condition. Tissue inhibitor of metalloproteinases (TIMP)-2 and insulin-like growth factor binding protein (IGFBP)7 are two recently discovered urinary biomarkers for AKI. We now report on the development, and diagnostic accuracy of two clinical cutoffs for a test using these markers. Methods We derived cutoffs based on sensitivity and specificity for prediction of Kidney Disease: Improving Global Outcomes Stages 2–3 AKI within 12 h using data from a previously published multicenter cohort (Sapphire). Next, we verified these cutoffs in a new study (Opal) enrolling 154 critically ill adults from six sites in the USA. Results One hundred subjects (14%) in Sapphire and 27 (18%) in Opal met the primary end point. The results of the Opal study replicated those of Sapphire. Relative risk (95% CI) in both studies for subjects testing at ≤0.3 versus \u3e0.3–2 were 4.7 (1.5–16) and 4.4 (2.5–8.7), or 12 (4.2–40) and 18 (10–37) for ≤0.3 versus \u3e2. For the 0.3 cutoff, sensitivity was 89% in both studies, and specificity 50 and 53%. For 2.0, sensitivity was 42 and 44%, and specificity 95 and 90%. Conclusions Urinary [TIMP-2]•[IGFBP7] values of 0.3 or greater identify patients at high risk and those \u3e2 at highest risk for AKI and provide new information to support clinical decision-making. Clinical Trials Registration Clintrials.gov # NCT01209169 (Sapphire) and NCT01846884 (Opal)

Structure, Photophysics and the Order-Disorder Transition to the Beta Phase in Poly(9,9-(di -n,n-octyl)fluorene)

X-ray diffraction, UV-vis absorption and photoluminescence (PL) spectroscopy have been used to study the well-known order-disorder transition (ODT) to the beta phase in poly(9,9-(di n,n-octyl)fluorene)) (PF8) thin film samples through combination of time-dependent and temperature-dependent measurements. The ODT is well described by a simple Avrami picture of one-dimensional nucleation and growth but crystallization, on cooling, proceeds only after molecular-level conformational relaxation to the so called beta phase. Rapid thermal quenching is employed for PF8 studies of pure alpha phase samples while extended low-temperature annealing is used for improved beta phase formation. Low temperature PL studies reveal sharp Franck-Condon type emission bands and, in the beta phase, two distinguishable vibronic sub-bands with energies of approximately 199 and 158 meV at 25 K. This improved molecular level structural order leads to a more complete analysis of the higher-order vibronic bands. A net Huang-Rhys coupling parameter of just under 0.7 is typically observed but the relative contributions by the two distinguishable vibronic sub-bands exhibit an anomalous temperature dependence. The PL studies also identify strongly correlated behavior between the relative beta phase 0-0 PL peak position and peak width. This relationship is modeled under the assumption that emission represents excitons in thermodynamic equilibrium from states at the bottom of a quasi-one-dimensional exciton band. The crystalline phase, as observed in annealed thin-film samples, has scattering peaks which are incompatible with a simple hexagonal packing of the PF8 chains.Comment: Submitted to PRB, 12 files; 1 tex, 1 bbl, 10 eps figure

Milagrito: a TeV air-shower array

Milagrito, a large, covered water-Cherenkov detector, was the world's first air-shower-particle detector sensitive to cosmic gamma rays below 1 TeV. It served as a prototype for the Milagro detector and operated from February 1997 to May 1998. This paper gives a description of Milagrito, a summary of the operating experience, and early results that demonstrate the capabilities of this technique.Comment: 38 pages including 24 figure

Low birth weight is associated with chronic kidney disease only in men

The association of low birth weight and chronic kidney disease was examined in a screened volunteer population by the National Kidney Foundation's Kidney Early Evaluation Program. This is a free, community-based health program enrolling individuals aged 18 years or older with diabetes, hypertension, or a family history of kidney disease, diabetes, or hypertension. Self-reported birth weight was categorized and chronic kidney disease defined as an estimated glomerular filtration rate less than 60 ml per min per 1.73 m2 or a urine albumin/creatinine ratio ≥30 mg/g. Among 12 364 participants, 15% reported a birth weight less than 2500 g. In men, significant corresponding odds ratios were found after adjustment for demographic characteristics and health conditions to this low birth weight and chronic kidney disease, but there was no association among women. There was no significant interaction between birth weight and race for either gender. Efforts to clinically understand the etiology of this association and potential means of prevention are essential to improving public health

Hard Photodisintegration of a Proton Pair

We present a study of high energy photodisintegration of proton-pairs through the gamma + 3He -> p+p+n channel. Photon energies from 0.8 to 4.7 GeV were used in kinematics corresponding to a proton pair with high relative momentum and a neutron nearly at rest. The s-11 scaling of the cross section, as predicted by the constituent counting rule for two nucleon photodisintegration, was observed for the first time. The onset of the scaling is at a higher energy and the cross section is significantly lower than for deuteron (pn pair) photodisintegration. For photon energies below the scaling region, the scaled cross section was found to present a strong energy-dependent structure not observed in deuteron photodisintegration.Comment: 7 pages, 3 figures, for submission to Phys. Lett.

Site-Selective Passivation of Defects in NiO Solar Photocathodes by Targeted Atomic Deposition

For nanomaterials, surface chemistry can dictate fundamental material properties, including charge-carrier lifetimes, doping levels, and electrical mobilities. In devices, surface defects are usually the key limiting factor for performance, particularly in solar-energy applications. Here, we develop a strategy to uniformly and selectively passivate defect sites in semiconductor nanomaterials using a vapor-phase process termed targeted atomic deposition (TAD). Because defects often consist of atomic vacancies and dangling bonds with heightened reactivity, we observe-for the widely used p-type cathode nickel oxide-that a volatile precursor such as trimethylaluminum can undergo a kinetically limited selective reaction with these sites. The TAD process eliminates all measurable defects in NiO, leading to a nearly 3-fold improvement in the performance of dye-sensitized solar cells. Our results suggest that TAD could be implemented with a range of vapor-phase precursors and be developed into a general strategy to passivate defects in zero-, one-, and two-dimensional nanomaterials