Single quantum dot states measured by optical modulation spectroscopy

Using optical modulation spectroscopy, we report the direct observation of absorption lines from excitons localized in GaAs single quantum dot potentials. The data provide a measurement of the linewidth, resonance energy, and oscillator strength of the transitions, and show that states which decay primarily by nonradiative processes can be directly probed using this technique. The experiments establish this technique for the characterization of single quantum dot transitions, thereby complementing luminescence studies. © 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70527/2/APPLAB-75-19-2933-1.pd

Current-Induced Entanglement of Nuclear Spins in Quantum Dots

We propose an entanglement mechanism of nuclear spins in quantum dots driven by the electric current accompanied by the spin flip. This situation is relevant to a leakage current in spin-blocked regions where electrons cannot be transported unless their spins are flipped. The current gradually increases the components of larger total spin of nuclei. This correlation among the nuclear spins markedly enhances the spin-flip rate of electrons and hence the leakage current. The enhancement of the current is observable when the residence time of electrons in the quantum dots is shorter than the dephasing time T*_2 of nuclear spins.Comment: 4 pages, 4 figure

Managing toxicities associated with immune checkpoint inhibitors: consensus recommendations from the Society for Immunotherapy of Cancer (SITC) Toxicity Management Working Group.

Cancer immunotherapy has transformed the treatment of cancer. However, increasing use of immune-based therapies, including the widely used class of agents known as immune checkpoint inhibitors, has exposed a discrete group of immune-related adverse events (irAEs). Many of these are driven by the same immunologic mechanisms responsible for the drugs\u27 therapeutic effects, namely blockade of inhibitory mechanisms that suppress the immune system and protect body tissues from an unconstrained acute or chronic immune response. Skin, gut, endocrine, lung and musculoskeletal irAEs are relatively common, whereas cardiovascular, hematologic, renal, neurologic and ophthalmologic irAEs occur much less frequently. The majority of irAEs are mild to moderate in severity; however, serious and occasionally life-threatening irAEs are reported in the literature, and treatment-related deaths occur in up to 2% of patients, varying by ICI. Immunotherapy-related irAEs typically have a delayed onset and prolonged duration compared to adverse events from chemotherapy, and effective management depends on early recognition and prompt intervention with immune suppression and/or immunomodulatory strategies. There is an urgent need for multidisciplinary guidance reflecting broad-based perspectives on how to recognize, report and manage organ-specific toxicities until evidence-based data are available to inform clinical decision-making. The Society for Immunotherapy of Cancer (SITC) established a multidisciplinary Toxicity Management Working Group, which met for a full-day workshop to develop recommendations to standardize management of irAEs. Here we present their consensus recommendations on managing toxicities associated with immune checkpoint inhibitor therapy

Remuneration and recidivism: The long-term impact of unemployment compensation on ex-offenders

The relationship between unemployment and crime is the subject of research and debate. We present evidence that suggests that recidivism among ex-offenders can be reduced by providing unemployment compensation available immediately after their release from prison. A California program made such benefits—transitional aid—available during the late 1970s and early 1980s. Using a 5-year follow-up and a failure-time model, we show how recidivism among an eligible group was consistently lower over those 5 years than for an ineligible group.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45112/1/10940_2005_Article_BF01065198.pd

A phase I open-label study evaluating the cardiovascular safety of sorafenib in patients with advanced cancer

Purpose: To characterize the cardiovascular profile of sorafenib, a multitargeted kinase inhibitor, in patients with advanced cancer. Methods: Fifty-three patients with advanced cancer received oral sorafenib 400 mg bid in continuous 28-day cycles in this open-label study. Left ventricular ejection fraction (LVEF) was evaluated using multigated acquisition scanning at baseline and after 2 and 4 cycles of sorafenib. QT/QTc interval on the electrocardiograph (ECG) was measured in triplicate with a Holter 12-lead ECG at baseline and after 1 cycle of sorafenib. Heart rate (HR) and blood pressure (BP) were obtained in duplicate at baseline and after 1 and 4 cycles of sorafenib. Plasma pharmacokinetic data were obtained for sorafenib and its 3 main metabolites after 1 and 4 cycles of sorafenib. Results: LVEF (SD) mean change from baseline was -0.8 ($\pm$8.6) LVEF(%) after 2 cycles (n=31) and -1.2 $\pm$7.8) LVEF(%) after 4 cycles of sorafenib (n=24). The QT/QTc mean changes from baseline observed at maximum sorafenib concentrations ($t_{max}$) after 1 cycle (n=31) were small (QTcB: 4.2 ms; QTcF: 9.0 ms). Mean changes observed after 1 cycle in BP (n=31) and HR (n=30) at maximum sorafenib concentrations ($t_{max}$) were moderate (up to 11.7 mm Hg and -6.6 bpm, respectively). No correlation was found between the AUC and ($C_{max}$) of sorafenib and its main metabolites and any cardiovascular parameters. Conclusions: The effects of sorafenib on changes in QT/QTc interval on the ECG, LVEF, BP, and HR were modest and unlikely to be of clinical significance in the setting of advanced cancer treatment

TiO2 Nanoparticles Are Phototoxic to Marine Phytoplankton

Nanoparticulate titanium dioxide (TiO2) is highly photoactive, and its function as a photocatalyst drives much of the application demand for TiO2. Because TiO2 generates reactive oxygen species (ROS) when exposed to ultraviolet radiation (UVR), nanoparticulate TiO2 has been used in antibacterial coatings and wastewater disinfection, and has been investigated as an anti-cancer agent. Oxidative stress mediated by photoactive TiO2 is the likely mechanism of its toxicity, and experiments demonstrating cytotoxicity of TiO2 have used exposure to strong artificial sources of ultraviolet radiation (UVR). In vivo tests of TiO2 toxicity with aquatic organisms have typically shown low toxicity, and results across studies have been variable. No work has demonstrated that photoactivity causes environmental toxicity of TiO2 under natural levels of UVR. Here we show that relatively low levels of ultraviolet light, consistent with those found in nature, can induce toxicity of TiO2 nanoparticles to marine phytoplankton, the most important primary producers on Earth. No effect of TiO2 on phytoplankton was found in treatments where UV light was blocked. Under low intensity UVR, ROS in seawater increased with increasing nano-TiO2 concentration. These increases may lead to increased overall oxidative stress in seawater contaminated by TiO2, and cause decreased resiliency of marine ecosystems. Phototoxicity must be considered when evaluating environmental impacts of nanomaterials, many of which are photoactive

A Climate Change Vulnerability Assessment of California's At-Risk Birds

Conservationists must develop new strategies and adapt existing tools to address the consequences of anthropogenic climate change. To support statewide climate change adaptation, we developed a framework for assessing climate change vulnerability of California's at-risk birds and integrating it into the existing California Bird Species of Special Concern list. We defined climate vulnerability as the amount of evidence that climate change will negatively impact a population. We quantified climate vulnerability by scoring sensitivity (intrinsic characteristics of an organism that make it vulnerable) and exposure (the magnitude of climate change expected) for each taxon. Using the combined sensitivity and exposure scores as an index, we ranked 358 avian taxa, and classified 128 as vulnerable to climate change. Birds associated with wetlands had the largest representation on the list relative to other habitat groups. Of the 29 state or federally listed taxa, 21 were also classified as climate vulnerable, further raising their conservation concern. Integrating climate vulnerability and California's Bird Species of Special Concern list resulted in the addition of five taxa and an increase in priority rank for ten. Our process illustrates a simple, immediate action that can be taken to inform climate change adaptation strategies for wildlife

The ineffectiveness of entrepreneurship policy:Is policy formulation to blame?

Entrepreneurship policy has been criticised for its lack of effectiveness. Some scholars, such as Scott Shane in this journal, have argued that it is ‘bad’ public policy. But this simply begs the question why the legislative process should generate bad policy? To answer this question this study examines the UK’s enterprise policy process in the 2009–2010 period. It suggests that a key factor for the ineffectiveness of policy is how it is formulated. This stage in the policy process is seldom visible to those outside of government departments and has been largely ignored by prior research. The application of institutional theory provides a detailed theoretical understanding of the actors and the process by which enterprise policy is formulated. We find that by opening up the ‘black box’ of enterprise policy formulation, the process is dominated by powerful actors who govern the process with their interests