A high-spin ground-state donor-acceptor conjugated polymer.

Interest in high-spin organic materials is driven by opportunities to enable far-reaching fundamental science and develop technologies that integrate light element spin, magnetic, and quantum functionalities. Although extensively studied, the intrinsic instability of these materials complicates synthesis and precludes an understanding of how fundamental properties associated with the nature of the chemical bond and electron pairing in organic materials systems manifest in practical applications. Here, we demonstrate a conjugated polymer semiconductor, based on alternating cyclopentadithiophene and thiadiazoloquinoxaline units, that is a ground-state triplet in its neutral form. Electron paramagnetic resonance and magnetic susceptibility measurements are consistent with a high-to-low spin energy gap of 9.30 × 10-3 kcal mol-1. The strongly correlated electronic structure, very narrow bandgap, intramolecular ferromagnetic coupling, high electrical conductivity, solution processability, and robust stability open access to a broad variety of technologically relevant applications once thought of as beyond the current scope of organic semiconductors.

Direct observation of individual hydrogen atoms at trapping sites in a ferritic steel.

The design of atomic-scale microstructural traps to limit the diffusion of hydrogen is one key strategy in the development of hydrogen-embrittlement-resistant materials. In the case of bearing steels, an effective trapping mechanism may be the incorporation of finely dispersed V-Mo-Nb carbides in a ferrite matrix. First, we charged a ferritic steel with deuterium by means of electrolytic loading to achieve a high hydrogen concentration. We then immobilized it in the microstructure with a cryogenic transfer protocol before atom probe tomography (APT) analysis. Using APT, we show trapping of hydrogen within the core of these carbides with quantitative composition profiles. Furthermore, with this method the experiment can be feasibly replicated in any APT-equipped laboratory by using a simple cold chain.

Characterization of activating mutations of NOTCH3 in T-cell acute lymphoblastic leukemia and anti-leukemic activity of NOTCH3 inhibitory antibodies.

Notch receptors have been implicated as oncogenic drivers in several cancers, the most notable example being NOTCH1 in T-cell acute lymphoblastic leukemia (T-ALL). To characterize the role of activated NOTCH3 in cancer, we generated an antibody that detects the neo-epitope created upon gamma-secretase cleavage of NOTCH3 to release its intracellular domain (ICD3), and sequenced the negative regulatory region (NRR) and PEST (proline, glutamate, serine, threonine) domain coding regions of NOTCH3 in a panel of cell lines. We also characterize NOTCH3 tumor-associated mutations that result in activation of signaling and report new inhibitory antibodies. We determined the structural basis for receptor inhibition by obtaining the first co-crystal structure of a NOTCH3 antibody with the NRR protein and defined two distinct epitopes for NRR antibodies. The antibodies exhibit potent anti-leukemic activity in cell lines and tumor xenografts harboring NOTCH3 activating mutations. Screening of primary T-ALL samples reveals that 2 of 40 tumors examined show active NOTCH3 signaling. We also identified evidence of NOTCH3 activation in 12 of 24 patient-derived orthotopic xenograft models, 2 of which exhibit activation of NOTCH3 without activation of NOTCH1. Our studies provide additional insights into NOTCH3 activation and offer a path forward for identification of cancers that are likely to respond to therapy with NOTCH3 selective inhibitory antibodies.

Quantification of oxide particle composition in model oxide dispersion strengthened steel alloys.

Oxide dispersion strengthened ferritic steels (ODS) are being considered for structural components of future designs of fission and fusion reactors because of their impressive high-temperature mechanical properties and resistance to radiation damage, both of which arise from the nanoscale oxide particles they contain. Because of the critical importance of these nanoscale phases, significant research activity has been dedicated to analysing their precise size, shape and composition (Odette et al., Annu. Rev. Mater. Res. 38 (2008) 471-503 [1]; Miller et al., Mater. Sci. Technol. 29(10) (2013) 1174-1178 [2]). As part of a project to develop new fuel cladding alloys in India, model ODS alloys have been produced with the compositions, Fe-0.3Y2O3, Fe-0.2Ti-0.3Y2O3 and Fe-14Cr-0.2Ti-0.3Y2O3. The oxide particles in these three model alloys have been studied by APT in their as-received state and following ion irradiation (as a proxy for neutron irradiation) at various temperatures. In order to adequately quantify the composition of the oxide clusters, several difficulties must be managed, including issues relating to the chemical identification (ranging and variable peak-overlaps); trajectory aberrations and chemical structure; and particle sizing. This paper presents how these issues can be addressed by the application of bespoke data analysis tools and correlative microscopy. A discussion follows concerning the achievable precision in these measurements, with reference to the fundamental limiting factors.

Ultrafast electron diffraction pattern simulations using GPU technology. Applications to lattice vibrations.

Graphical processing units (GPUs) offer a cost-effective and powerful means to enhance the processing power of computers. Here we show how GPUs can greatly increase the speed of electron diffraction pattern simulations by the implementation of a novel method to generate the phase grating used in multislice calculations. The increase in speed is especially apparent when using large supercell arrays and we illustrate the benefits of fast encoding the transmission function representing the atomic potentials through the simulation of thermal diffuse scattering in silicon brought about by specific vibrational modes.

Mechanism of efavirenz influence on methadone pharmacokinetics and pharmacodynamics.

Mechanisms by which efavirenz diminishes methadone plasma concentrations are unknown. This investigation determined efavirenz influence on clinical methadone disposition and miosis, intravenous and oral alfentanil clearance (hepatic and intestinal cytochrome P450 3A4/5 (CYP3A4/5) activity), fexofenadine disposition (intestinal transporters activity), and efavirenz clearance and 8-hydroxylation (CYP2B6 activity), and human hepatocyte effects. Efavirenz induced systemic and oral alfentanil clearances two- to fivefold and induced efavirenz 8-hydroxylation. Efavirenz stereoselectively decreased methadone plasma concentrations 50-70%. Methadone systemic and oral clearances, hepatic clearance and extraction ratio, N-demethylation, and metabolite formation clearance were stereoselectively increased two- to threefold. Bioavailability decreased. Efavirenz shifted methadone concentration-miosis curves leftward and upward. Efavirenz induced hepatocyte CYP2B6 and CYP3A4 expression, activity, and methadone N-demethylation. Results show that efavirenz coinduced hepatic CYP2B6 and CYP3A4/5, coinduced hepatic and intestinal CYP3A4/5, and coinduced gastrointestinal CYP3A4/5 and efflux transporters. Methadone disposition was most consistent with efavirenz induction of hepatic CYP2B6-mediated methadone N-demethylation. Efavirenz may alter methadone pharmacodynamics.

Sensitivity of intravenous and oral alfentanil and pupillary miosis as minimal and noninvasive probes for hepatic and first-pass CYP3A induction.

Systemic and oral clearances of alfentanil (ALF) are in vivo probes for hepatic and first-pass cytochrome P450 (CYP) 3A. Both ALF single-point plasma concentrations and miosis are surrogates for area under the concentration-time curve (AUC) and clearance and are minimal and noninvasive CYP3A probes. This investigation determined ALF sensitivity for detecting graded CYP3A induction and compared it with that of midazolam (MDZ). Twelve volunteers (sequential crossover) received 0, 5, 10, 25, or 75 mg oral rifampin for 5 days. MDZ and ALF were given intravenously and orally on sequential days. Dark-adapted pupil diameter was measured with blood sampling. Graded rifampin decreased plasma MDZ AUCs to 83, 76, 62, and 59% (intravenous (i.v.)) and 78, 66, 39, and 24% (oral) of control. Hepatic and first-pass CYP3A induction were detected comparably by plasma MDZ and ALF AUCs. Single ALF concentrations detected all CYP3A induction, whereas MDZ was less sensitive. ALF miosis detected induction of first-pass but not hepatic CYP3A.

Concurrent assessment of hepatic and intestinal cytochrome P450 3A activities using deuterated alfentanil.

Alfentanil (ALF) is a validated probe for hepatic, first-pass, and intestinal cytochrome P450 (CYP) 3A activity, using plasma clearances, single-point concentrations, and noninvasive pupil diameter change (miosis). Assessing intravenous (i.v.) and oral drug disposition typically requires separate dosing. This investigation evaluated concurrent administration of oral deuterated and i.v. unlabeled ALF to assess both intestinal and hepatic CYP3A, and compare sequential and simultaneous dosing. ALF disposition was evaluated after strong hepatic and/or intestinal CYP3A induction and inhibition by rifampin, ketoconazole, and grapefruit juice. Using plasma ALF concentrations and area under the curve (AUC), clearance, or single-point concentrations, both simultaneous and sequential dosing provided equivalent results and detected hepatic and intestinal CYP3A induction and inhibition. Miosis better detected CYP3A modulation with sequential vs. simultaneous dosing. These results show that concurrent administration of oral deuterated and i.v. ALF, either sequentially or simultaneously, is an efficient and effective approach to assessing hepatic and intestinal CYP3A activity.

Boosting T-cell immunity as a therapeutic approach for neurodegenerative conditions: the role of innate immunity.

Our research group has been working for more than a decade on the cross-talk between the immune and the nervous systems. Due to the unique nature of the central nervous system (CNS) as an immune privileged site, it was commonly believed that the nervous system functions optimally without any immune intervention, and that any immune cell infiltration to the CNS is a sign of pathology. However, since the immune system constitutes the body's major defense and repair mechanism, it seemed unreasonable that the CNS would have completely lost the need for assistance from this system. This insight prompted us to revisit the entire question of whether immune cells are required for recovery from CNS injuries. We subsequently made numerous fundamental observations that led us to formulate a unified theory linking all neurodegenerative conditions; thus, we suggested that "T-cell immunity to self maintains the self," at least in the CNS. According to this view, immunity to self ("protective autoimmunity") provides a pivotal role in maintenance, protection, and repair of the healthy and diseased CNS. We further showed that the T cells mediate their effect, at least under pathological conditions, by controlling the recruitment of blood-borne monocytes, which play a crucial local role that cannot be replaced by the resident microglia. Boosting of such a T cell response specific for brain proteins, while carefully choosing the antigen, the carrier, timing, dosing, and regimen should be considered as a way of augmenting a physiological repair mechanism needed to ameliorate disease conditions while restoring equilibrium needed for protection, repair and renewal; such therapy is not intended to modify a single mediator of a single disease, but rather, would serve as an approach for adjusting the levels of the immune response needed to restore a lost balance.

Ethical issues in haemophilia.

Ethical issues surrounding both the lack of global access to care as well as the implementation of advancing technologies, continue to challenge the international haemophilia community. Haemophilia is not given the priority it deserves in most developing countries. Given the heavy burdens of sickness and disease and severe resource constraints, it may not be possible to provide effective treatment to all who suffer from the various 'orphan' diseases. Nevertheless, through joint efforts, some package of effective interventions can be deployed for a significant number of those who are afflicted with 'orphan' diseases. With cost-effective utilization of limited resources, a national standard of care is possible and affordable. Gene-based diagnosis carries attendant ethical concerns whether for clinical testing or for research purposes, even as the list of its potential benefits to the haemophilia community grows rapidly. As large-scale genetic sequencing becomes quicker and cheaper, moving from the research to the clinic, we will face decisions about the implementation of prenatal, neonatal and other screening programs. Such debates will require input from not just the health care professionals but from all stakeholders in the haemophilia community. Finally, long-term therapeutic success gene transfer in small and large animal models raises the question of when and in which patient population the novel therapeutic approach should first be studied in humans with haemophilia. Although gene therapy represents a worthy goal, the central question for the haemophilia community should be whether it wishes to volunteer itself as a model for a much broader set of innovations.

Moving for care: findings from the US HIV Cost and Services Utilization Study.

This paper examines sociodemographic and HIV-related factors associated with moving post-HIV diagnosis for non-care- and care-related reasons (versus never moving post-HIV diagnosis). Distinctions are made between those who move for informal care only, formal care only, or informal and formal care. Data come from the nationally representative US HIV Cost and Services Utilization Study (N=2,864). Overall, 31.8% moved at least once post-HIV diagnosis and 16.3% moved most recently for care. Among those who moved for care, 32.6% moved for informal care only, 26.8% for formal care only, and 40.6% moved for both. Post-HIV diagnosis moves for reasons unrelated to care were less likely among African Americans and older persons, and more likely among those with longer durations positive. Moves for care were less likely among African Americans, older persons, and persons with higher educational attainments, while they were more likely among those with an AIDS diagnosis and longer durations HIV-positive. Among those who moved for care, women and persons with higher incomes were less likely to move for formal or mixed care than informal care only. Given that moving for care may reflect disparities in access to care and unmet needs, additional analyses with more detailed data are warranted.

Equipoise and international human-subjects research.

This paper examines the role of equipoise in evaluating international research. It distinguishes two possible formulations of the equipoise requirement that license very different evaluations of international research proposals. The interpretation that adopts a narrow criterion of similarity between clinical contexts has played an important role in one recent controversy, but it suffers from a number of problems. An alternative interpretation that adopts a broader criterion of similarity does a better job of avoiding both exploitation of the brute fact of social deprivation and the exploitation of needy populations for the benefit of more well-off populations. It also holds out the promise of reconciling the need to find interventions that can be employed in developing world contexts with the cluster of moral values that must constrain the way such research is carried out.

Effects of drug abuse and mental disorders on use and type of antiretroviral therapy in HIV-infected persons.

OBJECTIVE: To distinguish the effects of drug abuse, mental disorders, and problem drinking on antiretroviral therapy (ART) and highly active ART (HAART) use. DESIGN: Prospective population-based probability sample of 2,267 (representing 213,308) HIV-infected persons in care in the United States in early 1996. MEASUREMENTS: Self-reported ART from first (January 1997-July 1997) to second (August 1997-January 1998) follow-up interviews. Drug abuse/dependence, severity of abuse, alcohol use, and probable mental disorders assessed in the first follow-up interview. Adjusted odds ratios (AORs) and 95% confidence intervals (CIs) estimated from weighted models for 1) receipt of any ART, and 2) receipt of HAART among those on ART. RESULTS: Of our study population, ART was reported by 90% and HAART by 61%. Over one third had a probable mental disorder and nearly half had abused any drugs, but drug dependence (9%) or severe abuse (10%) was infrequent. Any ART was less likely for persons with dysthymia (AOR, 0.74; CI, 0.58 to 0.95) but only before adjustment for drug abuse. After full adjustment with mental health and drug abuse variables, any ART was less likely for drug dependence (AOR, 0.58; CI, 0.34 to 0.97), severe drug abuse (AOR, 0.52; CI, 0.32 to 0.87), and HIV risk from injection drug use (AOR, 0.55; CI, 0.39 to 0.79). Among drug users on ART, only mental health treatment was associated with HAART (AOR, 1.57; CI, 1.11 to 2.08). CONCLUSIONS: Drug abuse-related factors were greater barriers to ART use in this national sample than mental disorders but once on ART, these factors were unrelated to type of therapy.

Psychiatric disorders and drug use among human immunodeficiency virus-infected adults in the United States.

BACKGROUND: There have been no previous nationally representative estimates of the prevalence of mental disorders and drug use among adults receiving care for human immunodeficiency virus (HIV) disease in the United States. It is also not known which clinical and sociodemographic factors are associated with these disorders. SUBJECTS AND METHODS: We enrolled a nationally representative probability sample of 2864 adults receiving care for HIV in the United States in 1996. Participants were administered a brief structured psychiatric instrument that screened for psychiatric disorders (major depression, dysthymia, generalized anxiety disorders, and panic attacks) and drug use during the previous 12 months. Sociodemographic and clinical factors associated with screening positive for any psychiatric disorder and drug dependence were examined in multivariate logistic regression analyses. RESULTS: Nearly half of the sample screened positive for a psychiatric disorder, nearly 40% reported using an illicit drug other than marijuana, and more than 12% screened positive for drug dependence during the previous 12 months. Factors independently associated with screening positive for a psychiatric disorder included number of HIV-related symptoms, illicit drug use, drug dependence, heavy alcohol use, and being unemployed or disabled. Factors independently associated with screening positive for drug dependence included having many HIV-related symptoms, being younger, being heterosexual, having frequent heavy alcohol use, and screening positive for a psychiatric disorder. CONCLUSIONS: Many people infected with HIV may also have psychiatric and/or drug dependence disorders. Clinicians may need to actively identify those at risk and work with policymakers to ensure the availability of appropriate care for these treatable disorders.

Use of mental health and substance abuse treatment services among adults with HIV in the United States.

BACKGROUND: The need for mental health and substance abuse services is great among those with human immunodeficiency virus (HIV), but little information is available on services used by this population or on individual factors associated with access to care. METHODS: Data are from the HIV Cost and Services Utilization Study, a national probability survey of 2864 HIV-infected adults receiving medical care in the United States in 1996. We estimated 6-month use of services for mental health and substance abuse problems and examined socioeconomic, HIV illness, and regional factors associated with use. RESULTS: We estimated that 61.4% of 231 400 adults under care for HIV used mental health or substance abuse services: 1.8% had hospitalizations, 3.4% received residential substance abuse treatment, 26.0% made individual mental health specialty visits, 15.2% had group mental health treatment, 40.3% discussed emotional problems with medical providers, 29.6% took psychotherapeutic medications, 5.6% received outpatient substance abuse treatment, and 12.4% participated in substance abuse self-help groups. Socioeconomic factors commonly associated with poorer access to health services predicted lower likelihood of using mental health outpatient care, but greater likelihood of receiving substance abuse treatment services. Those with less severe HIV illness were less likely to access services. Persons living in the Northeast were more likely to receive services. CONCLUSIONS: The magnitude of mental health and substance abuse care provided to those with known HIV infection is substantial, and challenges to providers should be recognized. Inequalities in access to care are evident, but differ among general medical, specialty mental health, and substance abuse treatment sectors.

The independence of practical ethics.

After criticizing three common conceptions of the relationship between practical ethics and ethical theory, an alternative modeled on Aristotle's conception of the relationship between rhetoric and philosophical ethics is explored. This account is unique in that it neither denigrates the project of searching for an adequate comprehensive ethical theory nor subordinates practical ethics to that project. Because the purpose of practical ethics, on this view, is to secure the cooperation of other persons in a way that respects their status as free and equal, it seeks to influence the judgments of others by providing them with reasons that are accessible to their own understanding. On this account, the independence of practical ethics is rooted in an appreciation of the constraints that nonideal circumstances place on the role that the philosophically refined premises of moral theory can play in such public deliberations. Practical and philosophical ethics are united, not by shared theoretical frameworks or principles, but by the need to exercise intelligently the same intellectual and affective capacities. They are separated, not by the particularity or generality of their starting points, but by their responsiveness to the practical problem of facilitating sound normative deliberations among persons as we find them, under non-ideal circumstances.