Surfactant-Assisted Synthesis of Monodisperse Methylammonium Lead Iodide Perovskite Nanocrystals.

Lead iodide based perovskites are promising optoelectronic materials ideal for solar cells. Recently emerged perovskite nanocrystals (NCs) offer more advantages including improved size-tunable band gap, structural stability, and solvent-based processing. Here we report a simple surfactant-assisted two-step synthesis to produce monodisperse PbI2 NCs which are then converted to methylammonium lead iodide perovskite NCs. Based on electron microscopy characterization, these NCs showed competitive monodispersity. Combined results from X-ray diffraction patterns, optical absorption, and photoluminescence confirmed the formation of high quality methylammonium lead iodide perovskite NCs. More importantly, by avoiding the use of hard-to-remove chemicals, the resulted perovskite NCs can be readily integrated in applications, especially solar cells through versatile solution/colloidal-based methods.

pH-Dependent Assembly of Porphyrin-Silica Nanocomposites and Their Application in Targeted Photodynamic Therapy.

Structurally controlled nanoparticles, such as core-shell nanocomposite particles by combining two or more compositions, possess enhanced or new functionalities that benefited from the synergistic coupling of the two components. Here we report new nanocomposite particles with self-assembled porphyrin arrays as the core surrounded by amorphous silica as the shell. The synthesis of such nanocomposite nanoparticles was conducted through a combined surfactant micelle confined self-assembly and silicate sol-gel process using optically active porphyrin as a functional building block. Depending on kinetic conditions, these particles exhibit structure and function at multiple length scales and locations. At the molecular scale, the porphyrins as the building blocks provide well-defined macromolecular structures for noncovalent self-assembly and unique chemistry for high-yield generation of singlet oxygen for photodynamic therapy (PDT). On the nanoscale, controlled noncovalent interactions of the porphyrin building block result in an extensive self-assembled porphyrin network that enables efficient energy transfer and impressive fluorescence for cell labeling, evidenced by absorption and photoluminescence spectra. Finally, the thin silicate shell on the nanoparticle surface allows easy functionalization, and the resultant targeting porphyrin-silica nanocomposites can selectively destroy tumor cells upon receiving light irradiation.

Morphology-Controlled Synthesis and Metalation of Porphyrin Nanoparticles with Enhanced Photocatalytic Performance.

The design and engineering of the size, shape, and chemistry of photoactive building blocks enables the fabrication of functional nanoparticles for applications in light harvesting, photocatalytic synthesis, water splitting, phototherapy, and photodegradation. Here, we report the synthesis of such nanoparticles through a surfactant-assisted interfacial self-assembly process using optically active porphyrin as a functional building block. The self-assembly process relies on specific interactions such as π-π stacking and metalation (metal atoms and ligand coordination) between individual porphyrin building blocks. Depending on the kinetic conditions and type of surfactants, resulting structures exhibit well-defined one- to three-dimensional morphologies such as nanowires, nanooctahedra, and hierarchically ordered internal architectures. Specifically, electron microscopy and X-ray diffraction results indicate that these nanoparticles exhibit stable single-crystalline and nanoporous frameworks. Due to the hierarchical ordering of the porphyrins, the nanoparticles exhibit collective optical properties resulted from coupling of molecular porphyrins and photocatalytic activities such as photodegradation of methyl orange (MO) pollutants and hydrogen production.

Attorney views on the use of private agencies for probation supervision and treatment.

The exponential rise in probation caseloads has necessitated that some jurisdictions contract with private probation agencies and community-based private treatment providers. Regulations that monitor private providers are ill defined or absent, leaving standards open to broad interpretation. Attorneys in one jurisdiction that used private providers were surveyed to measure their beliefs about private treatment providers for people sentenced to probation. The research found that attorneys supported private provider representatives being present in court to contact defendants and to provide evidence to strengthen probation violations. Private agency reputation and standardized criteria were important to establish qualifications in offering supervision and treatment services.

The significance of the victim advocate for domestic violence victims in municipal court.

Previous research has examined factors that influence felony case prosecution in domestic violence cases, but few have analyzed how victim participation, or lack thereof, may affect the defendant's case outcome in misdemeanors. This study used 384 municipal cases from a specialized domestic violence court to examine the role of the victim advocate and variables that had an impact on victim participation with prosecution and case disposition. To ensure that decisions in all cases were consistent, all decision makers in the sample involved the same group: the court advocate, prosecutor, and judge. The analysis found that victim cooperation after arrest coupled with services provided by shelter court advocates were a strong predictor of victim cooperation at disposition and case outcome.

Misdemeanor Arrestees With Mental Health Needs: Diversion and Outpatient Services as a Recidivism Reduction Strategy.

Individuals with mental illnesses who are arrested for criminal activity cycle between criminal justice and mental health systems at disproportionately high rates. Studying recidivism of this population has been difficult due to separate system data bases. This study compared recidivism outcomes of 102 adults with mental illness who were arrested for a misdemeanor offense. One group had a diagnosed mental illness ( n = 58) and the other group was diagnosed with co-occurring mental health and substance abuse disorders ( n = 44). As a condition of their personal recognizance bond, both groups voluntarily agreed to stabilize on medication and report to community-based outpatient mental health clinic. Participants in both groups had fewer rearrests and fewer days in jail in the 12 months following discharge from diversion relative to the 12 months prior to diversion participation. Outpatient mental health service utilization following 24 hr in jail seems to be a viable means of reducing recidivism among accused misdemeanant defendants.

Pressure compression of CdSe nanoparticles into luminescent nanowires.

Oriented attachment (OA) of synthetic nanocrystals is emerging as an effective means of fabricating low-dimensional nanoscale materials. However, OA relies on energetically favorable nanocrystal facets to grow nanostructured materials. Consequently, nanostructures synthesized through OA are generally limited to a specific crystal facet in their final morphology. We report our discovery that high-pressure compression can induce consolidation of spherical CdSe nanocrystal arrays, leading to unexpected one-dimensional semiconductor nanowires that do not exhibit the typical crystal facet. In particular, in situ high-pressure synchrotron x-ray scattering, optical spectroscopy, and high-resolution transmission electron microscopy characterizations indicate that by manipulating the coupling between nanocrystals through external pressure, a reversible change in nanocrystal assemblies and properties can be achieved at modest pressure. When pressure is increased above a threshold, these nanocrystals begin to contact one another and consolidate, irreversibly forming one-dimensional luminescent nanowires. High-fidelity molecular dynamics (MD) methods were used to calculate surface energies and simulate compression and coalescence mechanisms of CdSe nanocrystals. The MD results provide new insight into nanowire assembly dynamics and phase stability of nanocrystalline structures.

School bullying, low self-control, and opportunity.

The theory of low self-control has been shown to be a valid predictor of a wide variety of criminal and deviant behaviors. However, a limited number of studies were conducted to understand the relationship between low self-control and bullying and the effects of opportunity factors (i.e., parental supervision, association with other bullies, negative school environment, and disciplinary measures used by teachers) on bullying in the context of low self-control theory. The present study, using a sample of nearly 300 youths, examined the effects of low self-control and opportunity factors on various types of bullying behaviors. Results indicated that youths with low self-control were likely to physically and psychologically bully, consistent with the theory's prediction. When opportunity measures were introduced, they were stronger explanations of bullying than low self-control, especially association with other bullies and youth who experienced disciplinary measures by their teacher. Negative school environment was a significant predictor of psychological bullying but not for physical bullying. Theoretical and policy implications are discussed.

Seroconversion risk perception among jail populations: a call for gender-specific HIV prevention programming.

The prevalence of HIV/AIDS infection among prisoners is 3 to 4 times higher than in the U.S. population. Given that one in seven HIV-positive Americans pass through a correctional facility every year, the criminal justice system is in an ideal position to aggressively implement effective HIV education, treatment, and prevention. This study examines barriers to the effective delivery of these services and evaluates differences in risk perception among nearly 600 female and male inmates. The results underscore gender differences in Perceived Risk of Seroconversion and Exposure to HIV Education, suggesting that jails should implement gender-specific HIV prevention programming.

Research and services partnerships: a partnership to develop a utilization-focused evaluation plan for a criminal justice diversion program.

More than 100,000 offenders in the Texas correctional system have a mental illness, which represents about 19% of the state's correctional population, including offenders in prison and under community correctional supervision. To reduce these numbers, a leading mental health service provider established the Community Reintegration Program (CRP) to divert misdemeanor offenders with mental illness to community-based treatment. This column describes a collaborative process between the University of Texas at San Antonio and community partners to develop a utilization-focused evaluation plan for the CRP that would benefit all stakeholders. The evaluation used data collected as part of routine clinical work.

Factors associated with recidivism among offenders with mental illness.

This study examined factors that explained or predicted recidivism of offenders who were mentally impaired and were under various correctional interventions. Offenders in a residential treatment program and specialized probation group, specialized probation alone, and mentally ill offenders who had served time in jail were examined. In comparison to the other two groups, the residential treatment offenders had a more extensive criminal history and were thus more likely to fail on supervision as well as to recidivate after supervision ended. Offenders with an alcohol problem were more likely to recidivate earlier and be rearrested for a violent offense than offenders without an alcohol problem.