DNA-Templated Nanofabrication of CdS-Au Nanoscale Schottky Contacts and Electrical Characterization.

DNA-templated nanofabrication presents an innovative approach to creating self-assembled nanoscale metal-semiconductor-based Schottky contacts, which can advance nanoelectronics. Herein, we report the successful fabrication of metal-semiconductor Schottky contacts using a DNA origami scaffold. The scaffold, consisting of DNA strands organized into a specific linear architecture, facilitates the competitive arrangement of Au and CdS nanorods, forming heterojunctions, and addresses previous limitations in low electrical conductance making DNA-templated electronics with semiconductor nanomaterials. Electroless gold plating extends the Au nanorods and makes the necessary electrical contacts. Tungsten electrical connection lines are further created by electron beam-induced deposition. Electrical characterization reveals nonlinear Schottky barrier behavior, with electrical conductance ranging from 0.5 × 10-4 to 1.7 × 10-4 S. The conductance of these DNA-templated junctions is several million times higher than with our prior Schottky contacts. Our research establishes an innovative self-assembly approach with applicable metal and semiconductor materials for making highly conductive nanoscale Schottky contacts, paving the way for the future development of DNA-based nanoscale electronics.

Impact of Polymer-Constrained Annealing on the Properties of DNA Origami-Templated Gold Nanowires.

DNA origami-templated fabrication enables bottom-up fabrication of nanoscale structures from a variety of functional materials, including metal nanowires. We studied the impact of low-temperature annealing on the morphology and conductance of DNA-templated nanowires. Nanowires were formed by selective seeding of gold nanorods on DNA origami and gold electroless plating of the seeded structures. At low annealing temperatures (160 °C for seeded-only and 180 °C for plated), the wires broke up and separated into multiple, isolated islands. Through the use of polymer-constrained annealing, the island formation in plated wires was suppressed up to annealing temperatures of 210 °C. Four-point electrical measurements showed that the wires remained conductive after a polymer-constrained annealing at 200 °C.

Seeding, Plating and Electrical Characterization of Gold Nanowires Formed on Self-Assembled DNA Nanotubes.

Self-assembly nanofabrication is increasingly appealing in complex nanostructures, as it requires fewer materials and has potential to reduce feature sizes. The use of DNA to control nanoscale and microscale features is promising but not fully developed. In this work, we study self-assembled DNA nanotubes to fabricate gold nanowires for use as interconnects in future nanoelectronic devices. We evaluate two approaches for seeding, gold and palladium, both using gold electroless plating to connect the seeds. These gold nanowires are characterized electrically utilizing electron beam induced deposition of tungsten and four-point probe techniques. Measured resistivity values for 15 successfully studied wires are between 9.3 × 10-6 and 1.2 × 10-3 Ωm. Our work yields new insights into reproducible formation and characterization of metal nanowires on DNA nanotubes, making them promising templates for future nanowires in complex electronic circuitry.

Four-Point Probe Electrical Measurements on Templated Gold Nanowires Formed on Single DNA Origami Tiles.

Bottom-up nanofabrication is increasingly making use of self-assembled DNA to fabricate nanowires and potential integrated circuits, although yields of such electronic nanostructures are inadequate, as is the ability to reliably make electrical measurements on them. In this paper, we report improved yields and unprecedented conductivity measurements for Au nanowires created on DNA origami tile substrates. We created several different self-assembled Au nanowire arrangements on DNA origami tiles that are approximately 70 nm × 90 nm, through anisotropic growth of Au nanorods attached to specific sites. Modifications to the tile design increased yields of the final desired nanostructures as much as 6-fold. In addition, we measured the conductivity of Au nanowires created on these DNA tiles (∼130 nm long, 10 nm diameter, and 40 nm spacing between measurement points) with a four-point measurement technique that utilized electron beam induced metal deposition to form probe electrodes. These nanowires formed on single DNA origami tiles were electrically conductive, having resistivities as low as 4.24 × 10-5 Ω m. This work demonstrates the creation and measurement of inorganic nanowires on single DNA origami tiles as a promising path toward future bottom-up fabrication of nanoelectronics.

Directional Growth of DNA-Functionalized Nanorods to Enable Continuous, Site-Specific Metallization of DNA Origami Templates.

This work examines the anisotropic electroless plating of DNA-functionalized gold nanorods attached to a DNA origami template to fabricate continuous metal structures of rectanglar, square, and T shapes. DNA origami, a versatile method for assembling a variety of 2- and 3-D nanostructures, is utilized to construct the DNA breadboard template used for this study. Staple strands on selective sites of the breadboard template are extended with an additional nucleotide sequence for the attachment of DNA-functionalized gold nanorods to the template via base pairing. The nanorod-seeded DNA templates are then introduced into an electroless gold plating solution to determine the extent to which the anisotropic growth of the nanorods is able to fill the gaps between seeds to create continuous structures. Our results show that the DNA-functionalized nanorods grow anisotropically during plating at a rate that is approximately 4 times faster in the length direction than in the width direction to effectively fill gaps of up to 11-13 nm in length. The feasibility of using this directional growth at specific sites to enable the fabrication of continuous metal nanostructures with diameters as thin as 10 nm is demonstrated and represents important progress toward the creation of devices and systems based on self-assembled biological templates.

Anisotropic Electroless Deposition on DNA Origami Templates To Form Small Diameter Conductive Nanowires.

An improved method for the metallization of DNA origami is examined in this work. DNA origami, a simple and robust method for creating a wide variety of nanostructured shapes and patterns, provides an enabling template for bottom-up fabrication of next-generation nanodevices. Selective metallization of these DNA templates is needed to make nanoelectronic devices. Here, we demonstrate a metallization process that uses gold nanorod seeds followed by anisotropic plating to provide improved morphology and greater control of the final metallized width of the structure. In our approach, gold nanorods are attached to an origami template to create a seed layer. Electroless gold deposition is then used to fill the gaps between seeds in order to create continuous, conductive nanowires. Importantly, growth during electroless deposition occurs preferentially in the length direction at a rate that is approximately 4 times the growth rate in the width direction, which enables fabrication of narrow, continuous wires. The electrical properties of 49 nanowires with widths ranging from 13 to 29 nm were characterized, and resistivity values as low as 8.9 × 10-7 Ω·m were measured. The anisotropic metallization process presented here represents important progress toward the creation of nanoelectronic devices by molecularly directed placement of functional components onto self-assembled biological templates.

Dual patterning of a poly(acrylic acid) layer by electron-beam and block copolymer lithographies.

We show the controllable patterning of palladium nanoparticles in both one and two dimensions using electron-beam lithography and reactive ion etching of a thin film of poly(acrylic acid) (PAA). After the initial patterning of the PAA, a monolayer of polystyrene-b-poly-2-vinylpyridine micelles is spun cast onto the surface. A short reactive ion etch is then used to transfer the micelle pattern into the patterned poly(acrylic acid). Finally, PdCl2 is loaded from solution into the patterned poly(acrylic acid) features, and a reactive-ion etching process is used to remove the remaining polymer and form Pd nanoparticles. This method yields location-controlled patches of nanoparticles, including single- and double-file lines and nanoparticle pairs. A locational accuracy of 9 nm or less in one direction was achieved by optimizing the size of the PAA features.

Electrically conductive gold- and copper-metallized DNA origami nanostructures.

This work demonstrates the use of a circuit-like DNA origami structure as a template to fabricate conductive gold and copper nanostructures on Si surfaces. We improved over previous results by using multiple Pd seeding steps to increase seed uniformity and density. Our process has also been characterized through atomic force microscopy, particle size distribution analysis, and scanning electron microscopy. We found that four successive Pd seeding steps yielded the best results for electroless metal plating on DNA origami. Electrical resistance measurements were done on both Au- and Cu-metallized nanostructures, with each showing ohmic behavior. Gold-plated DNA origami structures made under optimal conditions had an average resistivity of 7.0 × 10(-5) Ω·m, whereas copper-metallized structures had a resistivity as low as 3.6 × 10(-4) Ω·m. Importantly, this is the first demonstration of electrically conductive Cu nanostructures fabricated on either DNA or DNA origami templates. Although resistivities for both gold and copper samples were larger than those of the bulk metal, these metal nanostructures have the potential for use in electrically connecting small structures. In addition, these metallized objects might find use in surface-enhanced Raman scattering experiments.

Improved efficiency of reversed-phase carbon/nanodiamond/polymer core-shell particles for HPLC using carbonized poly(divinylbenzene) microspheres as the core materials.

Here, we report efficiencies up to 112,000 plates per meter (a reduced plate height, h, of 2.22) for RP, carbon/nanodiamond/aminopolymer particles using conventional injection conditions in HPLC. This efficiency greatly exceeds our best previously reported value of 71,000 N/m (h = 3.52). The carbon cores used in this study were derived from carbonized poly(divinylbenzene) spheres that were either made in-house by a two-step polymerization procedure or obtained commercially. The resulting particles showed good uniformity and were oxidized in nitric acid to increase their dispersability. X-ray photoelectron spectroscopy confirms particle oxidation and subsequent aminopolymer deposition. Layer-by-layer (LbL) growth of poly(allyamine) and nanodiamond was demonstrated to produce core-shell particles. After LbL growth, the particles were functionalized, sieved, and packed into columns. The column functionalization and packing were reproducible. Van Deemter curves indicated that the commercially obtained poly(divinylbenzene) spheres outperformed those synthesized in our laboratory. The columns appear to be stable at 120°C in a pH 11.3 mobile phase. Longer columns (2.1 × 50 mm) than previously reported were packed. Four essential oils were separated by gradient elution.

Block copolymer self-assembly to pattern gold nanodots for site-specific placement of DNA origami and attachment of nanomaterials.

Directed placement of DNA origami could play a key role in future integrated nanoelectronic devices. Here we demonstrated the site-selective attachment of DNA origami on gold dots formed using a pattern transfer method through block copolymer self-assembly. First, a random copolymer brush layer is grafted on the Si surface and then poly (styrene-b-methylmethacrylate) block copolymer is spin-coated to give a hexagonal nanoarray after annealing. UV irradiation followed by acetic acid etching is used to remove the PMMA, creating cylindrical holes and then oxygen plasma etching removes the random copolymer layer inside those holes. Next, metal evaporation, followed by lift-off creates a gold dot array. We evaluated different ligand functionalization of Au dots, as well as DNA hybridization to attach DNA origami to the nanodots. DNA-coated Au nanorods are assembled on the DNA origami as a step towards creating nanowires and to facilitate electron microscopy characterization of the attachment of DNA origami on these Au nanodots. The DNA hybridization approach showed better DNA attachment to Au nanodots than localization by electrostatic interaction. This work contributes to the understanding of DNA-templated assembly, nanomaterials, and block copolymer nanolithography. Furthermore, the work shows potential for creating DNA-templated nanodevices and their placement in ordered arrays in future nanoelectronics.

Scaling parallel dielectrophoresis of carbon nanotubes: an enabling geometry.

Dielectrophoresis has been used as a technique for the parallel localization and alignment of both semiconducting and metallic carbon nanotubes (CNTs) at junctions between electrodes. A variation of this technique known as floating potential dielectrophoresis (FPD) allows for a self-limiting number of CNTs to be localized at each junction, on a massively parallel scale. However, the smallest FPD geometries to date are restricted to conductive substrates and have a lower limit on floating electrode size. We present a geometry which eliminates this lower limit and enables FPD to be performed on non-conducting substrates. We also discuss experiments clarifying the self-limiting mechanism of CNT localization and how it can be used advantageously as devices are scaled downwards to smaller sizes.

Chemical alignment of DNA origami to block copolymer patterned arrays of 5 nm gold nanoparticles.

We have used block copolymer patterned arrays of 5 nm gold nanoparticles (AuNPs) for chemically aligned surface attachment of DNA origami. Addition of single-stranded DNA-thiol to AuNPs allowed a base paired attachment of sticky end modified DNA origami. Results indicate a stable, selective attachment between the DNA origami and ssDNA modified AuNPs. Yield data showed 74% of AuNP binding sites forming an attachment with a DNA origami rectangle, and control surfaces showed less than 0.5% nonspecific adsorption.

Effects of second responder programs on repeat incidents of family abuse: An updated systematic review and meta-analysis.

Background: Family abuse is a recurrent phenomenon within a select population of households. This form of abuse can include any physical or psychological harassment that occurs between family or household members, and often involves complex mental and emotional issues that are resistant to intervention. Traditional criminal justice strategies for combating this issue have evolved over time but have frequently demonstrated limited success. Within the past few decades, multiagency programs to address repeat family abuse have gained popularity. One such program, termed "second responders," teams police officers with social service workers, victim advocates, or counselors to conduct follow-up visits with victims of family abuse following a complaint. Second responders seek to educate victims about the cyclical nature of family abuse, engage in safety planning, and/or provide service referrals. These interventions are based on the premise that victims are more likely to be receptive to crime prevention opportunities immediately following victimization. Second responder interventions have received support from the US Department of Justice and their adoption has spread in both the United States and internationally, however, there remains little conclusive evidence on their effects. Objectives: To update and extend the findings of the prior second responders systematic review and meta-analysis by synthesizing the results of published and unpublished second responder evaluations through October of 2021. This review also examines the use of victim services as a secondary outcome and incorporates a number of additional moderator analyses. Search Methods: The Global Policing Database (GPD), a repository of all experimental and quasi-experimental evaluations of policing interventions conducted since 1950, was searched using keywords related to second responder interventions and repeat family violence from 2004 to December 2019 (https://gpd.uq.edu.au/s/gpd/page/about). This search was also supplemented with additional strategies, such as reference harvesting of prior reviews, searching 2020 and 2021 volumes of leading academic journals, reviewing the reference lists of eligible studies, searching additional gray literature repositories focused on domestic violence, and consulting with eligible study authors. Selection Criteria: Eligible studies were required to include a treatment group that received the second responder intervention and a comparison group that did not. Assignment to these conditions could be either experimental or quasi-experimental, but quasi-experimental studies were required to use either matched comparison groups or multivariate analysis methods to control for confounding factors. Eligibility was limited to studies reporting on at least one measure of repeat family abuse, such as intimate partner violence, elder abuse, or general family abuse. Measures of repeat abuse could be based on either official (i.e., police data) or unofficial (i.e., victim survey data) data sources. Data Collection and Analysis: Five new studies were identified between 2004 and 2019, all of which contained sufficient data for the calculation of at least one effect size. Along with the 10 studies included in the prior review, a total of 15 studies and 29 distinct effect sizes were analyzed across three outcome constructs. Effect sizes were calculated as logged odds ratios and results were synthesized using random effects models with restricted maximum likelihood estimation. Final results were exponentiated to represent the percentage point difference in the odds of a given outcome for treatment groups relative to control groups. Risk of bias was assessed using items adapted from the Cochrane Risk of Bias tools for experimental and quasi-experimental studies. Eligible studies were generally considered to be of low risk of bias, however, issues with survey success/contact rates and the analytical approaches to these problems led to concern in several studies. Results: These analyses suggest that second responder interventions produced no significant effects on either police or victim-reported measures of repeat family abuse, in aggregate. However, findings from the more rigorous experimental studies indicated that second responder interventions were associated with a statistically significant 22% (95% confidence interval [CI] [1.04, 1.43]) increase in the odds of a police-reported repeat family abuse incident, with no significant variability in individual study results. Additionally, studies that measured the use of victim services as a secondary outcome were associated with a statistically significant 9% (95% CI [1.02, 1.16]) increase in the odds of service use for treatment groups relative to control groups. Several study characteristics also proved to be important moderators of treatment effects. Increases in the speed of the second response were associated with significant decreases in the odds of a victim-reported repeat incident, and studies that measured repeat family abuse using households were associated with significantly higher odds of a police-reported repeat incident, compared to studies that used the same victim or victim/offender pairing more generally. Authors' Conclusions: Second responder interventions are undoubtedly appealing based on their logic and intentions. Yet, well-intentioned programs with sound logic can still backfire, and the results of this updated review provide evidence that may be suggestive of a backfire effect. Even so, any firm conclusions from this review are limited by a lack of knowledge on the mechanisms operating in between the implementation of the second response intervention and the observed effects, as well as the small sample sizes involved in many analyses. While it seems clear that these programs are not producing any broad reductions in self-reported victimization, the increase in police-reported violence seen in experimental studies could indicate either a true increase in abuse or an increased willingness to call the police. The lack of observed impact on victim-reported violence would suggest the latter, but without more specific measures, such conclusions should be avoided. If these results are indicative of increased reporting, however, many may consider this a desirable outcome, particularly given the often-underreported nature of family abuse and the potential for increased reporting to lead to long-term reductions in abuse. Furthermore, these results provide an indication that second responder programs can produce other intended effects, such as increasing the retention of victim services, and that the specific characteristics of these interventions may moderate their effects. It is unclear why elements such as the immediacy of the second response or the unit of analysis being evaluated would impact study results, but these observations are consistent with the theory that domestic violence interventions must capitalize on short windows of opportunity and create separation between victims and offenders to reduce exposure and subsequent victimization. This potential indicates a need for more research on second responder programs, but specifically research that examines these moderating characteristics and mechanisms. Even in light of this potential, second responder programs do not, on average, appear to reduce the prevalence of repeat family abuse. Given the presence of alternative (and possibly more effective) domestic violence interventions that now exist (e.g., Safe Dates, Shifting Boundaries, Green Dot, etc.), it seems that policymakers may wish to look elsewhere for efforts to reduce family abuse.

Pellicular particles with spherical carbon cores and porous nanodiamond/polymer shells for reversed-phase HPLC.

A new stationary phase for reversed-phase high performance liquid chromatography (RP HPLC) was created by coating spherical 3 µm carbon core particles in a layer-by-layer (LbL) fashion with poly(allylamine) (PAAm) and nanodiamond. Unfunctionalized core carbon particles were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and Raman spectroscopy. After LbL of PAAm and nanodiamond, which yields ca. 4 µm core-shell particles, the particles were simultaneously functionalized and cross-linked using a mixture of 1,2-epoxyoctadecane and 1,2,7,8-diepoxyoctane to obtain a mechanically stable C(18)/C(8) bonded outer layer. Core-shell particles were characterized by SEM, and their surface area, pore diameter, and volume were determined using the Brunauer-Emmett-Teller (BET) method. Short stainless steel columns (30 × 4.6 mm i.d.) were packed and the corresponding van Deemter plots obtained. The Supporting Information contains a MATLAB program used to fit the van Deemter data. The retentions of a suite of analytes were investigated on a conventional HPLC at various organic solvent compositions, pH values of mobile phases, including extreme pH values, and column temperatures. At 60 °C, a chromatogram of 2,6-diisopropylphenol showed 71,500 plates/m (N/m). Chromatograms obtained under acidic conditions (pH 2.7) of a mixture of acetaminophen, diazepam, and 2,6-diisopropylphenol and a mixture of phenol, 4-methylphenol, 2-chlorophenol, 4-chlorophenol, 4-bromophenol, and 1-tert-butyl-4-methylphenol are presented. Retention of amitriptyline, cholesterol, and diazinon at temperatures ranging from 35 to 80 °C and at pH 11.3 is reported. A series of five basic drugs was also separated at this pH. The stationary phase exhibits considerable hydrolytic stability at high pH (11.3) and even pH 13 over extended periods of time. An analysis run on a UHPLC with a "sandwich" injection appeared to reduce extra column band broadening and gave best efficiencies of 110,000-120,000 N/m.

Updated protocol: Effects of second responder programs on repeat incidents of family abuse: An updated systematic review and meta-analysis.

The US Department of Justice has extensively funded second responder programs. In England and Wales, funding of follow-up with victims is largely funded by local Police and Crime Commissioners. While these programs rapidly gained popularity in the United States and are gaining popularity in other countries as well, the evidence regarding their effectiveness is mixed. Although some research has indicated that second responder programs can prevent repeat victimization, several experimental studies have suggested that these programs may actually increase the odds of abuse recurring. The purpose of the review is to compile and synthesize published and unpublished empirical studies of the effects of second responder programs on repeat incidents of family violence, including those studies completed after the original review. The Global Police Database (http://www.gpd.uq.edu.au/) provides a resource unavailable at the time of the initial review that will ensure that a comprehensive set of qualifying studies is identified. In the updated review, we will address the following questions: 1. What impact do second responder programs have on the number of subsequent calls to the police? 2. What impact do second responder programs have on abuse as measured on victim surveys? 3. Does the impact of second responder programs differ between experimental and quasi-experimental studies or studies that employ different methods of drawing samples? Building on the original review, we also aim to expand our examination of effect size heterogeneity given sufficient data to do so. For instance, given the proposition that there may be only a small window of opportunity to intervene into the lives of family violence victims after an incident, the amount of time that elapses between a family violence call and the second response may be an important moderator of programmatic effects. Additional factors that could impact the effect of the intervention include the length of the follow-up data collection period, the type of family violence complaint (e.g., intimate partner violence vs. elder abuse), and the sociodemographic characteristics of the victim and the offender (see generally Sherman, 2018). Ultimately, this review seeks not only to update the results of the prior review with additional research, but also to explore the mechanisms behind the observed effects in a way that provides utility for future policy creation.

Safety, Tolerability, and Outcomes of Enteral Nutrition in Extracorporeal Membrane Oxygenation.

Extracorporeal membrane oxygenation (ECMO) is a supportive care system for patients with respiratory or cardiac failure. Patients requiring ECMO are at risk for significant inflammation, prolonged hospitalization, and acquired malnutrition and sarcopenia. Societal guidelines recommend early enteral nutrition in critically ill patients; however, in this population, optimal timing and dose of nutrition remains unknown and fear of reduced splanchnic perfusion, delayed gastric emptying, and bowel ischemia poses a barrier to appropriate energy and protein intake. This narrative review intends to provide an overview of ECMO, highlight the rationale for nutrition support in this population, and review the safety, tolerability, and outcomes associated with enteral nutrition during ECMO.

Bottom-Up Fabrication of DNA-Templated Electronic Nanomaterials and Their Characterization.

Bottom-up fabrication using DNA is a promising approach for the creation of nanoarchitectures. Accordingly, nanomaterials with specific electronic, photonic, or other functions are precisely and programmably positioned on DNA nanostructures from a disordered collection of smaller parts. These self-assembled structures offer significant potential in many domains such as sensing, drug delivery, and electronic device manufacturing. This review describes recent progress in organizing nanoscale morphologies of metals, semiconductors, and carbon nanotubes using DNA templates. We describe common substrates, DNA templates, seeding, plating, nanomaterial placement, and methods for structural and electrical characterization. Finally, our outlook for DNA-enabled bottom-up nanofabrication of materials is presented.

Chemical vapor deposition of three aminosilanes on silicon dioxide: surface characterization, stability, effects of silane concentration, and cyanine dye adsorption.

Covalently bonded monolayers of two monofunctional aminosilanes (3-aminopropyldimethylethoxysilane, APDMES, and 3-aminopropyldiisopropylethoxysilane, APDIPES) and one trifunctional aminosilane (3-aminopropyltriethoxysilane, APTES) have been deposited on dehydrated silicon substrates by chemical vapor deposition (CVD) at 150 °C and low pressure (a few Torr) using reproducible equipment. Standard surface analytical techniques such as x-ray photoelectron spectroscopy (XPS), contact angle goniometry, spectroscopic ellipsometry, atomic force microscopy, and time-of-flight secondary ion mass spectroscopy (ToF-SIMS) have been employed to characterize the resulting films. These methods indicate that essentially constant surface coverages are obtained over a wide range of gas phase concentrations of the aminosilanes. XPS data further indicate that the N1s/Si2p ratio is higher after CVD with the trifunctional silane (APTES) compared to the monofunctional ones, with a higher N1s/Si2p ratio for APDMES compared to that for APDIPES. AFM images show an average surface roughness of 0.12- 0.15 nm among all three aminosilane films. Stability tests indicate that APDIPES films retain most of their integrity at pH 10 for several hours and are more stable than APTES or APDMES layers. The films also showed good stability against storage in the laboratory. ToF-SIMS of these samples showed expected peaks, such as CN(-), as well as CNO(-), which may arise from an interaction between monolayer amine groups and silanols. Optical absorption measurements on adsorbed cyanine dye at the surface of the aminosilane films show the formation of dimer aggregates on the surface. This is further supported by ellipsometry measurements. The concentration of dye on each surface appears to be consistent with the density of the amines.

Attachment of polybutadienes to hydrogen-terminated silicon and post-derivatization of the adsorbed species.

We report the first attachment of polymers with pendant vinyl groups to hydrogen-terminated silicon(111) (Si(111)-H); 1,2-polybutadiene (M(w) = 3200-3500 g/mol) was attached to Si(111)-H under mild conditions at room temperature with visible light. We also report the partial functionalization, in solution, of 1,2-polybutadiene with various thiols using thiol-ene chemistry and the subsequent attachments of these compounds to Si(111)-H. The partially functionalized or unfunctionalized polybutadienes allow further functionalization at the surface through their unreacted carbon-carbon double bonds. We present this as a useful strategy for silicon surface modification. Surfaces were characterized with contact angle goniometry, spectroscopic ellipsometry, X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and atomic force microscopy (AFM).

The Effects of Legislation Mandating DNA Testing in Sexual Assault Cases: Results in Texas.

Many cities and states have taken steps to identify and process all untested sexual assault kits (SAKs). Texas was one of the first states to enact such legislation-SB 1636-which created a time line for a statewide audit and mandatory testing of SAKs. A mixed-methods approach was used to assess the effects of SB 1636 at both state and local levels. The study did not detect any effect of SB 1636 on reporting, arrests, or convictions. The legislation did have a significant effect on criminal justice workloads, particularly crime laboratories.