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.

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.

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.

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.

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.

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.

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.

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.

DNA testing in sexual assault cases: When do the benefits outweigh the costs?

OBJECTIVES: We examined 1200 sexual assault cold cases from Denver, Colorado to ascertain the rate of successful prosecution in which there was a DNA suspect match and the cost per conviction. RESULTS: Nearly 40% of the cases in which there was a DNA match failed to result in an arrest or prosecution primarily because victims were uncooperative or their testimony was judged to be unreliable. Other factors affecting conviction included crime context, victim availability, and the ability of the defendant to mount a consensual sex defense. Once an arrest had been made, however, the conviction rate exceeded 90%. We estimate that Denver's sexual assault DNA testing program cost roughly $16,000 per conviction. CONCLUSION: Our results lend strong support to the value of testing sexual assault kits (SAKs) even in cold cases. This suggests that programs such as Federal Solving Cold Cases with DNA Program are well worth the investment.

High surface-area carbon microcantilevers.

Microscale porous carbon mechanical resonators were formed using carbon nanotube templated microfabrication. These cantilever resonators exhibited nanoscale porosity resulting in a high surface area to volume ratio which could enable sensitive analyte detection in air. These resonators were shown to be mechanically robust and the porosity could be controllably varied resulting in densities from 102 to 103 kg m-3, with pore diameters on the order of hundreds of nanometers. Cantilevers with lengths ranging from 500 µm to 5 mm were clamped in a fixture for mechanical resonance testing where quality factors from 102 to 103 were observed at atmospheric pressure in air.

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.

Tissue-susceptibility matched carbon nanotube electrodes for magnetic resonance imaging.

Test disk electrodes were fabricated from carbon nanotubes (CNT) using the Carbon Nanotube Templated Microfabrication (CNT-M) technique. The CNT-M process uses patterned growth of carbon nanotube forests from surfaces to form complex patterns, enabling electrode sizing and shaping. The additional carbon infiltration process stabilizes these structures for further processing and handling. At a macroscopic scale, the electrochemical, electrical and magnetic properties, and magnetic resonance imaging (MRI) characteristics of the disk electrodes were investigated; their microstructure was also assessed. CNT disk electrodes showed electrical resistivity around 1â€¯Ω·cm, charge storage capacity between 3.4 and 38.4 mC/cm2, low electrochemical impedance and magnetic susceptibility of -5.9 to -8.1 ppm, closely matched to that of tissue (∼-9 ppm). Phantom MR imaging experiments showed almost no distortion caused by these electrodes compared with Cu and Pt-Ir reference electrodes, indicating the potential for significant improvement in accurate tip visualization.

Fabrication of High Aspect Ratio Millimeter-Tall Free-Standing Carbon Nanotube-Based Microelectrode Arrays.

Microelectrode arrays of carbon nanotube (CNT)/carbon composite posts with high aspect ratio and millimeter-length were fabricated using carbon-nanotube-templated microfabrication with a sacrificial "hedge". The high aspect ratio, mechanical robustness, and electrical conductivity of these electrodes make them a potential candidate for next-generation neural interfacing. Electrochemical measurements were also demonstrated using an individual CNT post microelectrode with a diameter of 25 µm and a length of 1 mm to perform cyclic voltammetry on both methyl viologen and dopamine in a phosphate-buffered saline solution. In addition to detection of the characteristic peaks, the CNT post microelectrodes show a fast electrochemical response, which may be enabling for in vivo and/or in vitro measurements. The CNT post electrode fabrication process was also integrated with other microfabrication techniques, resulting in individually addressable electrodes.

Increasing the Accessibility of Sexual Assault Forensic Examinations: Evaluation of Texas Law SB 1191.

INTRODUCTION: Texas SB 1191 was enacted in 2013 with the intent of increasing access to medical forensic examinations for sexual assault victims by requiring every hospital with an emergency department to be prepared to provide a medical forensic examination if requested by a sexual assault victim. To realize that goal, the law also required basic forensic training for medical professionals before conducting a medical forensic examination as well as a requirement that hospitals develop a "plan to train personnel on sexual assault forensic evidence collection." METHODS: Interviews were conducted in 18 healthcare facilities (five with sexual assault nurse examiner [SANE] programs and 13 without SANE programs) in Dallas, Lubbock, and Austin to determine their awareness and compliance with SB 1191. RESULTS: The data suggest that the law had a little effect on actual practice, and sexual assault survivors still sought a SANE program for a medical forensic examination. DISCUSSION: Although SB 1191 is an important state level effort to make forensic examinations more readily available, it did not fully account for the challenges faced by smaller hospitals that do not see enough sexual assault victims to justify training staff to SANE standards and did not adequately address the training required by medical professionals to feel prepared to conduct a medical forensic examination.

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.

Thin-Film Carbon Nanofuses for Permanent Data Storage.

In this study, we have fabricated nanofuses from thin-film, arc-deposited carbon for use in permanent data storage. Thin-film carbon fuses have fewer fabrication barriers and retain the required resistivity and structural stability to act as a data-storage medium. Carbon thin films were characterized for their electrical, microstructural, and chemical bonding properties. Annealing these films in an argon environment at 400 °C reduced the resistivity from about 4 × 10-2 Ω cm as deposited to about 5 × 10-4 Ω cm, allowing a lower blowing voltage. Nanofuses with widths ranging from 200 to 60 nm were fabricated and tested. They blow with voltages between 2 and 5.5 V, and the nanofuses remain stable in both "1" and "0" states under a constantly applied read voltage of 1 V for over 90 h.

A sweet spot for highly efficient growth of vertically aligned single-walled carbon nanotube forests enabling their unique structures and properties.

We investigated the correlation between growth efficiency and structural parameters of single-walled carbon nanotube (SWCNT) forests and report the existence of a SWCNT "sweet spot" in the CNT diameter and spacing domain for highly efficient synthesis. Only within this region could SWCNTs be grown efficiently. Through the investigation of the growth rates for ∼340 CNT forests spanning diameters from 1.3 to 8.0 nm and average spacing from 5 to 80 nm, this "sweet spot" was found to exist because highly efficient growth was constrained by several mechanistic boundaries that either hindered the formation or reduced the growth rate of SWCNT forests. Specifically, with increased diameter SWCNTs transitioned to multiwalled CNTs (multiwall border), small diameter SWCNTs could only be grown at low growth rates (low efficiency border), sparse SWCNTs lacked the requirements to vertically align (lateral growth border), and high density catalysts could not be prepared (high catalyst density border). As a result, the SWCNTs synthesized within this "sweet spot" possessed a unique set of characteristics vital for the development applications, such as large diameter, long, aligned, defective, and high specific surface area.