Efficient molecular encoding in multifunctional self-immolative urethanes.

Molecular encoding in sequence-defined polymers shows promise as a new paradigm for data storage. Here, we report what is, to our knowledge, the first use of self-immolative oligourethanes for storing and reading encoded information. As a proof of principle, we describe how a text passage from Jane Austen's Mansfield Park was encoded in sequence-defined oligourethanes and reconstructed via self-immolative sequencing. We develop Mol.E-coder, a software tool that uses a Huffman encoding scheme to convert the character table to hexadecimal. The oligourethanes are then generated by a high-throughput parallel synthesis. Sequencing of the oligourethanes by self-immolation is done concurrently in a parallel fashion, and the liquid chromatography-mass spectrometry (LC-MS) information decoded by our Mol.E-decoder software. The passage is capable of being reproduced wholly intact by a third-party, without any purifications or the use of tandem MS (MS/MS), despite multiple rounds of compression, encoding, and synthesis.

Skin-specific training experience of workers assessed for contact dermatitis.

Background: Contact dermatitis is a common and preventable work-related disease. Skin-specific training may be effective for preventing occupational contact dermatitis, but little information is available regarding actual workplace training and its effectiveness. Aims: To describe workplace skin-specific training among workers with suspected contact dermatitis. Methods: Patch test patients being assessed for suspected contact dermatitis at an occupational health clinic in Toronto, Canada, completed a questionnaire on training experiences, workplace characteristics, exposures and skin protection practices. Results: Of 175 patients approached, 122 (71%) workers completed questionnaires. Many (80%) had received general occupational health and safety and hazardous materials training (76%). Fewer (39%) received skin-specific training. Of those with work-related contact dermatitis, 52% did not receive skin-specific training. Skin-specific training was commonly provided by health and safety professionals or supervisors using video, classroom and online techniques. Content included glove use, exposure avoidance and hand washing information. Workers that received skin-specific training found it memorable (87%), useful (85%) and common sense in nature (100%). Conclusions: This study indicates gaps in workplace training on skin disease prevention for workers with contact dermatitis. Workers perceived skin-specific training to be useful. Understanding worker training experiences is important to prevention programme development and reducing work-related skin disease.

Modeling Scalable Pattern Generation in DNA Reaction Networks.

We have developed a theoretical framework for developing patterns in multiple dimensions using controllable diffusion and designed reactions implemented in DNA. This includes so-called strand displacement reactions in which one single-stranded DNA hybridizes to a hemi-duplex DNA and displaces another single-stranded DNA, reversibly or irreversibly. These reactions can be designed to proceed with designed rate and molecular specificity. By also controlling diffusion by partial complementarity to a stationary, cross-linked DNA, we can generate predictable patterns. We demonstrate this with several simulations showing deterministic, predictable shapes in space.

Pattern transformation with DNA circuits.

Readily programmable chemical networks are important tools as the scope of chemistry expands from individual molecules to larger molecular systems. Although many complex systems are constructed using conventional organic and inorganic chemistry, the programmability of biological molecules such as nucleic acids allows for precise, high-throughput and automated design, as well as simple, rapid and robust implementation. Here we show that systematic and quantitative control over the diffusivity and reactivity of DNA molecules yields highly programmable chemical reaction networks (CRNs) that execute at the macroscale. In particular, we designed and implemented non-enzymatic DNA circuits capable of performing pattern-transformation algorithms such as edge detection. We also showed that it is possible to fine-tune and multiplex such circuits. We believe these strategies will provide programmable platforms on which to prototype CRNs, discover bottom-up construction principles and generate patterns in materials.

Porcine lens nuclei as a model for comparison of 3 ultrasound modalities regarding efficiency and chatter.

PURPOSE: To validate a porcine lens model by comparing density and ultrasound (US) with known human standards using the Infiniti Ozil with Intelligent Phacoemulsification (torsional), Whitestar Signature Micropulse (longitudinal), and Ellips FX (transversal) modalities. SETTING: Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. DESIGN: Experimental study. METHODS: Lens nuclei were formalin soaked in hour-based intervals and divided into 2.0 mm cubes. Density was characterized by crushing experiments and compared with known human measures. Efficiency and chatter were examined. RESULTS: The mean weight to cut thickness in half ranged from 16.9 g ± 5.5 (SD) in the 0-hour group to 121.3 ± 47.5 gm in the 4-hour group. Lenses in the 2-hour group (mean 70.2 ± 19.1 g) best matched human density (P=.215). The mean efficiency ranged from 0.432 ± 0.178 seconds to 9.111 ± 2.925 seconds; chatter ranged from zero to 1.85 ± 1.927 bounces. No significant difference was detected when comparing the 2-hour formalin group with human lenses in torsional and transversal US. There was no significant difference between transversal and torsional modalities, consistent with human studies. Although longitudinal (6 milliseconds on, 12 milliseconds off) was significantly more efficient at 50% power than at 25%, there was no significant difference compared with transversal or torsional US. CONCLUSIONS: Animal lenses soaked for 2 hours in formalin were most comparable to human lenses. Longitudinal US may be an acceptable alternative to torsional and transversal US.

Cost and threshold analysis of an HIV/STI/hepatitis prevention intervention for young men leaving prison: Project START.

The objectives of this study were to: (a) estimate the costs of providing a single-session HIV prevention intervention and a multi-session intervention, and (b) estimate the number of HIV transmissions that would need to be prevented for the intervention to be cost-saving or cost-effective (threshold analysis). Project START was evaluated with 522 young men aged 18-29 years released from eight prisons located in California, Mississippi, Rhode Island, and Wisconsin. Cost data were collected prospectively. Costs per participant were $689 for the single-session comparison intervention, and ranged from $1,823 to 1,836 for the Project START multi-session intervention. From the incremental threshold analysis, the multi-session intervention would be cost-effective if it prevented one HIV transmission for every 753 participants compared to the single-session intervention. Costs are comparable with other HIV prevention programs. Program managers can use these data to gauge costs of initiating these HIV prevention programs in correctional facilities.

Reducing postrelease risk behavior among HIV seropositive prison inmates: the health promotion program.

The prevalence of AIDS is five times higher among prison inmates than in the general population. Because recidivism is common and many inmates are serving short sentences for parole violation, HIV-seropositive inmates move frequently between prison and their home communities. We designed an eight-session prerelease intervention for HIV seropositive inmates to decrease sexual and drug-related risk behavior and to increase use of community resources after release. The intervention sessions were delivered at the prison by community service providers. We found that a prerelease risk reduction intervention for HIV seropositive inmates was feasible. Descriptive results support the effectiveness of the program in reducing sexual and drug-related behaviors and in increasing use of community resources after release. Compared with men who signed up for the intervention but were unable to attend, men who received the intervention reported more use of community resources and less sexual and drug-related risk behavior in the months following release. We recommend dissemination and continued evaluation of this risk-reduction intervention.

Collaborative research to prevent HIV among male prison inmates and their female partners.

Despite the need for targeted HIV prevention interventions for prison inmates, institutional and access barriers have impeded development and evaluation of such programs. Over the past 6 years, the authors have developed a unique collaborative relationship to develop and evaluate HIV prevention interventions for prison inmates. The collaboration includes an academic research institution (the Center for AIDS Prevention Studies at the University of California, San Francisco), a community-based organization (Centerforce), and the staff and inmate peer educators inside a state prison. In this ongoing collaboration, the authors have developed and evaluated a series of HIV prevention interventions for prison inmates and for women who visit prison inmates. Results of these studies support the feasibility and effectiveness of HIV prevention programs for inmates and their partners both in prison and in the community. Access and institutional barriers to HIV intervention research in prisons can be overcome through the development of collaborative research partnerships.

Acute hematogenous osteomyelitis. A challenge to clinical acumen.

Acute hematogenous osteomyelitis is an infection of bone and marrow in which the offending organism is transmitted to the area via the bloodstream. The pathophysiology of the infection is closely related to the vascular anatomy of bone, which is age-dependent. Because of certain anatomic features of bone during infancy and childhood, the disease is most prevalent at these times. The diagnosis must be made clinically, although cultures and bone imaging may be of great help. The key to successful therapy is early and sufficiently long administration of appropriate antibiotics. Judicious use of surgical drainage is based on the specific clinical situation.

Status asthmaticus in childhood.

A useful definition of status asthmaticus is an attack which, in the physician's judgment, remains sufficiently severe following routine outpatient management to warrant admission to the hospital. Initial evaluation requires a careful history and physical and mental status examination, as well as arterial blood gas analysis. General supportive measures, oxygen and intravenous fluids are established, followed by the cornerstone of therapy, intravenous aminophylline. The second essential component is corticosteroids. Aerosolized bronchodilators and oral beta 2-adrenergic drugs are useful adjuncts.

XXYY syndrome discovered on routine physical examination.

The XXYY syndrome, an uncommon disorder of chromosome number, was discovered on routine physical examination of a 20-year-old patient. Despite numerous earlier contacts with physicians, including several visits during adolescence, insufficient consideration had been given to his apparent abnormalities. This case is presented to review the syndrome and to emphasize the importance of careful evaluation of pubertal development during the routine physical examination of an adolescent.