Thermal Dynamics Effects using Pulse-Shaping Laser Sintering of Printed Silver Inks.

In recent years, additive manufacturing has been evolving towards flexible substrates for the fabrication of printable electronic devices and circuits. Generally polymer-based, these emerging substrates suffer from their heat sensitivity and low glass-transition temperatures. As such they require new highly-localized sintering processes to treat the electronic inks without damaging the polymer-based substrate. Laser-based sintering techniques have shown great promises to achieve high-quality sintering locally, while controlling the heat penetration to preserve the polymer substrates integrity. In this report, we explore new optimization pathways for dynamic laser-based sintering of conductive silver inks. Multiple passes of a pulsed laser are first performed while varying pulse train frequencies and pulse energies as an attempt to optimize the properties of the silver inks. Then, time-domain pulse shaping is performed to alter the properties of the conductive inks. Together, these pathways allow for the careful control of the time-domain laser energy distribution in order to achieve the best electronic performances while preserving the substrate's integrity. Sheet resistance values as low as 0.024Ω/□ are achieved, which is comparable to conventional 1-hour oven annealing, with the processing time dramatically reduced to the milisecond range. These results are supported by finite element modeling of the laser-induced thermal dynamics.

Functional outcome of debridement, antibiotics and implant retention in periprosthetic joint infection involving the hip: a case-control study.

AIMS: Advocates of debridement, antibiotics and implant retention (DAIR) in hip periprosthetic joint infection (PJI) argue that a procedure not disturbing a sound prosthesis-bone interface is likely to lead to better survival and functional outcome compared with revision. This case-control study aims were to compare outcome of DAIRs for infected primary total hip arthroplasty (THA) with outcomes following primary THA and two-stage revision of infected primary THAs. PATIENTS AND METHODS: We retrospectively reviewed all DAIRs, performed for confirmed infected primary hip arthropasty (n = 82) at out institution, between 1997 and 2013. Data recorded included full patient information and type of surgery. Outcome measures included complications, mortality, implant survivorship and functional outcome. Outcome was compared with two control groups matched for gender and age; a cohort of primary THAs (n = 120) and a cohort of two-stage revisions for infection (n = 66). RESULTS: Mean age at DAIR was 69 years (33 to 87) and mean follow-up was eight years (2 to 17; standard deviation (sd) 5). A total of 52 (63%) of DAIRs were for early PJI (less than six weeks). Greater success in the eradication of infection with DAIR was identified with early PJI, comprising an interval less than a week between onset of symptoms and exchange of modular components with the DAIR procedure. Eradication of infection, complications and re-operation rates were similar in the DAIR and two-stage revision groups. For hips with successful eradication of infection with DAIR, the five-year survival (98%; 95% confidence interval (CI) 94 to 100) was similar to the primary THA group (98%; 95% CI 95 to 100) (n = 43; p = 0.3). The DAIR group had inferior mean Oxford Hip Scores (OHS) (38; 12 to 48) compared with the primary THA group (42; 15 to 48) (p = 0.02) but a significantly better mean OHS compared with the two-stage revision group (31; 0 to 48) (p = 0.008). Patients who required only one DAIR for eradication of infection had a similar mean OHS (41; 20 to 48) to the primary THA group (p = 0.2). CONCLUSION: The DAIR procedure is associated with a similar complication rate and ability to eradicate infection as two-stage revision. This study emphasises the need for exchange of modular components for improved chances of eradication of infection. This is the first study showing that DAIR is better than a two-stage revision regarding functional outcome. Cite this article: Bone Joint J 2017;99-B:614-22.

Effect of extreme pump pulse reshaping on intense terahertz emission in lithium niobate at multimilliJoule pump energies.

We report on terahertz (THz) generation via optical rectification in a room-temperature lithium niobate crystal under variable pump pulse durations, ranging from 100 to 300 fs, at 800 nm center wavelength. The efficiency for the process is predicted to have an order of magnitude increase when longer duration Fourier-limited pump pulses are used. Our results confirm this increase in efficiency, and we report a record 800 nm pump energy conversion efficiency of 0.35% with a saturation at >240 fs pulse duration. While promising, our findings show a series of key problems that must be overcome before the theoretical limit can be achieved, including the influence of the pump bandwidth broadening due to the cascaded nonlinearity taking place within the crystal.

Online system for temperature and accumulated dose control in plasma-based ion implantation.

Surface treatment optimization requires the control of the ion dose and the workpiece temperature, two parameters that are not trivially measurable in plasma-based ion implantation. A temperature and ion fluence monitoring system has been developed and implemented in a plasma-based ion implanter. It is based on the measurement with a thermopile of the radiation emitted from the back face of a thin copper disk inserted in the stainless steel sample holder. Since the incident ions carry practically all the incident power, the measurement of the Cu disk temperature that increases during implantation can provide an evaluation of the ion fluence in real time. A model has been developed for the deconvolution of the temperature data and has been fitted to the temperature behavior during implantation. A good agreement between the total integrated doses, evaluated with Rutherford backscattering spectroscopy characterization, and the ion fluence calculated by means of this model has been obtained with a discrepancy less than 16%.

Risk reconsidered: targets of violence in the social networks of people with serious psychiatric disorders.

Risk Reconsidered: Targets of violence in the Social Networks of People with Serious Mental illness. This exploratory analysis addresses the questions: 1) Who among the members of the social network of a person diagnosed with a major psychiatric disorder is likely to become a target of violence? 2) What kind of relationships do targets have with respondents in terms of the quality and quantity of interactions?, and 3) What are the risk factors that contribute to being a target of violence for people who are in the social networks of persons with serious mental disorders? The samples of 169 people with serious mental disorders were followed for 30 months. A logistic regression model of the risk for being a target of violence among the members of the cohort's social network reveals that both target and respondent characteristics are salient, and that mothers who live with adult children who have schizophrenia and co-occurring substance abuse bear a substantially elevated risk of becoming a target of violence, compared to other social network members. Other factors that elevate the risk for being a target of violence are being an immediate family members of the respondent, more time in residence with the respondent, and whether the respondent is financially dependent on the family. Respondents with the most mental health center visits had lower odds of committing an act or threat of violence against a social network member.

Discrepancy in the evaluation of visual impairment of elderly low-vision patients by general eye care practitioners and by low-vision practitioners.

Levels of impairment and disability determine eligibility for different welfare programs for visually handicapped persons. General eye care practitioners have to determine the level of impairment for administrative purposes, whereas the low-vision practitioner measures the level of impairment in order to plan the rehabilitation program. We compared the severity of visual impairment reported by the referring practitioners and the one reported by the low-vision specialists for the population of elderly low-vision patients receiving care from one of the largest rehabilitation centers for the visually handicapped in Quebec. Visual acuity ratings reported by general practitioners are lower than those reported by low-vision practitioners. The presence of visual handicap is generally well identified but the severity of visual impairment according to the World Health Organization (WHO)'s categories is not properly gauged by the general eye care practitioners as expressed by the sensitivity and the positive predictive value of the classification of the general practitioners in respect to the classification of the low-vision optometrists. The need to use existing standardized methods to measure visual acuity (VA) is emphasized. It may be hypothesized that this overestimation of the severity of the visual condition may have a negative impact on the process of rehabilitation of the elderly.

To use or not to use the refractive correction along with hand-held magnifiers.

Equivalent viewing power (EVP), field of view, and working distance (WD) were calculated for 4 different magnifier equivalent powers, four magnifier-to-eye distances, and for uncorrected spherical ametropias varying from +20.00 to -20.00 D in 0.25 D steps. Results show that the various viewing conditions which arise (depending on whether or not the refractive correction is worn) can differ considerably. The uncorrected unaccommodating myope has a greater EVP than the equivalent power of the magnifier if he chooses a magnifier-to-eye distance shorter than the focal length of the magnifier. In this situation, field of view is also enhanced. The uncorrected unaccommodating hyperope using a magnifier-to-eye distance longer than the focal length of the magnifier achieves a stronger EVP than the equivalent power of the magnifier. However, field of view is then reduced. For the uncorrected unaccommodating spherical ametrope, the use of a magnifier-to-eye distance corresponding to the focal length of the magnifier seems to be a good compromise between EVP, field of view, and working distance.

Effect of induced blur on visual acuity and stereoacuity.

The acuities of three subjects with good visual acuity and stereoacuity were reduced by the addition of diffusing filters placed before one or both eyes; these subjects then underwent automated stereoacuity and visual acuity tests. Results were idiosyncratic and differed from subject to subject to such an extent that no general rule sufficed to describe the effect of different degrees of blur on visual acuity and stereoacuity. It had been thought that blur degraded stereoacuity more than visual acuity but most of the results from one subject indicated the opposite effect. The effects of monocular vs. binocular blur are discussed.

Ethanol-induced alterations in EEG alpha activity and apparent source of the auditory P300 evoked response potential.

The relationship among topographic brain electrical activity mapping, auditory-evoked response potentials (ERPs), plasma ethanol levels and subjective reports of intoxication was examined in 4 male volunteers. The source of the auditory P300 ERP (a measure of selective attention and memory encoding) was estimated using a recently developed computer program. The effect of ethanol on the P300 wave was studied using a standard oddball paradigm both with and without a concomitant divided attention task. Ethanol (0.7 g/kg) administration produced marked increases in EEG alpha activity during the ascending limb of the blood ethanol curve. Acute ethanol administration caused a delay in the latency and a reduction in the amplitude of the auditory P300 ERP. A similar effect on P300 topography was noted in waves that were affected by the tones while the subjects also listened to a story (divided attention). After ethanol, the source of the P300 wave appeared to have shifted to a position posterior and inferior to its original location. P300 ERP's generated during the divided attention task were also disrupted and shifted to positions inferior to their original. However, the variability of the dipole vector was much greater during the divided attention task than after ethanol administration. These data demonstrate that ethanol's effects on cognitive processing skills may be similar to those produced when individuals experience distractions while concentrating on a task.

Routine intraoperative angioscopy in lower extremity revascularization.

The inability to see through blood remains the main obstacle to the widespread and routine use of angioscopy. Local irrigation with a balanced salt solution is presently the most widely used method to clear the blood. By applying basic principles of irrigation and using a unique, dedicated, irrigation pump, we found that routine angioscopy during lower extremity revascularization that yields consistent high-quality studies is feasible, clinically useful, and safe. Between May 1, 1987, and July 31, 1988, 136 intraoperative angioscopies were performed during 112 peripheral bypass procedures, 15 thrombectomies, 2 embolectomies, and 7 miscellaneous revascularization procedures. Mean total irrigation fluid used in the peripheral bypasses was 398 mL (range, 0 to 1400 mL). Good visual quality was obtained in more than 80% of angioscopies and the failure rate was only 1.8%. On the basis of the findings in 71 of the 136 angioscopies, 78 clinical or surgical decisions were made. No complications were directly attributable to the insertion of the angioscope or use of the pump.

Acute aortic thrombosis presenting as painless paraplegia.

Two patients with acute aortic thrombosis presented with painless paraplegia secondary to spinal cord infarction. In one case, the initial symptom was unilateral leg weakness, leading to the misdiagnosis of stroke. In the other case, a patient with a large, painful vulvar abscess, experienced spontaneous relief of pain. In the complete absence of pain, both patients slept undisturbed and awoke with complete paraplegia, incontinence, and cadaveric extremities. Aortic reconstruction was advised to obviate thigh or hindquarter amputation, not to restore limb function. One patient died on the second postoperative day; the second remains well but paraplegic two years later.

Stereoacuity testing: an illusion of tilt when viewing two parallel vertical rods or lines.

When stereoacuity was measured, some subjects (but not all) saw the two vertical rods of the test to be tilted. The perceived tilt indicated that the top of a rod was nearer to or farther from the observer than the bottom. Sometimes one rod appeared tilted and sometimes both. It was rare for both to appear tilted in the same direction. There are 9 possible tilt combinations including both rods vertical. All were observed but only 1 of the 3 subjects observed them all. In some instances, the frequency with which a particular tilt combination was seen was influenced by which rod was nearer and by the binocular disparity presented by the rods. During a stereoacuity test, tilt can confuse the identification of the nearer rod. Uncertainty is avoided by regarding the middle of the rods. Lines drawn on paper were also seen to tilt by some subjects.

Relative importance of after-effects, environment and socio-economic factors on the social integration of stroke victims.

This research is about the social integration of victims of a cerebrovascular accident. The objective is to evaluate the relative importance of physical after-effects, socio-economic characteristics, social and environmental factors on the degree of social integration subsequently achieved. This is a longitudinal evaluation with three data collections from an initial sample of 129 persons from the Quebec City area, Canada. Individual functional autonomy increases significantly while in institution and during the six months following discharge. At the time of discharge, 72.9% return to a normal home. A regression analysis shows that the determining factors relating to homecoming are motor functions and autonomy, personal perception of health conditions, proximity of children and relatives, relatively low age, regular presence of another person in the home, and proximity of friends. An important decrease in the practice of many activities occurs six months after homecoming: paid work, housework, management of personal affairs, and leisure activities. Absence of serious motor and language after-effects, a high level of perceived health condition, accessible facilities, proximity of relatives, and the ownership of a car are the factors most strongly associated with continued practice of these activities. Social contacts are more frequent than for comparable populations as far as children and relatives are concerned, but they are less frequent with friends. Proximity is a key factor. A quarter of the sample experiences problems relating to psychological well-being.