Unpacking the Longitudinal Associations between the Frequency of Substance Use, Substance Use Related Problems, and Academic Achievement among Adolescents.

Previous research repeatedly observed associations between academic achievement and substance use during adolescence. However, the simple frequency of substance use was not differentiated from the emergence of substance use related problems, such as abuse and dependence. This study presents autoregressive cross-lagged models describing inter-relations between academic achievement, frequency of substance use, and substance use related problems among a sample of 1034 seventh graders (46% female; 83% White North Americans; Mage = 12.64 years, SDage = 0.65) who participated in a four-year longitudinal study. The stability of measurement structure of frequency of substance use and substance use related problems was supported. Higher frequency of substance use and substance use related problems did not predict lower academic achievement. A higher academic achievement predicted a later increase in frequency of substance use and substance use related problems in boys, whereas a higher academic achievement predicted a lower frequency of substance use in girls. Although substance use related problems were mainly predicted by frequency of substance use, substance use can remain, nonetheless, non-problematic during adolescence.

Factors contributing to the success of folic acid public health campaigns.

BACKGROUND: Studies in the 1990s have found that periconceptional dietary folate, supplementation of folic acid or supplemental multivitamins containing folic acid, help prevent neural tube defect (NTDs) if taken at the right time. This literature review assesses the extant folic acid public health campaigns literature and identifies some common variables used in folic acid consumption campaign evaluations. METHODS: This review was part of a larger study that searched PUBMED, PsycINFO and Embase from 1976 to 2010 to identify articles related to the psychosocial and economic impact of NTDs (especially spina bifida) on patients and caregivers. RESULTS: Awareness of folic acid levels prior to conception improved post-campaign from 6 to 41%. Knowledge about consumption and correct periconceptional use of folic acid also improved. However, in most studies more than 50% of women did not take folic acid as prescribed. Many factors were associated with or without taking folic acid post-campaign, including incomplete outreach, prior awareness and knowledge, closeness to pregnancy, demographics and other personal characteristics. CONCLUSIONS: Sustained campaigning to maintain awareness about and promote periconceptional consumption of folic acid in order to reduce the incidence of NTDs is clearly needed. Additional initiatives could complement existing public health strategies.

Lichen planus and cicatricial conjunctivitis: disease course and response to therapy of 11 patients.

BACKGROUND: Lichen planus is an autoimmune, inflammatory dermatosis of unknown cause that affects the skin and mucous membranes. OBJECTIVE: The aim of this study was to report the clinical features and response to therapy in a series of patients with ocular lichen planus. METHODS: A retrospective chart review was performed to identify patients with ocular lichen planus. Information about clinical presentation, treatment, and therapeutic response was extracted from the medical records. RESULTS: Eleven patients with ocular lichen planus were identified. The diagnosis was confirmed histologically for 10 patients. Nine patients were women. The average time from onset of ocular symptoms to diagnosis was 4.1 years. Eight patients had mucous membrane involvement at other sites. Disease was well controlled in eight patients. CONCLUSION: Lichen planus should be considered in the differential diagnosis of cicatricial conjunctivitis, especially when severe lichen planus is noted at other sites.

An FPGA hardware/software co-design towards evolvable spiking neural networks for robotics application.

This paper presents an approach that permits the effective hardware realization of a novel Evolvable Spiking Neural Network (ESNN) paradigm on Field Programmable Gate Arrays (FPGAs). The ESNN possesses a hybrid learning algorithm that consists of a Spike Timing Dependent Plasticity (STDP) mechanism fused with a Genetic Algorithm (GA). The design and implementation direction utilizes the latest advancements in FPGA technology to provide a partitioned hardware/software co-design solution. The approach achieves the maximum FPGA flexibility obtainable for the ESNN paradigm. The algorithm was applied as an embedded intelligent system robotic controller to solve an autonomous navigation and obstacle avoidance problem.

An STDP training algorithm for a spiking neural network with dynamic threshold neurons.

This paper proposes a supervised training algorithm for Spiking Neural Networks (SNNs) which modifies the Spike Timing Dependent Plasticity (STDP)learning rule to support both local and network level training with multiple synaptic connections and axonal delays. The training algorithm applies the rule to two and three layer SNNs, and is benchmarked using the Iris and Wisconsin Breast Cancer (WBC) data sets. The effectiveness of hidden layer dynamic threshold neurons is also investigated and results are presented.

Chemical and photoluminescence properties of purified poly(2-methoxyaniline-5-sulfonic acid) and oligomer.

Both the chemical and the electrochemical synthesis of poly(2-methoxyaniline-5-sulfonate) (PMAS) in aqueous media have been found to give two distinct polymer fractions with molecular weights of approximately 8-10 and 2 kDa, respectively. It is now possible to isolate the pure high molecular weight (HMWT) PMAS and low molecular weight (LMWT) PMAS oligomer and to study their individual and combined photochemistry and redox chemistry. The HMWT PMAS fraction was confirmed to be an emeraldine salt by its characteristic redox and pH switching behavior, in contrast to the oligomeric LMWT PMAS, which was inert under the same conditions. Mixtures of these two fractions exhibit photoluminescence arising from the oligomeric LMWT PMAS fraction. The observed LMWT PMAS emission was modulated by the presence of the conducting HMWT PMAS emeraldine salt via a static resonant energy transfer arising from quenching at 460 nm when excited at 355 nm. The nonlinear fluorophore-quencher behavior suggests that the two PMAS fractions are strongly associated. The behavior fitted the static Perrin quenching model in which the oligomeric LMWT PMAS fluorophore is diffusionally restricted by the presence of HMWT PMAS quencher.

Fatty acid profile, tocopherol, squalene and phytosterol content of walnuts, almonds, peanuts, hazelnuts and the macadamia nut.

Nuts are high in fat but have a fatty acid profile that may be beneficial in relation to risk of coronary heart disease. Nuts also contain other potentially cardioprotective constituents including phytosterols, tocopherols and squalene. In the present study, the total oil content, peroxide value, composition of fatty acids, tocopherols, phytosterols and squalene content were determined in the oil extracted from freshly ground walnuts, almonds, peanuts, hazelnuts and the macadamia nut. The total oil content of the nuts ranged from 37.9 to 59.2%, while the peroxide values ranged from 0.19 to 0.43 meq O2/kg oil. The main monounsaturated fatty acid was oleic acid (C18:1) with substantial levels of palmitoleic acid (C16:1) present in the macadamia nut. The main polyunsaturated fatty acids present were linoleic acid (C18:2) and linolenic acid (C18:3). alpha-Tocopherol was the most prevalent tocopherol except in walnuts. The levels of squalene detected ranged from 9.4 to 186.4 microg/g. beta-Sitosterol was the most abundant sterol, ranging in concentration from 991.2 to 2071.7 microg/g oil. Campesterol and stigmasterol were also present in significant concentrations. Our data indicate that all five nuts are a good source of monounsaturated fatty acid, tocopherols, squalene and phytosterols.

Transpecific microsatellites for hard pines.

Microsatellites are difficult to recover from large plant genomes so cross-specific utilisation is an important source of markers. Fifty microsatellites were tested for cross-specific amplification and polymorphism to two New World hard pine species, slash pine ( Pinus elliottii var. elliottii) and Caribbean pine ( P. caribaea var. hondurensis). Twenty-nine (58%) markers amplified in both hard pine species, and 23 of these 29 were polymorphic. Soft pine (subgenus Strobus) microsatellite markers did amplify, but none were polymorphic. Pinus elliottii var. elliottii and P. caribaea var. hondurensis showed mutational changes in the flanking regions and the repeat motif that were informative for Pinus spp. phylogenetic relationships. Most allele length variation could be attributed to variability in repeat unit number. There was no evidence for ascertainment bias.

Comparison of Chen Medium and Optisol-GS for human corneal preservation at 4 degrees C: results of transplantation.

PURPOSE: To compare results after transplantation of donor corneas stored in Chen Medium (containing beta-hydroxybutyrate without sodium bicarbonate or chondroitin sulfate) to corneas stored in Optisol-GS medium (containing sodium bicarbonate and 2.5% chondroitin sulfate). METHODS: We performed 32 consecutive penetrating keratoplasties with donor corneas stored at 4 degrees C in either Chen Medium or Optisol-GS by random assignment. Corneal thickness measurements were made at 1 day, 1 week, 3 weeks, 2 months, and 1 year postkeratoplasty. Specular microscopic images of the donor endothelium were obtained at the beginning of storage and 2 months and 1 year postkeratoplasty. The percentage of intact epithelium 1 day after keratoplasty and the graft epithelialization time were estimated by the surgeons. Donor rim cultures were performed. RESULTS: No statistically significant differences in corneal thickness or endothelial cell loss between the corneas stored in the two media were found at any time, although differences of less than 12% cell loss or 0.09-mm thickness at 2 months or less than 25% cell loss or 0.10-mm thickness at 1 year could not be excluded with 90% certainty in this small series. The mean percentages of intact graft epithelium on day 1, 64% for Chen Medium and 65% for Optisol-GS, were not significantly different. Endothelial cell density 2 months postkeratoplasty was significantly decreased for corneas stored in both media. Endothelial cell loss at 2 months was directly correlated with storage time in both media. CONCLUSIONS: After keratoplasty, no statistically significant differences in corneal thickness, epithelial survival, and endothelial cell loss were found between corneas stored in Chen Medium and Optisol-GS. Endothelial cell loss at 2 months was significantly correlated with storage time in both media.

Demographics, treatment seeking, and diagnoses of anxiety support group participants.

Two peer-led anxiety disorder support groups were surveyed to ascertain characteristics of individuals seeking the services of these groups. Both groups had received information and consultation from the Anxiety Disorders Association of America. One hundred and eighty-four individuals were interviewed for diagnosis by structured clinical interview; demographics and treatment-seeking behaviors were ascertained by self-report questionnaires. Both groups surveyed were composed of more females than males and were predominantly Caucasian. Treatment was most frequently sought from psychiatrists, psychologists, and family doctors. One fourth of the sample had sought help for anxiety in a hospital emergency room. Eighty-eight subjects (94%) at the Dallas site and 57 subjects (61%) at the Durham site met criteria for at least one current anxiety or affective disorder. More than half of those who met criteria for current panic disorder with agoraphobia also met criteria for at least one other anxiety disorder, or for major depression. Approximately one third of each support group met criteria for current social phobia. Severity of social phobia symptoms was assessed by four scales. An increased risk of substance abuse was noted for individuals with a diagnosis of social phobia, as compared with diagnoses of other anxiety disorders.

Irreversible corneal decompensation in patients treated with topical dorzolamide.

PURPOSE: To describe irreversible corneal decompensation after topical dorzolamide hydrochloride (Trusopt; Merck and Co, Inc, West Point, Pennsylvania) therapy in nine patients who had histories consistent with corneal endothelial compromise. METHOD: Multicenter review of patients' charts. RESULTS: Nine eyes of nine patients developed overt corneal decompensation after starting topical dorzolamide, a condition that did not resolve with drug cessation. This occurred after 3 to 20 weeks (mean, 7.8) of therapy. All nine patients had undergone intraocular surgery. Eight patients had undergone cataract surgery; three were aphakic and three had posterior chamber intraocular lenses. Two patients had anterior chamber intraocular lenses and also had undergone trabeculectomies. Four patients had undergone penetrating keratoplasties, each case complicated by episodes of corneal allograft rejection that were successfully treated. Two patients had asymptomatic Fuchs endothelial dystrophy. Seven patients have since undergone successful penetrating keratoplasties. CONCLUSION: The reports suggest that dorzolamide can cause irreversible corneal edema in a subset of glaucoma patients with endothelial compromise. The findings suggest a rationale for research into the long-term effects of dorzolamide on the corneal endothelium.

Keratocyte density in vivo after photorefractive keratectomy in humans.

PURPOSE: To determine changes in keratocyte density in central human corneas in vivo after photorefractive keratectomy (PRK). METHODS: Fifteen patients (25 eyes) received excimer PRK (VISX Star) with epithelial removal by laser-scrape (43 microns ablation followed by manual scrape) to correct myopia between -1.5 D and -7.25 D. Corneas were examined by using confocal microscopy in vivo before PRK and at 1 day, 5 days, 1 month, and 3 months after PRK. A custom automated image-processing algorithm identified bright objects (keratocytes) against a dark background and estimated keratocyte density by using the number and size of the objects. Cell density was quantified in anteroposterior stromal regions after PRK and compared to cell density in corresponding pre-PRK regions. RESULTS: One day after PRK, keratocyte density increased 9% in the anterior third of the stroma (pi = .003), was unchanged in the middle third of the stroma (pi = .481), and decreased 6% in the posterior third of the stroma (pi = .038). Keratocyte density remained elevated in the anterior stroma to 3 months after PRK; at this time, there was a 13% increase in keratocyte density throughout the full-thickness stroma (pi < .001). CONCLUSIONS: Keratocyte density was increased in the anterior stroma immediately after PRK in humans. Three months later, keratocyte density was increased in all anteroposterior stromal regions, suggesting that PRK affects keratocytes throughout the entire central cornea.

The value of routine donor corneal rim cultures in penetrating keratoplasty.

OBJECTIVE: To investigate the value of donor corneal rim cultures performed routinely at the time of penetrating keratoplasty. DESIGN: Retrospective review of Mayo Clinic medical records for all corneal transplantations for which donor rim cultures have been performed. MAIN OUTCOME MEASURES: Frequency of positive cultures, occurrence of endophthalmitis within 2 months of undergoing surgery, action taken in response to the culture results, and costs of cultures. RESULTS: Donor rim culture results were available for 1078 of 1083 consecutive transplantations performed from 1981 to 1995. Three cases of endophthalmitis (0.28%) and 1 suture abscess occurred. Rim cultures were negative in all of these cases. Action was documented in response to positive cultures in 17 cases (8.1%). The estimated average cost of routine rim cultures in 1994 was $137 per donor cornea. Bacterial or fungal cultures were positive in 209 (19.4%) cases. Two microorganisms were cultured simultaneously in 17 cases (1.6%) and 3 in 2 cases (0.2%). Staphylococcus coagulase-negative (130 cases [12.1%]), and Streptococcus species, viridans group (23 cases [2.1%]), were the most common isolates. Fifty-two (62.7%) of 83 coagulase-negative Staphylococcus species isolates tested were resistant to gentamicin. There were more positive cultures from corneas stored in Optisol (37/183 [20%]) than in Optisol GS (16/144 [11%]) (P = .03). Fewer cultures were positive from live donors (9/93 [10%]) compared with cadaveric donors (181/ 909 [20%]) (P = .02). Positive cultures were more frequent for corneas excised in situ (39/125 [31.2%]) than for those enucleated (152/851 [17.9%]) (P < .001). CONCLUSIONS: Despite differences in rates of positive donor rim cultures with different harvesting and storage techniques, for our practice, routine donor corneal rim cultures had no predictive value for infective complications of penetrating keratoplasty and, therefore, added an unnecessary expense to the management of our patients.

Keratometric results of penetrating keratoplasty with the Hessburg-Barron and Hanna trephine systems using a standard double-running suture technique.

PURPOSE: To compare final, sutures-out, keratometric results of penetrating keratoplasty using two different suction trephine systems and a standard double-running suture technique. METHODS: Keratometric data after final suture removal were compared retrospectively for three groups of transplants: Group 1, 7.50-mm Hessburg-Barron recipient trephine and 7.70-mm modified Lieberman donor punch (n = 70); Group 2, 7.50-mm Hessburg-Barron recipient trephine and 8.00-mm modified Lieberman donor punch (n = 18); Group 3, 7.50-mm Hanna recipient trephine and 7.75-mm Hanna donor punch (n = 68). RESULTS: Final average keratometry was 46.7 +/- 2.4 D (mean +/- SD, diopters), and final median keratometric astigmatism was 4.6 D (2.6-7.4 D, interquartile range), with no significant difference between groups. Final average keratometry values increased from preoperative values by 3.3 +/- 2.7 D. The correlation between preoperative average keratometry values and final values was low (rs = 0.2; p = 0.07). Average keratometry values increased by 2.3 D (median) after 10/ 0 suture removal (p < 0.0001) and by 0.2 D (median) after 11/0 suture removal (p = 0.09), with no significant difference between groups. There was a negative correlation between donor age and overall change in average keratometry (rs = -0.3; p = 0.002). Visual acuity improved by a median of 5 lines, with no significant difference between trephine systems. CONCLUSIONS: There was no statistically significant difference in keratometric results using these two suction trephines with a standard suture technique. Final graft curvature was greater with both suction trephines compared with previously published results of transplants using hand-held trephines with the same suture technique.

Specular microscopy before and after enucleation of live donor eyes.

PURPOSE: To compare the results of specular microscopic examination of corneal endothelium before and after enucleation of eyes from live donors. METHODS: Endothelial cell density (ECD), coefficient of variation of cell area (CV), and percent hexagonal cells were compared for 34 cornea donors before enucleation of their eyes and after excision of the corneoscleral rims and placement in preservative media. RESULTS: There was no statistically significant difference in ECD, CV, or percent six-sided cells after enucleation. The pre-enucleation and post-enucleation ECD measurements were significantly correlated (rs = .85, P < .0001). Mean percentage change in ECD was -0.7% +/- 6.0%. CONCLUSIONS: There was no significant difference in ECD, CV, or percent six-sided cells between measurements taken from the epithelial side in vivo and those taken of the same corneas from the endothelial side in vitro after enucleation and corneoscleral rim excision. These findings suggest that it is reasonable to compare postkeratoplasty clinical measurements with those of the donor corneas taken in the eye bank.