Isotope Effects on the Vaporization of Organic Compounds from an Aqueous Solution-Insight from Experiment and Computations.

An isotope fractionation analysis of organic groundwater pollutants can assess the remediation at contaminated sites yet needs to consider physical processes as potentially confounding factors. This study explores the predictability of water-air partitioning isotope effects from experiments and computational predictions for benzene and trimethylamine (both H-bond acceptors) as well as chloroform (H-bond donor). A small, but significant, isotope fractionation of different direction and magnitude was measured with ε = -0.12‰ ± 0.07‰ (benzene), εC = 0.49‰ ± 0.23‰ (triethylamine), and εH = 1.79‰ ± 0.54‰ (chloroform) demonstrating that effects do not correlate with expected hydrogen-bond functionalities. Computations revealed that the overall isotope effect arises from contributions of different nature and extent: a weakening of intramolecular vibrations in the condensed phase plus additional vibrational modes from a complexation with surrounding water molecules. Subtle changes in benzene contrast with a stronger coupling between intra- and intermolecular modes in the chloroform-water system and a very local vibrational response with few atoms involved in a specific mode of triethylamine. An energy decomposition analysis revealed that each system was affected differently by electrostatics and dispersion, where dispersion was dominant for benzene and electrostatics dominated for chloroform and triethylamine. Interestingly, overall stabilization patterns in all studied systems originated from contributions of dispersion rather than other energy terms.

Toward Improved Accuracy in Chlorine Isotope Analysis: Synthesis Routes for In-House Standards and Characterization via Complementary Mass Spectrometry Methods.

Increasing applications of compound-specific chlorine isotope analysis (CSIA) emphasize the need for chlorine isotope standards that bracket a wider range of isotope values in order to ensure accurate results. With one exception (USGS38), however, all international chlorine isotope reference materials (chloride and perchlorate salts) fall within the narrow range of one per mille. Furthermore, compound-specific working standards are required for chlorine CSIA but are not available for most organic substances. We took advantage of isotope effects in chemical dehalogenation reactions to generate (i) silver chloride (CT16) depleted in 37Cl/35Cl and (ii) compound-specific standards of the herbicides acetochlor and S-metolachlor (Aceto2, Metola2) enriched in 37Cl/35Cl. Calibration against the international reference standards USGS38 (-87.90 ‰) and ISL-354 (+0.05 ‰) by complementary methods (gas chromatography-isotope ratio mass spectrometry, GC-IRMS, versus gas chromatography-multicollector inductively coupled plasma mass spectrometry, GC-MC-ICPMS) gave a consensus value of δ37ClCT16 = -26.82 ± 0.18 ‰. Preliminary GC-MC-ICPMS characterization of commercial Aceto1 and Metola1 versus Aceto2 and Metola2 resulted in tentative values of δ37ClAceto1 = 0.29 ± 0.29 ‰, δ37ClAceto2 = 18.54 ± 0.20 ‰, δ37ClMetola1 = -4.28 ± 0.17 ‰ and δ37ClMetola2 = 5.12 ± 0.27 ‰. The possibility to generate chlorine isotope in-house standards with pronounced shifts in isotope values offers a much-needed basis for accurate chlorine CSIA.

A Scientific Foundation of Simulation Games for the Analysis and Design of Complex Systems.

Background. The use of simulation games for complex systems analysis and design has been acknowledged about 50 years ago. However, articles do not combine all salient factors for successful simulation games, and often stem from a clear view of one particular field of science only. With combining multiple disciplines, connect analysis and design as well as research and practice, we provide deep insights in design and use of simulation games. Aim. This article analyzes the design and evaluation process of a variety of game-based projects and activities, using existing scientific concepts and approaches, in order to establish games as a valid research tool. Our focus lies on the approach towards the use of games as design instrument; using them as an intervention in a larger, complex context, in order to design this context. With our contribution, we aim at providing insights and recommendations on the design and use of games as valid research tools, the limitations of this use, possible pitfalls, but also best practices. Method. We carried out a literature review of related work to identify the most important scientific concepts related to our approach of game design. Further use of combined quantitative and qualitative case study analyses highlights the design process and results of our own game studies. Results. The analyses yielded a consolidated conceptualization of simulation games as research instruments in complex systems analysis and design. The results also include methods for the evaluation of simulation games, additional evaluation methods, and limitations to use simulation games as research instruments. Conclusions. We propose guidelines for using simulation games as research instruments that may be of value to practitioners and scientists alike. Recommendation. We recommend practitioners and scientists to apply the guidelines presented here in their efforts to analyze and design complex systems.

Comprehensive assessment of food and nutrient intake of children and adolescents in Germany: EsKiMo II - the eating study as a KiGGS module.

BACKGROUND: As part of the second wave of the German Health Interview and Examination Survey for Children and Adolescents (KiGGS Wave 2), food and nutrient intake of children and adolescents aged 6-17 years living in Germany is assessed in EsKiMo II - the Eating Study as a KiGGS Module. METHODS: EsKiMo II is a cross-sectional study, conducted from June 2015 until September 2017. The study population comprises 6 to 17-year-old study participants from the cross-sectional sample of KiGGS Wave 2 in 167 KiGGS sample points, which are revisited by trained nutritionists. Dietary intake is assessed by weighted food records during three consecutive days plus one randomly selected day within the following 3 months for children aged 6-11 years. Dietary intake for adolescents aged 12-17 years is assessed by computer-assisted dietary history interviews, reflecting the past four weeks, using the software DISHES. Further information, for example, about specific diets and dietary supplement intake, is reported during a standardised computer assisted interview for all participants. Food items are coded by the German Food Code and Nutrient Database (BLS 3.02). DISCUSSION: EsKiMo II provides actual data on the dietary behaviour of children and adolescents living in Germany and their determinants. Results of EsKiMo II will be relevant for decision-making, measures, and evaluations within nutrition, consumer and health policy.

Compound-Specific Stable Isotope Fractionation of Pesticides and Pharmaceuticals in a Mesoscale Aquifer Model.

Compound-specific isotope analysis (CSIA) receives increasing interest for its ability to detect natural degradation of pesticides and pharmaceuticals. Despite recent laboratory studies, CSIA investigations of such micropollutants in the environment are still rare. To explore the certainty of information obtainable by CSIA in a near-environmental setting, a pulse of the pesticide bentazone, the pesticide metabolite 2,6-dichlorobenzamide (BAM), and the pharmaceuticals diclofenac and ibuprofen was released into a mesoscale aquifer with quasi-two-dimensional flow. Concentration breakthrough curves (BTC) of BAM and ibuprofen demonstrated neither degradation nor sorption. Bentazone was transformed but did not sorb significantly, whereas diclofenac showed both degradation and sorption. Carbon and nitrogen CSIA could be accomplished in similar concentrations as for "traditional" priority pollutants (low µg/L range), however, at the cost of uncertainties (0.4-0.5‰ (carbon), 1‰ (nitrogen)). Nonetheless, invariant carbon and nitrogen isotope values confirmed that BAM was neither degraded nor sorbed, while significant enrichment of (13)C and in particular (15)N corroborated transformation of diclofenac and bentazone. Retardation of diclofenac was reflected in additional (15)N sorption isotope effects, whereas isotope fractionation of transverse dispersion could not be identified. These results provide a benchmark on the performance of CSIA to monitor the reactivity of micropollutants in aquifers and may guide future efforts to accomplish CSIA at even lower concentrations (ng/L range).

Differences between thermal and laser-induced diffusion.

A combination of femtosecond laser excitation with a low-temperature scanning tunneling microscope is used to study long-range interaction during diffusion of CO on Cu(111). Both thermal and laser-driven diffusion show an oscillatory energy dependence on the distance to neighboring molecules. Surprisingly, the phase is inverted; i.e., at distances at which thermal diffusion is most difficult, it is easiest for laser-driven diffusion and vice versa. We explain this unexpected behavior by a transient stabilization of the negative ion during diffusion as corroborated by ab initio calculations.

Characteristic isotope fractionation patterns in s-triazine degradation have their origin in multiple protonation options in the s-triazine hydrolase TrzN.

s-Triazine herbicides (atrazine, ametryn) are groundwater contaminants which may undergo microbial hydrolysis. Previously, inverse nitrogen isotope effects in atrazine degradation by Arthrobacter aurescens TC1 (i) delivered highly characteristic (13C/12C, 15N/14N) fractionation trends for pathway identification and (ii) suggested that the s-triazine ring nitrogen was protonated in the enzyme s-triazine hydrolase (TrzN) where (iii) TrzN crystal structure and mutagenesis indicated H+-transfer from the residue E241. This study tested the general validity of these conclusions for atrazine and ametryn with purified TrzN and a TrzN-E241Q site-directed mutant. TrzN-E241Q lacked activity with ametryn; otherwise, degradation consistently showed normal carbon isotope effects (εcarbon=-5.0‰±0.2‰ (atrazine/TrzN), εcarbon=-4.2‰±0.5‰ (atrazine/TrzN-E241Q), εcarbon=-2.4‰±0.3‰ (ametryn/TrzN)) and inverse nitrogen isotope effects (εnitrogen=2.5‰±0.1‰ (atrazine/TrzN), εnitrogen=2.1‰±0.3‰ (atrazine/TrzN-E241Q), εnitrogen=3.6‰±0.4‰ (ametryn/TrzN)). Surprisingly, TrzN-E241Q therefore still activated substrates through protonation implicating another proton donor besides E241. Sulfur isotope effects were larger in enzymatic (εsulfur=-14.7‰±1.0‰, ametryn/TrzN) than in acidic ametryn hydrolysis (εsulfur=-0.2‰±0.0‰, pH 1.75), indicating rate-determining C-S bond cleavage in TrzN. Our results highlight a robust inverse 15N/14N fractionation pattern for identifying microbial s-triazine hydrolysis in the environment caused by multiple protonation options in TrzN.

5-Iodo-1,2,3-triazolium-based multidentate halogen-bond donors as activating reagents.

Bi- and tridentate polycationic halogen bond donors based on 5-iodo-1,2,3-triazolium groups have been synthesized by 1,3-dipolar cycloaddition reactions. These halogen-based Lewis acids have been evaluated as activators in a halide-abstraction benchmark reaction.

Comparison of tendency-oriented perimetry and dynamic strategy in octopus perimetry as a screening tool in a clinical setting: a prospective study.

OBJECTIVE: The aim of this study was to compare the results of tendency-oriented perimetry (TOP) and a dynamic strategy in octopus perimetry as screening methods in clinical practice. DESIGN: A prospective single centre observational case series was performed. PARTICIPANTS AND METHODS: In a newly opened general ophthalmologic practice 89 consecutive patients (171 eyes) with a clinical indication for octopus static perimetry testing (ocular hypertension or suspicious optic nerve cupping) were examined prospectively with TOP and a dynamic strategy. The visual fields were graded by 3 masked observers as normal, borderline or abnormal without any further clinical information. RESULTS: 83% eyes showed the same result for both strategies. In 14% there was a small difference (with one visual field being abnormal or normal, the other being borderline). In only 2.9% of the eyes (5 cases) was there a contradictory result. In 4 out of 5 cases the dynamic visual field was abnormal and TOP was normal. 4 of these cases came back for a second examination. In all 4 the follow-up examination showed a normal second dynamic visual field. CONCLUSIONS: Octopus static perimetry using a TOP strategy is a fast, patient-friendly and very reliable screening tool for the general ophthalmological practice. We found no false-negative results in our series.

Sex differences in risk sensitivity under positive and negative budgets and predictors of choice.

The authors investigated sex differences in human risk sensitivity by using a computerized choice task with an energy budget analogue. In addition, they explored possible personality predictors of variance sensitivity. The authors modified the traditional energy budget model from those used in risk-sensitive foraging research with nonhuman animals for appropriate use with a human population. Participants chose between 2 computer icons, 1 yielding a fixed-point reward and the other offering variable points. Men were risk prone in the negative budget and risk averse in the positive budget. Women were risk averse in the negative budget. Personality was not predictive of risk-sensitive bias. Interpreting the results using an evolutionary model, the authors found support for a biological and environmental construct of risk-sensitive behavior.

[Clinical reasoning and decision-making in practice. A patient with oliguria following prostatectomy]. / Klinisch denken en beslissen in de praktijk. Een man met oligurie na een prostaatoperatie.

A 70-year-old man with clinically localised prostate carcinoma underwent extraperitoneal endoscopic radical prostatectomy. His medical history revealed hypertension, renal colic, hypogonadotropic hypogonadism and recurrent deep venous thrombosis in the legs. The operation was uneventful with 500 ml blood loss and no periods ofhypotension. The patient developed oliguria within 12 h after surgery. A hypovolemic state was initially suggested to explain the oliguria and increasing amounts of intravenous fluids were administered. The oliguria persisted, however, and the patient did not respond to a diuretic. There was no fluid loss in the drain. Blood pressure, pulse and temperature were normal. Peritonitis and bowel perforation were excluded. Ultrasound examination of the bladder and kidneys revealed an empty bladder and no dilatation of the upper urinary tract, which excluded a post-renal obstruction. The clinical situation deteriorated within hours as the patient developed anuria, bowel distension, metabolic acidosis with progressive renal failure and signs of respiratory distress for which mechanical ventilation was needed. A chest X-ray prior to intubation did not show pneumonia or signs indicating pulmonary embolism. CT of the abdomen was performed to evaluate urinary leakage but revealed no fluid collection or urinoma. Thus pre- and post-renal causes of oliguria were excluded. In view of the systemic symptoms, intra-abdominal pressure was measured using a bladder catheter; it varied between 25 and 35 cm water. Together with the clinical situation, a diagnosis of abdominal compartment syndrome was made and coeliotomy was performed immediately. Within 10 min after decompression of the peritoneal cavity, diuresis started spontaneously. Renal function was restored to preoperative levels in 3 weeks. Abdominal compartment syndrome is a potentially life-threatening cause of anuria. The syndrome should be part of the differential diagnosis for patients with postoperative anuria, including those who underwent extraperitoneal minimally invasive procedures.

['Sitting on air' in infants: a sign of simple delay in the gross motor milestones]. / 'Luchtzitten' bij zuigelingen: een teken van onschuldige achterstand in de grove motoriek.

A delay in motor maturation of infants usually presents as late mastery of gross motor milestones, such as rolling over, sitting, crawling, standing up and walking. Because this can be a symptom of serious neuromuscular disease or cerebral palsy, parents' and doctors' concern is understandable. Three children, a girl aged 17 months, and two boys aged 20 and 18 months respectively, were referred to the paediatric outpatient department because of delayed motor development. Physical examination revealed no pathological disorder; fine motor development, social-adaptive and language behaviour were age-appropriate. All three patients showed the characteristic 'sitting on air' posture while lifted vertically. With this information the diagnosis was 'dissociation of maturation', which can be managed by watchful waiting and has an excellent prognosis. All three patients recovered spontaneously.

Self-control in rhesus macaques (Macaca mulatta): controlling for differential stimulus exposure.

Previous research on self-control using macaques (Macaca fascicularis) showed these animals have a strong bias for a delayed, larger reinforcer (Self-control) over an immediate, smaller reinforcer (Impulsive). Typical studies of self-control have used a discrete trials methodology with a secondary discriminative stimulus during the delay periods. This results in a greater exposure to the stimulus representing the self-controlled option and may account for some of the early exclusive preference for self-control observed. The present experiment examined self-control bias in three rhesus macaques (Macaca mulatta) while controlling for differential durations of stimulus exposure. Subjects were presented stimuli via a computer monitor and made choices by touching the stimulus at which point both stimuli were removed for the delay periods. All three subjects displayed a nearly exclusive bias for the delayed, larger reinforcer self-control). These results are consistent with previous studies, despite the variations in methodology and species.

Who's in, who's out, and who's back: follow-up data on 59 juveniles incarcerated in adult prison for murder or attempted murder in the early 1980s.

Since the mid-1980s, when juvenile arrests for violent crime increased dramatically, interest has focused on juvenile offenders who commit violent acts. Legislatures across the United States have enacted a variety of measures to "get tough" with juveniles in response to escalating crime rates and the perceptions that longer sentences were needed. This manuscript provides follow-up data on 59 juveniles who were committed to the adult Department of Corrections in Florida during the period January 1982 through January 1984 for one or more counts of murder, attempted murder, or, in a few cases, manslaughter. Although many of these adolescents received lengthy prison sentences, more than two-thirds had been released from prison prior to November 1999. This article presents data on amount of time served and recidivism over the 15 to 17 year period. Results indicated that 60 percent of sample subjects released from prison were returned to prison, and most of those who failed did so within the first three years of release. Findings from the present study, when examined in the context of previous comparative follow-up studies of delinquent youths, suggest that the dialogue on how to handle violent youths must be continued if juvenile homicide offenders are going to be released to society at some point in the future.

Maternal uniparental disomy (UPD) for chromosome 2 discovered by exclusion of paternity.

Serological and molecular (DNA-STR) analysis of a paternity case demonstrated exclusion of paternity of the presumptive father in two markers (ACP and Apo B, both localized on chromosome 2, region 2p25.2 and 2p23/24, respectively) in a phenotypically normal girl with a normal karyotype 46,XX (by GT-banding). The index of paternity calculated for other serological (seven erythrocyte antigens, six serum protein systems, and seven isozymes, as well as the A- and B-HLA loci) and nine DNA markers, excluding ACP and Apo B, gives a very high (virtually certain) degree of paternity for the presumptive father. Maternal uniparental disomy (UPD) for chromosome 2 was suspected. Evaluation of polymorphic DNA markers (STRs) spanning chromosome 2 of the child, mother, and presumptive father demonstrated that the girl had inherited two maternal chromosome 2 homologues, whereas alleles for markers from other chromosomes were inherited from the father in a Mendelian fashion. The girl was homoallelic for informative markers mapping to the chromosomal regions 2p23-25, but she was heteroallelic for informative markers on the long arm of chromosome 2, establishing that the maternal UPD with partial isodisomy of the short arm was caused by a meiosis I nondisjunction event with genetic recombination (chiasmata in this region 2p23-25) during oogenesis.

Multicenter evaluation study on a new HEp2 ANA screening enzyme immune assay.

The COBAS Core HEp2 ANA enzyme immune assay (EIA) was evaluated in a precision and a clinical sample study in comparison to indirect immunofluorescence assay (IFA) on HEp2-cells. In the precision study the COBAS Core EIA yielded intraassay coefficient variations (CVs) mostly below 9%, and interassay CVs between 4.7% and 10.4%. When comparing the COBAS Core EIA to IFA, the results corresponded well in healthy subjects, systemic lupus erythematosus, mixed connective tissue disease and rheumatoid arthritis. In the case of Sjögren's syndrome and scleroderma patients the COBAS Core EIA yielded a lower rate of positive results compared to IFA. This discrepancy may be explained by the lack of detection of autoantibodies to nuclear antigens that can be identified only by IFA due to their compartmentalization and higher localized antigen density in HEp2 cells. The discrepancies in the group of dermato/polymyositis patients are due to the fact that the EIA contains mainly nuclear antigens and was able to detect only antibodies against the cytoplasmic Jo1 antigen that was added to the HEp2 nuclear extract. Routine sera were also evaluated; good agreement was found in sera from patients attending tertiary reference centres for autoimmune diseases but a higher number of discrepancies was reported in sera from unselected populations.

Juvenile homicide in America: how can we stop the killing?

Juvenile homicide remains a serious problem in the U.S., despite recent decreases in the juvenile arrest rate for murder. Reflecting on her clinical experiences evaluating 90 adolescent murderers, the author identifies 15 factors that appear to have contributed to the escalation in juvenile homicide beginning in the mid-1980s. These factors can be grouped into five categories: situational factors (child abuse and neglect, and the absence of positive male role models), societal influences (the crisis in leadership and lack of heroes, and witnessing violence), resource availability (access to guns, involvement in alcohol and drugs, and poverty and lack of resources), personality characteristics (low self-esteem, the inability to deal with strong feelings, boredom, poor judgment, and prejudice and hatred), and their cumulative effects (little or nothing left to lose and the biological connection). Strategies to reduce juvenile violence are addressed using parents, schools, communities, government leaders, the media, and individuals.

[Assessment of AIDS risks: effects of different scale ranges and preventive knowledge]. / Die Einschätzung von AIDS-Risiken: Auswirkungen unterschiedlicher Skalenvorgaben und präventiven Wissens.

In a sample of 552 respondents effects of different scale ranges and respondents' knowledge about AIDS for answering questions about AIDS-risks were examined. Knowledge was assessed with 12 items related to risks for HIV infections and preventive measures. AIDS hazards for different groups (prostitutes, fixers, hospital personnel, homosexuals, and haemophiliacs) had to be rated with five items, one for each group. Response variations were assessed in three parallel questionnaire versions with different ranges of risk assignments. Estimations had to be performed in comparison with the average population. Some groups were consistently rated to be at high risk, others were assigned low risks for becoming infected with the HIV-virus. The analysis of response patterns revealed that the three versions of numeric quantifiers determined the risk ratings only to some extent. The distribution patterns suggest that our subjects had an ordinal risk ordering in mind that might better be expressed in verbal terms. The knowledge about AIDS had no systematic effects on response behavior.

[Determination of autoimmune antibodies using Western blot technique in the routine laboratory. Problems with determining and comparing three test kits]. / Die Bestimmung von Autoimmunantikörpern mit Hilfe der Westernblottechnik im Routinelabor. Problematik der Bestimmung und Vergleich von drei Testkits.

For routine testing Western blot technique is a suitable method for the detection of autoimmune antibodies. Advantages of this procedure are the fast performance even for single samples, the detection of many different antibodies in one assay, and the possibility to save the strips for later reevaluation. There are several commercial test kits available. The spectrum of antibodies to be detected and the exact molecular weight of the antigens determine the choice of the test kit. Test kits from the companies AID (A), Viramed (V), and Biolab (B) were compared using serum samples from selected patients. Kits A and V were sensitive especially for the detection of SSA(Ro) and SSB(La) antibodies. The results using these two test kits corresponded well with the respective clinical diagnoses. Test kit A detected the highest number of different antibodies. The question of differentiating between U1-snRNP and Sm antibodies by immunoblotting is discussed.

Substance use/misuse among female prostitutes and female arrestees.

The literature has documented the correlation between prostitution and drug use/misuse. This study probed demographics, drug use experimentation and frequency, age of first drug use, and drug use treatment among 53 female prostitutes and 47 female arrestees. The results indicated that: 1) prostitutes were likely to drop out of school; 2) significantly more prostitutes had tried drugs, had used drugs with greater frequency and had begun drug/alcohol use at younger ages. These results imply that: 1) early drug/alcohol use and withdrawal from school could leave young women vulnerable and at higher risk of becoming involved in prostitution; and 2) drug use treatment and intervention needs to begin at younger ages.