Bond length dependence on quantum states as shown by spectroscopy

Undergraduate students often have the misconception that molecules have fixed, unchanging bond lengths. This article discusses how linear-molecule rotational band spacings in infrared spectroscopy can be used as a qualitative, visual demonstration of the elongation of average bond lengths on vibrational excitation. The method does not depend on a detailed mathematical analysis of the spectra. In UV–vis spectroscopy, the rotational band spacings give rise to distinctive linear-molecule rotational contours, which easily show whether the average bond length has increased or decreased. The method is based on a spreadsheet simulation of the vibration–rotation or rovibronic (electronic–vibration–rotation) spectrum and is applied to hydrogen chloride IR, iodine UV–vis, and nitrogen UV–vis spectra in this article.

Synthesis and reactivity of para-substituted benzoylmethyltellurium(II and IV) compounds: observation of intermolecular C-H-O hydrogen bonding in the crystal structure of (p-MeOC6H4COCH2)2TeBr2

Bis(p-substituted benzoylmethyl)tellurium dibromides, (p-YC₆H₄COCH₂)₂TeBr₂, (y=H (1a), Me (1b), MeO (1c)) can be prepared
either by direct insertion of elemental Te across CRf-Br bonds (where C_Rf refers to α-carbon of a functionalized organic moiety) or by the oxidative addition of bromine to (p-YC₆H₄COCH₂)₂Te (y = H (2a), Me (2b), MeO (2c)). Bis(p-substituted benzoylmethyl)tellurium dichlorides, (p-YC₆H₄COCH₂)₂TeCh (y = H (3a), Me (3b), MeO (3c)), are prepared by the reaction of the bis(p-substituted benzoylmethyl)tellurides 2a--c with S0₂Cl₂, whereas the corresponding diiodides (p-YC₆H₄COCH₂)₂Teh (y = H
(4a), Me (4b), MeO (4c)) can be obtained by the metathetical reaction of la--c with KI, or alternatively, by the oxidative addition of
iodine to 2a--c. The reaction of 2a--c with allyl bromide affords the diorganotellurium dibrornides la--c, rather than the expected
triorganotelluronium bromides. Compounds 1-4 were characterized by elemental analyses, IR spectroscopy, ¹H, ^l3C and ¹²⁵Te
NMR spectroscopy (solution and solid-state) and in case of Ie also by X-ray crystallography. (p-MeOC₆H₄COCH₂)₂TeBr₂ (1c) provides, a rare example, among organotellurium compounds, of a supramolecular architecture, where C-H-O hydrogen bonds appear to be the non-covalent intermolecular associative force that dominates the crystal packing.

ATP7B expression in human breast epithelial cells is mediated by lactational hormones

A role for the copper transporter, ATP7B, in secretion of copper from the human breast into milk has previously not been reported, although it is known that the murine ortholog of ATP7B facilitates copper secretion in the mouse mammary gland. We show here that ATP7B is expressed in luminal epithelial cells in both the resting and lactating human breast, where it has a perinuclear localization in resting epithelial cells and a diffuse location in lactating tissue. ATP7B protein was present in a different subset of vesicles from those containing milk proteins and did not overlap with Menkes ATPase, ATP-7A, except in the perinuclear region of cells. In the cultured human mammary line, PMC42-LA, treatment with lactational hormones induced a redistribution of ATP7B from a perinuclear region to a region adjacent, but not coincident with, the apical plasma membrane. Trafficking of ATP7B was copper dependent, suggesting that the hormone-induced redistribution of ATP7A was mediated through an increase in intracellular copper. Radioactive copper (⁶⁴Cu) studies using polarized PMC42-LA cells that overexpressed mAtp7B protein showed that this transporter facilitates copper efflux from the apical surface of the cells. In summary, our results are consistent with an important function of ATP7B in the secretion of copper from the human mammary gland.

Neurodevelopmental effects of maternal nutritional status and exposure to methylmercury from eating fish during pregnancy

Fish contain nutrients that promote optimal brain growth and development but also contain methylmercury (MeHg) that can have toxic effects. The present study tested the hypothesis that the intake of selected nutrients in fish or measures of maternal nutritional status may represent important confounders when estimating the effects of prenatal methylmercury exposure on child development. The study took place in the Republic of Seychelles, an Indian Ocean archipelago where fish consumption is high. A longitudinal cohort study design was used. A total of 300 mothers were enrolled early in pregnancy. Nutrients considered to be important for brain development were measured during pregnancy along with prenatal MeHg exposure. The children were evaluated periodically to age 30 months. There were 229 children with complete outcome and covariate data for analysis. The primary endpoint was the Bayley Scales of Infant Development-II (BSID-II), administered at 9 and 30 months of age. Combinations of four secondary measures of infant cognition and memory were also given at 5, 9 and 25 months. Cohort mothers consumed an average of 537 g of fish (nine meals containing fish) per week. The average prenatal MeHg exposure was 5.9 ppm in maternal hair. The primary analysis examined the associations between MeHg, maternal nutritional measures and children's scores on the BSID-II and showed an adverse association between MeHg and the mean Psychomotor Developmental Index (PDI) score at 30 months. Secondary analyses of the association between the PDI and only MeHg alone or nutritional factors alone showed only a borderline significant association between MeHg and the PDI at 30 months and no associations with nutritional factors. One experimental measure at 5 months of age was positively associated with iodine status, but not prenatal MeHg exposure. These findings suggest a possible confounding role of maternal nutrition in studies examining associations between prenatal MeHg exposures and developmental outcomes in children.

High mobility I− / I3− redox couple in a molecular plastic crystal: A potential new generation of electrolyte for solid-state photoelectrochemical cells

A series of new electrolyte materials based on a molecular plastic crystal doped by different iodide salts together with iodine have been prepared and characterized by thermal analysis, ionic conductivity, electrochemical and solid-state NMR diffusion measurements. In these materials, the plastic crystal phase of succinonitrile acts as a good matrix for the quaternary ammonium based iodides and iodine and appears to act in some cases as a solid-state “solvent” for the binary dopants. The materials were prepared by mixing the components in the molten state with subsequent cooling into the plastic crystalline state. This resulted in waxy-solid electrolytes in the temperature range from − 40 to 60 °C. The combination of structural variation of the cations, and fast redox couple diffusion (comparable with liquid-based electrolytes), as well as a high ionic conductivity of up to 3 × 10^{− 3} S cm^{− 1} at ambient temperature, make these materials very attractive for potential use in solid-state photoelectrochemical cells.

Rapid I−/I3− diffusion in a molecular-plastic-crystal electrolyte for potential application in solid-state photoelectrochemical cells

High current-carrying capacity and rapid, liquidlike diffusion were achieved in a dye-sensitized solar cell (DSSC) based on the plastic-crystalline electrolyte succinonitrile and the I⁻/I₃⁻ redox couple (see diagram). This could lead to the development of true solid-state DSSCs without conventional organic-liquid electrolytes, which can cause problems with long-term device stability.

Conductivity percolation in polyiodide/polymer complexes

Variable-temperature four-probe conductivity measurements and Raman spectroscopy were investigated for iodine in poly(propylene oxide) (PPO) and NaI₃ in PPO. The Raman spectra indicate the presence of both triiodide and polyiodide species in samples of I₂-doped PPO. The conductivity of these PPO/I₂ samples increased with increasing I₂ concentration and reached a plateau at approximately 12 vol % iodine. Raman spectra at 20 °C indicate that, at concentrations less than 23 vol % I₃-, the dominant species is the triiodide. Polymer salt complexes with varying amounts of I₃- appear to display a conductivity threshold near T_g, at 0.2 vol fraction of triiodide.

Ambient temperature plastic crystal electrolyte for efficient, all-solid-state dye-sensitized solar cell

Doping the molecular plastic crystal of succinonitrile with solid N-methyl-N-butylpyrrolidinium iodide salt and iodine has produced a highly conductive solid iodide/triiodide conductor. Furthermore, it was employed for a highly efficient, all-solid-state dye-sensitized solar cell.

Central venous dialysis : an Australian survey

Aim: To explore the current central venous dialysis catheter (CVDC) nursing care practices in Australia. Method: A survey of dialysis units in Australia. Results: 66% return rate (48/73) Internal jugular is the main insertion site (75%) and the majority are tunneled (85%). Insertion was performed most commonly by radiologists (34%) followed by intensivists (24%) with one center reporting insertion by nursing staff. CVDCs were most commonly inserted in radiology (54%), followed by theatre (33%). Dressings were attended weekly (55%) or on dialysis days (45%). Chlorhexidine was the antiseptic solution of choice (54%) followed by povidine-iodine (37%). In 21% of centres Mupirocin was routinely applied in addition to the antiseptic solution. Transparent dressings were overwhelmingly favoured however most centres recommended alternatives related to patient need. 21% of units reported enrolled nurses undertaking dressings. All units reported the use of sterile gloves and sterile dressing packs. 10% reported different routine care for tunneled and non-tunneled. 40% of the units collected data on infection rates per catheter days. General opinion (39%) was identified as the reason to base CVDC protocols while descriptive studies (25%), RCTs (23%) and guidelines (18%) were also reported. Conclusion: There are significant variations in the Australian nursing practice related to the care of CVDCs. Although there is still practice based on general opinion there is evidence that changes in practice in the past 8 years may be associated with knowledge derived from research.

Scores on the dietary guideline index for children and adolescents are associated with nutrient intake and socio-economic position but not adiposity 1-3

Diet quality indices reflect overall dietary patterns better than single nutrients or food groups. The study aims were to develop a measure of adherence with dietary guidelines applicable to child and adolescent populations in Australia and determine the association between index scores and food and nutrient intake, socio-demographic characteristics, and measures of adiposity. Data were analyzed from 4- to 16-y-old participants of the 2007 Australian Children’s Nutrition and Physical Activity Survey (n = 3416). The Dietary Guideline Index for Children and Adolescents (DGI-CA) comprises 11 components: 5 core food groups, wholegrain bread, reduced-fat dairy foods, extra foods (nutrient poor and high in fat, salt, and added sugar), healthy fats/oils, water, and diet variety (possible score of 100). The index criteria were age specific. The mean DGI-CA score was low (53.6 ± 0.4), similar between boys and girls, and differed by age; the youngest children scored higher than the oldest children (P < 0.0001). Higher DGI-CA scores were associated with lower energy intake, energy density, total and saturated fat, and sugar intake; higher protein, carbohydrate, fiber, calcium, iron, vitamin C, vitamin A, folate, phosphorous, magnesium, zinc, and iodine intakes; and a higher polyunsaturated:saturated fat ratio (P < 0.0001). DGI-CA scores were associated with socio-economic characteristics and measures of family circumstance. Weak positive associations were observed between DGI-CA score and BMI or waist circumference Z-scores in the 4- to 10-y and 12- to 16-y age groups only. This index is the first validated index in Australia and one of the few international indices to describe the diet quality of children and adolescents.

Porphyrin dye-sensitised solar cells utilising a solid-state electrolyte

We describe a porphyrin dye-sensitised solar cell utilising a solid state electrolyte containing the I¯/I₃¯ redox couple, which yields a performance of 5.3% under moderate light intensity and 4.8% at full sun.

Vitamin D-fortified milk achieves the targeted serum 25-hydroxyvitamin D concentration without affecting that of parathyroid hormone in New Zealand toddlers

For young children, the level of vitamin D required to ensure that most achieve targeted serum 25-hydroxyvitamin D [25(OH)D] ≥50 nmol/L has not been studied. We aimed to investigate the effect of vitamin D-fortified milk on serum 25(OH)D and parathyroid hormone (PTH) concentrations and to examine the dose–response relationship between vitamin D intake from study milks and serum 25(OH)D concentrations in healthy toddlers aged 12–20 mo living in Dunedin, New Zealand (latitude 46°S). Data from a 20-wk, partially blinded, randomized trial that investigated the effect of providing red meat or fortified toddler milk on the iron, zinc, iodine, and vitamin D status in young New Zealand children (n = 181; mean age 17 mo) were used. Adherence to the intervention was assessed by 7-d weighed diaries at wk 2, 7, 11, 15, and 19. Serum 25(OH)D concentration was measured at baseline and wk 20. Mean vitamin D intake provided by fortified milk was 3.7 μg/d (range, 0–10.4 μg/d). After 20 wk, serum 25(OH)D concentrations but not PTH were significantly different in the milk groups. The prevalence of having a serum 25(OH)D <50 nmol/L remained relatively unchanged at 43% in the meat group, whereas it significantly decreased to between 11 and 15% in those consuming fortified study milk. In New Zealand, vitamin D intake in young children is minimal. Our findings indicate that habitual consumption of vitamin D-fortified milk providing a mean intake of nearly 4 μg/d was effective in achieving adequate year-round serum 25(OH)D for most children.

Management of advanced neuroendocrine tumors with hepatic metastasis

Neuroendocrine tumors (NETs) in general and specifically these gastroenteropancreatic-neuroendocrine tumors often present a considerable diagnostic and therapeutic challenge, especially those that behave in an aggressive fashion. The majority of tumors are diagnosed at a stage that the only curative treatment, radical surgical intervention, is no longer an option and thus long-term therapy with somatostatin analogs is focused on symptom amelioration and in the improvement of quality of life. Although biotherapy is currently the most efficient treatment to achieve palliation, conventional chemotherapy may have some utility in undifferentiated or highly proliferating neuroendocrine carcinomas and pancreatic NETs. Hepatic metastases, depending on size, location, and number may be amenable to surgical resection or radiofrequency ablation. If surgery is not feasible, embolization either alone (bland), in combination with chemotherapeutic agents, or using radioactive microspheres can be used. Peptide receptor targeted radiotherapy using radiolabeled octapeptide analogs (⁹⁰Yttrium or ¹⁷⁷Lutetium-octreotide) may lead to reduction in tumor size, but in most circumstances has a tumor stabilizing effect. A variety of antiangiogenesis and growth factor-targeted agents have been evaluated, but to date, the results have failed to meet our expectations.

Tracking of dietary intakes in early childhood : the Melbourne InFANT program

Background/Objectives: The objectives of the present study were to describe food and nutrient intakes in children aged 9 and 18 months, and to assess tracking of intakes between these two ages.

Subjects/Methods: Participants were 177 children of first-time mothers from the control arm of the Melbourne Infant Feeding Activity and Nutrition Trial (InFANT) Program. Dietary intake was collected at 9 and 18 months using three 24 h diet recalls. Tracking was assessed for food and nutrient intakes using logistic regression analysis and estimating partial correlation coefficients, respectively.

Results: Although overall nutrient intakes estimated in this study did not indicate a particular risk of nutrient deficiency, our findings suggest that consumption of energy-dense, nutrient-poor foods occurred as early as 9 months of age, with some of these foods tracking highly over the weaning period. Intakes of healthier foods such as fruits, vegetables, dairy products, eggs, fish and water were also relatively stable over this transition from infancy to toddlerhood, along with moderate tracking for riboflavin, iodine, fibre, calcium and iron. Tracking was low but close to ρ=0.3 for zinc, magnesium and potassium intakes.

Conclusions: The tracking of energy-dense, nutrient-poor foods has important implications for public health, given the development of early eating behaviours is likely to be modifiable. At this stage of life, dietary intakes are largely influenced by the foods parents provide, parental feeding practices and modelling. This study supports the importance of promoting healthy dietary trajectories from infancy.

Food fortification : the evidence, ethics and politics of adding nutrients to food

This research book presents a critical analysis of mandatory food fortification as a technology for protecting and promoting public health. Increasing numbers of foods fortified with novel amounts and combinations of nutrients are being introduced into the food supplies of countries around the world to raise populations’ nutrient intakes. Three topical food fortification case studies representing the different public health rationales for adding nutrients to food were assessed for their public health benefits, risks and ethical considerations: Universal salt iodisation (USI) to help prevent iodine deficiency disorders; mandatory flour fortification with folic acid (MFFFA) to help prevent neural tube defects; and mandatory milk fortification with vitamin D (MMFVD) to help prevent vitamin D deficiency. These assessments found that whereas USI performs strongly as a public health intervention, MFFFA and MMFVD are associated with more risks and less ethical justification than an alternative policy option. Food fortification can be a blunt policy response to complex policy problems. The findings highlight that the primary predictor of a mandatory food fortification policy’s benefits, risks and ethics is its ability to address the underlying cause of the policy problem. The analysis of the policy-making processes for each case study found that certain powerful actors use their influence to determine what counts as evidence in policy processes to privilege food fortification activities over alternative policy options. Policy-making frequently was notable for the low prominence it afforded ethical considerations and its lack of public engagement. Priority activities to help strengthen policy processes and outcomes are suggested.