Chemoenzymatic Hydrogen Production from Methanol through the Interplay of Metal Complexes and Biocatalysts.

Microbial methylotrophic organisms can serve as great inspiration in the development of biomimetic strategies for the dehydrogenative conversion of C1 molecules under ambient conditions. In this Concept article, a concise personal perspective on the recent advancements in the field of biomimetic catalytic models for methanol and formaldehyde conversion, in the presence and absence of enzymes and co-factors, towards the formation of hydrogen under ambient conditions is given. In particular, formaldehyde dehydrogenase mimics have been introduced in stand-alone C1 -interconversion networks. Recently, coupled systems with alcohol oxidase and dehydrogenase enzymes have been also developed for in situ formation and decomposition of formaldehyde and/or reduced/oxidized nicotinamide adenine dinucleotide (NADH/ NAD+ ). Although C1 molecules are already used in many industries for hydrogen production, these conceptual bioinspired low-temperature energy conversion processes may lead one day to more efficient energy storage systems enabling renewable and sustainable hydrogen generation for hydrogen fuel cells under ambient conditions using C1 molecules as fuels for mobile and miniaturized energy storage solutions in which harsh conditions like those in industrial plants are not applicable.

Taste-Elicited Activity in Facial Muscle Regions in 5-8-Week-Old Infants.

The state of development of the sense of taste in humans during the first few months of life is only partially understood. Since taste plays a critical role in the feeding and nutrition of infants a better understanding of taste development during early life is required. Currently, information about the sense of taste in pre-verbal infants is obtained by analysis of videotaped facial expressions using the Baby FACS coding system. A potentially more objective faster procedure for assessing facial expressions not investigated in infants is electromyography (EMG). The method has been successfully used to study taste-elicited responses in the mid-face muscle regions of the levator labii and zygomaticus major of 6-9-year-olds and in a range of facial muscle regions in adults. Accordingly, this study aimed to investigate taste in young infants using EMG to 1) measure activity simultaneously in 4 facial muscle regions in response to 3 common tastants and 2) determine whether the activities of one or more muscle regions is needed to provide evidence of perception of a tastant by an infant. The results indicated that multiple facial muscle regions responded simultaneously but differentially to non-sweet and sweet tastants and recordings of activities from 3 or 4 regions simultaneously indicated that almost 100% of infants responded to the unpleasant tastes of quinine and citric acid, and 80% to sucrose.

Reduced taste function and taste papillae density in children with chronic kidney disease.

BACKGROUND: Taste loss may contribute to the loss of appetite in children with chronic kidney disease (CKD) and other serious medical conditions that result in malnutrition. Traditional methods for measurement of taste loss commonly use aqueous tastant solutions that can induce nausea, vomiting, or even pain in the mouth. An alternative is to measure fungiform papillae density on the anterior tongue since this correlates with taste sensitivity. Here we aimed to develop a non-invasive method for assessing papillae density on the anterior tongue and to use the method to determine if CKD patients [estimated glomerular filtrate (eGFR < 60 ml/min/1.73 m(2))] have a lower density than clinical controls (CC)(eGFR > 89 ml/min/1.73 m(2)). METHODS: Thirty-five healthy adults participated in the development of a method, which was assessed by 24 children, 12 of whom were CKD patients and 12 were clinical controls. RESULTS: Similar papillae densities were found using invasive and non-invasive methods (F(1,34) = 0.647, p = 0.427). The CKD group had a significantly lower papillae density (X(2) = 7.17, p = 0.007) and poorer taste sensitivity than the CC group (p = 0.0272), and the density correlated significantly with eGFR (r = 0.56, p < 0.01). CONCLUSIONS: Loss of taste in children with CKD is due to the reduced number of papillae and their taste-sensing receptor cells.

Smell and taste function in children with chronic kidney disease.

Loss of appetite and poor growth are common in children with chronic kidney disease (CKD), and changes in smell and/or taste function may be responsible, but the hypothesis has not been proven. This aims of this prospective age- and gender-controlled study were to determine whether: (1) changes in smell and taste function occur in children with CKD; (2) smell or taste dysfunction are associated with estimated glomerular filtration rate (eGFR); (3) there is an association between smell or taste loss and body mass index (BMI). The study cohort consisted of 72 children of whom 20 were CKD stage 3-5 patients, 12 were CKD stage 2 patients, 20 were clinical controls (CC) and 20 were healthy children (HC). The CKD patients and clinical controls were recruited from Sydney Children's Hospital and The Children's Hospital, Westmead, and healthy controls were recruited from a local school. Scores for each group from taste and smell chemosensory function tests were compared, and their relationship with renal function and BMI investigated. The CKD stage 3-5 group had a significantly lower taste identification score (85.6%, P < 0.001) than the CC (94.8%) and HC (94.8%) groups, with almost one third of the children in the CKD stage 3-5 group exhibiting taste loss. Decreased taste function was associated with decreased eGFR (r = 0.43, P < 0.01), but no association between BMI and taste function was found (r = 0.001, P > 0.9). Odour identification scores were not different; however, there was a positive relationship with BMI (r = 0.427, P = 0.006). We conclude that a loss of taste can occur in children with CKD and that when it occurs, it worsens as eGFR declines and is found early in kidney disease.

Copper-Catalyzed Formylation of Amines by using Methanol as the C1 Source.

Cu/TEMPO catalyst systems are known for the selective transformation of alcohols to aldehydes, as well as for the simultaneous coupling of alcohols and amines to imines under oxidative conditions. In this study, such a Cu/TEMPO catalyst system is found to catalyze the N-formylation of a variety of amines by initial oxidative activation of methanol as the carbonyl source via formaldehyde and formation of N,O-hemiacetals and oxidation of the latter under very mild conditions. A vast range of amines, including aromatic and aliphatic, primary and secondary, and linear and cyclic amines are formylated under these conditions with good to excellent yields. Moreover, paraformaldehyde can be used instead of methanol for the N-formylation.

Olfactory function in Australian aboriginal children and chronic otitis media.

Chronic suppurative otitis media (CSOM), a severe form of middle ear infection, affects most Australian Aboriginal children with up to 50% in some communities suffering hearing loss as a consequence. To date, there is no information on whether repeated exposure to the pathogens that characterize CSOM and that are present in the upper respiratory airway affect olfactory function. Accordingly, this study aimed to determine whether 1) there was a high prevalence of olfactory loss in Aboriginal children and 2) hearing loss is a predictor of olfactory loss. Two hundred and sixty one 9- to 12-year-old Aboriginal children from 16 rural communities reported to have high prevalences of CSOM and hearing loss were assessed for olfactory loss using a 16-odor identification test and hearing loss. One child was found to be anosmic, 4 were slightly hyposmic, and 42 had hearing loss. No relationship was found between olfactory loss and hearing loss. The test-retest reliability of the 16-odor identification test was 0.98. It was concluded that CSOM does not appear to affect olfactory function in the long term and that hearing loss in Aboriginal children is not a predictor of olfactory loss.

Cobalt Schiff-base complexes for electrocatalytic hydrogen generation.

Two cobalt(iii) complexes containing inexpensive Schiff-base ligands have been found to be active for proton reduction at low overpotentials. The dinitro and tetranitro derivatized Schiff-base complexes show catalytic activity at -0.96 V and -1.1 V vs. Fc+/Fc, respectively, resulting in overpotentials of 120 mV and 280 mV. Foot-of-the-wave analysis is used to examine the kinetic properties of these complexes, yielding a theoretical TOFmax of up to 4100 s-1. Experimental TOFs of 7 s-1and 3 s-1 are observed. Catalytic Tafel plots are also presented in order to benchmark the relationship between turnover frequency and overpotential.

Hydrogen evolution catalyzed by a cobalt complex containing an asymmetric Schiff-base ligand.

A cobalt(iii) complex containing an asymmetric Schiff-base ligand has been found to be active for proton reduction. Catalysis occurs at -1.2 V vs. Fc(+)/Fc (0.56 V vs. NHE), resulting in an overpotential of 350 mV. Additionally, the complex is active with a turnover frequency of 420 s(-1). An enhancement in activity is observed upon addition of water.

Chemosensory function and food preferences of children with cystic fibrosis.

A major problem for patients with cystic fibrosis (CF) is the maintenance of adequate nutrition to maintain normal growth. The hypotheses that poor nutrition could be due to smell and/or taste dysfunction has been pursued in several studies with contradictory results. None, however, investigated whether inadequate nutrition is due to CF patients having different liking for foods compared to healthy children and whether liking can be linked to specific changes in smell or taste function. Here, the relationships between food liking, BMI, and smell and taste function in 42 CF and 42 healthy 5- to 18-year olds is pursued. A three-choice 16-item odor identification test and a gustatory identification test involving five concentrations of sweet, sour, bitter, and salty tastes, were used to assess chemosensory function. Food liking was assessed using a 94-item questionnaire. Patients identified significantly fewer odors than controls (89.8% vs. 95.7% correct; P < 0.001). However, only a few patients were affected and their loss of olfactory function was not substantial and unlikely to affect their liking for foods. Taste identification was similar for the two groups (patients 92.6% vs. controls 94.2% correct). There was no correlation between age and odor identification ability, but taste performance improved with age (r = 0.39, P < 0.05), suggesting cognition was the cause. Patients liked several types of foods and high-fat foods more than the controls. Both groups had a similar liking for low-fat foods and both liked high-fat foods more than low-fat foods. No significant relationships existed between FEV(1) and smell or taste function or liking for foods, the BMI of the groups were similar and there was no relationship between BMI and smell or taste function. The results indicate that the abnormal eating behavior reported for many CF patients is not due to changes in chemosensory function which remains normal in most CF patients at least to 18 years of age.

Facial electromyography: responses of children to odor and taste stimuli.

The study investigated the potential for facial electromyography (EMG) to be used as a clinical tool for measuring the responses of children to pleasant and unpleasant smell and taste stimuli. Responses in the zygomaticus major and levator labii muscles to 4 odorants and 4 tastants were recorded from 34 children aged 6-9 years. The results indicated that EMG activities in the 2 muscles discriminated between pleasant and unpleasant stimuli within each modality in a manner that indicated that the children perceived the hedonic qualities of the stimuli in a manner similar to that reported for adults. Importantly, there was unanimous agreement across the children as regards the differential nature of the activities exhibited. These outcomes together with the results of earlier facial expression studies suggest that facial EMG may provide an objective procedure that could be suitable for the clinical assessment of taste and smell function in newborns and young infants.