Soil carbon stock in the tropical rangelands of Australia: Effects of soil type and grazing pressure, and determination of sampling requirement.

On-going, high-profile public debate about climate change has focussed attention on how to monitor the soil organic carbon stock (C(s)) of rangelands (savannas). Unfortunately, optimal sampling of the rangelands for baseline C(s) - the critical first step towards efficient monitoring - has received relatively little attention to date. Moreover, in the rangelands of tropical Australia relatively little is known about how C(s) is influenced by the practice of cattle grazing. To address these issues we used linear mixed models to: (i) unravel how grazing pressure (over a 12-year period) and soil type have affected C(s) and the stable carbon isotope ratio of soil organic carbon (delta(13)C) (a measure of the relative contributions of C(3) and C(4) vegetation to C(s)); (ii) examine the spatial covariation of C(s) and delta(13)C; and, (iii) explore the amount of soil sampling required to adequately determine baseline C(s). Modelling was done in the context of the material coordinate system for the soil profile, therefore the depths reported, while conventional, are only nominal. Linear mixed models revealed that soil type and grazing pressure interacted to influence C(s) to a depth of 0.3 m in the profile. At a depth of 0.5 m there was no effect of grazing on C(s), but the soil type effect on C(s) was significant. Soil type influenced delta(13)C to a soil depth of 0.5 m but there was no effect of grazing at any depth examined. The linear mixed model also revealed the strong negative correlation of C(s) with delta(13)C, particularly to a depth of 0.1 m in the soil profile. This suggested that increased C(s) at the study site was associated with increased input of C from C(3) trees and shrubs relative to the C(4) perennial grasses; as the latter form the bulk of the cattle diet, we contend that C sequestration may be negatively correlated with forage production. Our baseline C(s) sampling recommendation for cattle-grazing properties of the tropical rangelands of Australia is to: (i) divide the property into units of apparently uniform soil type and grazing management; (ii) use stratified simple random sampling to spread at least 25 soil sampling locations about each unit, with at least two samples collected per stratum. This will be adequate to accurately estimate baseline mean C(s) to within 20% of the true mean, to a nominal depth of 0.3 m in the profile.

Risk factors associated with corneal nerve alteration in type 1 diabetes in the absence of neuropathy: A longitudinal in vivo corneal confocal microscopy study

Purpose The aim of this study was to determine alterations to the corneal subbasal nerve plexus (SNP) over four years using in vivo corneal confocal microscopy (IVCM) in participants with type 1 diabetes and to identify significant risk factors associated with these alterations. Methods A cohort of 108 individuals with type 1 diabetes and no evidence of peripheral neuropathy at enrollment underwent laser-scanning IVCM, ocular screening, and health and metabolic assessment at baseline and the examinations continued for four subsequent annual visits. At each annual visit, eight central corneal images of the SNP were selected and analyzed to quantify corneal nerve fiber density (CNFD), branch density (CNBD) and fiber length (CNFL). Linear mixed model approaches were fitted to examine the relationship between risk factors and corneal nerve parameters. Results A total of 96 participants completed the final visit and 91 participants completed all visits. No significant relationships were found between corneal nerve parameters and time, sex, duration of diabetes, smoking, alcohol consumption, blood pressure or BMI. However, CNFD was negatively associated with HbA1c (β=-0.76, P<0.01) and age (β=-0.13, P<0.01) and positively related to high density lipids (HDL) (β=2.01, P=0.03). Higher HbA1c (β=-1.58, P=0.04) and age (β=-0.23, P<0.01) also negatively impacted CNBD. CNFL was only affected by higher age (β=-0.06, P<0.01). Conclusions Glycemic control, HDL and age have significant effects on SNP structure. These findings highlight the importance of diabetic management to prevent corneal nerve damage as well as the capability of IVCM for monitoring subclinical alterations in the corneal SNP in diabetes.

Biometry of eyes in type 1 diabetes

This is a comprehensive study of a large range of biometric and optical parameters in people with type 1 diabetes. The parameters of 74 people with type 1 diabetes and an age matched control group were assessed. Most of the people with diabetes had low levels of neuropathy, retinopathy and nephropathy. Marginal or no significant differences were found between groups for corneal shape, corneal thickness, pupil size, and pupil decentrations. Relative to the control group, the diabetes group demonstrated smaller anterior chamber depths, more curved lenses, greater lens thickness and lower lens equivalent refractive index. While the optics of diabetic eyes make them appear as older eyes than those of people of the same age without diabetes, the differences did not increase significantly with age. Age-related changes in the optics of the eyes of people with diabetes need not be accelerated if the diabetes is well controlled.

Straylight, lens yellowing and aberrations of eyes in type 1 diabetes

Straylight, lens yellowing and ocular aberrations were assessed in a group of people with type 1 diabetes and in an age matched control group. Most of the former had low levels of neuropathy. Relative to the control group, the type 1 diabetes group demonstrated greater straylight, greater lens yellowing, and differences in some higher-order aberration co-efficients without significant increase in root-mean-square higher-order aberrations. Differences between groups did not increase significantly with age. The results are similar to the findings for ocular biometry reported previously for this group of participants, and suggest that age-related changes in the optics of the eyes of people with well-controlled diabetes need not be accelerated.

Corneal confocal microscopy detects neuropathy in patients with type 1 diabetes without retinopathy or microalbuminuria

Objective Corneal innervation is increasingly used as a surrogate marker of human diabetic peripheral neuropathy (DPN) however its temporal relationship with the other microvascular complications of diabetes is not fully established. In this cross-sectional, observational study we aimed to assess whether neuropathy occurred in patients with type 1 diabetes, without retinopathy or microalbuminuria. Materials and Methods All participants underwent detailed assessment of peripheral neuropathy [neuropathy disability score (NDS), vibration perception threshold (VPT), peroneal motor nerve conduction velocity (PMNCV), sural sensory nerve conduction velocity (SSNCV) and in vivo corneal confocal microscopy (IVCCM)], retinopathy (digital fundus photography) and albuminuria status [albumin: creatinine ratio (ACR)]. Results 53 patients with Type 1 diabetes with (n=37) and without retinopathy (n=16) were compared to control subjects (n=27). SSNCV, corneal nerve fibre (CNFD) and branch (CNBD) density and length (CNFL) were reduced significantly (p<0.001) in diabetic patients without retinopathy compared to control subjects. Furthermore, CNFD, CNBD and CNFL were also significantly (p<0.001) reduced in diabetic patients without microalbuminuria (n=39), compared to control subjects. Greater neuropathic severity was associated with established retinopathy and microalbuminuria. Conclusions IVCCM detects early small fibre damage in the absence of retinopathy or microalbuminuria in patients with Type 1 diabetes.

Lens shape and refractive index distribution in type 1 diabetes

Purpose: To compare lens dimensions and refractive index distributions in type 1 diabetes and age-matched control groups. Methods: There were 17 participants with type 1 diabetes, consisting of two subgroups (7 young [23 ± 4 years] and 10 older [54 ± 4 years] participants), with 23 controls (13 young, 24 ± 4 years; 10 older, 55 ± 4 years). For each participant, one eye was tested with relaxed accommodation. A 3T clinical magnetic resonance imaging scanner was used to image the eye, employing a multiple spin echo (MSE) sequence to determine lens dimensions and refractive index profiles along the equatorial and axial directions. Results: The diabetes group had significantly smaller lens equatorial diameters and larger lens axial thicknesses than the control group (diameter mean ± 95% confidence interval [CI]: diabetes group 8.65 ± 0.26 mm, control group 9.42 ± 0.18 mm; axial thickness: diabetes group 4.33 ± 0.30 mm, control group 3.80 ± 0.14 mm). These differences were also significant within each age group. The older group had significantly greater axial thickness than the young group (older group 4.35 ± 0.26 mm, young group 3.70 ± 0.25 mm). Center refractive indices of diabetes and control groups were not significantly different. There were some statistically significant differences between the refractive index fitting parameters of young and older groups, but not between diabetes and control groups of the same age. Conclusions: Smaller lens diameters occurred in the diabetes groups than in the age-matched control groups. Differences in refractive index distribution between persons with and without diabetes are too small to have important effects on instruments measuring axial thickness.

Impact of the Human Bacterial Environment on Mycobacteriosis and Allergy

My work describes two sectors of the human bacterial environment: 1. The sources of exposure to infectious non-tuberculous mycobacteria. 2. Bacteria in dust, reflecting the airborne bacterial exposure in environments protecting from or predisposing to allergic disorders. Non-tuberculous mycobacteria (NTM) transmit to humans and animals from the environment. Infection by NTM in Finland has increased during the past decade beyond that by Mycobacterium tuberculosis. Among the farm animals, porcine mycobacteriosis is the predominant NTM disease in Finland. Symptoms of mycobacteriosis are found in 0.34 % of slaughtered pigs. Soil and drinking water are suspected as sources for humans and bedding materials for pigs. To achieve quantitative data on the sources of human and porcine NTM exposure, methods for quantitation of environmental NTM are needed. We developed a quantitative real-time PCR method, utilizing primers targeted at the 16S rRNA gene of the genus of Mycobacterium. With this method, I found in Finnish sphagnum peat, sandy soils and mud high contents of mycobacterial DNA, 106 to 107 genome equivalents per gram. A similar result was obtained by a method based on the Mycobacterium-specific hybridization of 16S rRNA. Since rRNA is found mainly in live cells, this result shows that the DNA detected by qPCR mainly represented live mycobacteria. Next, I investigated the occurrence of environmental mycobacteria in the bedding materials obtained from 5 pig farms with high prevalence (>4 %) of mycobacteriosis. When I used for quantification the same qPCR methods as for the soils, I found that piggery samples contained non-mycobacterial DNA that was amplified in spite of several mismatches with the primers. I therefore improved the qPCR assay by designing Mycobacterium-specific detection probes. Using the probe qPCR assay, I found 105 to 107 genome equivalents of mycobacterial DNA in unused bedding materials and up to 1000 fold more in the bedding collected after use in the piggery. This result shows that there was a source of mycobacteria in the bedding materials purchased by the piggery and that mycobacteria increased in the bedding materials during use in the piggery. Allergic diseases have reached epidemic proportions in urbanized countries. At the same time, childhood in rural environment or simple living conditions appears to protect against allergic disorders. Exposure to immunoreactive microbial components in rural environments seems to prevent allergies. I searched for differences in the bacterial communities of two indoor dusts, an urban house dust shown to possess immunoreactivity of the TH2-type and a farm barn dust with TH1-activity. The immunoreactivities of the dusts were revealed by my collaborators, in vitro in human dendritic cells and in vivo in mouse. The dusts accumulated >10 years in the respiratory zone (>1.5 m above floor), thus reflecting the long-term content of airborne bacteria at the two sites. I investigated these dusts by cloning and sequencing of bacterial 16S rRNA genes from dust contained DNA. From the TH2-active urban house dust, I isolated 139 16S rRNA gene clones. The most prevalent genera among the clones were Corynebacterium (5 species, 34 clones), Streptococcus (8 species, 33 clones), Staphylococcus (5 species, 9 clones) and Finegoldia (1 species, 9 clones). Almost all of these species are known as colonizers of the human skin and oral cavity. Species of Corynebacterium and Streptococcus have been reported to contain anti-inflammatory lipoarabinomannans and immunmoreactive beta-glucans respectively. Streptococcus mitis, found in the urban house dust is known as an inducer of TH2 polarized immunity, characteristic of allergic disorders. I isolated 152 DNA clones from the TH1-active farm barn dust and found species quite different from those found from the urban house dust. Among others, I found DNA clones representing Bacillus licheniformis, Acinetobacter lwoffii and Lactobacillus each of which was recently reported to possess anti-allergy immunoreactivity. Moreover, the farm barn dust contained dramatically higher bacterial diversity than the urban house dust. Exposure to this dust thus stimulated the human dendritic cells by multiple microbial components. Such stimulation was reported to promote TH1 immunity. The biodiversity in dust may thus be connected to its immunoreactivity. Furthermore, the bacterial biomass in the farm barn dust consisted of live intact bacteria mainly. In the urban house dust only ~1 % of the biomass appeared as intact bacteria, as judged by microscoping. Fragmented microbes may possess bioactivity different from that of intact cells. This was recently shown for moulds. If this is also valid for bacteria, the different immunoreactivities of the two dusts may be explained by the intactness of dustborne bacteria. Based on these results, we offer three factors potentially contributing to the polarized immunoreactivities of the two dusts: (i) the species-composition, (ii) the biodiversity and (iii) the intactness of the dustborne bacterial biomass. The risk of childhood atopic diseases is 4-fold lower in the Russian compared with the Finnish Karelia. This difference across the country border is not explainable by different geo-climatic factors or genetic susceptibilities of the two populations. Instead, the explanation must be lifestyle-related. It has already been reported that the microbiological quality of drinking water differs on the two sides of the borders. In collaboration with allergists, I investigated dusts collected from homes in the Russian Karelia and in the Finnish Karelia. I found that bacterial 16S rRNA genes cloned from the Russian Karelian dusts (10 homes, 234 clones) predominantly represented Gram-positive taxa (the phyla Actinobacteria and Firmicutes, 67%). The Russian Karelian dusts contained nine-fold more of muramic acid (60 to 70 ng mg-1) than the Finnish Karelian dusts (3 to 11 ng mg-1). Among the DNA clones isolated from the Finnish side (n=231), Gram-negative taxa (40%) outnumbered the Gram-positives (34%). Out of the 465 DNA clones isolated from the Karelian dusts, 242 were assigned to cultured validly described bacterial species. In Russian Karelia, animal-associated species e.g. Staphylococcus and Macrococcus were numerous (27 clones, 14 unique species). This finding may connect to the difference in the prevalence of allergy, as childhood contacts with pets and farm animals have been connected with low allergy risk. Plant-associated bacteria and plant-borne 16S rRNA genes (chloroplast) were frequent among the DNA clones isolated from the Finnish Karelia, indicating components originating from plants. In conclusion, my work revealed three major differences between the bacterial communtites in the Russian and in the Finnish Karelian homes: (i) the high prevalence of Gram-positive bacteria on the Russian side and of Gram-negative bacteria on the Finnish side and (ii) the rich presence of animal-associated bacteria on the Russian side whereas (iii) plant-associated bacteria prevailed on the Finnish side. One or several of these factors may connect to the differences in the prevalence of allergy.

Changes in straylight and corneal light scattering in a newly diagnosed case of type 2 diabetes

Visual problems may be the first symptoms of diabetes. There have been several reports of transient changes in refraction of people newly diagnosed with diabetes. Visual acuity and refraction may be affected when there are ocular biometric changes. Small but significant biometrical changes have been found by some authors during hyperglycaemia and during reduction of hyperglycaemia.[4] Here, we describe a case of type 2 diabetes that was detected from ocular straylight and intraocular thickness measurements...

Photolysis of the dithiolactone 4-isopropylidene-3,3-dimethyl-1-thietan-2-thione; a Norrish type I reaction

The dithiolactone (1) upon excitation gives the dithione (2) in cyclohexane and other aprotic solvents and a 1 : 1 adduct in hydroxylic solvents from an n* excited singlet state via an -cleavage process.

Fatty acids, fibre, carotenoids and tocopherols in relation to glucose metabolism in subjects at high risk for type 2 diabetes : a cross-sectional analysis

Fatty acids, fibre, carotenoids and tocopherols in relation to glucose metabolism in subjects at high risk for type 2 diabetes a cross-sectional analysis Type 2 diabetes (T2D) is a heterogeneous disorder of carbohydrate, lipid and protein metabolism, resulting from genetics, environmental influences and interactions between these. The disease is characterized by insulin resistance, β-cell dysfunction, hepatic glucose overproduction and disordered fat mobilization and storage. The literature on associations between dietary factors and glucose metabolism is inconsistent. One factor behind the discrepant results may be genetic heterogeneity of study populations. Data on nutrient-gene interactions in relation to glucose metabolism are scarce. Thus, investigating high-risk populations and exploring nutrient-gene interactions are essential for improving the understanding of T2D aetiology. Ideally, this information could help to develop prevention programmes that take into account the genetic predisposition to the disease. In this study, associations between measures of glucose metabolism predicting T2D and fatty acids, antioxidative nutrients and fibre were examined in a high-risk population, i.e., in non-diabetic relatives of affected patients. Interactions between the PPARG Pro12Ala polymorphism and fatty acids on glucose metabolism were taken into consideration. This common polymorphism plays an important role in the regulation of glucose metabolism. The inverse associations observed between dietary fibre and insulin resistance are consistent with the prevailing recommendations urging increased intake of fibre to prevent T2D. Beneficial associations observed between the intake of carotenoids and glucose levels stress that a high consumption of vegetables, fruits and berries rich in carotenoids might also play a role in the prevention of T2D. Whether tocopherols have an independent association with glucose metabolism remains questionable. Observed interactions between fatty acids and glucose metabolism suggest that a high intake of palmitic acid is associated with high fasting glucose levels mainly in female Ala allele carriers. Furthermore, the PPARG Pro12Ala polymorphism may modify the metabolic response to dietary marine fat. The beneficial associations of high intake of marine n 3 fatty acids with insulin resistance and glucose levels may be restricted to carriers of the Ala allele. The findings pertain to subjects with a family history of T2D, and the cross-sectional nature of the study precludes inferences about causality. Results nevertheless show that associations of dietary factors with glucose metabolism may be modulated by the genetic makeup of an individual. Additional research is warranted to elucidate the role of probably numerous nutrient-gene interactions, some of which may be sex-specific, in the aetiology of T2D.

A Fredholm-type theory for third-kind linear integral equations

The third-kind linear integral equation Image where g(t) vanishes at a finite number of points in (a, b), is considered. In general, the Fredholm Alternative theory [[5.]] does not hold good for this type of integral equation. However, imposing certain conditions on g(t) and K(t, t′), the above integral equation was shown [[1.], 49–57] to obey a Fredholm-type theory, except for a certain class of kernels for which the question was left open. In this note a theory is presented for the equation under consideration with some additional assumptions on such kernels.

Links between emotional job demands and occupational well-being: Age differences depend on type of demand

In the growing health care sector, meeting emotional job demands is crucial to organizational outcomes but may negatively affect employees’ well-being. Drawing on the emotional aging literature, we predicted that two common emotional job demands, display demands (expressing positive, negative, and neutral emotions toward clients) and sensitivity demands (knowing what the client is feeling), affect older health care workers’ occupational well-being differently than young workers, as indicated by their job satisfaction and need for recovery. Survey data from employees of senior care homes (N = 141, aged between 17 and 62 years) confirmed the moderating role of age for links between emotional job demands and occupational well-being indicators. Emotional display demands were generally positively associated with emotional dissonance; however, the association between demands to display neutral emotions and emotional dissonance was stronger among young compared with older employees. In contrast, among older but not young employees, emotional dissonance was negatively associated with job satisfaction, and emotional sensitivity demands were positively associated with need for recovery. These findings suggest that age may confer both advantages (facing neutral display demands) and vulnerabilities (facing emotional dissonance and sensitivity demands) in managing emotional job demands.

Existence theorem for a generalized Hammerstein type equation

An existence theorem is obtained for a generalized Hammerstein type equation