Farm management and husbandry practices associated with spontaneous humeral fractures in New Zealand dairy heifers.

AIMS: To use a farm-based survey to identify characteristics of the New Zealand dairy system associated with the risk of spontaneous humeral fracture in dairy heifers. METHODS: A questionnaire was designed and made available in print and online to collect information from dairy farmers and/or veterinarians, across New Zealand, about the management and nutrition of cows from birth to first lactation. Data were collected from July 2019 to March 2020 from farms that either had recorded (case farms) or not recorded (control farms) cases of humeral fractures in dairy heifers. RESULTS: A total of 68 completed questionnaires were returned, with 35 responses from case farms and 33 responses from control farms. Twenty-six responses (38%) were from the South Island (13 case farms and 13 control farms) and 38 responses (56%) were from the North Island (20 case farms and 18 control farms). For four questionnaires (6%) farm location was not given. Adjusting for the effect of age when calves accessed pasture, case farms had increased odds of having Holstein-Friesian Jersey crossbreed cows as the predominant breed (OR = 9.7; 95% CI = 3.1-36.0; p < 0.001). Adjusting for the effect of breed, allowing calves access to pasture a week later decreased the odds of being a case farm (OR = 0.68; 95% CI = 0.47-0.90; p = 0.006). CONCLUSIONS: Cows being Holstein-Friesian Jersey crossbreed was identified as a possible risk factor associated with spontaneous humeral fracture in dairy heifers in New Zealand. Given the small sample size, the likely multifactorial aetiology for humeral fractures, and the non-randomised survey, this risk factor, and the possible association between age at turn out and herd production with humeral fractures, all require further investigation.

Biochemical profile of heifers with spontaneous humeral fractures suggest that protein-energy malnutrition could be an important factor in the pathology of this disease.

CASE HISTORY: Serum and liver samples from 35, 2-year-old dairy heifers that had fractured one or both humeri post-calving between July and December 2019 were submitted to a diagnostic laboratory for analysis. Serum samples were analysed for albumin, ß-hydroxybutyrate (BHB), creatinine, Ca, Mg, phosphate, non-esterified fatty acids (NEFA), and serum Cu concentration. Liver samples were analysed for liver Cu concentration. Data were compared to published reference intervals. Data values for heifers that prior to fracture had grazed fodder beet were also compared to values for those that had grazed pasture. CLINICAL FINDINGS: Sixty-nine percent of heifers with humeral fracture had serum creatinine concentrations below the lower value of the reference range (55-130 µmol/L). In 3/32 (9%) heifers, serum NEFA concentrations were increased above the reference value indicating body fat mobilisation (≥1.2 mmol/L for peri-partum cows) and in 20/35 (57%) heifers BHB serum concentrations were above the reference value indicating subclinical ketosis (≥1.1 mmol/L for peri-partum cows). In 24/35 (69%) heifers, liver Cu concentration was low (≤ 44 µmol/kg) or marginal (45-94 µmol/kg). The concentration of Cu in serum was low (≤ 4.5 µmol/L) in 2/33 (6%) heifers and marginal (4.6-7.9 µmol/L) in 5/33 (15%) heifers. There was moderate positive correlation between the logged concentrations of Cu in paired liver and serum samples, r(31) = 0.43; (95% CI = 0.1-0.79; p = 0.014). One heifer had a serum phosphate concentration below the lower limit of the reference range (< 1.10 mmol/L). For all heifers, the concentrations of albumin, Ca, and Mg in serum were within the reference intervals (23-38 g/L, 2.00-2.60 mmol/L, and 0.49-1.15 mmol/L respectively). Over winter, 15/35 (43%) heifers grazed predominantly pasture, 14/35 (40%) grazed fodder beet and 6/35 (17%) had a mixed diet. CLINICAL RELEVANCE: In some of these heifers with humeral fractures, there was evidence for protein and/or energy malnutrition in the form of elevated NEFA and BHB concentrations and low creatinine concentrations in serum. Liver Cu concentrations were also reduced in most affected heifers. However, the absence of a control group means it is not possible to determine if these are risk factors for fracture or features common to all periparturient heifers. Clinical trials and molecular studies are needed to determine the true contribution of Cu and protein-energy metabolism to the pathogenesis of spontaneous humeral fractures in dairy heifers. ABBREVIATIONS: BHB: ß-hydroxybutyrate; NEFA: Non-esterified fatty acids.

Growth, milk production, reproductive performance, and stayability of dairy heifers born from 2-year-old or mixed-age dams.

Keeping replacement heifers that were the progeny of primiparous cows mated by artificial insemination enhances rates of genetic gain. Previous research has shown that heifers that were the progeny of primiparous cows were lighter at birth and grew at a slower rate to first calving compared with heifers born to multiparous dams. Furthermore, heifers that were heavier before first calving produced more milk than did lighter heifers. This study aimed to determine whether there were body weight, milk production, or reproductive disadvantages for heifers born from primiparous compared with multiparous dams. Data comprised body weight records from 189,936 New Zealand dairy heifers. Dams were allocated to 4 groups according to their age: 2 yr old (n = 13,717), 3 yr old (n = 39,258), 4 to 8 yr old (n = 120,859), and 9 yr or older (n = 16,102). Heifers that were the progeny of 2-yr-old dams were lighter from 3 to 21 mo of age than heifers that were the progeny of 3-yr-old and 4- to 8-yr-old dams. The progeny of 2- and 3-yr-old dams produced similar milk solids yields (± standard error of the mean) during their first lactation (304.9 ± 1.6 and 304.1 ± 1.5 kg, respectively), but more than that of 4- to 8-yr-old dams (302.4 ± 1.5). Furthermore, the progeny of 2-yr-old dams had similar stayabilities to first, second, and third calving to that of the progeny of 4- to 8-yr-old and ≥9-yr-old dams. Reproductive performance, as measured by calving and recalving rates was similar in first-calving heifers of all age-of-dam classes. Additionally, second and third calving rates were similar for the progeny of 2- and 3-yr-old dams. Interestingly, the progeny of dams ≥9 yr old had the lowest milk solids production in first (297.8 ± 1.6 kg), second (341.6 ± 1.8 kg), and third lactations (393.2 ± 2.4 kg). Based on the results of this study, keeping replacements from dams aged 9 yr and over could not be recommended. Furthermore, heifers born to 2-yr-old dams were lighter but produced more milk than heifers from older dams, in addition to having superior genetic merit.

Body weight of dairy heifers is positively associated with reproduction and stayability.

This study investigated the relationships between body weight (BW) and stayability, and BW and calving pattern, of 189,936 New Zealand dairy heifers. Heifers were classified into 5 breed groups: Holstein-Friesian (F), Holstein-Friesian crossbred (FX), Jersey (J), Jersey crossbred (JX), and Holstein-Friesian × Jersey crossbred (FJ). Body weight was predicted using Legendre polynomials at 6, 12, and 15 mo of age, and we analyzed their relationships with stayability, calving rate, and re-calving rate over the first 3 calvings. Approximately 92% of heifers calved for the first time at age 2 yr, 76% a second time at 3 yr, and 61% a third time at 4 yr. Heifers that were heavier were more likely to remain in the herd for first, second, and third calving compared with heifers that were lighter. Furthermore, we found positive curvilinear relationships between pre-breeding BW and reproductive performance of dairy heifers. Heifers that were heavier at 6, 12, and 15 mo were more likely to calve early for first calving compared with heifers that were lighter, regardless of breed group. In addition, we found a large range in BW where the probability of calving or re-calving early was high. For example, FJ heifers that were between 255 and 396 kg at 15 mo of age had 21-d calving and re-calving rates above 75 and 70%, respectively. For second and third lactations, however, heifer pre-breeding BW showed only small effects on the 21-d calving and re-calving rates. For heifers that were at the heaviest end of the BW range in the current study, slight declines in stayability and reproductive performance occurred, compared with heifers in the mid-range of BW. Consequently, for heifers that were above average in BW, the benefit of increasing BW before first breeding would be small and might even result in slight declines in stayability and reproductive performance. For heifers that were below average in BW, considerable beneficial effects on stayability and reproductive performance are predicted as a result of improving rearing practices to produce heavier heifers throughout the pre-breeding rearing phase.

Increased yearling weight as a proportion of 21-month weight was associated with increased milk production in dairy heifers.

Aims: To examine the relationship between liveweight (LWT) at 12 months as a proportion of LWT at 21 months of age (LWT(12/21)%) and first lactation and cumulative 3-year milk production in dairy heifers in New Zealand. Methods: Liveweight and milk production records were obtained for dairy heifers born from June to December (spring-calving season) between 2006-2007 and 2013-2014 dairy seasons; production records included first lactation (n = 140,113) and cumulative 3-year (n = 67,833) milksolids and energy-corrected milk (ECM) yields. Heifers were classified into five breed groups; Holstein-Friesian, Holstein-Friesian crossbred, Jersey, Jersey crossbred and Holstein-Friesian-Jersey crossbred. Within each breed group heifers were categorised into quintiles based on 21-month LWT. The LWT(12/21)% was calculated for each animal. Relationships between LWT(12/21)% and milk production within each breed group and LWT category were estimated using linear mixed effects models including the linear and quadratic effects of LWT(12/21)%. Results: The relationship between LWT(12/21)% and milk production was predominantly curvilinear, with lower milk production at lesser LWT(12/21)% compared with greater LWT(12/21)%. For all breed groups and most LWT categories, heifers that were 55 or 65% LWT(12/21)% produced greater ECM and milksolids yields compared with heifers that were 45% LWT(12/21)%. Holstein-Friesian, Holstein-Friesian crossbred and Holstein-Friesian-Jersey crossbred heifers that were 65% LWT(12/21)% produced greater cumulative 3-year ECM and milksolids yields compared with heifers of the same breed group that were 45% LWT(12/21)% Conclusions and clinical relevance: Heifers that were a greater proportion of their 21-month LWT at 12 months of age produced more first lactation and cumulative 3-year milk yields than heifers that were a lesser proportion of their 21-month LWT at 12 months of age. These results indicate that increased growth in early life of New Zealand dairy heifers is beneficial to future milk production.

Interaction-Induced Shubnikov-de Haas Oscillations in Optical Conductivity of Monolayer MoSe_{2}.

We report polarization-resolved resonant reflection spectroscopy of a charge-tunable atomically thin valley semiconductor hosting tightly bound excitons coupled to a dilute system of fully spin- and valley-polarized holes in the presence of a strong magnetic field. We find that exciton-hole interactions manifest themselves in hole-density dependent, Shubnikov-de Haas-like oscillations in the energy and line broadening of the excitonic resonances. These oscillations are evidenced to be precisely correlated with the occupation of Landau levels, thus demonstrating that strong interactions between the excitons and Landau-quantized itinerant carriers enable optical investigation of quantum-Hall physics in transition metal dichalcogenides.

Positive relationships between body weight of dairy heifers and their first-lactation and accumulated three-parity lactation production.

This study investigated the relationships between body weight (BW) and milk production of 140,113 New Zealand dairy heifers. Heifers were classified into 5 breed groups: Holstein-Friesian, Holstein-Friesian crossbred, Jersey, Jersey crossbred, and Holstein-Friesian-Jersey crossbred. Body weights were assessed at intervals of 3 mo from 3 to 21 mo of age and their relationships with first-lactation and accumulated milk production over the first 3 lactations (3-parity) were analyzed. We found positive curvilinear relationships between BW and milk production. The response to an increase in BW was greater for lighter heifers compared with heavier heifers, indicating possible benefits of preferentially feeding lighter heifers to attain heavier BW. Within the age range and BW range studied, an increase in BW was always associated with an increase in first-lactation energy-corrected milk (ECM) and milk solids (milk fat plus milk protein) yield for breed groups other than Holstein-Friesian. For Holstein-Friesian heifers, there was a positive relationship between BW and ECM and milk solids yields for all ages except for 3 mo of age, when no relationship existed. These results show the potential to increase first-lactation milk production of New Zealand dairy heifers by increasing heifer BW. Likewise, for 3-parity accumulated yields, the BW at which maximum ECM and milk solids yields occurred were at the heavier end of the BW range studied. The costs of rearing a heifer are incurred regardless of how long she remains in the herd. Potential bias exists from considering only cows that survived to lactate each year if particular cows had better survival than others. Therefore, the data in the current study for 3-parity production includes all heifers that were old enough to have completed 3 lactations, regardless of whether they did or not. Including the heifers that did not complete all 3 lactations describes the effect that BW of replacement heifers has on accumulated milk yields without discriminating whether the increased milk yield came from greater survival or from greater production per surviving cow. Further research on the relationships between BW and survival of heifers is required to confirm whether the heavier heifers survived longer than the lighter heifers, but could explain why the relationship between BW and 3-parity milk yields was more curvilinear than the relationship between BW and first-lactation milk production. Holstein-Friesian heifers that were 450 kg in BW at 21 mo of age were estimated to produce 168 and 509 kg more ECM than 425-kg Holstein-Friesian heifers in first-lactation and 3-parity accumulated yields, respectively. A further increase in BW at 21 mo of age, from 450 to 475 kg, was estimated to result in 157 and 409 kg more ECM in first-lactation and 3-parity accumulated yields, respectively. Consequently, for heifers that were average and below average in BW, considerable milk production benefits would occur over the first 3 lactations by improving rearing practices to result in heavier heifers throughout the precalving phase.

Teaching Ethics to Pediatric Residents: A Literature Analysis and Synthesis.

BACKGROUND: Ethics education rarely exists in pediatric resident curricula, although ethical conflicts are common in the clinical practice. Ethics education can prepare residents to successfully handle these conflicts. AIM: We searched for methods in teaching ethics to clinical and especially pediatric residents, and identified recurring barriers to ethics teaching and solutions to overcome them. DESIGN: Literature from 4 electronic databases with peer-reviewed articles was screened in 3 phases and analyzed. The literature included papers referring to applied methods or recommendations to teaching ethics to clinical residents, and on a second level focusing especially on pediatrics. An analysis and critical appraisal was conducted. RESULTS: 3 231 articles were identified. 96 papers were included. The applied learning theory, the reported teaching approaches, the barriers to teaching ethics and the provided solutions were studied and analyzed. CONCLUSIONS: We recommend case-based ethics education, including lectures, discussion, individual study; regular teaching sessions in groups, under supervision; affiliation to an ethics department, institutional and departmental support; ethics rounds and consultations not as core teaching activity; recurring problems to teaching ethics, primarily deriving from the complexity of residential duties to be addressed in advance; teaching ethics preferably in the first years of residency. We may be cautious generalizing the implementation of results on populations with different cultural backgrounds.

Ad libitum Pasture Feeding in Late Pregnancy Does Not Improve the Performance of Twin-bearing Ewes and Their Lambs.

The present study evaluated the effect of controlled ryegrass-white clover herbage availability from day 128 until day 142 of pregnancy in comparison to unrestricted availability, on the performance of twin-bearing ewes of varying body condition score (BCS; 2.0, 2.5, or 3.0) and their lambs. It was hypothesised that under conditions of controlled herbage availability, the performance of lambs born to ewes with a greater BCS would be greater than those born to ewes with a lower BCS. During the period that the nutritional regimens were imposed, the pre- and post-grazing herbage masses of the Control regimen (1,070±69 and 801±30 kg dry matter [DM]/ha) were lower than the ad libitum regimen (1,784±69 and 1,333±33 kg DM/ha; p<0.05). The average herbage masses during lactation were 1,410±31 kg DM/ha. Nutritional regimen had no effect on ewe live weight, BCS and back fat depth or on lamb live weight, indices of colostrum uptake, maximal heat production, total litter weight weaned or survival to weaning (p>0.05). The difference in ewe BCSs and back fats observed among body condition groups was maintained throughout pregnancy (p<0.05). At weaning, ewes from the BCS2.0 group had lower BCS and live weight (2.4±0.2, 74.3±2.6 kg) than both the BCS2.5 (2.6±0.2, 78.6±2.4 kg) and BCS3.0 ewes (2.7±0.2, 79.0±2.6 kg; p<0.05), which did not differ (p>0.05). Ewe BCS group had no effect on lamb live weight at birth or weaning or on maximal heat production (p>0.05). Serum gamma glutamyl transferase concentrations of lambs born to BCS3.0 ewes were higher within 36 hours of birth than lambs born to BCS2.0 ewes and BCS2.5 ewes (51.8±1.9 vs 46.5±1.9 and 45.6±1.9 IU/mL, respectively [p<0.05]). There was, however, no effect of ewe body condition on lamb plasma glucose concentration (p>0.05). Lamb survival was the only lamb parameter that showed an interaction between ewe nutritional regimen and ewe BCS whereby survival of lambs born to BCS2.5 and BCS3.0 ewes differed but only within the Control nutritional regimen ewes (p<0.05). These results indicate farmers can provide twin-bearing ewes with pre- and post-grazing ryegrass-white clover herbage covers of approximately 1,100 and 800 kg DM/ha in late pregnancy, provided that herbage covers are 1400 in lactation, without affecting lamb performance to weaning. The present results also indicate that under these grazing conditions, there is little difference in ewe performance within the BCS range of 2.0 to 3.0 and therefore they do not need to be managed separately.

Penetration, photo-reactivity and photoprotective properties of nanosized ZnO.

The oxidizing capacity and skin penetration of a commercial nanosized ZnO, Nanosun™ (Micronisers-Australia), were evaluated in vitro using porcine skin. Nanosun™ was initially characterized regarding its photo-reactivity and size distribution. An assay using methylene blue was performed to confirm the Nanosun™ photo-reactivity by exposing the labile molecule to UVA irradiation in the presence and absence of the nanosized ZnO. The nanosized ZnO was photo-reactive, reducing the methylene blue concentration to 7% while its concentration remained constant in the control formulation (without ZnO). The product label states that the average particle size is 30 nm. X-ray diffraction, nitrogen sorption and UV-spectrophotometry confirmed the presence of nanometric particles of approximately 30 nm. On the other hand, laser diffractometry showed micrometric particles in the size distribution profile. These analyses indicated that the nanoparticles are arranged as agglomerates and aggregates of micrometric proportions ranging from 0.6 to 60 µm. The skin lipid peroxidation was determined by the formation of thiobarbituric acid reactive species (TBARS) and quantified by UV-spectrophotometry. When exposed to UVA radiation the nanosized ZnO applied porcine skin showed a lower production of TBARS (7.2 ± 1.5 nmol g(-1)) than the controls, the MCT applied porcine skin (18.4 ± 2.8 nmol g(-1)) and the blank porcine skin (14.0 ± 2.0 nmol g(-1)). The penetration of ZnO nanoparticles was studied by scanning electron microscopy and energy dispersive X-ray spectroscopy. The tested ZnO particles did not penetrate into viable layers of the intact porcine skin. The particles tend to accumulate on the skin folds and in these regions they may penetrate into the horny layer.

Insulin resistance in divergent strains of Holstein-Friesian dairy cows offered fresh pasture and increasing amounts of concentrate in early lactation.

The objective of this study was to determine whether the physiological response to an intravenous glucose challenge would be affected by genetic strain or concentrate supplementation in grazing Holstein-Friesian cows in early lactation. North American (NA; n = 30) or New Zealand (NZ; n = 30) cows were randomly allocated to 1 of 3 feeding treatments. All cows were offered a generous pasture allowance, and 4 of the 6 groups received either 3 or 6 kg of dry matter (DM)/cow per day of concentrates. During wk 5 of lactation, all cows underwent an intravenous glucose challenge. Cows of NA origin produced more milk than NZ cows, but there was no significant strain effect on milk fat or protein yield. Milk yield and the yield of individual components increased with increasing level of concentrate eaten, but there were no significant strain x diet interactions. During wk 1 to 6, mean body weight and body condition score decreased in all treatments. Average body weight was greater in NA cows, but body condition score was greater for NZ cows. There was no strain or diet effect on the length of the postpartum anovulatory interval, with cows ovulating before 40 d postpartum on average. Glucose fractional turnover rate was greater in NZ cows compared with those of NA origin and in all cows receiving 6 kg of DM concentrates, indicating a less severe insulin resistance in those treatments. Consistent with this, the time taken to dispose of half the peak glucose concentration was less when 6 kg of DM concentrate was fed, and tended to be less in NZ than in NA cows. There was no effect of genetic strain on glucose area under the curve (AUC) at 60 or 120 min, but AUC at both time points was less in cows receiving 6 kg of DM concentrates per day. Neither genetic strain nor nutrition affected basal or peak insulin concentrations, insulin increment, or insulin AUC, and there were no strain x diet interactions for any of the glucose challenge response variables measured. In conclusion, differences in milk production between NA and NZ cows in early lactation can, at least in part, be explained by the greater degree of insulin resistance in the NA cows, and this insulin resistance can be overcome by supplementing grazing cows with 6 kg of DM concentrates.

[Public health genomics. The future is built today!]. / Public Health Genomics. Die Zukunft wird heute gestaltet!

The task of public health genomics (PHG) has become a challenge for all healthcare systems having major implications for future research and policy strategies. The various stakeholders in public health play a key role in translating the implications of genomics such as deriving from systems biology, epigenomics, integrative genomics or genome-environmental interactions. Recent advances in systems biology indicate that specific cellular functions are infrequently carried out by single genes, but rather by groups of cellular components. This network-based research is already starting to change nosology as well as to challenge population-based genetic screening or epidemiological methods like HTA. This knowledge will not only enable clinical interventions but also health promotion messages and disease prevention programs to be targeted at susceptible individuals as well as subgroups of the population (personalized healthcare). So far there has been no systematic integration of genome-based knowledge and technologies into public health research, policy, and practice. Thus, the public health agenda demands a vision that reaches beyond the research horizon to arrive at application and health impact of these innovations. The Public Health Genomics European Network (PHGEN) aims to fulfill this task in Europe.

Cryptococcal pneumonia in African miners at autopsy.

SETTING: Deceased miners from South Africa whose cardiorespiratory organs were submitted for autopsy for compensation for occupational lung diseases from 1996 to 2000. OBJECTIVES: To 1) calculate the prevalence of cryptococcal pneumonia in 8421 autopsied miners, a population with a high prevalence of human immunodeficiency virus (HIV) infection; 2) document the association of cryptococcal pneumonia with other pulmonary infection; 3) document the association of cryptococcal pneumonia with a clinical diagnosis of cryptococcal meningitis; and 4) determine the accuracy of the clinical diagnosis of cryptococcal pneumonia. DESIGN: Case series of 589 black miners with histological evidence of cryptococcal pneumonia at autopsy, defined as the presence of cryptococcal organisms in the lung parenchyma, identified by staining of the mucinous capsule. RESULTS: The incidence of cryptococcal pneumonia at autopsy was 7%. Ninety-seven of the 589 cases (16.5%) had a concomitant respiratory infection, most commonly Pneumocystis jirovecii pneumonia (51.5%), followed by mycobacterial infection (42.3%). In life, cryptococcal meningitis was diagnosed in 46.9% and cryptococcal pneumonia in only 2.7%. CONCLUSION: Although tuberculosis remains the most common HIV-associated respiratory disease in Africa, it is important to consider the diagnosis of cryptococcal pneumonia in acquired immune-deficiency syndrome (AIDS) patients, and to bear in mind the possibility of dual pathology.

Pneumocystis jirovecii pneumonia in African miners at autopsy.

SETTING: Deceased miners from South Africa whose cardio-respiratory organs were submitted for autopsy for compensation for occupational lung diseases from 1996 to 2000. OBJECTIVES: 1) To document the incidence of Pneumocystis jirovecii pneumonia (PJP) in autopsied miners; 2) to compare the incidence of PJP over a 5-year period; 3) to record the incidence of concomitant lower respiratory tract infection in a group of PJP-infected deceased miners coming to autopsy from 1996 to 2000; and 4) to describe the accuracy of the in-life diagnosis of PJP in this group. DESIGN: Case series of 328 deceased Black miners with histological evidence of PJP at autopsy. RESULTS: Of the 328 miners with PJP at autopsy, 107 (32.6%) had a concomitant respiratory infection, the most common being cryptococcal pneumonia (46.7%), followed by bacterial pneumonia (34.6%) and pulmonary tuberculosis (13.1%). Overall, Pneumocystis pneumonia was unsuspected prior to death in 89% of cases; however, diagnostic accuracy in life improved from 7% in 1996 to 21% in 2000. CONCLUSION: The high rate of undiagnosed PJP is cause for concern. Clinicians should have a heightened awareness for PJP in Africa, particularly as the disease is treatable at low cost and effective prophylaxis is available.

Practical aspects of shielded gradient-coil design for localised in vivo NMR spectroscopy and small-scale imaging.

For a number of NMR applications the availability of screened gradients is crucial to minimize the effect of eddy currents on the NMR signal. In this paper we review two types of shielded gradient design: the target field and minimum inductance methods. The two designs are compared and construction details are presented. A novel coil design constructed with a double-sided primary and a single layered screen is outlined. Experimental results for both target field and minimum inductance coils are presented and compared.

Role of the waxy skin layer in moisture loss during dehydration of prunes.

Permeability studies of water through the skin and flesh of d'Agen plums have been carried out by radiotracer and PGSE NMR techniques as a function of moisture content. The results have shown that the diffusion coefficient of water through the skin layer increases as the fruit is dried at 70 degrees C or above. By contrast, the water diffusion through the fruit becomes more hindered as moisture is lost and structural collapse of the cell layers takes place. Values for diffusion coefficients of water at 21 degrees C through the fruit of 1 x 10(-)(9) m(2) s(-)(1) for fresh plums and 2.0 x 10(-)(10) m(2) s(-)(1) for fruit dried to 50% moisture content (wet basis) were found. Structural studies using scanning electron microscopy techniques were also performed. These showed that drying induces marked changes to the waxy skin layer of the fruit as well as the fruit flesh. These results are discussed in terms of the important role that the plum skin has in modulating the moisture loss process during dehydration, particularly at early stages of drying.

Some biophysical applications of motional contrast in n.m.r. microscopy.

The principal advantage of the n.m.r. imaging method lies in the specific contrasts which are available. In this work we describe the use of velocity and diffusion contrast methods in biophysical applications and at microscopic spatial resolution. In the first example, involving water-protein interactions, the relationship between water self-diffusion and water concentration, as measured using pulsed gradient spin echo n.m.r., is shown. It is demonstrated that this relationship can be used to provide a water concentration image. The result is compared with the conventional proton density and transverse relaxation maps. The next example concerns the use of dynamic n.m.r. microscopy to obtain water diffusion and velocity maps for wheat grain in vivo. Finally we suggest how the method may be used in the study of polymer-water interactions in an unusual adjunct to conventional polymer self-diffusion studies.

Equity in public health: an epigenetic perspective.

Evidence emerging from the study of epigenetics and epigenomics challenges notions of health by enhancing understanding of disease etiologies and improving awareness of new health risks. New paradigms arising from epigenetic and epigenomic research present challenging cases through which to debate theories of justice in health because they expand the concept of health and, controversially, place value on what was previously assumed to be 'healthy' individual variance. Discoveries of the dynamic nature of the epigenome and its variable sensitivity towards change in numerous phenomena add further complexity to the assessment of health inequalities. Such evidence can cast doubt on perceptions of justice in health, which in turn raises questions over the suitability of actions taken in pursuit of equity. This article discusses how recent developments in epigenetics and epigenomics may impact upon assessments of equity in health. A review of literature discussing possible health risks associated with acquired yet heritable epigenetic variance is used to highlight the diversity of possible pathways through which health may be influenced. From this context, the consideration of health risk with respect to epigenetics, it is argued, demands a more inclusive concept of health when used in discussions of inequities.

Long-term alteration of follicular steroid concentrations in relation to subclinical endometritis in postpartum dairy cows.

The focus of this study was to investigate the effect of subclinical endometritis (scEndo) on ovarian follicular steroid concentrations in early postpartum pasture-fed dairy cows. Mixed-age lactating dairy cows (n = 169) were examined to ascertain uterine health status on d 21 postpartum (±3 d). From this herd, a cohort of scEndo and uninfected cows (n = 47) were selected using uterine cytology to determine scEndo. To ensure cows with scEndo were selected for the study, a conservative threshold [>18% polymorphonuclear (PMN) cells among uterine nucleated cells] was chosen as a selection threshold. Ovarian follicular dynamics were assessed by ultrasonography on d 21, 42, and 63 postpartum. On the latter 2 d, all follicles >4 mm in diameter were ablated, and 4 d later, the largest (F1) and second largest (F2) follicles were measured and their follicular fluid aspirated. Hematological variables and plasma metabolites were measured also on these days to further characterize scEndo cows. On d 21, the prevalence of scEndo was approximately 9% in this herd; by d 42 infections had self-resolved in the majority (81%) of those cows classified as having scEndo on d 21. The scEndo cows had a delayed return to cyclicity; however, no effect was evident on ovarian follicle size or growth rate. Weeks after scEndo had self-resolved and cyclicity was restored, decreased (P = 0.07) testosterone and increased (P = 0.07) cortisol concentrations were evident in F1 follicles of scEndo compared with uninfected cows. Progesterone concentrations of F1 increased (P < 0.05) in 11- to 16-mm diameter follicles of scEndo cows, whereas estradiol, androstendione, and dehydroepiandrosterone concentrations were decreased (P < 0.05) in F1 8- to 10-mm diameter follicles of scEndo cows. These 3 steroids also differed (P < 0.05) between F1 follicle size categories of scEndo but not uninfected cows. On d 21, mean plasma albumin concentration was decreased (P = 0.02) in scEndo cows. In summary, early postpartum scEndo had surprisingly long-term influences on the steroid concentrations of ovarian follicles long after infections had self-resolved. This is likely to affect oocyte quality and may partially explain the reduced conception rates and longer interval between calving and conception that are often associated with scEndo, although more detailed investigations are required to substantiate this theory.