Magnetic properties of γ-Fe2O3 nanoparticles in a porous SiO2 shell for drug delivery.

A method is presented for synthesizing core-shell nanoparticles with a magnetic core and a porous shell suitable for drug delivery and other medical applications. The core contains multiple γ-Fe2O3 nanoparticles (∼15 nm) enclosed in a SiO2 (∼100-200 nm) matrix using either methyl (denoted TMOS-γ-Fe2O3) or ethyl (TEOS-γ-Fe2O3) template groups. Low-temperature Mössbauer spectroscopy showed that the magnetic nanoparticles have the maghemite structure, γ-Fe2O3, with all the vacancies in the octahedral sites. Saturation magnetization measurements revealed that the density of γ-Fe2O3 was greater in the TMOS-γ-Fe2O3 nanoparticles than TEOS-γ-Fe2O3 nanoparticles, presumably because of the smaller methyl group. Magnetization measurements showed that the blocking temperature is around room temperature for the TMOS-γ-Fe2O3 and around 250 K for the TEOS-γ-Fe2O3. Three dimensional topography analysis shows clearly that the magnetic nanoparticles are not only at the surface but have penetrated deep in the silica to form the core-shell structure.

Size-dependent magnetic properties of γ-Fe2O3 nanocrystallites.

A route for synthesizing monodisperse magnetic nanocrystallites of maghemite, [Formula: see text]-Fe2O3, with various sizes has been revisited. A systematic investigation of three [Formula: see text]-Fe2O3 nanocrystalline samples by different techniques has been performed to characterize their size-dependent magnetic properties. Zero-field-cooled and field-cooled magnetization measurements reveal that the superparamagnetic blocking temperatures are around 230 K, 170 K, and 50 K for the 15.0 nm, 11.8 nm, and 6.1 nm nanocrystallites, respectively. Low-temperature Mössbauer spectra show that all three nanocrystallites have the maghemite structure with all the vacancies in the B-sites. Furthermore, detailed analysis shows that there are more vacancies on the B-sites for the 6.1 nm nanocrystallites compared to 0.33 for the bulk maghemite.

Biomarkers of diabetes risk in the National Diet and Nutrition Survey rolling programme (2008-2011).

This study describes the distribution of glycosylated haemoglobin (Hb(A1c)) and glucose concentrations in the combined year 1 (2008-2009), year 2 (2009-2010) and year 3 (2010-2011) of the National Diet and Nutrition Survey (NDNS) rolling programme. The NDNS rolling programme is a nationally representative survey of food consumption, nutrient intakes and nutritional status of people aged 1.5 years and over living in England, Wales, Scotland and Northern Ireland. The study population comprised survey members who completed three or four days of dietary recording and who provided a blood sample. After excluding survey members with self-reported diabetes (n=25), there were 1016 results for HbA1c and 942 for glucose (not the same individuals in each case). Around 5.4% of men and 1.7% of women aged 19-64 years, and 5.1% of men and 5.9% of women aged ≥65 years had impaired fasting glucose (glucose concentrations 6.1-6.9 mmol/L). Over 20% of men aged ≥65 years had fasting glucose concentrations above the clinical cut-off for diabetes (≥7 mmol/L) compared to 2.1% of women of similar age (p=0.007). Similarly, 16.4% of men had Hb(A1c) concentrations ≥6.5%, compared to 1.5% of women (p=0.003). Children and teenagers had fasting glucose and Hb(A1c) values largely within the normal range. To conclude, this is the first study to provide data on the distribution of HbA1c and glucose concentrations in a nationally representative sample of the British population. The high prevalence of men aged ≥65 years with Hb(A1c) and glucose concentrations above the clinical cut-off of diabetes warrants further attention.

The psychiatric disease risk factors DISC1 and TNIK interact to regulate synapse composition and function.

Disrupted in schizophrenia 1 (DISC1), a genetic risk factor for multiple serious psychiatric diseases including schizophrenia, bipolar disorder and autism, is a key regulator of multiple neuronal functions linked to both normal development and disease processes. As these diseases are thought to share a common deficit in synaptic function and architecture, we have analyzed the role of DISC1 using an approach that focuses on understanding the protein-protein interactions of DISC1 specifically at synapses. We identify the Traf2 and Nck-interacting kinase (TNIK), an emerging risk factor itself for disease, as a key synaptic partner for DISC1, and provide evidence that the DISC1-TNIK interaction regulates synaptic composition and activity by stabilizing the levels of key postsynaptic density proteins. Understanding the novel DISC1-TNIK interaction is likely to provide insights into the etiology and underlying synaptic deficits found in major psychiatric diseases.

How lay people respond to messages about genetics, health, and race.

There is a growing movement in medical genetics to develop, implement, and promote a model of race-based medicine. Although race-based medicine may become a widely disseminated standard of care, messages that advocate race-based selection for diagnosing, screening and prescribing drugs may exacerbate health disparities. These messages are present in clinical genetic counseling sessions, mass media, and everyday talk. Messages promoting linkages among genes, race, and health and messages emphasizing genetic causation may promote both general racism and genetically based racism. This mini-review examines research in three areas: studies that address the effects of these messages about genetics on levels of genetic determinism and genetic discrimination; studies that address the effects of these messages on attitudes about race; and, studies of the impacts of race-specific genetic messages on recipients. Following an integration of this research, this mini-review suggests that the current literature appears fragmented because of methodological and measurement issues and offers strategies for future research. Finally, the authors offer a path model to help organize future research examining the effects of messages about genetics on socioculturally based racism, genetically based racism, and unaccounted for racism. Research in this area is needed to understand and mitigate the negative attitudinal effects of messages that link genes, race, and health and/or emphasize genetic causation.

Exploration of the impact of messages about genes and race on lay attitudes.

The effect of messages about genetics on lay audiences was assessed through an experimental study that exposed participants (n = 96) to a Public Service Announcement about race, genes, and heart disease. Participants who received a message that specified either 'Whites' or 'Blacks' as the subject of the message demonstrated elevated levels of racism, genetic basis for racism, and one dimension of genetic discrimination as compared to those receiving a version of the message with no race specification or in a no-message control condition. The presentation of such messages to the public is not recommended until additional research clarifies this finding and perhaps describes mitigating vocabularies or approaches.

Linking atmospheric circulation to daily rainfall patterns across the Murrumbidgee River Basin.

The hydrological cycle in Australia covers an extraordinary range of climatic and hydrologic regimes. It is now widely accepted that Australian hydrology is significantly different from all other regions and continents with the partial exception of southern Africa. Rainfall variability is very high in almost all regions with respect to amount and the lengths of wet and dry spells. These factors are keys to the behaviour and health of Australian aquatic ecosystems and water resources. Thus assessment of how rainfall may change under a potential future climate is critical. For a case study of the Murrumbidgee River Basin (MRB), a statistical downscaling model that links broad scale atmospheric circulation to multi-site, daily precipitation is assessed using observed data. This model can be driven with climate model simulations to produce rainfall scenarios at the scale required by impacts models. These can then be used in probabilistic risk assessments of climate change impacts on river health. These issues will be discussed in the context of assessing the potential impacts of precipitation changes due to projected climate change on river health.

Subtalar and knee joint interaction during running at various stride lengths.

AIM: It has been suggested that during running proper coordination between subtalar pronation/supination and knee flexion/extension via tibial rotation is important to attenuate ground reaction impact forces (GRIF). Lack of coordination over time may produce a wide range of injuries. It was hypothesized that increasing stride length would result in higher GRIF. It was also hypothesized that alterations in stride length would result in changes of the subtalar/knee coordination. METHODS: Six subjects ran under 3 different stride lengths (normal stride, understride and overstride) at their self-selected pace. Sagittal, rear view kinematic data and GRIF kinetic data were collected. The subtalar/knee coordination was evaluated via timing and relative velocity measures. Repeated measures ANOVA were performed on these measures with a Tukey post-hoc analysis conducted where appropriate (p<0.01). RESULTS: Increased stride length produced significant increases in GRIF and significantly augmented the differences between rearfoot and knee angular velocities. A change in the rearfoot angle curve from a unimodal (1 minimum) to a bimodal (2 minimums) parabolic configuration was also observed. The appearance of the additional minimum was attributed to the increased impact with the ground. CONCLUSION: The results indicated that increases in GRIF via changes in stride length could disrupt the coordination between subtalar and knee joint actions.

Characteristics of shock attenuation during fatigued running.

The aim of this study was to examine shock attenuation before and after completing a maximal effort graded exercise test while running on a treadmill. Ten individuals ran before and after a maximal graded exercise test with running speed controlled between conditions. Transfer functions were calculated using surface-mounted accelerometers to represent shock attenuation. An accelerometer was mounted on the distal aspect of the tibia and another on the anterior aspect of the forehead. Ten strides were analysed in each condition for all participants. Paired t-tests were used to compare each dependent variable (shock attenuation, stride length, rate of oxygen consumption) between conditions (running before vs after the exercise test). Oxygen consumption was 16% greater when running after the graded exercise test (47.9 +/- 5.0 ml x kg(-1) x min(-1); mean+/-s) than when running before it (41.1 +/- 2.7 ml x kg(-1) x min(-1)) (P < 0.05). Stride length was similar during running before (2.71 +/- 0.15 m) and after (2.75 +/- 0.17 m) the graded exercise test (P > 0.05). Shock attenuation was, on average, 12% lower during running after (-9.8 +/- 2.6 dB) than before (-11.3 +/- 2.7 dB) the graded exercise test (P < 0.05). We conclude that less shock was attenuated during fatigued than non-fatigued running and that only subtle changes in stride length were made while fatigued.

Attachment for infants in foster care: the role of caregiver state of mind.

The concordance between foster mothers' attachment state of mind and foster infants' attachment quality was examined for 50 foster mother-infant dyads. Babies had been placed into the care of their foster mothers between birth and 20 months of age. Attachment quality was assessed between 12 and 24 months of age, at least 3 months after the infants' placement into foster care. The two-way correspondence between maternal state of mind and infant attachment quality was 72%, kappa = .43, similar to the level seen among biologically intact mother-infant dyads. Contrary to expectations, age at placement was not related to attachment quality. Rather, concordance between maternal state of mind and infant attachment was seen for relatively late-placed babies, as well as early placed babies. These findings have two major implications. First, following a disruption in care during the first year and a half of life, babies appear capable of organizing their behavior around the availability of new caregivers. Second, these data argue for a nongenetic mechanism for the intergenerational transmission of attachment.

Conditional deletion of brain-derived neurotrophic factor in the postnatal brain leads to obesity and hyperactivity.

Brain-derived neurotrophic factor has been associated previously with the regulation of food intake. To help elucidate the role of this neurotrophin in weight regulation, we have generated conditional mutants in which brain-derived neurotrophic factor has been eliminated from the brain after birth through the use of the cre-loxP recombination system. Brain-derived neurotrophic factor conditional mutants were hyperactive after exposure to stressors and had higher levels of anxiety when evaluated in the light/dark exploration test. They also had mature onset obesity characterized by a dramatic 80-150% increase in body weight, increased linear growth, and elevated serum levels of leptin, insulin, glucose, and cholesterol. In addition, the mutants had an abnormal starvation response and elevated basal levels of POMC, an anorexigenic factor and the precursor for alpha-MSH. Our results demonstrate that brain derived neurotrophic factor has an essential maintenance function in the regulation of anxiety-related behavior and in food intake through central mediators in both the basal and fasted state.

Neurotrophin-3 modulates noradrenergic neuron function and opiate withdrawal.

Somatic symptoms and aversion of opiate withdrawal, regulated by noradrenergic signaling, were attenuated in mice with a CNS-wide conditional ablation of neurotrophin-3. This occurred in conjunction with altered cAMP-mediated excitation and reduced upregulation of tyrosine hydroxylase in A6 (locus coeruleus) without loss of neurons. Transgene-derived NT-3 expressed by noradrenergic neurons of conditional mutants restored opiate withdrawal symptoms. Endogenous NT-3 expression, strikingly absent in noradrenergic neurons of postnatal and adult brain, is present in afferent sources of the dorsal medulla and is upregulated after chronic morphine exposure in noradrenergic projection areas of the ventral forebrain. NT-3 expressed by non-catecholaminergic neurons may modulate opiate withdrawal and noradrenergic signalling.

Correlation of scores for the Comprehensive Osteopathic Medical Licensing Examination with osteopathic medical school grades.

The authors evaluated construct validity of scores for the Comprehensive Osteopathic Medical Licensing Examination (COMLEX-USA), the examination used to evaluate osteopathic physicians for licensure. They computed correlations between students' grades in the first 2 years of osteopathic medical school and their scores on the COMPLEX-USA Level 1 (N = 187) and Level 2 (N = 86), as well as correlations between third- and fourth-year clerkship grades and the COMLEX-USA Level 2. Correlations of Level 1 scores with grades for years one, two, and the first 2 years combined were .74, .80, and .81, respectively; for Level 2, correlations were .59, .70, and .71. Correlation between clerkship grades and scores for the COMLEX-USA Level 2 was .26. The strong correlation between COMLEX-USA results and grades for the didactic curriculum in the first 2 years of medical school provides evidence for the construct validity of scores for the COMLEX-USA Levels 1 and 2.

Treatment of spent filter backwash water using dissolved air flotation.

There is increasing interest in treating recovered spent filter backwash water in the drinking water industry. In the USA the Filter Backwash Recycling Rule will come into effect in the near future. The purpose of the Rule is to prevent the concentrated pathogenic agents, potentially in the filter backwash water, from being returned to the head of the water treatment works without some form of treatment or dilution. By treating this flow both public health and financial liability can be better managed by the operating utility. Dissolved Air Flotation (DAF) was investigated as a possible technology alternative to simple or advanced sedimentation techniques. This application is not widespread but sits somewhere in between the two normal applications of DAF as a high solids sludge thickener and a low turbidity clarification system. Given this a pilot plant program, supported by jar testing, was undertaken to determine the process capability and the design parameters for this application. DAF proved to be very suitable for backwash water recovery. DAF effluent turbidities of < 1.0 NTU could be easily obtained, when raw water turbidities were in excess of 50 NTU. Chemical requirements were low with only a single low dose of polymer required to bind the floc particles to form a solids matrix suitable for flotation. Flocculation contact times ranged from 0-10 minutes depending on the nature of the raw water. Recycle rates as low as 5% performed satisfactorily with no significant improvement when increased to 20%. Sludge solids of 3.5-9.6% dry solids were found and very low volumes of sludge, < 0.1% of the incoming flow make the DAF solids handling system very compact.

A smoking cessation helpline for Louisiana smokers--and a new resource for medical professionals.

The Louisiana Office of Public Health Tobacco Control and Prevention Program received funding from the Louisiana State Legislature to expand smoking cessation activities in the state. The Tobacco Control Program conducted a review of other states' current smoking cessation programs, cessation programs in Louisiana, and epidemiological evidence in planning the expansion of the Louisiana tobacco smoking cessation program. As a result, a smoking cessation helpline has been developed. Medical clinicians in Louisiana have a powerful impact on their patients' smoking cessation success. Simple discussion by physicians with their patients about how to quit smoking has improved successful quitting rates by 40%. Approximately 70% of smokers visit a physician each year and 60% visit a dentist, so there is clearly an opportunity to reach many persons at risk. The telephone smoking cessation helpline at 1-800-LUNG-USA is a tool for clinicians to use when advising their patients on ways to improve their health and prevent disease.

A dynamical systems investigation of lower extremity coordination during running over obstacles.

OBJECTIVE: To investigate intralimb coordination during running over a level surface and over obstacles of three different heights. DESIGN: The phasing relationships between the foot and leg motions in the frontal plane, and the shank and thigh motions in the sagittal plane were used to compare patterns of coordination. BACKGROUND: The coordinated actions of lower extremity segments are necessary to absorb the impact forces generated during running. The behavioral patterns of these segments can be studied under changing task demands using analysis techniques from the Dynamical Systems Theory. METHODS: Ten subjects ran at their self-selected pace under four conditions: over a level surface and over obstacles of different heights (5%, 10%, 15% of their standing height). A force platform was used to record impact forces during landing after obstacle clearance, while kinematics were collected using a two-camera system. RESULTS: The increases in obstacle height resulted in significant changes in impact forces (34% increase between the two extreme conditions) and more in-phase relationships between the segments during early stance. No changes were observed in the variability of the phasing relationships. CONCLUSIONS: The coordination changes observed might be compensatory strategies aimed to reduce forces and potential injury. However, since the impact forces still increased significantly, it is also possible that the observed changes might be at-risk movement patterns predisposing runners to injury.

Inpatient rehabilitation after stroke: a comparison of lengths of stay and outcomes in the Veterans Affairs and non-Veterans Affairs health care system.

BACKGROUND: Patients have longer lengths of hospital stay (LOS) in VA medical centers than in the general health care system. OBJECTIVE: The objective of this study was to determine whether resource use and outcome differences between VA and non-VA inpatient rehabilitation facilities remain after controlling for patient and medical care delivery differences. DESIGN: This analysis involved 60 VA inpatient rehabilitation units and 467 non-VA rehabilitation hospitals and units. Multivariate adjusted resource use and patient outcome differences were compared across setting within patients grouped by severity of disability at admission through assignment to the Function Related Group (FRG) patient classification system. SUBJECTS: The study included 55,438 stroke patients. MEASURES: Study measures were LOS, functional status at discharge, and community discharge. RESULTS: The VA serves a higher proportion of patients who are single, separated, or divorced; are unemployed or retired as a result of disability, and are not white (P < 0.0001). These traits tended to be associated with longer LOS, lower functional outcomes, and reduced rates of community discharge. After adjusting for these and other differences, depending on FRG, average LOS remained from 30% to 200% longer in the VA centers (P < 0.05); average functional outcomes were significantly higher in 8 and lower in 2 FRGs (P < 0.05); and community discharge rates were lower in 12 FRGs (P < 0.05). CONCLUSIONS: While certain variables accounted for some of the observed differences in resource use and outcomes, differences remained after adjustment. Fewer incentives for cost containment and less support in patients' home environments may be among the most important unmeasured determinants of VA differences.

DNA hypomethylation perturbs the function and survival of CNS neurons in postnatal animals.

DNA methyltransferase I (Dnmt1), the maintenance enzyme for DNA cytosine methylation, is expressed at high levels in the CNS during embryogenesis and after birth. Because embryos deficient for Dnmt1 die at gastrulation, the role of Dnmt1 in the development and function of the nervous system could not be studied by using this mutation. We therefore used the cre/loxP system to produce conditional mutants that lack Dnmt1 in neuroblasts of embryonic day 12 embryos or in postmitotic neurons of the postnatal animal. Conditional deletion of the Dnmt1 gene resulted in rapid depletion of Dnmt1 proteins, indicating that the enzyme in postmitotic neurons turns over quickly. Dnmt1 deficiency in postmitotic neurons neither affected levels of global DNA methylation nor influenced cell survival during postnatal life. In contrast, Dnmt1 deficiency in mitotic CNS precursor cells resulted in DNA hypomethylation in daughter cells. Whereas mutant embryos carrying 95% hypomethylated cells in the brain died immediately after birth because of respiratory distress, mosaic animals with 30% hypomethylated CNS cells were viable into adulthood. However, these mutant cells were eliminated quickly from the brain within 3 weeks of postnatal life. Thus, hypomethylated CNS neurons were impaired functionally and were selected against at postnatal stages.

Effects of injury proneness and task difficulty on joint kinetic variability.

PURPOSE: The purpose was to investigate the effects of lower extremity overuse injury proneness and landing height on the variability of selected joint moment characteristics. METHODS: Ten subjects from each of two groups (healthy and injury prone) performed 10 landings from a platform (heights: 50, 100, and 200% of maximum vertical jump). Force platform (1000 Hz) and video (200 Hz) information were collected and used to compute ankle, knee, and hip joint moment values during impact (0-100 ms post contact). Moment peak, time to peak, and impulse values were used to determine variability across 10 trials for each subject and height. MANOVAs and univariate follow-up tests were used to assess variability differences between groups and among heights. RESULTS: Results revealed ankle moment variability differences (P < or = 0.05; Tukey) between groups for peak and time to peak variables at the 100% and 50% heights, respectively. The injury-prone group exhibited greater variability for the peak variable, whereas the healthy group showed greater variability for the temporal variable. Groups also differed on the impulse variables (P < or = 0.02; MANOVA), but follow-up tests failed to determine specific joints or directions of differences. Both groups exhibited tendencies for greater variability (P < or = 0.05; Tukey) with increases in height up to 100% MVJ and decreases in variability with further height increases. CONCLUSIONS: Results suggest that groups differed in joint moment variability, possibly indicating a relationship between variability and overuse injuries, although the variables and directions of differences were inconsistent. For some variables, variability increased and then decreased with height increases for both groups, suggesting a range of heights within which the neuromuscular system adapted.