Longitudinal Impacts of Precision Greenness on Alzheimer's Disease.

BACKGROUND: The potential for greenness as a novel protective factor for Alzheimer's disease (AD) requires further exploration. OBJECTIVES: This study assesses prospectively and longitudinally the association between precision greenness - greenness measured at the micro-environmental level, defined as the Census block - and AD incidence. DESIGN: Older adults living in consistently high greenness Census blocks across 2011 and 2016 were compared to those living in consistently low greenness blocks on AD incidence during 2012-2016. SETTING: Miami-Dade County, Florida, USA. PARTICIPANTS: 230,738 U.S. Medicare beneficiaries. MEASUREMENTS: U.S. Centers for Medicare and Medicaid Services Chronic Condition Algorithm for AD based on ICD-9 codes, Normalized Difference Vegetation Index, age, sex, race/ethnicity, neighborhood income, and walkability. RESULTS: Older adults living in the consistently high greenness tertile, compared to those in the consistently low greenness tertile, had 16% lower odds of AD incidence (OR=0.84, 95% CI: 0.76-0.94, p=0.0014), adjusting for age, sex, race/ethnicity, and neighborhood income. Age, neighborhood income and walkability moderated greenness' relationship to odds of AD incidence, such that younger ages (65-74), lower-income, and non-car dependent neighborhoods may benefit most from high greenness. CONCLUSIONS: High greenness, compared to low greenness, is associated with lower 5-year AD incidence. Residents who are younger and/or who reside in lower-income, walkable neighborhoods may benefit the most from high greenness. These findings suggest that consistently high greenness at the Census block-level, may be associated with reduced odds of AD incidence at a population level.

Bartonella diversity and zoonotic potential in indigenous Tete Veld rats (Aethomys ineptus) from South Africa.

Bartonellosis is a vector-borne disease that is often misdiagnosed due to a broad range of clinical symptoms, compounded by a lack of awareness regarding the prevalence, diversity and public health impacts of regional strains. Despite recent PCR-based confirmation of Bartonella in 9.7% of non-malarial, acute febrile patients in South Africa, data regarding reservoirs of infection are limited. As the majority of Bartonella species described to date are associated with rodent species globally, including zoonotic species such as B. elizabethae, and as rodent biodiversity is high in southern Africa, we evaluated Bartonella in the Tete Veld rat (Aethomys ineptus), a highly adaptable murid rodent that thrives in both natural and commensal settings. These rodents are infested with a broad range of ectoparasite species, and often occur in sympatry with Micaelamys namaquensis, an indigenous rodent previously shown to host B. elizabethae. DNA extracts from heart samples of 75 A. ineptus trapped over an eight-month period, from the Roodeplaat Nature Reserve (RNR), were evaluated using a multi-locus sequence analysis (MLSA) approach. Nucleotide sequencing and phylogenetic analyses of individual (gltA, ribC, rpoB and nuoG) and concatenated gene datasets confirmed the presence of three discrete Bartonella lineages (I-III). Lineages I and II, are genetically distinct from all currently recognised Bartonella species but cluster with strains present in other indigenous rodents from South and East Africa, whereas lineage III contained B. elizabethae, a zoonotic species associated with Rattus species globally. Records confirming R. tanezumi presence in this nature reserve, which is situated in close proximity to Pretoria, the administrative capital of South Africa, suggests the likelihood of spill-over from invasive to indigenous species. These results together with the high levels of infection (86.7%) and co-infection (33.8%), indicate that A. ineptus is a natural reservoir for multiple Bartonella species in South Africa, including one with zoonotic potential.

Molecular assessment of Bartonella in Gerbillus nanus from Saudi Arabia reveals high levels of prevalence, diversity and co-infection.

Bartonellae bacteria are associated with several re-emerging human diseases. These vector-borne pathogens have a global distribution, yet data on Bartonella prevalence and diversity in the Arabian Peninsula are limited. In this study we assessed the Bartonella infection status of the Baluchistan gerbil (Gerbillus nanus), a species associated with pastoral communities throughout the Middle East region, using a multi-gene PCR screening approach. The results demonstrated that 94 (68.1%) of the 138 gerbils trapped on a monthly basis, over a period of one year, were PCR-positive. Sequencing of the gltA gene region confirmed the presence of four discrete Bartonella lineages (I-IV) and high levels of co-infection (33.0%). Each of the four lineages, varied in overall abundance (7.5%-47.9%) and had discernible seasonal peaks. Bartonella status was significantly correlated with ectoparasite presence, but not with sex, nor with season. Statistical analyses further revealed that co-infected individuals had a significantly higher relative body condition. Multi-locus sequence analysis (MLSA) performed with a concatenated dataset of three genetic loci (gltA, nuoG, and rpoB), 1452 nucleotides (nt) in length confirmed that lineage IV, which occurred in 24 PCR-positive animals (25.5%), is most closely related to zoonotic B. elizabethae. The remaining three lineages (I-III) formed a monophyletic clade which, on the basis of gltA was shown to contain bartonellae from diverse Gerbillinae species from the Middle East, suggestive of a gerbil-associated species complex in this region. Lineage I was identical to a Candidatus B. sanaae strain identified previously in Bushy-tailed jirds (Sekeetamys calurus) from Egypt, wherease MLSA indicate that lineages II and III are novel. The high levels of infection and co-infection, together with the presence of multiple Bartonella lineages indicate that Gerbillus nanus is likely a natural reservoir of Bartonella in the Arabian Peninsula.

The effects of wide pulse neuromuscular electrical stimulation on elbow flexion torque in individuals with chronic hemiparetic stroke.

OBJECTIVE: Neuromuscular electrical stimulation that incorporates wide pulse widths (1ms) and high frequencies (100Hz; wide pulse-NMES (WP-NMES)) augments contractions through an increased reflexive recruitment of motoneurons in individuals without neurological impairments and those with spinal cord injury. The current study was designed to investigate whether WP-NMES also augments contractions after stroke. We hypothesized that WP-NMES would generate larger contractions in the paretic arm compared to the non-paretic arm due to increased reflex excitability for paretic muscles after stroke. METHODS: The biceps brachii muscles were stimulated bilaterally in 10 individuals with chronic hemiparetic stroke. Four stimulation patterns were delivered to explore the effects of pulse width and frequency on contraction amplitude: 20-100-20Hz (4s each phase, 1ms pulse width); 20-100-20Hz (4s each phase, 0.1ms); 20Hz for 12s (1ms); and 100Hz for 12s (1ms). Elbow flexion torque and electromyography were recorded. RESULTS: Stimulation that incorporated 1ms pulses evoked more torque in the paretic arm than the non-paretic arm. When 0.1ms pulses were used there was no difference in torque between arms. For both arms, torque declined significantly during the constant frequency 100Hz stimulation and did not change during the constant frequency 20Hz stimulation. CONCLUSIONS: The larger contractions generated by WP-NMES are likely due to increased reflexive recruitment of motoneurons, resulting from increased reflex excitability on the paretic side. SIGNIFICANCE: NMES that elicits larger contractions may allow for development of more effective stroke rehabilitation paradigms and functional neural prostheses.

2-Methyl-1,3-benzoxazol-4-yl diphenyl-phosphinate.

The title compound, C(20)H(16)NO(3)P, was synthesized by the addition of diphenyl-phosphine chloride to a tetra-hydro-furan solution of Et(3)N and 2-methyl-1,3-benzoxazol-4-ol at 233 K. In the mol-ecule, the almost planar (r.m.s. deviation = 0.010 Å) benzoxazole moiety is attached to the slightly distorted tetra-hedral P atom [C-P-C-C torsion angle = 132.20 (18)°]. The crystal structure does not exhibit any significant inter-molecular inter-actions.

Transient chirality in a distal-substituted resorcinarene metal complex.

A novel distal bidentate S/S resorcinarene ligand has been synthesised and a bis-mu-chloro-bridged palladium(II) complex obtained. The solid state structure for this complex represents the first crystal structure evidence for a bispalladium-mu-chloro-bridged complex bound to thioether ligands. Furthermore, solution NMR studies revealed conformational changes in the flexible resorcinarene ligand and discreet transient chirality around the sulfur centres.

The effects of asymmetric tonic neck reflex during reaching movement following stroke: preliminary results.

Previous studies and clinical observations reveal that stroke survivors show the resurgence of the asymmetric tonic neck reflex (ATNR) both in static and dynamic conditions during maximal efforts. This observation may imply more reliance on the brainstem pathways following stroke. However, the effect of ATNR during a dynamic condition that represents more natural movement, such as reaching, has not been studied before. During reaching movements, the application of a robot controlled haptic environment is important to quantify the effect of ATNR following stroke. Therefore, this paper reports the use of a novel setup using the ACT(3D) robotic device to investigate and quantify this reflexive behavior. Our preliminary results demonstrate that the effect of ATNR is significant in the stroke population when abducting the shoulder at 25% of maximum ability. These results show that the ATNR affects reaching distance especially when shoulder loading in abduction is required. In conclusion, these preliminary results provide evidence that the effect of ATNR in stroke subjects during reaching task can be quantified by using a novel 3-D robotic setup.

Electron spin resonance and raman scattering spectroscopy of multi-walled carbon nanotubes: a function of acid treatment.

We compare the fundamental transport mechanism in multi-walled carbon nanotubes (MWNTs) by means of electron spin resonance (ESR) and Raman spectroscopy as a function of acid treatment. The ESR and Raman results show that the acid treatment reduces the density of states at the Fermi level. Defects introduced through the acid treatment move the Fermi level closer to the K points in the valence band, and consequently conduction is reduced. These defects are identified as Stone-Wales type from the Raman results.

EEG-based Discrimination of Elbow/Shoulder Torques using Brain Computer Interface Algorithms: Implications for Rehabilitation.

Brain computer interface (BCI) algorithms are used to predict the torque generation in the direction of shoulder abduction or elbow flexion using scalp EEG signals from 163 electrodes. Based on features extracted from both frequency and time domains, three classifiers are employed including support vector classifier, classification trees and K nearest neighbor. Support vector classifier achieves the highest recognition rate of 92.9% on two able-bodied subjects in average. The recognition rates we obtained on the able-bodied subjects are among the highest compared with previous reports on predicting motor intent using scalp EEG. This demonstrates the feasibility of separating the shoulder/elbow torques using scalp EEG as well as the potential of support vector classifier in applications of BCI. Preliminary experiments on two hemiparetic stroke subjects using support vector classifier reports an accuracy of 84.1% in average, which shows an increased difficulty in predicting intent presumably due to cortical reorganization resulting from the stroke.

Muscular torque generation during imposed joint rotation: torque-angle relationships when subjects' only goal is to make a constant effort.

It is a reasonable expectation that voluntarily activated spinal motoneurons will be further excited by increases in spindle afferent activity produced by muscle stretch. Human motor behavior attributed to tonic stretch reflexes and to reflexes recruited by relatively slow joint rotation has been reported from several laboratories. We reinvestigated this issue by rotating the elbow joint over the central portion of its range while subjects focused on keeping their elbow flexion effort constant at one of three different levels and made no attempt to control the position, speed or direction of movement of their forearm. There is evidence that subjects' voluntary motor status is constant under these conditions so that any change in torque would be of involuntary origin. On average, torques rose somewhat and then fell as the elbow was flexed through a range of 80 degrees at 10, 20 and 60 degrees/s and a similar pattern occurred during elbow extension; i.e., both concentric and eccentric torque-angle profiles had roughly similar shapes and neither produced consistent stabilizing cross-range stiffness. The negative stiffness (rising torque) during the early part of a concentric movement and the negative stiffness (falling torque) during the later part of an eccentric movement would not have occurred if a stabilizing stretch reflex had been present. Positive stiffness rarely gave rise to torque changes greater than 20% in either individual or cross-subject averaged data. When angular regions of negative stiffness are combined with regions of low positive stiffness (torque change 10% or less), much of the range of motion was not well stabilized, especially during eccentric movements. The sum of the EMGs from biceps brachii, brachioradialis and brachialis showed a pattern opposite to that expected for a stretch reflex; there was an upward trend in the EMG as the elbow was flexed and a downward trend as the elbow was extended. There was little change in the shape of this EMG-angle relationship with either direction or velocity. The individual EMG-angle relationships were distinctive for each of these three elbow flexor muscles in four of the six subjects; in the remaining two, biceps was distinctive, but brachioradialis and brachialis appeared to be coupled. Although the EMGs of individual muscles were modulated over the angular range, no consistent stretch reflexes could be seen in the individual records. Thus, we could find no clear evidence for stretch reflex stabilization of human subjects maintaining a constant effort. Rather, muscle torque appears to be reflexly modulated across a much used portion of the elbow's angular range so that any appreciable stabilizing stiffness that is sustained for more than fractions of a second is associated with a change in effort.

Career retention in the dental hygiene workforce in Texas.

PURPOSE: The purpose of this study was to determine the factors that influence the retention and attrition of dental hygienists within the workforce in Texas. Respondents' perception of the role of employee benefits and practice of dental hygiene on career retention were explored. Demographic descriptors, including educational level, marital status, age, employment setting, and practice statuses, were also examined. METHODS: A questionnaire modified from the American Dental Hygienists' Association Extension Study: Retention of Dental Hygienists in the Workforce Final Report, April 1992, was mailed to a systematic sample of licensed Texas dental hygienists in March 1999. Descriptive statistics were computed for dental hygienists currently in practice in Texas and those not in practice at the time of the survey. Differences in demographics, benefits, and attitudes between dental hygienists currently in practice in Texas and dental hygienists not in practice at the time of the survey were tested using independent t-tests for interval data and chi-squared tests for categorical data. All statistical analyses were conducted using the Statistical Package for Social Scientists (SPSS v. 9, Chicago, Illinois). RESULTS: A response rate of 68.1% was obtained. Results revealed the primary reasons for remaining in the practice of dental hygiene were salary, family responsibility, professional collaboration, and variety of work. The primary reasons for leaving dental hygiene practice were family responsibility, boredom, salary, and lack of benefits. Secondary and tertiary reasons stated for staying in clinical practice revealed additional factors including benefits, participation in decision-making, and a safe environment. Dental hygienists in clinical practice were more likely to be employed by a dentist in a single practice and see more patients per day, have a certificate or associate's degree, be unmarried, have fewer children, and be younger than dental hygienists not in practice. CONCLUSION: The findings suggest that dental hygienists in Texas who remain in the workforce are positively influenced primarily by salary. Dental hygienists in Texas who had left the workforce were primarily influenced to leave practice because of family responsibility. Boredom and lack of benefits were also important factors in deciding to leave clinical practice. Employers of dental hygienists need to be aware of these factors in the hiring process. In addition, dental hygiene educators should prepare students in interviewing techniques for better communication regarding retention factors.

Lipid phosphate phosphatase-1 dephosphorylates exogenous lysophosphatidate and thereby attenuates its effects on cell signalling.

The serum-derived phospholipid growth factor, lysophosphatidate (LPA), activates cells through a family of G-protein-coupled EDG receptors. The present article examines the role of lipid phosphate phosphatase-1 (LPP-1, or phosphatidate phosphate 2A) in regulating cell activation by LPA. Overexpressing LPP-1 approximately doubled the rate of dephosphorylation of exogenous LPA by Rat2 fibroblasts. The amount of LPA dephosphorylation was restricted to less than 10% of the total exogenous LPA. Over-expression of LPP-1 attenuated cell activation as indicated by diminished responses including cAMP, Ca2+, activation of phospholipase D and ERK, DNA synthesis and cell division. LPP-1 therefore provides a novel level of regulation for controlling cell signalling by exogenous LPA.

Abnormal joint torque patterns in the paretic upper limb of subjects with hemiparesis.

This study presents the results of a novel paradigm for characterizing abnormal coordination in subjects with hemiparesis. Subjects generated maximum voluntary torques (MVTs) isometrically in four randomly ordered blocks consisting of elbow flexion/extension, shoulder flexion/extension, shoulder abduction/adduction, and shoulder external/internal rotation. A 6-degree-of-freedom (DOF) load cell was used to measure torques in secondary DOFs at the elbow and shoulder, as well as in the torque direction the subject was attempting to maximize. This allowed characterization of the multijoint torque patterns associated with the generation of MVTs in the eight directions examined. Significant differences were found between the torque patterns exhibited by the paretic limb of the hemiparetic group (n = 8) and those observed for the nonparetic limb and control group (n = 4). Potential neural and biomechanical mechanisms underlying these abnormal torque patterns are discussed along with implications for the functional use of the paretic limb.

Upper-limb discoordination in hemiparetic stroke: implications for neurorehabilitation.

Clinically, upper-limb discoordination after stroke is evident in the form of stereotypic movement patterns that reflect a loss of independent joint control. These movement abnormalities, in conjunction with our recent quantitative findings under isometric conditions, provide evidence for an impaired capacity to generate certain muscle coactivation patterns in the impaired limb. In this article, we examine the parallels that exist between coordination disturbances observed under isometric and movement conditions. Our results suggest that discoordination in stroke may largely represent a manifestation of additional neural constraints on motor outflow. The neurotherapeutic implications of our findings are discussed.

Lipid phosphate phosphatase-1 and Ca2+ control lysophosphatidate signaling through EDG-2 receptors.

The serum-derived phospholipid growth factor, lysophosphatidate (LPA), activates cells through the EDG family of G protein-coupled receptors. The present study investigated mechanisms by which dephosphorylation of exogenous LPA by lipid phosphate phosphatase-1 (LPP-1) controls cell signaling. Overexpressing LPP-1 decreased the net specific cell association of LPA with Rat2 fibroblasts by approximately 50% at 37 degrees C when less than 10% of LPA was dephosphorylated. This attenuated cell activation as indicated by diminished responses, including cAMP, Ca(2+), activation of phospholipase D and ERK, DNA synthesis, and cell division. Conversely, decreasing LPP-1 expression increased net LPA association, ERK stimulation, and DNA synthesis. Whereas changing LPP-1 expression did not alter the apparent K(d) and B(max) for LPA binding at 4 degrees C, increasing Ca(2+) from 0 to 50 micrometer increased the K(d) from 40 to 900 nm. Decreasing extracellular Ca(2+) from 1.8 mm to 10 micrometer increased LPA binding by 20-fold, shifting the threshold for ERK activation to the nanomolar range. Hence the Ca(2+) dependence of the apparent K(d) values explains the long-standing discrepancy of why micromolar LPA is often needed to activate cells at physiological Ca(2+) levels. In addition, the work demonstrates that LPP-1 can regulate specific LPA association with cells without significantly depleting bulk LPA concentrations in the extracellular medium. This identifies a novel mechanism for controlling EDG-2 receptor activation.

Deficits in the coordination of multijoint arm movements in patients with hemiparesis: evidence for disturbed control of limb dynamics.

This study provides a detailed analysis of disturbances in the kinematics and dynamics of the acceleration phase of multijoint arm movements in six patients with chronic hemiparesis. Movements of the dominant and nondominant limbs were also examined in three control subjects. Subjects performed rapid movements from a central starting point to 16 targets located equidistantly around the circumference of a circle. Support of the upper limb was provided by an air-bearing apparatus, which allowed very low friction movements in the horizontal plane. We found that patients retained the capacity to modulate, in response to target direction, the initial direction of movements performed with the paretic limb. However, in comparison to the nonparetic limb or control subjects, movements of the paretic limb were misdirected systematically. An inverse dynamics analysis revealed an abnormal spatial tuning of the muscle torque at the elbow used to initiate movements of the paretic limb. Based on electromyographic recordings, similar spatial abnormalities were also apparent in the initial activations of elbow muscles. We argue that these spatial abnormalities result from a systematic disturbance in the control signal to limb muscles that cannot be attributed to previously identified mechanisms such as weakness, spasticity mediated restraint, or stereotypic muscle activation patterns (muscle synergies). Instead, our analysis of movement dynamics and simulation studies demonstrate that the spatial abnormalities are consistent with an impaired feedforward control of the passive interaction torques which arise during multijoint movements. This impaired control is hypothesized to reflect a degradation of the internal representation of limb dynamics that occurs either as a primary consequence of brain injury or secondary to disuse.

Stretch reflex adaptation in elbow flexors during repeated passive movements in unilateral brain-injured patients.

OBJECTIVE: To evaluate the effects of repeated, externally imposed, flexion-extension movements of the elbow on the resulting stretch reflex response in hemiparetic spastic brain-injured patients. These effects were compared within a recording session and across sessions for the same subject to determine the impact of movement history on the quantification of spastic hypertonia using the stretch reflex response. DESIGN: Twenty to 30 sequential, constant velocity flexion-extension movements were applied to the impaired elbow of our cohort, with a 10-second hold interposed between flexion and extension. Movements were applied regularly at 1-minute intervals. Changes in stretch reflex responses were monitored during the applied movements. PARTICIPANTS: We examined a convenience sample of seven hemiparetic brain-injured subjects between the ages of 26 and 60 yrs, with moderate-to-severe spastic hypertonia of elbow muscles (Ashworth score 2-4/4). Subjects participated in 2 to 9 sessions. MEASURES: Elbow torque, position, velocity, and electromyograms of the biceps, brachioradialis, and triceps muscles were recorded for each flexion and extension movement. Stretch reflex torque was calculated by subtracting passive torque from total elbow torque, recorded over large amplitude movements. A linear regression analysis quantified both the initial torque response of the stretch reflex and the ensuing adaptation of the stretch reflex during sequential movements. Intersession variability was characterized both for spastic hypertonia measures and for stretch reflex adaptation. RESULTS: Repeated, externally imposed, sequential flexion-extension movements of the elbow decreased the elbow flexor stretch reflex in six of seven subjects. The mean reduction in reflex torque after 30 movements was 50% of the initial torque values (p = .001, t test vs. 0% change). Intersession stretch reflex responses for each subject were found to vary greatly (SDs of reflex torque ranged from 0.1 to 4.0 Nm), and there were also significant variations in the degree of adaptation between subjects. CONCLUSIONS: Stretch reflex adaptation must be taken into consideration when spastic hypertonia is quantified using repeated joint motion, as is often the case. The magnitude of intersession variation in spastic hypertonia measures suggests that ideally, such measurements should be made across multiple sessions before conclusions are made regarding the efficacy of spastic hypertonia interventions. This study provides quantitative evidence that repeated joint movements may have a significant short-term beneficial effect on spastic hypertonia.

Identification of structurally important domains of lipid phosphate phosphatase-1: implications for its sites of action.

Lipid phosphate phosphatase-1 (LPP-1) dephosphorylates exogenous lysophosphatidate and thereby regulates the activation of lysophosphatidate receptors and cell division. Mutation of seven amino acids in three conserved domains of mouse LPP-1 abolished its activity. A glycosylation site was demonstrated between conserved Domains 1 and 2. LPP-1 is expressed in the plasma membrane, and the present results demonstrate the active site to be located on the outer surface.

Developing a competency-based curriculum for a dental hygiene program.

A three-step process was used that involved developing a competency document, an evaluation plan, and a curriculum inventory. The competency document, Competencies for the Dental Hygienist, included three domains, nine major competencies, and fifty-four supporting competencies. These became the department's educational goals. The evaluation plan included multiple methods for assessing each of the nine major competencies. The faculty initially identified evaluation methods that were currently in place and then added strategies for the various gaps in the plan. The curriculum inventory defined the entire curriculum in terms of the competencies. For each supporting competency, there was a list of major and foundation topics, each linked to specific courses. The strategy used to identify both the evaluation methods and curriculum topics was to survey the faculty. Information from assessments and the curriculum inventory directed the modification of the curriculum for alignment with the competencies. This process has resulted in improvements in teaching, evaluation, and student learning. The strengths and weaknesses of this competency-based curriculum development are presented, with specific recommendations for other-programs undergoing similar curriculum development.

Reorganization of flexion reflexes in the upper extremity of hemiparetic subjects.

We examined spatiotemporal abnormalities in the flexor reflex response in the impaired upper extremity of hemiparetic subjects. Electrical stimulation was used to elicit flexion reflexes in both upper extremities of 8 hemiparetic brain-injured and 6 control subjects. Electromyograms (EMGs) were recorded from 12 arm muscles, and reflex forces and moments were recorded at the wrist with a load cell, and converted to shoulder and elbow torques. We found that the onset of reflex torque and EMG was delayed in the impaired arm and delays were greater at the shoulder than at the elbow. The normal reflex torque response consisted of elbow flexion, shoulder extension, and shoulder adduction. In contrast, in the impaired limb shoulder, flexion torque was observed in 7 subjects and shoulder abduction in 3. The delays in reflex onset and altered torque patterns in the impaired arm may be related to the abnormal movement synergies observed following stroke. © 1999 John Wiley & Sons, Inc.