Ferromagnetism in Li doped ZnO nanoparticles: The role of interstitial Li

ZnO nanoparticles doped with Li (Zn1−yLiyO, y ≤ 0.1) have been investigated with emphasis on the correlation between their magnetic, electronic, and structural properties. In particular, defects such as interstitial Li and Zn atoms, substitutional Li atoms, and oxygen vacancies have been identified by X-ray photoelectron spectroscopy(XPS) and their respective roles in stabilization of the magnetic moment are discussed. X-ray diffraction(XRD) and XPS give clear evidence of Li presence at both substitutional and interstitial sites. XPS studies further show that the amount of substitutional Li defects (Lizn) and interstitial Li defects (Lii) vary non-monotonically with the Li concentration, with the Lii defects being noticeably high for the y = 0.02, 0.08, and 0.10 concentrations, in agreement with the XRD results. Magnetization studies show room temperature ferromagnetism in these nanoparticles with the moment being largest for the particles with high concentration of interstitial lithium and vice versa. Both interstitialZn(Zni) defects and Zn-O bonds were determined from the Zn LMM Auger peaks; however, the variation of these with Li concentrations was not large. Oxygen vacancies (Vo) concentrations are estimated to be relatively constant over the entire Li concentration range. We relate the Lii and Zni defects to the formation and stabilization of Znvacancies and thus stabilizing the p-type ferromagnetism predicted for cation (zinc)vacancy in the ZnO type oxides

Effect of personality traits on sensitivity, annoyance and loudness perception of low and high frequency noise

This paper presents investigations into a comparative assessment of the effects of low and high frequency noise in relation to personality traits. The high and low-frequency noises used are produced in the research laboratory using CoolEdit software. 80 candidates are exposed to equivalent continuous sound pressure level of 65 dBA of low and high frequency noise in an acoustic room with a 2 week interval. After 1 hour of exposure to noise, participants were asked to complete noise annoyance scale, Weinstein noise sensitivity questionnaire, loudness perception. The results obtained indicate that there is a significant difference between annoyance and perception of low frequency noise in comparison to annoyance and perception of high frequency noise, but no significant difference is noted between sensitivity to low and high frequency noise. The multivariate analysis of covariance test is applied, which reveals that personality traits have a significant effect on sensitivity to low and high frequency noise, annoyance due to low and high frequency noise, loudness perception of low frequency noise, but no interaction effects are found. It is further shown that personality traits are more effective on sensitivity, annoyance and loudness perception to high frequency noise than those of low frequency noise, and such effects are not only influenced by severity of noise, but also by personality traits and frequency components

Job Satisfactions of Quantity Surveyors in Building Construction Firms in Dar-Es-Salaam, Tanzania

Human resource is the key component for any organization’s success. It is crucial for organization to manage their human resources effectively and to their satisfaction, so that they stay longer without leaving the organization. Job satisfaction is identified as one of the factor that causes turnover intention of human resources in any organization. The study evaluates the job satisfaction of quantity surveyors in building construction firms of Dar-Es-salaam, Tanzania; with objectives being; to identify factors influencing job satisfaction; to determine level of job satisfaction; and to recommend interventions that can be applied to improve job satisfaction of quantity surveyors in building construction firms. The study considered a descriptive design where quantity surveyors employed by Class I to IV building construction firms were used, as a unit of analysis. In collecting data, a total of 55 questionnaires were distributed, whereby 42 were returned. Quantitative data were analyzed using Statistical Package for Social Sciences (SPSS), while qualitative data were analyzed thematically. The study revealed the major factors influencing job satisfaction of quantity surveyors, in order of importance, which includes; the working condition; organization commitment; pay; self-satisfaction of work done; job recognition; appreciation; relationship with co-workers; training and development opportunities; job security; job feedback; and job involvement in decision making and responsibilities. Furthermore, findings indicated that; the overall level of job satisfaction of quantity surveyors in building construction firms, is an average level of satisfaction with the mean score value of 3.02 and mode of 4.00. Moreover, it revealed that; quantity surveyors in building construction firm, have low level satisfaction in terms of job involvement in decision making and responsibilities; feedback and communication; job security; level of supervision; training and development opportunities; and the company’s promotion policies. Various interventions recommended to improve job satisfaction of quantity surveyors in building construction firms includes; adequate recognition of the work by the quantity surveyors in the construction firms should be fully appreciated, and encroachment by other professionals should be highly discouraged. Advancement opportunity in career progression and professional development should be encouraged to improve quality service delivery. The work to be done by quantity surveyors should have clear goals, while objectives and interference by other professionals should be checked

Relationship among sera lipoprotein abnormalities in healthy individuals with background of diabetic sibling

As the prevalence of lipoprotein abnormalities in adolescents is increasing dramatically, the identification of relevant risk factors is a major public health challenge. The aim of this study was to investigate whether a family history of diabetes could be a risk factor for lipid abnormalities in healthy individuals. This study is a cross-sectional case control study. 179 men and women were studied in two equal-member groups (with diabetic parents' background and without any diabetic sibling). Both groups matched in body mass index (BMI), age and sex. The serum concentration of oxidized-low density lipoprotein (LDL), Apo B100 and insulin were measured by enzyme linked immunosorbant assay technique and TG, Chol, HDL-C, FBS and GTT by enzymatic methods. The LDL-C level was calculated using the Friedewald formula. The results show that there were no significant variation in the amount of plasma FBS, GTT, Cho, TG, LDL and HDL between the two groups, whereas a significant increase was found in the amount of insulin (P = 0.02), Apo B100 (P = 0.001), OX-LDL (P = 0.001) and HOMA-IR (P = 0.03) in the case group as compared to the control group. We conclude that a family history of diabetic parents can lead to lipid parameters abnormalities and CVD risk factor via aggregation of inherited defected genes.Key words: Diabetes, oxidized-low density lipoprotein (LDL), Apo B100, lipoproteins

Neural correlates of cognitive motor signals in primary somatosensory cortex

Classical systems neuroscience positions primary sensory areas as early feed-forward processing stations for refining incoming sensory information. This view may oversimplify their role given extensive bi-directional connectivity with multimodal cortical and subcortical regions. Here we show that single units in human primary somatosensory cortex encode imagined reaches centered on imagined limb positions in a cognitive motor task. This result suggests a broader role of primary somatosensory cortex in cortical function than previously demonstrated

Evidence for the existence of powder sub-populations in micronized materials : Aerodynamic size-fractions of aerosolized powders possess distinct physicochemical properties

This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.Purpose: To investigate the agglomeration behaviour of the fine ( 12.8 µm) particle fractions of salmeterol xinafoate (SX) and fluticasone propionate (FP) by isolating aerodynamic size fractions and characterising their physicochemical and re-dispersal properties. Methods: Aerodynamic fractionation was conducted using the Next Generation Impactor (NGI). Re-crystallized control particles, unfractionated and fractionated materials were characterized for particle size, morphology, crystallinity and surface energy. Re-dispersal of the particles was assessed using dry dispersion laser diffraction and NGI analysis. Results: Aerosolized SX and FP particles deposited in the NGI as agglomerates of consistent particle/agglomerate morphology. SX particles depositing on Stages 3 and 5 had higher total surface energy than unfractionated SX, with Stage 5 particles showing the greatest surface energy heterogeneity. FP fractions had comparable surface energy distributions and bulk crystallinity but differences in surface chemistry. SX fractions demonstrated higher bulk disorder than unfractionated and re-crystallized particles. Upon aerosolization, the fractions differed in their intrinsic emission and dispersion into a fine particle fraction (< 5.0 µm). Conclusions: Micronized powders consisted of sub-populations of particles displaying distinct physicochemical and powder dispersal properties compared to the unfractionated bulk material. This may have implications for the efficiency of inhaled drug deliveryPeer reviewe

Study of the Emitted Dose After Two Separate Inhalations at Different Inhalation Flow Rates and Volumes and an Assessment of Aerodynamic Characteristics of Indacaterol Onbrez Breezhaler® 150 and 300 μg

Onbrez Breezhaler® is a low-resistance capsule-based device that was developed to deliver indacaterol maleate. The study was designed to investigate the effects of both maximum flow rate (MIF) and inhalation volume (Vin) on the dose emission of indacaterol 150 and 300 μg dose strengths after one and two inhalations using dose unit sampling apparatus (DUSA) as well as to study the aerodynamic characteristics of indacaterol Breezhaler® using the Andersen cascade impactor (ACI) at a different set of MIF and Vin. Indacaterol 150 and 300 μg contain equal amounts of lactose per carrier. However, 150 μg has the smallest carrier size. The particle size distribution (PSD) of indacaterol DPI formulations 150 and 300 μg showed that the density of fine particles increased with the increase of the primary pressure. For both strengths (150 μg and 300 μg), ED1 increased and ED2 decreased when the inhalation flow rate and inhaled volume increased. The reduction in ED1 and subsequent increase in ED2 was such that when the Vin is greater than 1 L, then 60 L/min could be regarded as the minimum MIF. The Breezhaler was effective in producing respirable particles with an MMAD ≤5 μm irrespective of the inhalation flow rate, but the mass fraction of particles with an aerodynamic diameter <3 μm is more pronounced between 60 and 90 L/min. The dose emission of indacaterol was comparable for both dose strengths 150 and 300 μg. These in vitro results suggest that a minimum MIF of 60 L/min is required during routine use of Onbrez Breezhaler®, and confirm the good practice to make two separate inhalations from the same dose

Formulation Pre-screening of Inhalation Powders Using Computational Atom–Atom Systematic Search Method

The synthonic modeling approach provides a molecule-centered understanding of the surface properties of crystals. It has been applied extensively to understand crystallization processes. This study aimed to investigate the functional relevance of synthonic modeling to the formulation of inhalation powders by assessing cohesivity of three active pharmaceutical ingredients (APIs, fluticasone propionate (FP), budesonide (Bud), and salbutamol base (SB)) and the commonly used excipient, α-lactose monohydrate (LMH). It is found that FP (−11.5 kcal/mol) has a higher cohesive strength than Bud (−9.9 kcal/mol) or SB (−7.8 kcal/mol). The prediction correlated directly to cohesive strength measurements using laser diffraction, where the airflow pressure required for complete dispersion (CPP) was 3.5, 2.0, and 1.0 bar for FP, Bud, and SB, respectively. The highest cohesive strength was predicted for LMH (−15.9 kcal/mol), which did not correlate with the CPP value of 2.0 bar (i.e., ranking lower than FP). High FP–LMH adhesive forces (−11.7 kcal/mol) were predicted. However, aerosolization studies revealed that the FP–LMH blends consisted of agglomerated FP particles with a large median diameter (∼4–5 μm) that were not disrupted by LMH. Modeling of the crystal and surface chemistry of LMH identified high electrostatic and H-bond components of its cohesive energy due to the presence of water and hydroxyl groups in lactose, unlike the APIs. A direct comparison of the predicted and measured cohesive balance of LMH with APIs will require a more in-depth understanding of highly hydrogen-bonded systems with respect to the synthonic engineering modeling tool, as well as the influence of agglomerate structure on surface–surface contact geometry. Overall, this research has demonstrated the possible application and relevance of synthonic engineering tools for rapid pre-screening in drug formulation and design