Drop-off Technique Research Articles

The Prevalence of Overweight and Obesity Among Women in Jordan: A Risk Factor for Developing Chronic Diseases.

ObjectiveThe study aimed to investigate the prevalence of obesity among Jordanian women and its association with a wide range of chronic diseases.MethodsSubjects were enrolled in the present cross-sectional study based on a random drop-off technique at the Obstetrics and Gynecology clinics at Jordan University Hospital. Initially, any female 18 years of age and older was asked to enroll in the study. Relevant data were gathered using a questionnaire composed of 30 questions, and body mass index (BMI) was determined from each participant’s weight and height. The following variables were collected: socio-demographic, chronic diseases, and health status. Each variable’s frequencies were reported, and the 95% confidence interval (95% CI) for each variable was calculated. For association analysis, Chi-square analysis was performed with an odds ratio (OR) and 95% CI. Multinomial logistic regression analysis was applied to a combination of independent variables and a dependent condition with covariate factors.ResultsThe age-standardized prevalence of overweight/obese Jordanian women was 70.6% (95% CI 66.0–74.8%). On the other hand, the age-standardized prevalence of only obese women was 36.4 (95% Cl 31.9–41.2%). Furthermore, the association between age and overweight/obesity was significant (p<0.0001). The percentage of overweight and obesity started to be significant in the 30–39 year age group. Moreover, the OR for obesity ranged from 2.7 to 7.0 (p<0.05–0.01) for those women with only elementary education. Besides, high parity was significantly associated with obesity and elementary education. For chronic conditions, the percentages of hypertension, diabetes, hypertriglyceridemia, osteoporosis, and rheumatoid arthritis were significantly correlated with increased BMI in Jordanian women. With age adjustment, however, only hypertension was associated with obese level 3 with OR of 7.2 and 95% CI of 2.1–25.1 (p<0.01).ConclusionThere is a high prevalence of overweight/obesity among women in Jordan, which was related to high parity and low education level. This high prevalence of obesity increased the incidence of chronic diseases, such as hypertension. Therefore, community-based multiple strategies are required to combat obesity in Jordanian women.

Age of Natural Menopause Among Jordanian Women and Factors Related to Premature and Early Menopause.

ObjectiveThe aim of this study was to assess factors related to the onset of premature/early natural menopause among Jordanian women.MethodsA cross-sectional study was conducted in early 2016. Subjects were enrolled based on random drop-off technique to the Obstetrics and Gynecology clinics at the Jordan University Hospital. Women 18 years of age and above were initially eligible to enroll, and women who had surgically induced menopause or specific disease were excluded from the analysis. Relevant data were collected using a questionnaire that included 30 questions. The following variables were collected: socio-demographic, body mass index, chronic conditions, diseases, reproductive characteristics, and health status. Hormone indicators of menopause were tested by measuring estrogen (E2) and follicle-stimulating hormone (FSH) levels. Age at natural menopause (ANM) was self-reported retrospectively and considered an independent variable against BMI, smoking, hormone therapy, and concomitant diseases. Association analysis and multinomial logistic regression were used to examine the associated factors of ANM with adjusted odds ratios (ORs), and their 95% confidence intervals (CIs) were reported.ResultsA total of 409 women were included in the analysis, aged between 20−75 years. The mean ANM in our sample was 48.5±5.0, with 2.7% of the women experienced premature menopause (ANM <40) and 7.8% early menopause (ANM 40–44). Within the menopause women (n=242), the percentage of women who had premature menopause was 4.5%, 13.6% with early menopause, and 21.1% with late menopause (ANM >52). Smoking was the major risk factor for premature/early menopausal age among Jordanian women with an OR of 2.46 (95% CI: 1.08–5.59, p<0.05). On the other hand, women with occasional arthritis symptoms and diseases such as hypertension, diabetes, dyslipidemia, and their combination were associated with average (45–52 years) or late menopause (>52 years).ConclusionSmoking is the main contributor of premature/early menopause in Jordanian women. Increased awareness and public health policy about the adverse effects of smoking on women’s reproductive health are needed.

The effects of drop vertical jump technique on landing and jumping kinetics and jump performance

The drop vertical jump is a popular plyometric exercise. Two distinct techniques are commonly used to initiate the drop vertical jump. With the ‘step-off’ technique, athletes step off a raised platform with their dominant limb, while their non-dominant limb remains on the platform. In contrast, with the ‘drop-off’ technique, athletes lean forward and drop off the platform, with both feet leaving the platform more simultaneously. The purpose of this study was to compare landing and jumping kinetics, inter-limb kinetic symmetry, and jump performance when individuals used the step-off and drop-off techniques, and to examine whether potential differences between these techniques are affected by platform height. Sixteen subjects completed drop vertical jumps with the drop-off and step-off techniques, from relatively low and high platform heights. Ground reactions forces were recorded for the dominant and non-dominant limbs during the land-and-jump phase of the drop vertical jump. Subjects demonstrated greater inter-limb asymmetry in peak impact forces when using the step-off technique, vs. the drop-off technique. This difference between the techniques was consistent across platform heights. The step-off technique appears to result in greater asymmetry in limb loading, which could contribute to the development of neuromuscular asymmetries between the limbs and/or asymmetric landing patterns.

Movable-Type Transfer and Stacking of van der Waals Heterostructures for Spintronics

The key to achieving high-quality van der Waals heterostructure devices made from various two-dimensional (2D) materials lies in the control over clean and flexible interfaces. However, existing transfer methods based on different mediators possess insufficiencies including the presence of residues, the unavailability of flexible interface engineering, and the selectivity towards materials and substrates since their adhesions differ considerably with the various preparation conditions, from chemical vapor deposition (CVD) growth to mechanical exfoliation. In this paper, we introduce a more universal method using a prefabricated polyvinyl alcohol (PVA) film to transfer and stack 2D materials, whether they are prepared by CVD or exfoliation. This peel-off and drop-off technique promises an ideal interface of the materials without introducing contamination. In addition, the method exhibits a micron-scale spatial transfer accuracy and meets special experimental conditions such as the preparation of twisted graphene and the 2D/metal heterostructure construction. We illustrate the superiority of this method with a WSe2 vertical spin valve device, whose performance verifies the applicability and advantages of such a method for spintronics. Our PVA-assisted transfer process will promote the development of high-performance 2D-material-based devices.

The influence of absorptive capacity and networking capabilities on small and medium enterprises

Background: In response to the ever-growing complexity in the business environment that has resulted from the dramatic technological transformation, businesses have altered the way they conduct business. The influence of the external business environment is increasing in significance, rendering traditional methods of operating business outdated and forcing the adoption of new methods.Objective: The aim of this study is to investigate how organisational capabilities influence small and medium enterprises’ (SMEs) operational performance (OP), by specifically looking at absorptive capacity (ACAP), networking capabilities (NCs) and customer relational capabilities (CRCs).Setting: This study was conducted in Zimbabwe and was spread across the 10 provinces, focusing on 388 randomly selected SMEs.Methods: Data were collected through self-administering questionnaires to respondents, using the drop-off or pickup technique and making telephonic follow-ups to increase the response rate. Analysis of the data in this study was largely quantitative in nature and it was performed using a two-step structural equation modelling approach.Results: The results of the study indicate that CRCs lead both ACAP and NCs to improve OP.Conclusion: This study enlightens both SMEs’ managers and policymakers on the significance of capabilities, as opposed to resources, in the growth of the SMEs sector. In light of the results, it is imperative that firms orientate themselves to embrace networking and ACAP as central tenets of their day-to-day operations while attending to customers timely and innovatively.

Cosmological Parameter Estimation Using the Genus Amplitude—Application to Mock Galaxy Catalogs

Abstract We study the topology of the matter density field in two-dimensional slices and consider how we can use the amplitude A of the genus for cosmological parameter estimation. Using the latest Horizon Run 4 simulation data, we calculate the genus of the smoothed density field constructed from light cone mock galaxy catalogs. Information can be extracted from the amplitude of the genus by considering both its redshift evolution and magnitude. The constancy of the genus amplitude with redshift can be used as a standard population, from which we derive constraints on the equation of state of dark energy —by measuring A at and , we can place an order constraint on . By comparing A to its Gaussian expectation value, we can potentially derive an additional stringent constraint on the matter density . We discuss the primary sources of contamination associated with the two measurements—redshift space distortion (RSD) and shot noise. With accurate knowledge of galaxy bias, we can successfully remove the effect of RSD, and the combined effect of shot noise and nonlinear gravitational evolution is suppressed by smoothing over suitably large scales . Without knowledge of the bias, we discuss how joint measurements of the two- and three-dimensional genus can be used to constrain the growth factor . The method can be applied optimally to redshift slices of a galaxy distribution generated using the drop-off technique.

Functional droplets that recognize, collect, and transport debris on surfaces.

We describe polymer-stabilized droplets capable of recognizing and picking up nanoparticles from substrates in experiments designed for transporting hydroxyapatite nanoparticles that represent the principal elemental composition of bone. Our experiments, which are inspired by cells that carry out materials transport in vivo, used oil-in-water droplets that traverse a nanoparticle-coated substrate driven by an imposed fluid flow. Nanoparticle capture is realized by interaction of the particles with chemical functionality embedded within the polymeric stabilizing layer on the droplets. Nanoparticle uptake efficiency is controlled by solution conditions and the extent of functionality available for contact with the nanoparticles. Moreover, in an elementary demonstration of nanoparticle transportation, particles retrieved initially from the substrate were later deposited "downstream," illustrating a pickup and drop-off technique that represents a first step toward mimicking point-to-point transportation events conducted in living systems.

Diamond-coated three-dimensional GaN micromembranes: Effect of nucleation and deposition techniques

In this work, we present technological issues in the deposition of polycrystalline diamond films as a backside heat spreader for GaN membranes. We compared three nucleation techniques, including standard ultrasonic seeding by diamond powder (DP) in deionized water, drop-off technique with DP in solution and polymer based nucleation by polyvinyl alcohol (PVA) polymer composite containing fine grained DP. The diamond growth was performed in a hot filament or microwave plasma chemical vapor deposition system. We found that standard nucleation techniques (ultrasonic seeding or immersing in diamond powder solution) resulted in damaging or cracking of GaN membranes, or low nucleation efficiency in the Z-depth of the structures. Implementation of a novel nucleation technique with PVA polymer composite containing diamond powder led to coating of both bottom and top parts of the membrane including side walls. The coverage homogeneity was evaluated by scanning electron microscopy and Raman spectroscopy. The obtained results indicate that the efficiency (and/or nucleation density) of the polymer-based technique is comparable with standard ultrasonic seeding and could be used in preference for nucleation of soft and fragile substrates.

Etch-stop method for reliably fabricating sharp yet mechanically stable scanning tunneling microscope tips

An extension of the direct-current, double-lamella drop-off technique for electrochemically etching tungsten scanning tunneling microscope (STM) tips is presented. The key fabrication step introduced here is the use of an etch stop as a simple but accurate way to optimize the contact area between the etchant and the wire. By restricting the etching process, the final cone angle of the tips can be made sharp and mechanically stable without a lot of finesse from the STM tip maker.

Reproducible tip fabrication and cleaning for UHV STM

Several technical modifications related to the fabrication and ultra-high vacuum (UHV) treatments of the scanning tunneling microscope (STM) tips have been implemented to improve a reliability of the tip preparation for high-resolution STM. Widely used electrochemical etching drop-off technique has been further refined to enable a reproducible fabrication of the tips with a radius ⩽3 nm. For tip cleaning by a controllable UHV annealing, simple and flexible setup has been developed. Proper W tip preparation has been demonstrated via an imaging of the TiO 2 (1 1 0) surface atomic structure.

Characterization of electrochemically etched tungsten tips for scanning tunneling microscopy

Shape and composition of electrochemically etched tungsten tips for use in scanning tunneling microscopy (STM) were investigated in a transmission electron microscope (TEM) with a Gathan imaging filter (GIP). The tips are prepared by a lamella drop-off technique. We observe typical tip radii of less than 10 nm. After a storage of some days under ambient conditions, an amorphous oxide film is detectable. The electron energy-loss spectroscopy confirms that the surface is contaminated by compounds that contain carbon, too.

An improved lamellae drop-off technique for sharp tip preparation in scanning tunneling microscopy

A superior lamellae etching drop-off technique is described for the preparation of W tips without the use of CCl4. Sharp tips with an apex of 25 nm or less can be produced routinely. In the case of Pt/Ir wire, the chemical inertness of the material means that it has to be reduced in diameter before being etched to yield a tip. In order to accomplish this, a capillary diameter reduction technique has also been developed for use in combination with the lamellae etching drop-off technique. The apparatus does not require the use of micromanipulators or micromovers. The shapes of tips with apexes as small as 25 nm can be investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). This low cost method of producing sharp tips scanning tunneling microscopy is very effective and it would probably be feasible to develop an automatic tip preparation with a little more technical effort. Since it is possible to produce well shaped W tips almost every time after acquiring a little skill, it is not usually necessary to check their shape by TEM or SEM before use. In contrast, the success rate with Pt/Ir tips is only up to 70%, so that it is advisable to check their shapes by TEM.

Progressive Matrix Crack Modeling in Off-Axis Plies

Composite laminates are engineered to exhibit tendencies toward gradual (or progressive) failure as opposed to the less desirable catastrophic failure. Localized fail ures begin to occur early in the loading history of a laminate, but due to the laminate's abil ity to redistribute its load internally, the laminate as a whole remains unfailed and contin ues to perform its load-carrying function. In trying to model laminate failure, it is important to recognize the progressive nature of the failure process in order to obtain a correct strength prediction. Localized failures can generally be categorized into various modes: transverse matrix cracking (through-the-thickness cracks running parallel to the fiber direction), periodic matrix cracks (cracks running perpendicular to the fiber direc tion and bridged by the fibers), fiber failure (cracking or splitting), and delamination. The onset of transverse matrix cracking has been found to be a key occurrence in the laminate failure process, and as a result much research has been devoted to its modeling. Con tinuum damage models as well as many shear-lag approaches have been proposed for ana lyzing cross-ply laminates. In this paper, we extend the shear-lag analysis for modeling transverse matrix cracking to a general symmetric multilayer system. The elasticity prob lem for the region of the laminate between two parallel matrix cracks having a general off- axis orientation is set up from equilibrium considerations in terms of the average (through- the-thickness) stresses and solved using the generalized shear-lag relation and the appropriate boundary conditions. This model is then included in a computer program designed for probabilistic laminate analysis, and the results are compared to those deter mined using the ply drop-off technique.

Lyme Disease in California: Interrelationship of Ixodid Ticks (Acari), Rodents, and Borrelia burgdorferi

The association of immature ixodid ticks, several species of rodents, and the Lyme disease spirochete, Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner, was studied in two habitats in northern California in spring and summer 1985 and year-round in 1986. A total of 428 rodents were collected from ecotonal chaparral and a woodland-grass-rock outcrop; the former habitat yielded six species, the latter three species. The deer mouse, Peromyscus maniculatus (Wagner), and the piñon mouse, P. truei (Shufeldt), were the dominant species year-round and collectively comprised 78% of rodents captured within chaparral and 87% from the rock outcrop in 1986. In both habitats, rodents were trapped most frequently in winter and spring, and least often in summer and fall. A total of 306 rodent blood films from all six species were assayed for spirochetes by direct immunofluorescence; of these, only one film prepared from P. truei (n = 123 films from 53 individual mice) was found to contain spirochetes. Immature western black-legged ticks, Ixodes pacificus Cooley & Kohls, and Pacific Coast ticks, Dermacentor occidentalis Marx, were collected from each species of rodent. Larvae of I. pacificus infested P. maniculatus and P. truei in low numbers year-round, but nymphs of this tick rarely parasitized these rodents. D. occidentalis larvae infested P. maniculatus and P. truei in spring and particularly in summer; nymphal ticks infested these mice primarily in summer. The efficiency of visual inspection for collecting immatures of these ticks from P. maniculatus ranged from 45 to 69% in spring and summer, whereas the efficiency of a drop-off technique appeared to be 100%. Spirochetes were detected in <1% of D. occidentalis larvae (n = 310) and nymphs (n = 120), and in approximately 4% of I. pacificus larvae (n = 75) derived from these hosts. The potential significance od these findings in the enzootiology of B. burgdorferi is discussed.