Constant Positioning Research Articles

Targeting the dependence on PIK3C3-mTORC1 signaling in dormancy-prone breast cancer cells blunts metastasis initiation.

We reveal that dormancy-prone breast cancer cells depend on the class III PI3K to mediate a constant peripheral lysosomal positioning and mTORC1 hyperactivity. Targeting this pathway might blunt breast cancer metastasis.

The Sea Lady

The Sea Lady

Semi-enclosed paper sensor for highly sensitive and selective detection of proline

In the current study, we have utilized semi-enclosed, leak-proof, microfluidic paper-based analytical devices (μPAD's) modified with isatin conjugated chitosan as specific colorimetric reagent for the detection of proline. Proline is one of the globally accepted stress biomarker in plants and also one of the prominent amino acid present in wine and some processed food. Quantification of proline is regularly required in agriculture field, food and wine industries. Specific interaction of isatin with proline, uniform film forming ability of chitosan which results in uniform coloration and the presence of leak-proof layer which prevent the diffusion of colorimetric reagent deeper resulted in enhancement of color signal intensity at the reaction zone were utilized. Further, the images of the μPAD's were captured using smartphone with 3D printed imaging box which houses smartphone and μPAD's. This platform utilizes smartphone flash for uniform illumination and ensures constant positioning of μPAD's to capture images. This greatly enhances the sensitivity and accuracy of our platform. Compared to previously published highly sensitive multi-layer, paper-based platform for detection of proline, current method has enhanced detection range (∼7 fold) and has comparable limit of detection of 23.75 μM. Moreover, the developed μPAD's platform has reduced optimum reaction temperature and time compared to previous work. The developed paper based platform was utilized for evaluation of proline content in young Arabidopsis plants which are subjected to water stress for 5 days. The devised paper-based methods have the potential to be applicable for the on-site evaluation of various stresses in plants.

Numerical Characterization of the Performance Curve of a Regenerative Pump-as-Turbine

Abstract Energy companies in the power generation field are continuously searching for green technologies to reduce pollutant emissions. In that context, small hydropower plants represent an attractive solution for distributed electricity generation. Reverse-running centrifugal pumps (also known as “pump-as-turbines,” PaT) are increasingly selected in that field. Amongst the existing type of pumps, drag-type regenerative pumps (RP) can perform similarly to radial centrifugal pumps in terms of head and efficiency for low specific speed values. For a fixed rotational speed, RPs with linear blades work as pumps or turbines only depending on the flow rate. Such peculiarity makes it particularly intriguing to evaluate RPs working characteristics in the turbine operating mode. In this paper, the performance of three regenerative pump-as-turbines (RPaT) is analyzed using computational fluid dynamics (CFD). The numerical approach is validated using experimental data for both an RP (in the pump working region) and a regenerative turbine (RT) (in the turbine working region). Finally, the numerical simulation of a small-scale RP allows for characterizing both the pump and the turbine regions. Results show that for an RPaT it is possible to find a “switch region” where the machine turns from behaving as a pump to behaving as a turbine, the losses not being overcome by the turbine power output. The analysis of the RPaT also shows the inversion of the flow pattern and the constant positioning of the pivot around which the flow creates the typical helical structure that characterizes RPs.

Artificial Deformation of Skulls from Bronze Age and Iron Age Armenia

Cultural practices resulting in lasting modifications of the body can be a productive focus of investigation. Artificial cranial modification involves the alteration of cranial vault shape by cultural means, and is performed during infancy or early childhood while the cranial bones remain malleable. Our results indicate that tumpline deformation and cradle deformation should be added to the suite of cranial deformations that were detected in Armenia. It has been determined that the occipital modification is most likely unintentional. Post-coronal depression also appears to be unintentional. Cradle deformation is heavily influenced by infant sleep position, and constant supine positioning is a frequent cause of deformation during infancy. In the Armenian burials 32 skulls showing signs of cradle deformation are identified. Post-coronal depression, positioned on both parietals and slightly posterior to the coronal suture, was detected on 44 of the skulls. The deformation was a correlate of economic activities of the population and was an inadvertent consequence of carrying loads with a band across the parietal bones. In 12 cases a combination of the two types of deformation (tumpline and cradle), is observed. The only modification that has been classified as intentional is one case of parieto-temporal modification. Key words: Armenia, Bronze Age, Iron Age, post-coronal depression, cradle deformation, parieto-temporal modification

A supervised learning approach for the robust detection of heart beat in plethysmographic data.

Wearable devices equipped with photoplethysmography (PPG) sensors are gaining an increased interest in the context of biometric signal monitoring within clinical, e-health and fitness settings. When used in everyday life and during exercise, PPG traces are heavily affected by artifacts originating from motion and from a non constant positioning and contact of the PPG sensor with the skin. Many algorithms have been developed for the estimation of heart-rate from photoplethysmography signals. We remark that they were mainly conceived and tested in controlled settings and, in turn, do not provide robust performance, even during moderate exercise. Only a few of them have been designed for signals acquired at rest and during fitness. However, they provide the required resilience to motion artifacts at the cost of using computationally demanding signal processing tools. At variance with other methods from the literature, we propose a supervised learning approach, where a classifier is trained on a set of labelled data to detect the presence of heart beats at each position of a PPG signal, with only little preprocessing and postprocessing. We show that the results obtained on the TROIKA dataset using our approach are comparable with those shown in the original paper, providing a classification error of 14% in the detection of heart beat positions, that reduces to 2.86% on the heart-rate estimates after the postprocessing step.

UAV Position Estimation and Collision Avoidance Using the Extended Kalman Filter

Unmanned aerial vehicles (UAVs) play an invaluable role in information collection and data fusion. Because of their mobility and the complexity of deployed environments, constant position awareness and collision avoidance are essential. UAVs may encounter and/or cause danger if their Global Positioning System (GPS) signal is weak or unavailable. This paper tackles the problem of constant positioning and collision avoidance on UAVs in outdoor (wildness) search scenarios by using received signal strength (RSS) from the onboard communication module. Colored noise is found in the RSS, which invalidates the unbiased assumptions in least squares (LS) algorithms that are widely used in RSS-based position estimation. A colored noise model is thus proposed and applied in the extended Kalman filter (EKF) for distance estimation. Furthermore, the constantly changing path-loss factor during UAV flight can also affect the accuracy of estimation. To overcome this challenge, we present an adaptive algorithm to estimate the path-loss factor. Given the position and velocity information, if a collision is detected, we further employ an orthogonal rule to adapt the UAV predefined trajectory. Theoretical results prove that such an algorithm can provide effective modification to satisfy the required performance. Experiments have confirmed the advantages of the proposed algorithms.

Validation of a multilevel sampling device to determine the vertical variability of chlorinated solvent in a contaminated aquifer

The vertical heterogeneity of contaminant concentrations in aquifers is well known, but obtaining representative samples is still a subject of debate. In this paper, the question arises from sites where numerous fully screened wells exist and there is a need to define the vertical distribution of contaminants. For this purpose, several wells were investigated with different techniques on a site contaminated with chlorinated solvents. A core-bored well shows that a tetrachloroethene (PCE) phase is sitting on and infiltrating a less permeable layer. Downstream of the cored well, the following sampling techniques were compared on fully screened wells: low flow pumping at several depths, pumping between packers and a new multilevel sampler for fully screened wells. Concerning low flow rate pumping, very low gradients were found, which may be due to the existence of vertical flow inside the well or in the gravel pack. Sampling between packers gave results comparable with the cores, separating a layer with PCE and trichloroethene from another one with cis1,2-dichloroethene and vinyl chloride as major compounds. Detailed sampling according to pumped volume shows that even between packers, cleaning of the inter-packer volume is necessary before each sampling. Lastly, the proposed new multilevel sampler gives results similar to the packers but has the advantages of much faster sampling and a constant vertical positioning, which is fairly important for long-term monitoring in highly stratified aquifers.

“Silent” monologues, “loud” dialogues and the emergence of hibernated I-positions in the negotiation of multivoiced cultural identities

Drawing on dialogical self theory (Hermans, 2001) and employing a case study approach, this article aims to provide insights into the dialogical processes through which two British-born siblings of Pakistani background construct and negotiate their cultural identities. The analysis suggests that both young people were moving towards their multivoiced cultural identities through a constant positioning and re-positioning within their communities, which resulted in dialogical negotiation of aspects of differences/similarities and belonging within their majority and minority communities as well as living in a multicultural society. When their negotiation is a struggle shaped by issues of racism and religious discrimination, two opposing processes are constructed, a dynamic dialogical and a monological one. We introduce the notion of hibernated I-positions as a resource to deal with rapid change, threat and uncertainty. I-positions that are inactive, or are in a hibernated state and silenced, are always available to re-emerge and become engaged in a new dialogue to help retain identity continuity. In this article, we challenge linear assumptions which assume that all immigrant groups undergo the same kind of psychological acculturation process.

Working (with) dance: Notes on contemporary dance and choreography in Morocco and Tunisia

The paper focuses on the conditions, environments and challenges that dancers and choreographers working (with) contemporary dance and choreography in Morocco and Tunisia encounter today. Based on observations and interviews during her visits of two festivals in Marrakech and Tunis in 2012, Sandra Noeth provides an analysis of the artists’ work on establishing space and attention, visibility and impulses for contemporary dance in their countries and abroad. At the same time she reflects predominant political, religious and social contexts and their implications for the freedom of expression, the representation of the body in public and private space as well as consequences for the body in the context of human rights. Following a critical take on the concept of contemporaneity and by the way of the concrete examples, she approaches the situation and the needs of contemporary dance in the Arab region and in North Africa in dialogue with broader societal and political movements of disorder and dissolution in the orders of the world and asks for our individual as well as collective capacity for action and the body's role within it. Understanding choreography as an aesthetic but also societal and political practice of constant positioning and re-positioning, thus a practice of perspectivating, she formulates an overall challenge of re-writing the history of dance and choreography and thereby reconsidering our relation to the ‘Other’.

Ultrasound Circular Cyclo-Coagulation – Innovation in Glaucoma with High Intensity Focused Ultrasound

Existing treatment modalities for glaucoma, including pharmacological therapy, lasers, surgery and shunts, are all associated with shortcomings. Ultrasonic coagulation of the ciliary body with pinpoint precision using high intensity focused ultrasound (HIFU) enables significant reduction of aqueous inflow and intraocular pressure (IOP). Energy is focused through non-optically transparent media with controlled energy absorption, reducing effects on adjacent tissues. Energy deposition and tissue heating at the focus site do not depend on tissue pigmentation, thus improving predictability. Currently, high-frequency miniaturised transducers create small focal zones for improved treatment area targeting, and ultrasound focusing provides enhanced control. The high operating frequency allows a sharp transition between the focal zone and the untreated area, reducing risks of heating adjacent healthy tissue. Such transducers are used extensively in malignant tumour treatments. Novel Ultrasound Circular Cyclo-Coagulation (UC3) with a miniaturised annular transducer uses HIFU technology. The circular geometry of the device allows precise, constant and reproducible positioning. Results from animal studies and from a clinical pilot study of patients with refractory glaucoma indicate that ultrasonic coagulation of the ciliary body using HIFU delivered by a circular miniaturised transducer is an effective and well-tolerated method of reducing IOP. The single-step procedure is short, easy to perform and accurate. Glaucoma impacts patients’ quality of life, including unpleasant treatment side effects and social and physical aspects. Gold-standard trabeculectomy shortcomings highlight the need for precise, focused surgical modalities. HIFU is a non-invasive, cost-effective innovation that, should the multicentre clinical trial demonstrate similar results to the preclinical and pilot studies, will be a useful addition to current glaucoma management techniques.

The organization of creativity in Japanese advertising production

This article makes use of the results of ethnographic participant observation to analyze how creativity is organized in the production of Japanese advertising. An ad campaign, like many other creative products, is produced by `motley crews' of personnel from both within an agency contracted to conceptualize the campaign on behalf of its client (an account team) and freelance professionals hired to realize the account team's creative concept (a production team). The concepts of frame analysis and art worlds are used to analyze the symbolic space of the studio and the transformations that occur there, while that of field enables a comparative analysis of advertising's `space of possibles' in which different actors position themselves and their clients' products. Creativity is used to establish relations of power among advertising personnel, as well as over consumers, by means of the constant (re)positioning of advertisers' products. This is the function of advertising's motley crew.

The Reproducibility of Radiographic Measurement of Medial Meniscus Horn Position

The objective of this investigation was to evaluate the possibility of locating and reproducing the tibial insertion areas of the anterior and posterior horns of the medial meniscus on preoperative radiographs according to an established method for the lateral meniscus. In 20 tibia heads, we prepared anterior and posterior horn insertions and marked their circumference with radiopaque steel balls of 1.6 mm in diameter. Standardized anteroposterior and lateral radiographs were made. On these radiographs, different landmarks were defined, their distances measured (tibial width and depth, distance from lateral tibia border to meniscus insertion midpoint, distance from anterior tibia border to meniscus insertion midpoint, distance from anterior and lateral tibia border to medial intercondylar spine), and ratios determined. The anterior horn midpoint is located at 57.3% +/- 2.7% of tibial width and 12.0% +/- 1.0% of tibial depth, and the posterior horn midpoint is located at 56.5% +/- 1.6% of tibial width and 81.6% +/- 3.4% of tibial depth. The statistical analysis of these measures showed a precise and constant positioning of the medial meniscus insertions on the tibia plateau. We also found constant topographic relations to the medial intercondylar spine. The midpoints of both insertion areas of the medial meniscus have constant positions at 57.3% and 56.5% of tibial width and at 12.0% and 81.6% of tibial depth for the anterior and posterior horn, respectively. They can precisely and reproducibly be defined on radiographs. We have developed a technique for precise radiographic tibial horn determination, exact placement of the tibial tunnels, and thus reconstruction of meniscus insertion anatomy in medial meniscus transplantation.

The Reproducibility of Radiographic Measurement of Lateral Meniscus Horn Position

The objective of our investigation was to evaluate whether it is possible to locate and reproduce the tibial insertion areas of the anterior and posterior horns of the lateral meniscus on preoperative radiographs. In 20 tibia heads, we prepared anterior and posterior horn insertions and marked their circumference with radiopaque steel balls of 1.6 mm in diameter. Standardized anteroposterior and lateral radiographs were made. On these radiographs, different landmarks were defined, their distances measured (tibial width and depth, distance from lateral tibia border to meniscus insertion midpoint, distance from anterior tibia border to meniscus insertion midpoint, distance from anterior and lateral tibia border to lateral intercondylar spine), and ratios determined. The anterior horn midpoint is located at 45.1% +/- 1.3% of tibial width and 41.9% +/- 3.2% of tibial depth, and the posterior horn midpoint is located at 49.8% +/- 1.9% of tibial width and 72.1% +/- 2.3% of tibial depth. The statistical analysis of these measures showed a precise and constant positioning of the lateral meniscus insertions on the tibia plateau. We also found constant topographic relations to the lateral intercondylar spine. Anterior and posterior lateral meniscus horn insertions can be determined on radiographs with a high precision and reproducibility. We have developed a technique for precise radiographic tibial horn determination in lateral meniscus transplantation.

The effects of minor hip flexion, abduction or adduction and x-ray beam angle on the radiographic joint space width of the hip

Joint pain may cause patients to hold their limbs in mild flexion, abduction or adduction to minimize pain, regardless of the extent of articular pathology, and these positional changes may have substantial effects on the interpretation of radiographic joint space. We aimed to study the impacts of minor degrees of flexion, abduction or adduction of the hip, as well as the angle of the x-ray beam on the radiographic joint space width (JSW) of the hip joint. In the first part of the study, 65 patients (44 males, 21 females, mean+/-SD age 49+/-17) without clinical evidence of hip osteoarthritis (OA) who underwent intravenous pyelography (IVP) were studied. The hips were differentially positioned during the sequential radiographs required for the IVP procedure. Baseline radiographs were taken at 15 degrees internal rotation of the hips [the standard position for anteroposterior (AP) pelvis radiography]; additional positions included the hips at 15 degrees and/or 30 degrees flexion, and 15 degrees adduction and/or 30 degrees abduction. Radiographic JSWs were measured at three sites using a dial caliper: superomedial, superolateral, and the point of narrowest JSW. In the second part, 15 patients without clinical evidence of hip OA who underwent supine abdominal radiography for non-rheumatological indications were evaluated by standard (AP) pelvis x-ray in the same setting and JSW measurements were made as described above. When the average of the three measurements of the JSW was taken for each hip, baseline JSW was 4.38+/-0.55 mm (mean+/-SD). Positioning of the hip significantly (P<0.01) affected the radiographic JSW, with apparent widening during adduction and 30 degrees flexion, (JSW 4.56+/-0.51 mm and 4.53+/-0.58 mm, mean+/-SD), respectively, but narrowing during abduction (4.17+/-0.59 mm, mean+/-SD). Fifteen degree flexion of the hip did not result in statistically significant change in JSW measurements. Upon comparison of the AP pelvis view with the supine abdominal view, neither the average JSW nor the point of narrowest JSW differed significantly, although the superolateral JSW was significantly greater on the AP pelvis view (P=0.02). Subtle positional changes in the hip, such as may occur during pain or in OA, may artifactually alter the measured radiographic JSW. Thus, longitudinal studies which employ hip JSW to assess disease progression may yield biased results due to changes in pain rather than structure unless care is taken to ensure constant positioning of the hip.

Occlusal accuracy of casts made and articulated differently

This study evaluated the occlusal accuracy of gypsum casts constructed from irreversible hydrocolloid and selected nonaqueous elastomeric materials. Master metal casts were attached to a vertically moving apparatus that allowed their occlusal surfaces to produce repeatable contacts. Impressions were made with irreversible hydrocolloid, polysulfide, and vinylsiloxane. Resulting maxillary casts were mounted with a constant positioning device and mandibular casts were mounted with zinc oxide-eugenol paste records or by maximum intercuspation. Four specific master occlusal contacts were compared with contacts generated from the mounted gypsum casts; a perfect score was 40 (four contacts × 10 casts). A chi-square linear model for category data was used to compare groups. Results indicated that casts made from irreversible hydrocolloid should not be articulated with the use of a zinc oxide-eugenol paste but are best articulated by using maximum intercuspation (32/40 contacts).

A simple distraction technique for ankle arthroscopy

Arthroscopy of the ankle is now an established method for management of a wide variety of ankle disorders (1-4). Despite the relatively small size and intrinsic stability of the ankle joint, with adequate distraction and plantar flexion, a large portion of the joint can usually be visualized. Patient positioning and methods of distraction vary widely from surgeon to surgeon. Usually, an assistant is required to maintain constant distraction and positioning of the ankle. This may prevent the assistant from actually helping with the instrumentation and procedure and places him in a position that is awkward and detrimental to the surgeon. It is difficult to maintain constant positioning and distraction of the ankle by manual methods. Various distraction devices involving external fixators and transosseous pin fixation have been employed (2), but the iffcreased chance of complications with these invasive techniques is undesirable. We utilized a simple method of ankle distraction that frees the hands of the surgeon and assistant and presents no increased morbidity to the patient.

Lingual vibrotactile threshold alterations in response to varying stimulation levels of intensity and duration.

Lingual vibrotactile thresholds were obtained at a frequency of 250 Hz by using an ascending-continuous series of stimulation during five sessions. Each of three adult male Ss attended a control session which included a prescribed period of constant tongue positioning, a pre-experimental session where the mean of six thresholds was obtained as a basis of further testing, and three experimental sessions. In the experimental sessions vibrotactile thresholds after exposure to vibratory stimulation of varying levels of intensity and duration were obtained. The findings of the control session reflected a slight pattern of decreased lingual sensitivity indicative of the influential factor of constant maintenance of tongue positioning. Results from the experimental sessions demonstrated shifts toward progressively decreased lingual sensitivity after exposure to vibratory signals of increased levels of intensity and duration. A recovery phase to near-normal sensitivity followed each stimulus presentation.