Reliable Sampling Technique Research Articles

A novel beamforming technique using mmWave antenna arrays for 5G wireless communication networks

Millimeter wave (mmWave) multiple-input multiple-output (MIMO) and beamforming technologies are most likely the integral parts and the key enablers of 5G-and-Beyond (5G-B) wireless communication systems. From that perspective, this manuscript proposes an efficient digital beamforming technique for 5G applications. The suggested approach is formulated based on a reliable sampling technique that effectively samples the interference-plus-noise covariance matrix (IPNCM) to construct an efficient projection matrix (PM). The proposed technique is therefore named interference-plus-noise PM (IPNPM) beamformer. Next, a compact-size rectangular microstrip antenna operating at 49.3 GHz having 1.7 GHz potential bandwidth is designed using CST microwave studio. The designed antenna is subsequently used to model a 32-element uniform linear array (ULA) representing a typical 5G base station. The elements of the modeled ULA are then manually fed with the complex-weights generated from the proposed beamformer to produce high-power beams and deep nulls toward the desired and undesired locations, respectively. To further improve the beamformer performance in terms of minimizing radiating power within undesired regions, an iterative sidelobe level (SLL) suppression technique is developed and integrated with the proposed beamformer. The conducted theoretical analysis justifies that the IPNPM beamformer requires less arithmetic operations than the well-known beamforming approaches. To reveal the benefits of the proposed technique, the array radiation pattern based on the proposed beamformer is plotted and compared with those for the three widely used approaches. An intensive Monte Carlo simulation is also carried out in which the IPNPM beamformer performance is systemically compared with the popular approaches based on the output signal to interference-plus-noise ratio (SINR) criterion. The achieved results demonstrate that the proposed approach is superior and surpasses the rival algorithms in terms of generating deeper nulls, enhanced output SINR, and lower execution time. It is also demonstrated that, unlike the existing SLL reduction techniques, the newly developed SLL suppressor reduces the SLLs of the proposed beamformer to a predefined threshold value (i.e., −24 dB) after few iterations.

Desorption Electrospray Ionization (DESI) of Digital Polymers: Direct Tandem Mass Spectrometry Decoding and Imaging from Materials Surfaces

AbstractSequence‐defined synthetic polymers have recently emerged as an attractive medium to store information at the molecular level, where comonomers of the chains are defined as letters of an alphabet. The main read‐out methodology employed to retrieve such molecularly encoded information is tandem mass spectrometry (MS/MS), but a major current limitation remains the low storage capacity of readable chains. Ordering short oligomers at discrete locations onto surfaces to compose long messages is an attractive alternative to the difficult synthesis of long coded polymers. Yet, such surface storage requires a reliable sampling technique to be coupled on‐line with MS/MS. Because it combines fast surface extraction with efficient analyte ionization in ambient conditions, desorption electrospray ionization (DESI) is shown here to be perfectly suited to envisage bidimensional data storage. The present study demonstrates performances of DESI‐MS/MS at mapping oligomers used to write letters of a word, extracting digital labels from materials tagged for anticounterfeiting purposes, and imaging text written with coded polymeric inks.

Presence of emerging organic contaminants and solvents in schools using passive sampling

In this study, we report on the applicability of passive sampling with Carbopack X adsorbent tubes followed by thermal desorption gas-chromatography-mass spectrometry (TD-GC–MS) to monitor the concentrations of emerging organic contaminants (EOCs) and solvents in ten indoor environments in a conventional and a vocational training school. However, if passive sampling is to be used as a reliable sampling technique, a specific diffusive uptake rate is required for each target compound. Accordingly, the aim of the present study was twofold. The first was to determine the experimental diffusive uptake rates of the target EOCs and solvents in one of the sampling sites of the vocational training school using Carbopack X adsorbent tubes and active sampling as the reference technique. The results showed experimental diffusive uptake rates between 0.46 mL min−1 and 0.94 mL min−1 with RSD % below 5% for the 28 target compounds. The second was to apply the uptake rates obtained experimentally to determine EOCs and solvents in schools. The monitoring results showed that solvents were ubiquitous throughout the conventional school with a concentrations range between 51.93 μg m−3 and 164.6 μg m−3, while EOCs were detected to a lesser extent. Moreover, the concentrations of EOCs in the vocational training school were much higher than those in the conventional school with concentrations of up to 562.9 μg m−3 for solvents and 344.3 μg m−3 for acrylate polymer monomers. After actively sampling for seven days in each school, we concluded that the concentrations of EOCs and solvents found are mostly linked to cleaning products (conventional school) and the activities carried out in the classroom (vocational training school).

Passive sampling of volatile organic compounds in industrial atmospheres: Uptake rate determinations and application

This study describes the implementation of a passive sampling-based method followed by thermal desorption gas-chromatography-mass spectrometry (TD-GC–MS) for the monitoring of volatile organic compounds (VOCs) in industrial atmospheres. However, in order to employ passive sampling as a reliable sampling technique, a specific diffusive uptake rate is required for each compound. Accordingly, the aim of the present study was twofold. First, the experimental diffusive uptake rates of the target VOCs were determined under real industrial air conditions using Carbopack X thermal desorption tubes, and active sampling as reference method. The sampling campaigns carried out between October 2017 and May 2018 provided us of experimental diffusive uptake rates between 0.40 mL min−1 and 0.70 mL min−1 and stable over time (RSD % < 8%) for up to 41 VOCs. Secondly, the uptake rates obtained experimentally were applied for the determination of VOCs concentrations at 16 sampling sites in the North Industrial Complex of Tarragona. The results showed i-pentane, n-pentane and the compounds known as BTEX as the most representative ones. Moreover, some sporadic peaks of 1,3-butadiene, acrylonitrile, ethylbenzene and styrene resulting from certain industrial activities were detected.

Sol-gel-based SPME fiber as a reliable sampling technique for studying biogenic volatile organic compounds released from Clostridium tetani.

A novel and efficient headspace solid-phase microextraction (HS-SPME) method, followed by gas chromatography mass spectrometry (GC-MS), was developed to study volatile organic compounds (VOCs) emerging from microorganisms. Two homemade SPME fibers, a semi-polar poly (dimethylsiloxane) (PDMS) fiber, and a polar polyethylene glycol (PEG) fiber, along with two commercial fibers (PDMS and PDMS/DVB) were used to collect VOCs emerging from Clostridium tetani which was cultured in different media. The adsorbed VOCs were desorbed and identified, in vitro, using GC-MS. The adsorption efficiency was improved by optimizing the time duration of adsorption and desorption. About 50 components were identified by the proposed method. The main detected compounds appeared to be sulfur containing compounds such as butanethioic acid S-methyl ester, dimethyl trisulfide, and dimethyl tetrasulfide. These volatile sulfur containing compounds are derived from amino acids containing the sulfur element, which probably coexist in the mentioned bacterium or are added to the culture media. The developed HS-SPME-GC-MS method allowed the determination of the chemical fingerprint of Clostridium tetani volatile constituents, and thus provides a new, simple, and reliable tool for studying the growth of microorganisms. Graphical abstract Investigation of biogenic VOCs released from Clostridium tetani using SPME-GC-MS.

Using public participation to sample trace metals in lake surface sediments: the OPAL Metals Survey

Members of the public in England were invited in 2010 to take part in a national metals survey, by collecting samples of littoral sediment from a standing water body for geochemical analysis. To our knowledge, this is the first national sediment metals survey using public participation and reveals a snapshot of the extent of metals contamination in ponds and lakes across England. Hg, Ni, Cu, Zn and Pb concentrations exceeding sediment quality guidelines for the health of aquatic biota are ubiquitous in ponds and lakes, not just in areas with a legacy of industrial activity. To validate the public sampling approach, a calibration exercise was conducted at ten water bodies selected to represent a range of lakes found across England. Sediment concentrations of Hg, Ni, Cu, Zn and Pb were measured in samples of soil, stream and littoral and deep water sediment to assess inputs. Significant differences between littoral sediment metal concentrations occur due to local variability, but also organic content, especially in upland, peat soil catchments. Variability of metal concentrations between littoral samples is shown to be low in small (<20 ha) lowland lakes. Larger and upland lakes with more complex inputs and variation in organic content of littoral samples have a greater variability. Collection of littoral sediments in small lakes and ponds, with or without voluntary participation, can provide a reliable sampling technique for the preliminary assessment of metal contamination in standing waters. However, the heterogeneity of geology, soils and history/extent of metal contamination in the English landscape, combined with the random nature of sample collection, shows that systematic sampling for evaluating the full extent of metal contamination in lakes is still required.

Effect of sedation on the intrapulmonary position of a bronchoalveolar lavage catheter in calves

BOVINE respiratory disease (BRD) has a major economic impact in different cattle production systems worldwide (Griffin 1997, Pardon and others 2013, Lehenbauer 2014) and is the main reason of antimicrobial...

Association Between Bagrada hilaris Density and Feeding Damage in Broccoli: Implications for Pest Management

Bagrada hilaris (Burmeister) (Hemiptera:Pentatomidae) has become a serious economic pest of brassica crops in Arizona and southern California. Feeding damage on broccoli can result in excessive seedling mortality and, on established plants, in malformed plants which are not commercially marketable. Although management tactics have been developed for this new pest, a reliable sampling technique for estimating adult density is lacking. Here, we analyzed data from 18 insecticide trials conducted from 2011 to 2014 in plots planted to broccoli to determine if estimates of fresh feeding damage on broccoli plants can be used to forecast B. hilaris densities. The proportion of plants with fresh feeding damage in a plot was significantly affected by year, trial nested within year, number of insecticides applied, and time after insecticide application. Average density of B. hilaris adults per plant in a plot was significantly affected by year, trial nested within year, and number of insecticides applied, while time after insecticide application had a marginal effect on population density. Across plots and years, the proportion of plants with fresh feeding damage was strongly and positively associated with the average number of B. hilaris adults per plant. Our results suggest that sampling young plants for signs of fresh feeding damage will provide a reliable and accurate sampling technique for monitoring B. hilaris in broccoli fields. We recommend that growers and pest control advisers focus their monitoring efforts on sampling broccoli plants for the presence of fresh feeding damage, rather than adults alone, when making pest management decisions. Accepted for publication 10 November 2015. Published 12 November 2015.

Vacuum-assisted breast biopsy for breast cancer.

Sonographic examination of the breast with state-of-the-art equipment has become an essential part of the clinical work-up of breast lesions and a valuable adjunct to mammographic screening and physical examination. Fine-needle aspiration (FNA) and core-needle biopsy (CNB) are well-established, valuable techniques that are still used in most cases, whereas vacuum-assisted breast biopsy (VABB) is a more recent technique. VABB has proven clinical value and can be used under sonographic, mammographic, and magnetic resonance imaging guidance. The main indication for the use of VABB is for biopsies of clustered microcalcifications, which are usually performed under stereotactic guidance. This method has been proven reliable and should replace surgical biopsies. The ultrasound-guided procedure is still more a matter of discussion, but it should also replace surgical biopsies for nodular lesions, and it should even replace surgery for the complete removal of benign lesions. This viewpoint is gradually gaining acceptance. Different authors have shown increased diagnostic accuracy of VABB compared to FNA and CNB. VABB particularly leads to less histological underestimation. The other indications for VABB are palpable or nonpalpable nodular lesions or American College of Radiology Breast Imaging Reporting and Data System 3 and 4A lesions. For masses that are likely benign or indeterminate, we attempt to completely remove the lesion to eliminate uncertainty on later follow-up images. VABB offers the best possible histological sampling and aids avoidance of unnecessary operations. VABB complications include bleeding or pain during the procedure, as well as postoperative pain, hemorrhaging, and hematomas. But, these hemorrhaging could be controlled by the post-procedural compression and bed resting. Overall, VABB is a reliable sampling technique with few complications, is relatively easy to use, and is well-tolerated by patients. The larger amount of extracted tissue reduces sampling error.

Diffusive sampling of 25 volatile organic compounds in indoor air: Uptake rate determination and application in Flemish homes for the elderly

Passive sampling of volatile organic compounds (VOCs) in air has received increasing attention in recent years. However, in order to use passive sampling as a reliable sampling technique a compound and sampler specific uptake rate is needed. Therefore, the scope of our study was threefold. First, uptake rates for 25 VOCs were determined under real indoor and outdoor conditions using axial-sampling tube-type samplers filled with Tenax TA, and active (pumped) sampling as a reference technique. Secondly, the mechanisms of passive sampling were investigated by comparing the experimentally determined uptake rates (0.13–0.46 ml min−1) to the ideal uptake rates, calculated based on Fick’s first law of diffusion and sampler geometry. Sampling efficiency SE, defined as the ratio between the experimental and ideal uptake rate, was introduced as a correction factor and showed that ideal uptake rates may underestimate VOC concentrations by a factor up to 4. This compound dependent SE is explained in terms of the partitioning coefficient K, i.e. the compound’s Tenax TA to air concentration equilibrium ratio. Compounds with a low K-value showed the most pronounced non-ideal sorptive behavior. Third, the experimentally determined uptake rates were used to determine VOC concentrations (between 12 and 311 μg m−3) in 6 homes for the elderly in Antwerp (Belgium). This study provides unique data for indoor air quality at care centers in Flanders.

What is the most reliable endometrial sampling technique in the diagnosis of intrauterine pathologies?

What is the most reliable endometrial sampling technique in the diagnosis of intrauterine pathologies?

Fatty Acid Composition within Each Structural Part and Section of a Soybean Seed

Seed coat, axis, sections of cotyledons, and the whole seed of six soybean genotypes were analyzed by gas chromatography. Relative percentages of fatty acids were homogeneous within cotyledons but varied greatly among structural parts. The axis had highest percentage of polyunsaturated fatty acids, whereas the coat had highest percentage of saturated fatty acids. Due to the cotyledons representing the largest proportion, the fatty acid composition of cotyledons represented that of the whole seed, suggesting that slicing a portion of cotyledons for breeding screen of fatty acids is a reliable sampling technique. Furthermore, regardless of the great variation in fatty acid profile of the six genotypes selected, the ratio in relative percentage of an individual fatty acid between the axis and cotyledons was highly conserved, implying that (1) events of lipid metabolism in maturing seeds may be correlated between axis and cotyledons, and (2) given a fatty acid composition of one tissue, one can predict that of the other

Improved Formulae for the Judgement of Intrathecal Produced IgA and IgM in the Presence of Blood CSF Barrier Damage

In order to discriminate between transsudated and intrathecally produced IgA and IgM in patients with blood cerebrospinal fluid (CSF) barrier (BCB) damage, we developed extended indices (IgA-EI and IgM-EI) for these immunoglobulins according to the general formula for extended index of a component X in CSF: X-EI = (CSF-X/serum-X)/(CSF-albumin/serum-albumin)a where a is a parameter specific for X. For IgA parameter a was found to be 1.15 and for IgM 1.9. A preliminary evaluation of IgA-EI and IgM-EI indicated lower false positive rates as compared to CSF IgA and IgM concentrations as well as 'conventional' IgA and IgM indices in cases with BCB damage, and essentially the same rates as for the hyperbolic formulae of Reiber and Felgenhauer. The importance of reliable sampling and analytical technique for IgM in CSF is discussed.

Salivary Cortisol: A Nontraumatic Sampling Technique for Assaying Cortisol Dynamics

Changes in cortisol dynamics are important correlates of various psychophysiological states in children. The two most important measures of the cortisol dynamics are changes in plasma cortisol concentrations at predetermined times and the dexamethasone suppression test (DST). Unfortunately, much restandardization of adult norms is required before these tests can be applied to infants. Measurements of salivary cortisol appear to be a reliable, accurate and nontraumatic sampling technique for assaying cortisol dynamics. Salivary cortisol values should provide a noninvasive method in the application of the DST to the investigation of psychophysiological states in infants and children.

A Sex Pheromone in the Lesser Cornstalk Borer 12

The lesser cornstalk borer (LCB), Elasmopalpus lignosellus (Zeller), is one of the most destructive insect pests of cultivated peanuts. Its range extends throughout the peanut-growing areas of the southwestern and southeastern U. S. (Leuck 1966, King et al. 1961, Walton et al. 1964). To provide for a reliable adult sampling technique and a potential, noninsecticidal method for borer control the following study was conducted to determine the presence or absence of a sex pheromone in the lesser cornstalk borer.