Unsatisfactory Sampling Research Articles

Feature Recognition and High-Quality Nonuniform Sampling for Spatial Curves

Traditional uniform sampling methods often ignore important features lying on a curve and thus provide unsatisfactory sampling results. To resolve this problem, a high-quality nonuniform sampling method using feature recognition is proposed for spatial curves, which generates a prescribed number of sampled points including feature points and auxiliary points. Firstly, all the approximate locations of local maximum curvature points and maximum torsion points on a curve are obtained through the parabolic interpolation method, and they are chosen after filtering as feature points to better capture intrinsic shape of spatial curves. Then, by defining the characteristic function in a weighted combination of arc length, curvature and torsion, auxiliary points are adaptively selected from the original curve. Compared with three state-of-the-art sampling methods, numerical experiments demonstrate that this method can achieve more high-quality sampling results and has better applicability, thus further improving the B-spline fitting effect for spatial curves.

An alternative method for smear preparation of fine-needle aspiration cytology of cystic thyroid lesions: Evaluation of sample adequacy.

Cystic thyroid lesions represent one of the most common causes of unsatisfactory fine-needle aspiration sampling. Thus, it is important to access the maximum number of follicular cells from cystic fluid in order to reduce unsatisfactory rates. We compared the traditional method of smearing with an alternative one. For each thyroid nodule, two smears were collected. Each smear was prepared using a distinct approach: either using the traditional technique or the alternative. Clinical data were taken from cytopathological request forms. The cytological aspects of the smears (eg, adequacy and number of cells) were observed during microscopy analysis. No cases were found to be suspicious for malignancy during ultrasound analysis (categories TR1 or TR2 according to ACR TI-RADS). Thirty-five cases were analyzed. For smears prepared using both the traditional and the alternative techniques, 20 and 4 cases, respectively, were unsatisfactory. In the 20 unsatisfactory traditional smear cases, 9 (45%) showed enough cells for diagnosis in cytospin and/or cell block samples; the four unsatisfactory alternative method cases showed the same. There was a statistical difference between the two methods of collecting a smear concerning sample adequacy (P < .001), but there was no statistical difference regarding the cellularity (P = .842). In our data, the alternative method of using only one slide and the needle tip had higher rates of adequate sampling. Since it is cost effective and does not change the cytological analysis, this proposed alternative method can be useful in cases of cystic thyroid lesions.

ENDOBRONCHIAL ULTRASOUND-GUIDED TRANSBRONCHIAL NEEDLE ASPIRATION (EBUS-TBNA) THROUGH RAPID ON SITE EVALUATION (ROSE) TINTED GLASSES

SESSION TITLE: Tuesday Abstract Posters SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/22/2019 01:00 PM - 02:00 PM PURPOSE: This is a retrospective analysis which determine the need of ROSE along with EBUS TBNA in improving diagnostic yield of mediastinal lymph node sampling. METHODS: At our centre when EBUS was introduced, diagnostic yield was lower than other international centers. Among the 25 cases Pre ROSE, 6(24%) of samples were unsatisfactory and hence non diagnostic. Hence we introduced ROSE for EBUS mediastinal lymph node sampling with the intention to improve the diagnostic yield and reduce unsatisfactory samples by 50%. This Quality improvement study was conducted at the Bronchoscopy suite of Hamad General Hospital. The intervention was to perform ROSE on all diagnostic samples by a cytologist at every nodal sampling. The nodal sampling is continued until confirmation of adequate diagnostic material. A representative sample of the pre ROSE over 6 months in 2016 was compared to the representative sample of Post ROSE over 6 months in 2018. RESULTS: EBUS was performed on 25 patients before ROSE. The diagnosis was obtained in 12 (48%) of the patients. (Table1) Following the introduction of ROSE, there was a statistically significant increase in diagnosis 21(84%) of the 25 patients (P 0.018) (Fig 1). This resulted in a relative increase of 175% of diagnosis. Pre ROSE sampling was non-diagnostic in 13(52%), 6 (24%) was unsatisfactory samples and 7(28%) were nodal sampling but inadequate for diagnosis. Post Rose sampling was non-diagnostic in only 4 (16%); 1(4%) out of these were unsatisfactory and 3(12%) were nodal samples but inadequate for diagnosis (Fig 2).This resulted in a 325% relative decrease in non-diagnostic sampling. CONCLUSIONS: The utility of ROSE during EBUS-TBNA has been reported in literature. There had been conflicting results up to date. However, a high concordance rate is reported in a recent study (4). Our study has demonstrated that the introduction of ROSE has resulted in improved diagnostic yield of EBUS TBNA. This would also translate into lesser number of invasive procedures like mediastinoscopy required for the nondiagnostic EBUS TBNA sampling. Given our findings ROSE during EBUS TBNA is our new standard of care at Hamad General Hospital. We would therefore recommend that ROSE should be the standard of care for EBUS TBNA across HMC if the services are being expanded at other sites. A randomised prospective trial evaluating the utility of ROSE would help strengthen our conclusions and support for ROSE. The limitation of this study was that it was performed at a single institution. Therefore, generalisation to other institutions may be limited. CLINICAL IMPLICATIONS: Combining ROSE with EBUS TBNA improves diagnostic yield, reduces unsatisfactory nodal sampling and procedure time. DISCLOSURES: no disclosure on file for Hisham Abdulsattar; No relevant relationships by Mushtaq Ahmad, source=Web Response No relevant relationships by MUSTAFA AKRAM YOUSIF Al-TIKRITY, source=Web Response No relevant relationships by Abbas Alabbas, source=Web Response No relevant relationships by mohammad ali, source=Web Response No relevant relationships by Nikolaos Chantziantoniou, source=Web Response No relevant relationships by Mansoor Hameed, source=Web Response No relevant relationships by Mostafa Suhail Najim Najim, source=Web Response No relevant relationships by Merlin Thomas, source=Web Response

Studying equilibria of polymers in solution by direct molecular dynamics simulations: poly(N-isopropylacrylamide) in water as a test case

It is well known that studying equilibria of polymers in solution by atomistic simulations is computationally demanding as a large phase space has to be adequately sampled. Nevertheless, direct molecular dynamics (MD) simulations are often used for this purpose in the literature. To assess whether such approach is adequate, we have conducted a case study for a polymer + solvent system that has been commonly studied with direct MD simulations by many authors: poly(N-isopropylacrylamide) (PNIPAM) in water. The total simulation time of the present study is much longer than that typically used in MD simulations of that system. A NIPAM chain of 30 monomers was studied in explicit water at 295 K. Three initial configurations were used. For each configuration, five replicas were run for 1000 ns. The statistical analysis of our data shows that the equilibration time is of the order of 600–700 ns and that the remaining time for the production run is not sufficient to sample the equilibrium state adequately. These results underpin the well-known difficulty of sampling equilibrium states of polymers in solution with direct MD simulations and the need for a careful interpretation of results of such studies. The problem with the unsatisfactory sampling persists despite the increasing available computing power. Therefore, enhanced sampling techniques and workarounds, such as simplified scenarios or coarse-graining, remain important.

The Sensitivity and Specificity of Fine-Needle Aspiration in Thyroid Neoplasia

Abstract Objective: To evaluate and demonstrate the accuracy of fine-needle aspiration (FNA) in thyroid lesions in our department and to highlight probable causes of errors leading to unsatisfactory sampling, which may depend on the characteristics of the nodule. Methods: This is a retrospective study conducted on 319 diagnosed cases of thyroid nodules referred to the Surgery Unit of Puls hospital, Tîrgu Mureș in the January 2014 – December 2015 period, who underwent fine-needle aspiration. Histological examination was considered to be the gold standard; therefore we compared the cytological diagnosis with the histological one. Results: Of the 319 cases, 289 (90.6%) were female and 30 (9.4%) male patients; 210 cases (69.3%) were interpreted as benign, 46 cases (15.2%) as follicular lesion of undetermined significance, 4 cases (1.3%) as suspect for malignancy, 1 case (0.3%) as malignant sampling, and 42 cases (13.9%) as unsatisfactory. We compared the results of fine-needle aspiration cytology (FNAC) with the corresponding histopathological results (49 in total). FNAC achieved a sensitivity of 76.47%, a specificity of 83.1%, a positive predictive value of 35.1%, a negative predictive value of 96.7%, a false positive rate of 16.9%, a false negative rate of 23%, and an overall accuracy of 82.3%. Conclusions: The results of our study demonstrate the accuracy of the FNA technique in the first-line diagnosis of thyroid nodules.

Ultrasound-Guided Core Needle Biopsy for Head and Neck Mass Lesions in Patients Undergoing Antiplatelet or Anticoagulation Therapy: A Preliminary Report

We compared the complications and diagnostic adequacy of ultrasound (US)-guided core needle biopsy (CNB) for head and neck mass lesions between patients who did and did not receive antiplatelet/anticoagulation therapy. This study was designed as a prospective case study including 146 consecutive patients who underwent US-guided CNB for head and neck mass lesions. Of these, 32 patients were undergoing antiplatelet/anticoagulation therapy involving aspirin, clopidogrel, cilostazol, and warfarin. None of the patients had clinical bleeding/hematoma in either group. Subclinical bleeding/hematoma recognized only by a US examination was not significantly different between the groups (P = .229). No other complications were noticed. The rate of unsatisfactory sampling was also not different between the groups (P > .999). Furthermore, when patients receiving aspirin (n = 18) were reclassified into the no-antiplatelet/anticoagulation therapy group, there was still no significant difference in the incidences of complications compared with the patients receiving clopidogrel, cilostazol, or warfarin (n = 14). Our study suggests that US-guided CNB is safe and provides good diagnostic results without necessitating the discontinuation of antiplatelet/anticoagulation therapy in patients with head and neck mass lesions. However, as this was a preliminary study, the cohort was relatively small. Larger studies are needed to confirm our findings.

Feasibility of surgeon-performed ultrasound-guided core needle biopsy in the thyroid and lymph nodes.

The purpose of this study was to evaluate the feasibility of ultrasound-guided core needle biopsy (CNB) performed by a surgeon for mass lesions in the thyroid and lymph nodes. A single surgeon performed 30 office-based ultrasound-guided CNB procedures for mass lesions in the thyroid and lymph nodes that were previously biopsied by ultrasound-guided fine-needle aspiration cytology (FNAC). The procedure time, targeting success, pathological diagnosis, and complications were evaluated. The mean procedure time for ultrasound-guided CNB was 6.7 minutes, and it reached a plateau of 4 to 7 minutes after the first 5 procedures. The overall unsatisfactory sampling rate was 3.3% (1 of 30). Specific pathological diagnoses that permitted the surgeon to establish an appropriate treatment plan were provided in 93.3% of the patients (28 of 30). There were no major complications. Ultrasound-guided CNB is technically feasible for a head and neck surgeon and a useful adjunct technique when ultrasound-guided FNAC is inadequate for mass lesions in the thyroid and lymph nodes. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1413-E1418, 2016.

Value of biomedical scientists providing on-site specimen adequacy assessment for fine-needle aspirations

ABSTRACTFine-needle aspiration (FNA) is accepted as a first-line investigation in patients with superficial or deep-seated mass lesions. One of the fundamental principles of successful aspiration is harvesting sufficient numbers of cells that are representative of the lesion being investigated. Central Manchester University Hospitals NHS Foundation Trust provides FNA services to Christie Hospital, including non-attended and biomedical scientist-attended aspirations, some of which are assessed on-site for specimen adequacy. This study audits the FNA coverage provided to Christie Hospital by exploring the contribution of biomedical scientist on-site specimen adequacy assessment to successful aspirations and identifies potential areas for service improvement such that unsatisfactory sampling is reduced. Satisfactory sampling rates varied between biomedical scientist-attended (79%) and non-attended (70%) procedures. Within the former group, 100% satisfactory sampling was achieved with on-site assessment, falling to 77% without on-site assessment. The highest unsatisfactory sampling rate was identified at 33% for thyroid aspirations in endocrinology, while rates elsewhere varied between 21% and 23%. This audit demonstrated the value of on-site specimen adequacy assessment as the ultimate goal of any FNA is to negate the need for more invasive procedures. In terms of flexibility and economic value, having adequately trained biomedical scientists to perform on-site assessment is quite feasible. Extending this biomedical scientist-led service to other departments would reduce unsatisfactory sample rates and the requirement for more invasive procedures.

Immature stages of Euchirinae (Coleoptera:Scarabaeoidea): genera Cheirotonus and Propomacrus with comments on their phylogeny based on larval and adult characters

We report the discovery of the larvae of Propomacrus bimucronatus (Pallas, 1781) in their natural habitat; providing notes on their biology based on field observations and laboratory-bred specimens. We give a detailed description of Cheirotonus formosanus Ohaus, 1913 and P. cypriacus Alexis &amp; Markis, 2002 larvae as well as a redescription of the immature stages of P. bimucronatus and present the first diagnosis of larval Euchirinae. Based on 105 morphological and ecological characters of adults and larvae in 24 taxa of Scarabaeoidea, we discuss the phylogenetic relationships of Euchirinae within the group. Our results corroborate Euchirinae monophyly, supported by two larval synapomorphic characters; however, no adult autapomorphic characters were detected. The results of 15 separate phylogenetic analyses (differing in the set of terminalia, characters and in the optimality criteria) indicate a possible sister group relationship between Euchirinae and a clade comprising Melolonthinae + Rutelinae + Dynastinae, with Cetoniinae being a sister group to the whole clade. Larval characters represent a valuable source of information for the systematics of Scarabaeoidea; however, special effort should be paid to improve the still unsatisfactory sampling of immature data.

New Curimatid, Cyphocharax laticlavius (Ostariophysi, Characiformes), from Amazonian Ecuador, with a Major Range Extension for C. gouldingi

Cyphocharax laticlavius, new species, is described from Amazonian Ecuador. It is distinguished from congeners by the combination of a dark midlateral stripe originating at the hypural joint and extending to at least the vertical line through the midbase of the dorsal fin, possession of 31 or 32 pored lateral-line scales, and by the extreme reduction of the sixth infraorbital. The distribution of Cyphocharax gouldingi, previously known only from the eastern portions of the Amazon basin and adjoining drainages of Brazil, is extended to Ecuador. CYPHOCHARAX, the most speciose of the eight genera of the detritivorous characiform family Curimatidae, is widely distributed in the running and still waters of much of lowland South America (Vari, 1989:58). Whereas many Cyphocharax species are distributed across broad areas as evidenced by extensive series of specimens, some of their congeners have restricted known distributions, often being represented by a few specimens from a single drainage basin or locality. The latter pattern, in conjunction with the unsatisfactory sampling to date of the South America freshwater fish fauna, makes it likely that additional collecting efforts will yield undescribed species. Subsequent to

The Effect of Ethylene and Propylene Pulses on Respiration, Ripening Advancement, Ethylene-Forming Enzyme, and 1-Aminocyclopropane-1-carboxylic Acid Synthase Activity in Avocado Fruit

When early-season avocado fruit (Persea americana Mill. cv Hass) were treated with ethylene or propylene for 24 hours immediately on picking, the time to the onset of the respiratory climacteric, i.e. the lag period, remained unchanged compared with that in untreated fruit. When fruit were pulsed 24 hours after picking, on the other hand, the lag period was shortened. In both cases, however, a 24 hour ethylene or propylene pulse induced a transient increase in respiration, called the pulse-peak, unaccompanied by ethylene production (IL Eaks [1980] Am Soc Hortic Sci 105: 744-747). The pulse also caused a sharp rise in ethylene-forming enzyme activity in both cases, without any increase in the low level of 1-aminocyclopropane-1-carboxylic acid synthase activity. Thus, the shortening of the lag period by an ethylene pulse is not due to an effect of ethylene on either of the two key enzymes in ethylene biosynthesis. A comparison of two-dimensional polyacrylamide gel electrophoresis polypeptide profiles of in vitro translation products of poly(A(+)) mRNA from control and ethylene-pulsed fruit showed both up- and down-regulation in response to ethylene pulsing of a number of genes expressed during the ripening syndrome. It is proposed that the pulse-peak or its underlying events reflect an intrinsic element in the ripening process that in late-season or continuously ethylene-treated fruit may be subsumed in the overall climacteric response. A computerized system that allows continuous readout of multiple samples has established that the continued presentation of exogeneous ethylene or propylene to preclimacteric fruit elicits a dual respiration response comprising the merged pulse-peak and climacteric peak in series. The sequential removal of cores from a single fruit has proven an unsatisfactory sampling procedure inasmuch as coring induces wound ethylene, evokes a positive respiration response, and advances ripening.

On Using the Box-Muller Transformation with Multiplicative Congruential Pseudo-Random Number Generators

SUMMARY In a recent Monte Carlo study, a most unsatisfactory sampling distribution was obtained when supposedly standard techniques were employed to simulate a simple random sample from the standard normal distribution. A selection of observed and expected frequencies (the latter rounded to the nearest integer) in the tails of the distribution for a sample of size 1,000,000 is given in Table 1. It hardly needs a chi-square test to indicate that the observed frequencies are not following the expected pattern! Note particularly that all the 1,000,000 observations are restricted to the range (-333 36), and that the sampling distribution has marked local maxima approximately at the points - 33, 3 0 and 3-6. This paper investigates such phenomena.