Marker Dots Research Articles

Measurements of micro particle rotation by applying marking points using additive manufacturing tools

The rotation can significantly influence the impact behavior of fine particles. By performing collision experiments with marked particles, the rotation depended particle- wall or particle–particle interactions, like rebound angle and energy dissipation, can be investigated. This method is widely used for particles with a diameter >1 mm. A sufficient method to mark micro particles has not been presented yet. Therefore, a validation method for collision theories and contact models for the Discrete Element Method for micro particles with rotation is missing. This study introduces two different methods, named pin contact and micro stamp method, to apply marker dots to spherical particles smaller 1000 µm using tools produced by two different additive manufacturing techniques. Free fall tests of marked particle on an inclined wall were performed to proof these methods regarding their handling and quality of the imprinted tracer dots.

Soft Robotic Finger Embedded with Visual Sensor for Bending Perception

SUMMARYThe various vision-based tactile sensors have been developed for robotic perception in recent years. In this paper, the novel soft robotic finger embedded with the visual sensor is proposed for perception. It consists of a colored soft inner chamber, an outer structure, and an endoscope camera. The bending perception algorithm based on image preprocessing and deep learning is proposed. The boundary of color regions and the position of marker dots are extracted from the inner chamber image and label image, respectively. Then the convolutional neural network with multi-task learning is trained to obtain bending states of the finger. Finally, the experiments are implemented to verify the effectiveness of the proposed method.

Application of dental floss traction-assisted endoscopic submucosa dissection to rectal neuroendocrine neoplasm

Objective: To evaluate the safety and efficacy of dental floss traction-assisted endoscopic submucosal dissection (DFS-ESD) for rectal neuroendocrine neoplasm (NEN). Methods: A retrospective cohort study was performed. Clinical data of rectal NEN patients undergoing ESD at Endoscopy Center of Zhongshan Hospital, Fudan University from January 2016 to December 2017 were retrospectively analyzed. Inclusion criteria: 1) age of 18 to 80 years old; 2) maximal diameter of lesions <1.5 cm; 3) tumor locating in the submucosa without invasion into the muscularis propria; 4) no enlarged lymph nodes around bowel and in abdominal cavity; 5) ESD requested actively by patients. A total of 37 patients were enrolled, including 23 male and 14 female cases with mean age of (56.0±11.3) years. All the lesions were single tumor of stage T1, and the mean size was 0.8±0.2(0.5-1.2) cm. Postoperative pathology revealed all samples as neuroendocrine tumors (NET). Seventeen patients received DFS-ESD treatment (DFS-ESD group) and 20 patient received conventional ESD treatment (conventional ESD group). In DFS-ESD group, after the mucosa was partly incised along the marker dots, the endoscopy was extracted, and the dental floss was tied to one arm of the metallic clip. When the endoscope was reinserted, the hemoclip was attached onto the incised mucosa; another hemoclip was attached onto normal mucosa opposite to the lesion in the same way. The submucosa was clearly exposed with the traction of dental floss and the resection could proceed. The conventional ESD group received the traditional ESD operation procedure. The operation time, modified operation time (remaining time after excluding the assembly time of dental floss traction in DFS-ESD group), en bloc resection rate, R0 resection rate, morbidity of operative complication, recurrence and metastasis were compared between two groups. Results: The average tumor size was (0.8±0.2) cm in DFS-ESD group and (0.7±0.2) cm in conventional ESD group (t=0.425, P=0.673). According to postoperative pathological grading of rectal neuroendocrine neoplasm, 13 were G1 and 4 were G2 in DFS-ESD group, while 17 cases were G1 and 3 cases were G2 in conventional ESD group without significant difference (P=0.680). There were no significant differences in baseline data between in the two groups (all P>0.05). All the basal resection margins were negative, the en bloc resection rate was 100% and the R0 resection rate was 100%. Pathological results showed tumor tissue close to the burning margin in 5 cases of conventional ESD group and in 2 cases of DFS-ESD group (P=0.416). The operation time was (17.9±6.6) minutes in conventional ESD group and (14.7±3.3) minutes in DFS-ESD group (t=1.776, P=0.084). The modified operation time of DFS-ESD group was (11.9±2.8) minutes, which was significantly shorter than (17.9±6.6) minutes in conventional ESD group (t=3.425, P=0.002). The hospital stay was (2.3±0.6) days and (2.0±0.5) days in conventional ESD group and DFS-ESD group, respectively, without significant difference (t=1.436, P=0.160). No patient was transferred to surgery, and no delayed bleeding or perforation occurred in either group. There was no recurrence or primary tumor-related death, and all the patients recovered well during a follow-up period of 14(1-24) months. Conclusion: Dental floss traction-assisted ESD for rectal neuroendocrine neoplasm can simplify operation and ensure negative basal margin.

Gross Chromosomal Aberrations are Early Alarms for Malignancy: A Re-Emphasis

A few chromatin dots of variable sizes were encountered in squashes of brain tumour tissues viz. medulloblastoma, ependymoma and tuberculoma along with hyper and hypoploid chromosome counts way back in 1973. Similar chromosomal features were again observed in metaphases of persons exposed to methylisocyanate gas in Bhopal during midnight of 2nd to 3rd December, 1984. Follow-up studies continued during 1984-1999 and comparative assessments on chromosomal damages were attempted by SCE (sister chromatid exchanges) as well as by scoring more than a dozen types of chromosomal aberrations on 678 individuals by C and G-banding and Feulgen’s and Aceto-orcein staining procedures on cultured-lymphocytes, details of which, have been published earlier. This short paper reemphasizes the importance of certain chromatin dots (named as Marker dots) which were seen emanating from chromosomes. These marker dots appeared reliable early indicators of neoplastic transformations. During follow-up studies on various malignancies we had recorded presence of these marker dots in almost all of them. This computation of slides involved careful scrutiny of more than 40,000 metaphases from patients of various malignancies, pathological disorders and newly discovered chromosome syndromes (e.g. Crossed Renal Ectopia with pelvic lipomatosis; Hemihypertrophy with melanosis of Ito, etc.). Intriguingly, only selective chromosomes are involved (chromosomes 1, 2, 3, 5, 6, 8, 9, 11, 12, 13, 16, 17 and Y) in emanating marker dots. Obviously, it appears that the molecular attenuation of chromatin structures movable from chromosomes is related with triggering neoplastic transformations. Specific attention was paid on appearance of “marker dots” which were observed in seemingly normal persons but later, after a gap of 2 to 6 years, some of them exhibited signs of malignancy. Such observations were possible only on those persons who could be re investigated after a gap of 2 or 3 years. Gross chromosomal aberrations such as PCD (premature centromeric divisions) acrocentric associations, hyperploid cells, translocations and deletions with marker dots appear to be precursors to firm installation of chromosomal mutagenesis in cultured lymphocytes. Obviously, search for marker dots and these aberrations in metaphases of person(s) belonging to a cancer-patient family can be of vital importance to warn for early diagnosis and prognostic approach. Marker dots simply “alarm” to inform firm installation of chromosomal mutagenesis which encompasses various chromosomal aberrations. In turn, due to many other intragenic factors, cells are transformed to malignant cells in certain individuals.

Cells With Chromosomal Aberrations Trigger Neoplastic Transformations in Humans.

Human population cytogenetic studies have revealed that a majority of persons who are prone to developing malignant features possess chromatin bodies termed as marker dots (MDs) measuring nearly 2 to 3 microns. These MDs are seen emanating from certain specific chromosomes, which may be early indicators of neoplastic transformation within cells.

Procedure Oriented Torsional Anatomy of the Forearm for Spasticity Injection.

: This is the second in a series of articles related to the concept of "torsional" anatomy. The objective of this article is to provide musculoskeletal ultrasound (MSKUS) anatomy of the forearm in the position of hemispastic flexion as a reference relevant to needle procedures. The MSKUS images were obtained in a healthy human subject. Marker dots were placed over common injection sites in the forearm for spasticity. The MSKUS probe was centered over each dot to obtain a cross-sectional view. A pair of MSKUS images was recorded for each site: the first in anatomic neutral and second in hemiparetic spastic position. The images were compared side to side. In addition, a video recording was made at each site to track the movement of the muscles and nerves during internal rotation. The pronator teres (PT) rotated medially and the brachialis and biceps tendon rotated in view. In addition, the median nerve became more superficial. The flexor carpi radialis rotated medially and was replaced by PT and the median nerve. The flexor carpi ulnaris and flexor digitorum profundus rotated medially and were replaced by the flexor carpi radialis, PT and median nerve. The flexor digitorum superficialis was replaced by the brachioradialis, extensor carpi radialis brevis, and radial nerve. The brachioradialis was replaced by the extensor carpi radialis brevis and extensor digitorum communis. Intended muscle targets rotate out of view and injection range. These are replaced by other muscles and nerves that could inadvertently be injected. This potentially could result in both increased complications and decreased efficacy of the procedure. It is hoped that this series of images will increase the accuracy and safety of needle placement for spasticity injections in the forearm.

Endoscopic excavation for gastric heterotopic pancreas: an analysis of 42 cases from a tertiary center.

Because of the difficulty associated with making an accurate diagnosis of gastric heterotopic pancreas (HP) before surgery, surgical resection is usually performed in suspected cases. However, this is an invasive procedure and prone to certain surgical complications. This study was designed to evaluate the feasibility of endoscopic excavation for gastric HP, as well as the value of endoscopic ultrasonography (EUS) in diagnosing gastric HP. Between January 2007 and January 2013, 42 consecutive patients with gastric HP were enrolled in this retrospective study. Key steps: (1) Injection of a solution (100 ml saline + 2 ml indigo carmine + 1 ml epinephrine) into the submucosal layer after making several dots around the lesion; (2) Incision of the mucosa outside the marker dots with a needle-knife, and then circumferential excavation until complete resection of the lesion; (3) Closure of the artificial ulcer with several clips after tumor removal. In this study, 18 cases (42.9%) were suspected as gastric HP (assessed by two experienced endoscopists before endoscopic excavation), 8 (19.0%) were suspected as gastrointestinal stromal tumors, 7 (16.7%) as gastric polyp, and the remaining 9 cases (21.4%) were still unknown. The mean procedure duration was 28.6 min. En bloc resection by endoscopic excavation was achieved in 40 cases (95.2%), and no massive bleeding, delayed bleeding, perforation, or other severe complication occurred in these patients. Among the 42 lesions, a tube echo could be detected in 11 cases by EUS. Those 11 cases were diagnosed as gastric HP by histopathology. Endoscopic excavation appears to be a safe and feasible procedure for accurate histopathologic evaluation and curative treatment in gastric HP. Use of EUS has some value in the diagnosis of gastric HP before the procedure

Two-dimensional high-resolution motility mapping in the isolated feline duodenum: methodology and initial results.

Several types of electrical events occur in the small intestine but their spatial and temporal contributions to overall motility are not clear. In order to quantify local motility in greater detail, a new technique of recording and analysing movements at multiple sites was developed. Use was made of isolated segments of feline duodenum superfused in a tissue bath. Multiple marker dots (20-75) were placed on the serosal surface by applying fine spots of candle soot in rectangular arrays (1-2 mm dot separation). A digital video camera was used to record spontaneous movements of the dots for periods of 10-30 min. After each experiment, 4-6 periods (10-60 s each) of video frames were transferred to a computer (25 fps, 720 x 576 pixels) and the movements of the dots was tracked every 40 ms using custom-made software. Initial results (eight experiments) show that spontaneous motility is remarkably variable, both in space and time. Three types of movement could be discerned: (i) periodic, rolling or pendular movements, with a frequency of approximately 15 min-1 occurring predominantly in the longitudinal direction; (ii) twitches, wherein a subset of dots were suddenly displaced longitudinally; and (iii) drifts of most of the dots in a circular or oblique direction. All three types of movement occurred throughout every recording session although their relative magnitudes differed greatly from moment to moment. Occasionally, it was possible to detect propagated 'contractions' with an apparent velocity of 10 mm s(-1). Immobilizing the preparation at one point by inserting a needle through the middle of the array of markers had a negligible effect on the displacements, whereas application of verapamil (10(-5) mol L(-1)) reduced or abolished motility. In summary, we present a new technique to map in detail two-dimensional motility at the surface of the intestine. Initial results seem to suggest that motility at the serosal surface is not uniform and highly anisotropic.

Image registration of MR and CT images using a frameless fiducial marker system

A new system of fiducial stereotactic markers that can easily be adapted to various imaging modalities without losing image registration was developed and tested. Utilizing MR and CT imaging the accuracy of the new system was evaluated with phantom studies and preliminary patient studies. The markers are clearly visible without artifacts on both imaging modalities. The clear delineation of the marker dots on the images enables an accurate automated marker detection. Using the marker system, image registration was found to yield an accuracy of up to 1 mm, depending on the imaging modality and the employed marker arrangement. The presented marker system shall improve patient comfort in comparison to conventional fixed stereotactic frames if repeated, highly accurate registrations are necessary over longer periods.

Cytogenetic studies of chromosome aberrations

Two papers appeared in a recent issue of Human Genetics which, if true, have important implications. However, I have serious concerns about the methodology and conclusions of both papers. The first of these papers is that of Goswami et al. (1990) entitled "Search for chromosomal variations among gas-exposed persons in Bhopal". The authors studied chromosome damage in three groups of patients, a control group of randomly selected individuals not exposed to methyl isocyanate (MIC), a second control group of individuals who were not themselves exposed to MIC but who had an exposed relative, and a group of 53 MIC exposed individuals. The slides from each group were scored blind. However, the account of the chromosome damage seen in both the control and exposed individuals is incomprehensible. It is customary when scoring chromosome damage to have a table with the total number of cells scored, the number of ceils showing one and two hit aberrations, the total number of aberrant cells and the number of aberrations per cell (Buckton and Evans 1973). None of this information is provided in the paper. The authors score a number of novel types of chromosome aberrations not normally produced by clastogen exposure none of which are defined; for example "marker dots", "Robertsonian translocations", "mosaic cells" and "premature centromere division". The meaning of some of these is clear from other contexts but the meaning of others, such as mosaic cells, is obscure. The authors provide us with two illustrations, presumably of their best preparations (none of us illustrate papers with our worst preparations!). Both are of very poor quality and neither illustrate the cytogenetic phenomena that they purport to. Figure 1 shows examples of satellite associations, not Robertsonian translocations, and the chromosomes are numbered in spite of the fact that it is not possible to separately identify chromosome pairs in a preparation of this quality. Figure 2 shows a purportedly deleted chromosome 5 which is a chromosome 11, a deleted chromosome 9 which is a chromosome 12, and a chromatid deletion which appears to be a twisted chromatid. It is apparent, both from the way that the data are presented and the standard of the illustrations, that the authors of this paper are familiar neither with human chromosome morphology nor with the nature of chromosome damage and the way it is scored. Therefore their conclusions cannot be accepted. The second paper is by Eva van den Berg-de Ruiter and her colleagues (1990) entitled "Chromosomal damage in peripheral blood lymphocytes of patients treated for testicular cancer". In this paper chromosome damage was scored in blood leucocytes from a series of patients with testicular cancer. Twenty six patients having had surgery alone while 35 patients had surgery followed by chemotherapy. Chromosome damage was purportedly found in both series of patients at similar frequencies. This observation leads the authors to conclude that some patients exhibit genetic instability which predisposes them to the development of malignancy. Unfortunately there were no controls and therefore: (1) there is no information on the level of damage in patients who do not have a malignancy and (2) the preparations could not be scored in a blind fashion. Furthermore, while the authors report every single abnormal cell, the great majority do not show chromosome damage but merely have missing chromosomes. The most reasonable explanation for the observations is that the preparations contain a large number of broken cells. The conclusions in this paper cannot be accepted in the absence of control observations, blind analysis and conventional aberration scoring.

Computer aided study of human locomotion

A subject walking in front of a coded background is photographed with a high speed movie camera. For greater accuracy, the camera is moved parallel to the subject at his walking speed. The successive film frames are analyzed by a flying spot scanner under computer control. The computer program determines the location of the camera using the background code and finds the position co-ordinates of marker dots placed over various points of interest on the subject's body and limbs. From the location of the marker dots the trajectories of the various limbs and joints can be obtained in graphical form, as well as data pertaining to joint velocities and angular displacements. It is felt that this information can have important clinical use for assessing walking disabilities and for measuring gait improvement in amputees.

Television measurement pulse generator-mixer.

Measurement instrumentation is presented that has been designed for use with the Intra-oral Television Microscope and Television Micro and Macrodensity Instrumentation. It can also be applied to any television display from other input sources. The equipment, which is capable of collecting measurement data from a particular scan line and/or any point within a scan line of the television image, is discussed from the standpoint of design and operation. Identification of the area measured, along with illuminated reference marker dots within the scan line being measured, make it possible to calibrate the instrumentation, regardless of the magnification of the televised image.