scholarly journals Dispersion Dynamics of Clustered Particles by Centrifugal Force

2022 ◽  
Vol 2148 (1) ◽  
pp. 012016
Author(s):  
Tiancong Feng

Abstract In this paper an approach is proposed to solve the problem of aggregation in nanomaterials through the mean of rotational separation aiming to quickly disperse clustered nanoparticles while not affecting their purity. If it is possible, this approach may replace the current mean of mechanical mixing, which may cause impurities issues. The hypothesis is that the centrifugal force due to rotational velocity acting on the nanoparticles can overcome the cohesive force between the nanoparticles, therefore dispersing the clustered nanoparticles. The experimental mean is to put different spheres connected by different types of glues imitating different nanoparticle clusters into centrifuges imitating the swivel plate. The results from both the theoretical model and the experiment show that for a cluster with a cohesive force of 1.75N, a rotational velocity of about 800rad./s is required to disperse the cluster. While for a cluster with a cohesive force of 0.25N and the same mass and position, a rotational velocity of about 150 rad./s is required to disperse the cluster. Except for the cohesive force, the mass and position of the nanoparticle on the swivel plate also have a large effect on the required rotational velocity. The observation of the physical mechanism of the dispersion has also shown that while using this way, the cluster is dispersed slowly with small parts separated from it. Therefore, this way can also eliminate re-clustering problems of nanoparticles.

Author(s):  
Michał S. Nowak ◽  
Bożena Romanowska-Dixon ◽  
Iwona Grabska-Liberek ◽  
Michał Żurek

Background: The present study aimed to investigate the incidence and characteristics of retinoblastoma in the overall population of Poland. Methods: The retrospective survey of both National Health Fund (NHF) and National Cancer Registry (NCR) databases were performed to identify all retinoblastoma cases in Poland in the years 2010–2017. Results: During 2010–2017, the mean age-standardised incidence of retinoblastoma (the unit of incidence is per 1,000,000 person-years) was 10.15 (95% CI 7.23–13.08) among children aged 0 to 4 years and 5.39 (95% CI 4.18–6.60) in those aged 0 to 9 years. During 2010–2014 (to allow 5 years of follow-up), the mean incidence of retinoblastoma by birth cohort analysis in Poland was 4.89 (95% CI 4.04–5.74) per 100,000 live births, corresponding to an incidence of 1 per 20,561 (95% CI 15,855–25,267) live births. In Poland, 14.6% of children with retinoblastoma had enucleation of the eye globe, 76.8% received different types of chemotherapy combined with focal treatment, 5.9% were treated with external beam radiotherapy, and 2.7% were treated with focal treatments only. Conclusions: The incidence of retinoblastoma and the pattern of medical management of retinoblastoma in Poland was similar to that reported in developed countries in Western Europe, Asia, and North America.


Medicina ◽  
2021 ◽  
Vol 57 (4) ◽  
pp. 319
Author(s):  
Ivajlo Popov ◽  
Veronika Popova ◽  
Juraj Sekac ◽  
Vladimir Krasnik

Background and Objectives: To evaluate the performance of intraocular lenses (IOLs) using power calculation formulas on different types of IOL. Materials and Methods: 120 eyes and four IOL types (BioLine Yellow Accurate Aspheric IOL (i-Medical), TECNIS ZCB00, TECNIS ZA9003 (Johnson & Johnson) (3-piece IOL) and Softec HD (Lenstec)) were analyzed. The performance of Haigis, Barret Universal II and SKR-II formulas were compared between IOL types. The mean prediction error (ME) and mean absolute prediction error (MAE) were analyzed. Results: The overall percentage of eyes predicted within ±0.25 diopters (D) was 40.8% for Barret; 39.2% Haigis and 31.7% for SRK-II. Barret and Haigis had a significantly lower MAE than SRK-II (p < 0.05). The results differed among IOL types. The largest portion of eyes predicted within ±0.25 D was with the Barret formula in ZCB00 (33.3%) and ZA9003 (43.3%). Haigis was the most accurate in Softec HD (50%) and SRK-II in Biolline Yellow IOL (50%). ZCB00 showed a clinically significant hypermetropic ME compared to other IOLs. Conclusions: In general, Barret formulas had the best performance as a universal formula. However, the formula should be chosen according to the type of IOL in order to obtain the best results. Constant optimizations are necessary for the Tecnis IOL ZCB00 and ZA9003, as all of the analyzed formulas achieved a clinically significant poor performance in this type of IOL. ZCB00 also showed a hypermetropic shift in ME in all the formulas.


2009 ◽  
Vol 24 (S1) ◽  
pp. 1-1
Author(s):  
J. Wancata ◽  
M. Freidl ◽  
F. Friedrich ◽  
T. Matschnig ◽  
A. Unger ◽  
...  

Aims:The purpose of this study was to investigate disability among patients suffering from schizophrenia and to identify predictors of disability.Methods:101 patients from different types of psychiatric services in Vienna and diagnosed with schizophrenia according to ICD-10 were included. They were investigates by means of 36-Item self-administered version of the WHO Disability Assessment Schedule II (WHO-DAS-II) and the PANSS-scale. Patients’ mothers and fathers were asked to fill in the Family Problem Questionnaire.Results:The mean total score of the WHO-DAS-II was 74.1 (SD 21.9). When using weighted sub-scores the highest disability scores were found for social contacts, participation in society and household (means 2.58, 2.57 and 2.51 respectively). Using logistic regression, overall disability was positively associated with patient's age, overall severity of symptoms (PANSS) and number of previous hospital admissions. Overall disability was not associated with duration of illness and or patient's gender. The subjective burden experienced by patients’ fathers and mothers were increased by reduced social contacts and impaired participation in society, while we could not find an association with other domains of patient's disability (understanding, mobility, self-care, household).Conclusions:This study shows that schizophrenia results in disability in several domains. Family caregivers’ burden was predominantly increased by social consequences of schizophrenia.


1964 ◽  
Vol 46 (4) ◽  
pp. 597-607 ◽  
Author(s):  
Jan Erik Kihlström ◽  
Otto Hornstein

ABSTRACT Recently some physiological characteristics of a sex cycle in male animals have been demonstrated. However, nothing is known at present about any morphological expressions of this cycle, and particularly about any rhythmical variation in exfoliation of cells comparable with that of the vaginal mucous membrane. On the assumption that such a rhythm may occur in the male urethra, the exfoliation of cells in this organ has been studied by taking daily smears. Cyclically varying frequencies of four different types of exfoliated cells, mainly in an immature stage, were demonstrated. Only a fifth type of cells, characterized by cornification and nuclear degeneration, is not subjected to such rhythmical variation. The mean duration of these cycles is about four days. Simultaneous investigations on the seminal volume and body temperature showed some relation to the cycle of cell desquamation. The results give additional evidence for the existence of a male sex cycle, probably with a hormonal background.


1997 ◽  
Vol 77 (4) ◽  
pp. 1939-1949 ◽  
Author(s):  
Mohamed Ouardouz ◽  
Jean-Claude Lacaille

Ouardouz, Mohamed and Jean-Claude Lacaille. Properties of unitary IPSCs in hippocampal pyramidal cells originating from different types of interneurons in young rats. J. Neurophysiol. 77: 1939–1949, 1997. Whole cell recordings were used in hippocampal slices of young rats to examine unitary inhibitory postsynaptic currents (uIPSCs) evoked in CA1 pyramidal cells at room temperature. Loose cell-attached stimulation was applied to activate single interneurons of different subtypes located in stratum oriens (OR), near stratum pyramidale (PYR), and at the border of stratum radiatum and lacunosum-moleculare (LM). uIPSCs evoked by stimulation of PYR and OR interneurons had similar onset latency, rise time, peak amplitude, and decay. In contrast, uIPSCs elicited by activation of LM interneurons were significantly smaller in amplitude and had a slower time course. The mean reversal potential of uIPSCs was −53.1 ± 2.1 (SE) mV during recordings with intracellular solution containing potassium gluconate. With the use of recording solution containing the potassium channel blocker cesium, the reversal potential of uIPSCs was not significantly different (−58.5 ± 2.6 mV), suggesting that these synaptic currents were not mediated by potassium conductances. Bath application of the γ-aminobutyric acid-A (GABAA) receptor antagonist bicuculline (25 μM) reversibly blocked uIPSCs evoked by stimulation of all interneuron subtypes. In bicuculline, the mean peak amplitude of uIPSCs recorded with potassium gluconate was reduced to 3.5 ± 4.4% of control ( n = 7). Similarly, with cesium methanesulfonate, the mean amplitude in bicuculline was 2.9 ± 3.1% of control ( n = 13). Application of the GABAB receptor antagonist CGP 55845A (5 μM) resulted in a significant and reversible increase in the mean amplitude of uIPSCs recorded with cesium-containing intracellular solution. Thus uIPSCs from all cell types appeared under tonic presynaptic inhibition by GABAB receptors. Paired stimulation of individual interneurons at 100- to 200-ms intervals did not result in paired pulse depression of uIPSCs. For individual responses, a significant negative correlation was observed between the amplitude of the first and second uIPSCs. A significant paired pulse facilitation (154.0 ± 8.0%) was observed when the first uIPSC was smaller than the mean of all first uIPSCs. A small, but not significant, paired pulse depression (90.8 ± 4.0%) was found when the first uIPSC was larger than the mean of all first uIPSCs. Our results indicate that these different subtypes of hippocampal interneurons generate Cl−-mediated GABAA uIPSCs. uIPSCs originating from different types of interneurons may have heterogeneous properties and may be subject to tonic presynaptic inhibition via heterosynaptic GABAB receptors. These results suggest a specialization of function for inhibitory interneurons and point to complex presynaptic modulation of interneuron function.


1996 ◽  
Vol 59 (8) ◽  
pp. 898-900 ◽  
Author(s):  
Mª JOSÉ BARRIOS ◽  
Mª JESÚS GUALDA ◽  
J. M. CABANAS ◽  
L. M. MEDINA ◽  
R. JORDANO

Thirty-five samples of commercial cheeses, 9 fresh, 9 semicured or semiripened and 17 ripened made with different types of milk (cow, ewe, goat and mixtures of milk of various species) produced in the South of Spain were analyzed for the presence of aflatoxin M1 (AFM1) by high-performance liquid chromatography, In 16 of the 35 samples (45.71%) the presence of AFM1 was detected in concentrations ranging between 20 and 200 ng/g of cheese, In the positive cases, the mean levels of AFM1 were 105.33 ng/g in ripened cheeses, 73.80 ng/g in semiripened cheeses and 42.60 ng/g in fresh cheeses.


2018 ◽  
Vol 14 (1) ◽  
pp. 18-23
Author(s):  
Kurdo Akram Qradaghi

Background: The recognized procedures that have been used to treat gynecomastia are said to have relatively a long operative time, less patient satisfaction rate, they are merely used, in mild to moderate gynecomastia, leaves a mild bulging over the nipple areola complex, resulting in aesthetically unsatisfactory results. The more the grade of gynecomastia, the more complicated the used surgical techniques. This study evaluates the success rate of these simplest surgical technique in higher grades of gynecomastia. Objectives: to present the experiences with use of Modification of Combined Vibrated Power Assisted Liposuction with Periareolar Gland Excision in management of in different type Gynecomastia Type of the study: This is a retrospective study Methods: The study  includes the use of a modification of combine vibrated power-assisted liposuction with periareolar gland excision applied for managing different types of gynecomastia. In 23 consecutive patients (46 breasts) treated between February of 2011 and March of 2016. Results: 23 patients (46 breasts) were successfully treated using this technique. Volume aspirated in both breast was 792 ml (range, 450 to 1600 ml). Using the periareolar excision technique, the mean operative time was 55 minutes (range, 45 to 90 minute). Complications were minimal (1.5 % per breasts), and no revisions were required. Conclusions: The modified Combined vibrated power assisted liposuction and the periareolartechnique have demonstrated to be a less time consuming versatileapproach, for the treatment of gynecomastia and consistently produces a smoothcontoured male breast, it is promising method to achieve good aesthetic results in gynecomastia surgerywhile resulting in an inconspicuous scar.


Author(s):  
Refangga Lova Nusantara Efendi ◽  
Zulfachmi Wahab ◽  
M. Riza Setiawan

Background: Obesity can affect severity of knee osteoarthritis sufferers. Several studies have examined relationship between obesity and osteoarthritis, but no one has examined the different types of obesity on osteoarthritis, therefore, researchers wanted to know differences of central and peripheral obesity on severity osteoarthritis.Methods: A retrospective studi, with cross-sectional, simple random sampling method, conducted between 1 August 2014 and 30 September 2014 in Semarang City. Samples people > 50 years old. Data were analyzed by rank Spearman and Anova correlation.Results: In this study, 45.7% (n = 32) reported severe osteoarthritis. The results of the statistical test obtained p1 = 0,000 (reject Ho). The correlation coefficient (r) is 0.857 (strong), and the linear pattern is positive. The coefficient of determination (r2) is obtained (0.857) 2 = 0.73 = 73%. And 37.1% (N = 26) reported being obese. p2 = 0.043 (reject Ho). The mean deviation (MD) was 0.048 (not significant) between central obesity and peripheral obesity.Conclusion: Obesity affects severity of knee osteoarthritis. The greater body mass index, greater severity of knee osteoarthritis. 73% of severity of knee osteoarthritis is influenced by obesity, but there is no significant effect between central and peripheral obesity on the occurrence of knee osteoarthritis.


2011 ◽  
Vol 188 ◽  
pp. 481-486 ◽  
Author(s):  
J.C. Xiao ◽  
S.H. Xiao ◽  
H. Wu

The sintered neodymium-iron-boron (Nd-Fe-B) material is used in most of PM machines. The kind of PM materials has small tensile strength and cannot withstand large centrifugal force due to high rotational velocity. A nonmagnetic steel enclosure is needed to cover the PM material. The tensile stress of the PM can reduced by pre-pressure applied to the outer surface of the PM through shrink-fitting into the enclosure. Based on the elasticity theory and the elastic-plastic contact theory, in soft ANSYS it is feasibility to establish a finite element mechanical model of interference fit between the enclosure and motor rotor PM at high rotating speed. This paper simulates the effects of the temperature and rotating speed (centrifugal force) on the displacement and the contact pressure on the interference-fitting surfaces .By finite element non-linear contact model analysis, if setting up right fit clearance, this paper could ensure the security of the PM rotor under rotational velocity up to 300,000 r/min high and temperature up to 150°C.


Plant Disease ◽  
2018 ◽  
Vol 102 (12) ◽  
pp. 2531-2538 ◽  
Author(s):  
Tegwe Soko ◽  
Cornelia M. Bender ◽  
Renée Prins ◽  
Zacharias A. Pretorius

Puccinia graminis f. sp. tritici race Ug99 (syn. TTKSK) has been identified as a major threat to wheat production based on its broad virulence. Despite its importance, the effect of Ug99 on different types of resistance in wheat has not been thoroughly researched. In field trials conducted with P. graminis f. sp. tritici race PTKST (Ug99 race group) over 2 years, AUDPC differentiated the moderately susceptible variety SC Stallion (515) and susceptible entries SC Nduna (995) and Line 37-07 (1634) from those with adult plant resistance (APR). AUDPC of APR varieties W1406 (256), W6979 (399), and Kingbird (209) was higher than the mean of 25 recorded for the all stage resistant (ASR) variety SC Sky. In fungicide-protected and unprotected plots, race PTKST resulted in a mean yield loss of 21.3%, with susceptible Line 37-03 recording a 47.9% decrease in grain yield. Yield reduction in APR varieties reached 19.5% in W1406, whereas the ASR control SC Sky showed a mean loss of 6.4%. Although APR reduced the effects of stem rust on yield and yield components under conditions of high disease pressure, it did not provide the same protection as effective ASR.


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