The lesion detection efficacy of deep learning on automatic breast ultrasound and factors affecting its efficacy: a pilot study

2021 ◽  
Author(s):  
Xiao Luo PhD ◽  
Min Xu ◽  
Guoxue Tang ◽  
Yi Wang PhD ◽  
Na Wang ◽  
...  
Keyword(s):  
Deep Learning ◽  
Breast Tissue ◽  
Test Group ◽  
Lesion Size ◽  
Breast Ultrasound ◽  
Lesion Detection ◽  
Detection Sensitivity ◽  
Control Group ◽  
Factors Affecting ◽  
Handheld Ultrasound

Objectives: The aim of this study was to investigate the detection efficacy of deep learning (DL) for automatic breast ultrasound (ABUS) and factors affecting its efficacy. Methods: Women who underwent ABUS and handheld ultrasound from May 2016 to June 2017 (N = 397) were enrolled and divided into training (n = 163 patients with breast cancer and 33 with benign lesions), test (n = 57) and control (n = 144) groups. A convolutional neural network was optimised to detect lesions in ABUS. The sensitivity and false positives (FPs) were evaluated and compared for different breast tissue compositions, lesion sizes, morphologies and echo patterns. Results: In the training set, with 688 lesion regions (LRs), the network achieved sensitivities of 93.8%, 97.2 and 100%, based on volume, lesion and patient, respectively, with 1.9 FPs per volume. In the test group with 247 LRs, the sensitivities were 92.7%, 94.5 and 96.5%, respectively, with 2.4 FPs per volume. The control group, with 900 volumes, showed 0.24 FPs per volume. The sensitivity was 98% for lesions > 1 cm3, but 87% for those ≤1 cm3 (p < 0.05). Similar sensitivities and FPs were observed for different breast tissue compositions (homogeneous, 97.5%, 2.1; heterogeneous, 93.6%, 2.1), lesion morphologies (mass, 96.3%, 2.1; non-mass, 95.8%, 2.0) and echo patterns (homogeneous, 96.1%, 2.1; heterogeneous 96.8%, 2.1). Conclusions: DL had high detection sensitivity with a low FP but was affected by lesion size. Advances in knowledge: DL is technically feasible for the automatic detection of lesions in ABUS.

scholarly journals AutoProstate: Towards Automated Reporting of Prostate MRI for Prostate Cancer Assessment Using Deep Learning

Cancers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 6138
Author(s):  
Pritesh Mehta ◽  
Michela Antonelli ◽  
Saurabh Singh ◽  
Natalia Grondecka ◽  
Edward W. Johnston ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Deep Learning ◽  
Specific Antigen ◽  
Reporting Quality ◽  
Lesion Detection ◽  
Observer Agreement ◽  
Detection Sensitivity ◽  
Automatic Assessment ◽  
Experienced Radiologist ◽  
Clinically Significant

Multiparametric magnetic resonance imaging (mpMRI) of the prostate is used by radiologists to identify, score, and stage abnormalities that may correspond to clinically significant prostate cancer (CSPCa). Automatic assessment of prostate mpMRI using artificial intelligence algorithms may facilitate a reduction in missed cancers and unnecessary biopsies, an increase in inter-observer agreement between radiologists, and an improvement in reporting quality. In this work, we introduce AutoProstate, a deep learning-powered framework for automatic MRI-based prostate cancer assessment. AutoProstate comprises of three modules: Zone-Segmenter, CSPCa-Segmenter, and Report-Generator. Zone-Segmenter segments the prostatic zones on T2-weighted imaging, CSPCa-Segmenter detects and segments CSPCa lesions using biparametric MRI, and Report-Generator generates an automatic web-based report containing four sections: Patient Details, Prostate Size and PSA Density, Clinically Significant Lesion Candidates, and Findings Summary. In our experiment, AutoProstate was trained using the publicly available PROSTATEx dataset, and externally validated using the PICTURE dataset. Moreover, the performance of AutoProstate was compared to the performance of an experienced radiologist who prospectively read PICTURE dataset cases. In comparison to the radiologist, AutoProstate showed statistically significant improvements in prostate volume and prostate-specific antigen density estimation. Furthermore, AutoProstate matched the CSPCa lesion detection sensitivity of the radiologist, which is paramount, but produced more false positive detections.

scholarly journals Preliminary Study on the Diagnostic Performance of a Deep Learning System for Submandibular Gland Inflammation Using Ultrasonography Images

2021 ◽  
Vol 10 (19) ◽  
pp. 4508
Author(s):  
Yoshitaka Kise ◽  
Chiaki Kuwada ◽  
Yoshiko Ariji ◽  
Munetaka Naitoh ◽  
Eiichiro Ariji
Keyword(s):  
Deep Learning ◽  
Diagnostic Performance ◽  
Test Group ◽  
Training Group ◽  
Learning System ◽  
Control Group ◽  
Preliminary Study ◽  
And Control ◽  
Learning Analysis ◽  
Total Accuracy

This study was performed to evaluate the diagnostic performance of deep learning systems using ultrasonography (USG) images of the submandibular glands (SMGs) in three different conditions: obstructive sialoadenitis, Sjögren’s syndrome (SjS), and normal glands. Fifty USG images with a confirmed diagnosis of obstructive sialoadenitis, 50 USG images with a confirmed diagnosis of SjS, and 50 USG images with no SMG abnormalities were included in the study. The training group comprised 40 obstructive sialoadenitis images, 40 SjS images, and 40 control images, and the test group comprised 10 obstructive sialoadenitis images, 10 SjS images, and 10 control images for deep learning analysis. The performance of the deep learning system was calculated and compared between two experienced radiologists. The sensitivity of the deep learning system in the obstructive sialoadenitis group, SjS group, and control group was 55.0%, 83.0%, and 73.0%, respectively, and the total accuracy was 70.3%. The sensitivity of the two radiologists was 64.0%, 72.0%, and 86.0%, respectively, and the total accuracy was 74.0%. This study revealed that the deep learning system was more sensitive than experienced radiologists in diagnosing SjS in USG images of two case groups and a group of healthy subjects in inflammation of SMGs.

scholarly journals Image Enhancement Model Based on Deep Learning Applied to the Ureteroscopic Diagnosis of Ureteral Stones during Pregnancy

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Xiao-Yan Miao ◽  
Xiao-Nan Miao ◽  
Li-Yin Ye ◽  
Hong Cheng
Keyword(s):  
Deep Learning ◽  
Image Enhancement ◽  
Medical Diagnosis ◽  
Test Group ◽  
Tube Placement ◽  
Ureteral Stones ◽  
Control Group ◽  
Model Based ◽  
The Media ◽  
The Difference

Objective. To explore the image enhancement model based on deep learning on the effect of ureteroscopy with double J tube placement and drainage on ureteral stones during pregnancy. We compare the clinical effect of ureteroscopy with double J tube placement on pregnancy complicated with ureteral stones and use medical imaging to diagnose the patient’s condition and design a treatment plan. Methods. The image enhancement model is constructed using deep learning and implemented for quality improvement in terms of image clarity. In the way, the relationship of the media transmittance and the image with blurring artifacts was established, and the model can estimate the ureteral stone predicted map of each region. Firstly, we proposed the evolution-based detail enhancement method. Then, the feature extraction network is used to capture blurring artifact-related features. Finally, the regression subnetwork is used to predict the media transmittance in the local area. Eighty pregnant patients with ureteral calculi treated in our hospital were selected as the research object and were divided into a test group and a control group according to the random number table method, 40 cases in each group. The test group underwent ureteroscopy double J tube placement, and the control group underwent ureteroscopy lithotripsy. Combined with the ultrasound scan results of the patients before and after the operation, the operation time, time to get out of bed, and hospitalization time of the two groups of patients were compared. The operation success rate and the incidence of complications within 1 month after surgery were counted in the two groups of patients. Results. We are able to improve the quality of the images prior to medical diagnosis. The total effective rate of the observation group was 100.0%, which is higher than that of the control group (90.0%). The difference between the two groups was statistically significant ( P < 0.05 ). The adverse reaction rate in the observation group was 5.0%, which was lower than 17.5% in the control group. The difference between the two groups was statistically significant ( P < 0.05 ). The comparison results are then prepared. Conclusions. The image enhancement model based on deep learning is able to improve medical diagnosis which can assist radiologists to better locate the ureteral stones. Based on our method, double J tube placement under ureteroscopy has a significant effect on the treatment of ureteral stones during pregnancy, and it has good safety and is worthy of widespread application.

Myringoplasty With an Ultrathin Cartilage-Perichondrium Complex Graft Versus Temporalis Fascia Graft: A Propensity Score–Matched Analysis

2020 ◽  
pp. 019459982096594
Author(s):  
Yi-Bo Huang ◽  
Lu-lu Hu ◽  
Dong-Dong Ren ◽  
Zhao Han
Keyword(s):  
Propensity Score ◽  
Middle Ear ◽  
Test Group ◽  
Control Group ◽  
Temporalis Fascia ◽  
Closure Rate ◽  
Factors Affecting ◽  
Fascia Graft ◽  
Endoscopic Myringoplasty ◽  
Air Conduction

Objective To compare endoscopic myringoplasty using the cartilage-perichondrium complex as a graft (test group) with temporalis fascia microscopic myringoplasty (control group). Study Design A retrospective cohort study. Setting Department of Otorhinolaryngology in a tertiary Chinese hospital. Methods Data were collected on patients between 2017 and 2019. To balance the baseline characteristics between groups, we performed a propensity score–matched analysis, and 44 patients were included in each group. Hearing improvement and eardrum closure rates were compared, and risk factors affecting them were analyzed. Results In the control and test groups, 90.90% and 86.36% of patients had a mean air-bone gap ≤20 dB after the surgery, respectively ( P = .843). The air conduction (AC) threshold gain at each frequency was similar in the 2 groups ( P > .05). The closure rates were 95.45% and 93.18%, respectively ( P = .645). The air-bone gap improved significantly after surgery, F(1, 61) = 6.729, P = .012. Age, group, middle ear mucosal status, and location of the perforation did not affect the change in air-bone gap or the drum closure rate ( P > .05). However, there was an interaction between the change in air-bone gap and the size of the perforation, F(1, 61) = 11.067, P = 0001. Conclusion Endoscopic myringoplasty using a cartilage-perichondrium complex graft is comparable with traditional surgery. Age, location of the perforation, and middle ear mucosal status did not significantly affect the change in air-bone gap or the drum closure rate. A perforation size ≥50% was always associated with a better air-bone gap improvement.

scholarly journals Automated breast ultrasound system (ABUS): can it replace mammography as a screening tool?

2019 ◽  
Vol 50 (1) ◽  
Author(s):  
Yasser I. Abd Elkhalek ◽  
Ahmed M. Bassiouny ◽  
Rasha Wessam Abdel Rahman Abdel Hamid
Keyword(s):  
Breast Tissue ◽  
Screening Tool ◽  
Ultrasound Examination ◽  
Breast Ultrasound ◽  
Alternative Methods ◽  
Breast Lesions ◽  
Age Group ◽  
Handheld Ultrasound ◽  
Ultrasound System ◽  
Automated Breast Ultrasound

Abstract Background Mammography is the most accepted, accurate, and effective modality in screening of breast cancer, yet its sensitivity is affected by the density of the breast tissue. Alternative methods for screening are the sonography and MRI but both had their limitations. A new option named ABUS (automated breast ultrasound system) is now proposed to overcome the breast US limitation as it is time-consuming and operator-dependent and to overcome the costly time-consuming MRI. The objectives of the study are to evaluate the accuracy of ABUS in the detection of different breast lesions as a substitution for mammography. This prospective study included 25 women outreached for digital mammography or handheld ultrasound examination at the period between January 2017 and February 2018. Women have no specific age group. Results Significant improvement in the detection of breast lesions by ABUS use with mammogram especially in dense breasts (ACR class C and D) Conclusion ABUS is a promising competitor to mammogram in screening of breast lesions

Assessment of healing of dental implant surgical site following Low-Level Laser Therapy using Bio-Clinical parameters: An Exploratory Study

2020 ◽  
Author(s):  
VARSHA PALLED ◽  
DR. JITENDRA RAO ◽  
DR. RAGHUWAR DAYAL SINGH ◽  
DR. SHUCHI TRIPATHI ◽  
DR. KALPANA SINGH ◽  
...  
Keyword(s):  
Laser Therapy ◽  
Test Group ◽  
Low Level Laser Therapy ◽  
Control Group ◽  
Clinical Parameters ◽  
Implant Stability ◽  
Low Level ◽  
Implant Stability Quotient ◽  
Low Level Laser ◽  
Level Laser

The purpose of this study was to evaluate whether Low-Level Laser Therapy (LLLT) improves the healing of the implant surgical site with clinical and biochemical parameters.Thirty patients with an edentulous space spanning a single tooth were selected. The patients were randomly allocated to two groups - the control group and the test group. The test group received laser energy at a power of 2J/cm 2 with a total of 4-6J energy over each implant. Clinical parameters (Implant Stability Quotient, probing index, modified sulcus bleeding index)and osteoprotegerin (OPG) were assessed at baseline and follow-up intervals (2 weeks, 6 weeks, and 3 months).The test group showed significantly higher implant stability quotient compared to thecontrol group at 2 weeks(57.93±3.95 and 35.67±3.08; p&lt;0.01) and 3months(58.86±3.75 and 67.06±3.78; p&lt;0.01). A significant rise in OPG levels of the test group(686.30±125.36pg/ml at baseline and 784.25±108.30pg/ml at 3months;p&lt;0.01) was seen contrary to significant decline in the control group (839.50±249.08pg/ml at baseline,415.30±78.39pg/ml at 3months;p&lt;0.01). Within the limitations of the study, the study suggests that the healing of peri-implant hard and soft tissues may be enhanced with the use of LLLT as an explicit modality during the post-operative period.

Effects of Virgin Coconut Oil as Adjunct Therapy in the Treatment of Allergic Rhinitis

2016 ◽  
Vol 1 (1) ◽  
pp. 22
Author(s):  
Nazli Zainuddin ◽  
Nurul Azira Mohd Shah ◽  
Rosdan Salim
Keyword(s):  
Allergic Rhinitis ◽  
Side Effects ◽  
Coconut Oil ◽  
Test Group ◽  
Nasal Symptom ◽  
Control Group ◽  
Virgin Coconut Oil ◽  
Control Groups ◽  
Significant Difference ◽  
And Control

Introduction: The role of virgin coconut oil in the treatment of allergic rhinitis is controversial. Thus, the aim of the present study is to determine the effects of virgin coconut oil ingestion, in addition to standard medications, on allergic rhinitis. We also studied the side effects of consumption of virgin coconut oil. Methods: Fifty two subjects were equally divided into test and control groups. All subjects received a daily dose of 10mg of loratadine for 28 days. The test group was given 10ml of virgin coconut oil three times a day in addition to loratadine. The symptoms of allergic rhinitis were scored at the beginning and end of the study. Results:, the symptom score were divided into nasal and non-nasal symptom scores. Sneezing score showed a significant difference, however the score was more in control group than test group, indicating that improvement in symptom was more in control group. The rest of the nasal symptom and non-nasal symptom score showed no significant difference between test and control groups. Approximately 58% of the test subjects developed side effects from consumption of virgin coconut oil, mainly gastrointestinal side effects. Conclusion: In the present study, ingestion of virgin coconut oil does not improve the overall and individual symptoms of allergic rhinitis, furthermore it has side effects.

ВЛИЯНИЕ КОМПЛЕКСНОЙ МИНЕРАЛЬНО-ВИТАМИННОЙ КОРМОВОЙ ДОБАВКИ НА ГЕМАТОЛОГИЧЕСКИЕ И БИОХИМИЧЕСКИЕ ПОКАЗАТЕЛИ КРОВИ ТЕЛЯТ

2020 ◽  
Author(s):  
M.T. SABITOV ◽  
A.R. FARKHUTDINOVA ◽  
M.G. MALIKOVA ◽  
N.G. FENCHENKO ◽  
N.I. KHAIRULLINA ◽  
...  
Keyword(s):  
Animal Feed ◽  
Food Additives ◽  
Test Group ◽  
Feed Additives ◽  
Feed Additive ◽  
Control Group ◽  
Special Role ◽  
Young Stock ◽  
Black And White ◽  
Calcium Phosphorus

Изучена целесообразность использования в рационах телят черно-пестрой породы комплексной минерально-витаминной кормовой добавки (КМВКД). Установлено пониженное содержание в кормах таких элементов, как кальций, фосфор, магний, сера, марганец, медь, цинк и кобальт. Соотношение питательных и минеральных веществ, степень их доступности для усвоения организмом не обеспечивают их потребность. Использование КМВКД способствовало улучшению всех гематологических показателей. Все испытываемые рецепты, имеющие в своем составе разные варианты макро-, микроэлементов и витаминов положительно влияют на обменные про- цессы в организме животных. У молодняка опытной группы, получавшей подкормку по рецепту 1, количество эритроцитов в сравнении с животными контрольной группы увеличилось на 6,6, гемоглобина на 6,93 соответственно, по рецепту 2 11,05 и 11,39 по рецепту 3 16,75 и 15,27, то есть соотношение макро- и микроэлементов, имеющихся в составе КМВКД и взаимодействие между собой меди, железа и кобальта сыграли особую роль на концентрацию форменных элементов. У молодняка, получавшего подкормку по рецепту 1 количество общего белка в сравнении с животными контрольной группы увеличилось на 1,99, кальция на 16,02, каротина на 10,92 соответственно, по рецепту 2 4,91, 25,96 и 19,12 по рецепту 3 на 3,58, 27,07 и 20,21. Значительное повышение содержания белка, кальция, фосфора и каротина по сравнению с животными контрольной группы объясняется тем, что недостаток их в рационах восполнялся за счет используемой подкормки, в результате их содержание увеличилось в сыворотке, но не выходило за пределы нормативных данных и соответствовало физиологическим нормам.Practicability of using a complex mineral and vitamin feed additive (CMVFA) in the ration of black-and-white calf breed was studied. Decreased content of such elements as calcium, phosphorus, magnesium, sulfur, manganese, copper, zinc, and cobalt was registered. The correlation of nutritive and mineral substances, and the level of their availability for digestion did not provide for their need. CMVFA use facilitated the increase of all hematologic parameters. Tested recipes which had different content of sapropel and zeolite, as well as various types of macronutrients, microelements, and vitamins, positively influenced the digestive processes in animal bodies. Young stock from the test group that was receiving food additives according to recipe No. 1 showed 6.6 increase in the quantity of red blood cells compared to control group animals, and 6.93 increase in hemoglobin quantity the ones who were fed according to recipe No. 2 demonstrated the increase by 11.05 and 11.39 recipe No. 3 showed 16.75 and 15.27 increase, which means that the ratio of macronutrients and microelements present in CMVFA and the mutual interaction of copper, iron, and cobalt played a special role in the concentration of formed elements due to the fact that they are integral elements of blood. Total protein of young stock that was receiving food additives according to recipe No. 1 was 1.99 higher than in test group animals calcium 16.02 higher carotene 10.92 as for recipe No. 2 the values were increased by 4.91, 25.96, and 19.12 recipe No. 3 3.58, 27.07, and 20.21. Substantial increase in the content of protein, calcium, phosphorus, and carotene compared to control group animals can be explained by the fact that their insufficiency in animal feed was replenished due to the use of feed additives, and as a result their content increased in the serum but did not go beyond the norm and corresponded to physiological norms.

POSTURAL STABILITY IN PATIENTS WITH LATENT TRIGGER ZONES OF NECK MUSCULATURE

2019 ◽  
pp. 114-123
Author(s):  
E.R. Mukhametova ◽  
A.D. Militskova ◽  
T.V. Baltina
Keyword(s):  
Postural Control ◽  
Postural Stability ◽  
Test Group ◽  
Trigger Points ◽  
Control Group ◽  
Neck Muscle ◽  
Pressure Center ◽  
Cervical Muscles ◽  
Equilibrium Function ◽  
Romberg Test

There are many reasons for postural disorder development, but dysfunction of the cervical spine muscles is the most disputable reason. The purpose of the study is to reveal the influence of latent myogenic trigger zones of the cervical muscles on postural resistance. Materials and Methods. The authors used the method of computer posturography. Latent myogenic trigger zones (LMTZs) were determined by an indurated nodule or bundle in the neck muscle and by hyperesthesia in this zona. Assessment of postural resistance in subjects with LMTZs was carried out using standard posturography tests and Romberg test. Both classical and vector indicators were evaluated in a standard sample. Results. In fact, only vector indicators changed significantly in subjects with multiple LMTZs (4 or more). Thus, a decrease in the equilibrium function quality was established, as well as an increase in the average linear velocity of the pressure center and an increase in the normalized vectorogram area if compared with the indices in the control group and the group with sporadic LMTZs (from 1 to 3). The obtained results indicate a postural control decrease in individuals with multiple LMTZs. Subjects with sporadic LMTZs demonstrated a significant decrease in classical and a number of vector indicators, which shows the improvement in postural resistance in this test group. In Romberg test, all subjects with LMTZs, regardless of the zone number, showed an increasd Romberg coefficient. Conclusion. Multiple LMTZs of cervical muscles can reduce postural stability through increased afferentation from the cervical proprioreceptors. It is more obvious during in case of eye control elimination. Keywords: latent myogenic trigger points, postural control, posturography, Romberg test. Выделяют множество причин развития постуральных нарушений, среди которых дисфункция мышц шейного отдела позвоночника является наиболее спорной. Цель исследования. Выявить влияние латентных миогенных триггерных зон шейной мускулатуры на постуральную устойчивость. Материалы и методы. Использовался метод компьютерной стабилографии. Латентные миогенные триггерные зоны (лМТЗ) определялись по наличию в мышце шеи уплотненного узелка или пучка и по повышенной болевой чувствительности в этой области. Оценка постуральной устойчивости у испытуемых с лМТЗ осуществлялась с помощью стандартного стабилографического тестирования и теста Ромберга. В стандартной пробе оценивались как классические, так и векторные показатели. Результаты. Показано, что у испытуемых с множественными лМТЗ (4 и более) достоверно изменяются только векторные показатели. Так, установлено снижение качества функции равновесия, а также повышение средней линейной скорости центра давления и увеличение нормированной площади векторограммы по сравнению показателями в группе контроля и группе с единичными лМТЗ (от 1 до 3), что указывает на снижение постурального контроля у лиц с множественными лМТЗ. У испытуемых с единичными лМТЗ отмечено достоверное снижение классических показателей и ряда векторных, что свидетельствует об улучшении постуральной устойчивости в данной группе испытуемых. В пробе Ромберга все субъекты с лМТЗ независимо от количества последних показали повышение коэффициента Ромберга. Выводы. Множественные лМТЗ шейной мускулатуры могут снизить постуральную устойчивость через усиление афферентации от шейных проприорецепторов, что наиболее выражено при элиминации зрительного контроля. Ключевые слова: латентные миогенные триггерные точки, постуральный контроль, стабилография, тест Ромберга.

ZINC IN THE RATIONS OF CALVES

2019 ◽  
Keyword(s):  
Body Mass ◽  
Test Group ◽  
Hair Follicles ◽  
Control Group ◽  
Albumin Concentration ◽  
Zinc Compounds ◽  
Entire Duration ◽  
Zinc Salts ◽  
Group A ◽  
Hair Cortex

According to the Tambovagrochemcenter data, zinc deficiency in animal rations exceeds 33%. To de-termine the efficiency of ration additives 3 groups of calves were formed, one of which was control and received regular feed, first test group received additional Zinc Sulphate, and second test group received additional Zinc Bioplex. To assess the results, we take into account the following values: chemical com-position and nutritional values of the feed, body mass value, amount of immunoglobulins in blood, bio-chemical and hematological values of blood, morphological values of fur and skin. Noticeable results were achieved in 4 months, with first and second test groups receiving accordingly 3,15% and 6,13% more body mass increase over the control group. A tendency towards higher albumin concentration in both test groups was noted, and calves of the second test group had higher amounts of hemoglobin and higher concentrations of it per erythrocyte. In samples of epidermis and hairs of the second test group the papillary layer was well developed, with the amount of hair and hair follicles exceeding 7 in the field of view, with the thickness of hairs being at least 70 μm. Inner papilla of hair contained 6 to 8 layers of hair, thickness of awn hairs reaching 80-90 μm, down hairs reaching 40 μm, with the hair cortex making up more than 80% of the hair thickness. Thus, introducing zinc salts and chelated zinc compounds to the milk-fed calves’ ration, has resulted in monetary profit increases over the control group by 255,0 and 612,0 roubles accordingly. By all researched values, the highest results were reached from adding zinc bioplex with approximately 360 mg added per animal for the entire duration of the growth process.

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