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Woo CC, Miranda B, Sathishkumar M, Dehkordi-Vakil F, Yassa MA, Leon M. Overnight olfactory enrichment using an odorant diffuser improves memory and modifies the uncinate fasciculus in older adults. Front Neurosci 2023; 17:1200448. [PMID: 37554295 PMCID: PMC10405466 DOI: 10.3389/fnins.2023.1200448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 07/07/2023] [Indexed: 08/10/2023] Open
Abstract
OBJECTIVE Cognitive loss in older adults is a growing issue in our society, and there is a need to develop inexpensive, simple, effective in-home treatments. This study was conducted to explore the use of olfactory enrichment at night to improve cognitive ability in healthy older adults. METHODS Male and female older adults (N = 43), age 60-85, were enrolled in the study and randomly assigned to an Olfactory Enriched or Control group. Individuals in the enriched group were exposed to 7 different odorants a week, one per night, for 2 h, using an odorant diffuser. Individuals in the control group had the same experience with de minimis amounts of odorant. Neuropsychological assessments and fMRI scans were administered at the beginning of the study and after 6 months. RESULTS A statistically significant 226% improvement was observed in the enriched group compared to the control group on the Rey Auditory Verbal Learning Test and improved functioning was observed in the left uncinate fasciculus, as assessed by mean diffusivity. CONCLUSION Minimal olfactory enrichment administered at night produces improvements in both cognitive and neural functioning. Thus, olfactory enrichment may provide an effective and low-effort pathway to improved brain health.
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Affiliation(s)
- Cynthia C. Woo
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, United States
| | - Blake Miranda
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, United States
- Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA, United States
| | - Mithra Sathishkumar
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, United States
- Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA, United States
| | | | - Michael A. Yassa
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, United States
- Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA, United States
| | - Michael Leon
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, United States
- Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA, United States
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA, United States
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Leon M, Woo CC. Olfactory loss is a predisposing factor for depression, while olfactory enrichment is an effective treatment for depression. Front Neurosci 2022; 16:1013363. [PMID: 36248633 PMCID: PMC9558899 DOI: 10.3389/fnins.2022.1013363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Accepted: 09/08/2022] [Indexed: 11/13/2022] Open
Abstract
The loss of olfactory stimulation correlates well with at least 68 widely differing neurological disorders, including depression, and we raise the possibility that this relationship may be causal. That is, it seems possible that olfactory loss makes the brain vulnerable to expressing the symptoms of these neurological disorders, while daily olfactory enrichment may decrease the risk of expressing these symptoms. This situation resembles the cognitive reserve that is thought to protect people with Alzheimer’s neuropathology from expressing the functional deficit in memory through the cumulative effect of intellectual stimulation. These relationships also resemble the functional response of animal models of human neurological disorders to environmental enrichment, wherein the animals continue to have the induced neuropathology, but do not express the symptoms as they do in a standard environment with restricted sensorimotor stimulation.
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Affiliation(s)
- Michael Leon
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, United States
- Center for the Neurobiology of Learning and Memory, Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA, United States
- *Correspondence: Michael Leon,
| | - Cynthia C. Woo
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, United States
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Haehner A, Chen B, Espin M, Haussmann R, Matthes C, Desser D, Loessner L, Brandt MD, Donix M, Hummel T. Training with Odors Impacts Hippocampal Thickness in Patients with Mild Cognitive Impairment. J Alzheimers Dis 2022; 88:743-755. [DOI: 10.3233/jad-220248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background: The olfactory system is affected early in Alzheimer’s disease and olfactory loss can already be observed in patients with mild cognitive impairment (MCI). Olfactory training is effective for improving olfactory and cognitive function by stimulating the olfactory pathway, but its effect on patients with MCI remains unclear. Objective: The aim of this randomized, prospective, controlled, blinded study was to assess whether a 4-month period of olfactory training (frequent short-term sniffing various odors) may have an effect on olfactory function, cognitive function, and morphology of medial temporal lobe (MTL) subregions and olfactory bulb in MCI patients. Methods: A total of thirty-seven MCI patients were randomly assigned to the training group or a placebo group, which were performed twice a day for 4 months. Olfactory assessments, cognitive tests and magnetic resonance imaging were performed at the baseline and follow-up period. Results: After the training, there was an increase in odor discrimination, and increased cortical thickness of bilateral hippocampus (CA23DG and CA1) and mean MTL. Additionally, the change of olfactory score was positively associated with change of volume of olfactory bulb and hippocampus; the change of global cognition was positively associated with change of cortical thickness of hippocampus, entorhinal cortex and mean MTL; the change of cortical thickness of entorhinal cortex was positively associated with change of executive function. Conclusion: Olfactory training was associated with an increase in cortical thickness of the hippocampus but not olfactory bulb volume in patients with MCI. Olfactory training may serve as an early intervention of preventing hippocampal atrophy.
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Affiliation(s)
| | - Ben Chen
- Smell & Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Dresden, Germany
- Memory Clinic, Department of Geriatric Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong Province, China
| | - Melanie Espin
- Smell & Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Dresden, Germany
| | | | | | - Dmitriy Desser
- Smell & Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Dresden, Germany
| | | | - Moritz D. Brandt
- Department of Neurology, TU Dresden, Dresden, Germany
- German Center for Neurodegenerative Diseases (DZNE), Dresden, Germany
| | - Markus Donix
- Department of Psychiatry, TU Dresden, Dresden, Germany
- German Center for Neurodegenerative Diseases (DZNE), Dresden, Germany
| | - Thomas Hummel
- Smell & Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Dresden, Germany
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Rebeca H, Karen PA, Elva A, Carmen C, Fernando P. Main Olfactory Bulb Reconfiguration by Prolonged Passive Olfactory Experience Correlates with Increased Brain‐Derived Neurotrophic Factor and Improved Innate Olfaction. Eur J Neurosci 2022; 55:1141-1161. [DOI: 10.1111/ejn.15610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 01/19/2022] [Accepted: 01/21/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Hernández‐Soto Rebeca
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM‐Campus Juriquilla México
| | - Pimentel‐Farfan Ana Karen
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM‐Campus Juriquilla México
| | - Adan‐Castro Elva
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, UNAM‐Campus Juriquilla México
| | - Clapp Carmen
- Departamento de Neurobiología Celular y Molecular, Instituto de Neurobiología, UNAM‐Campus Juriquilla México
| | - Peña‐Ortega Fernando
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM‐Campus Juriquilla México
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Nomura S, Monobe M, Ema K, Yoshida K, Yamashita S, Ogino A, Nesumi A. Effects of a Tea Cultivar "MK5601" on Behaviors and Hippocampal Neurotrophin-3 Levels in Middle-Aged Mice. J Nutr Sci Vitaminol (Tokyo) 2021; 67:170-179. [PMID: 34193676 DOI: 10.3177/jnsv.67.170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Dietary factors are thought to play an important role in the prevention of cognition diseases and depression in late life. In the present study, we compared the effects between the theogallin-rich tea cultivar, "MK5601" and a common Japanese tea cultivar, "Yabukita" on behaviors and hippocampal neurotrophin levels in experimental animals. Middle-aged mice (aged 8 mo) were given either of the tea infusions or water ad libitum for 4 mo. In the novel object location test, the middle-aged mice drinking water or "Yabukita" performed worse than young mice (aged 2-3 mo) although the middle-aged mice drinking "MK5601" retained spatial memory at the same level as the young mice. We also found that the middle-aged mice drinking "MK5601" showed high levels of neurotrophin-3 in the hippocampus. In conclusion, the "MK5601" tea infusion appears to be effective in preventing age-related changes in cognitive function, as compared with a common Japanese tea cultivar.
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Affiliation(s)
- Sachiko Nomura
- Tea Research Division, Institute of Fruit Tree and Tea Science, National Agriculture and Food Research Organization (NARO)
| | - Manami Monobe
- Tea Research Division, Institute of Fruit Tree and Tea Science, National Agriculture and Food Research Organization (NARO)
| | - Kaori Ema
- Tea Research Division, Institute of Fruit Tree and Tea Science, National Agriculture and Food Research Organization (NARO)
| | - Katsuyuki Yoshida
- Tea Research Division, Institute of Fruit Tree and Tea Science, National Agriculture and Food Research Organization (NARO)
| | - Shuya Yamashita
- Tea Research Division, Institute of Fruit Tree and Tea Science, National Agriculture and Food Research Organization (NARO)
| | - Akiko Ogino
- Tea Research Division, Institute of Fruit Tree and Tea Science, National Agriculture and Food Research Organization (NARO)
| | - Atsushi Nesumi
- Tea Research Division, Institute of Fruit Tree and Tea Science, National Agriculture and Food Research Organization (NARO)
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6
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Dixit A, Bhattacharya B. Sensory perception of environmental cues as a modulator of aging and neurodegeneration: Insights from Caenorhabditis elegans. J Neurosci Res 2021; 99:2416-2426. [PMID: 34232538 DOI: 10.1002/jnr.24910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/01/2021] [Accepted: 06/08/2021] [Indexed: 11/09/2022]
Abstract
Environmental stimuli such as temperature, food, and smell significantly influence the physiology and behavior of animals. Animals are differentially adapted to maintain their internal body functions in response to varied environmental conditions. These external cues are sensed by specialized neurons which are a part of the chemosensory and thermosensory systems. The inability to respond correctly to varied environmental conditions may result in compromised bodily functions and reduced longevity. For example, the ability to sense food is derived from the integrated action of olfactory and gustatory systems. The damage to the olfactory system will affect our decision of palatable food items which in turn can affect the response of the gustatory system, ultimately causing abnormal feeding habits. Recent studies have provided evidence that aging is regulated by sensory perception of environment. Aging is one of the most common causes of various neurodegenerative diseases and the perception of environmental cues is also found to regulate the development of neurodegenerative phenotype in several animal models. However, specific molecular signaling pathways involved in the process are not completely understood. The research conducted on one of the best-studied animal models of aging, Caenorhabditis elegans, has demonstrated multiple examples of gene-environment interaction at the neuronal level which affects life span. The findings may be useful to identify the key neuronal regulators of aging and age-related diseases in humans owing to conserved core metabolic and aging pathways from worms to humans.
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Affiliation(s)
- Anubhuti Dixit
- Amity Institute of Neuropsychology and Neurosciences, Amity University, Noida, India
| | - Bidisha Bhattacharya
- Amity Institute of Neuropsychology and Neurosciences, Amity University, Noida, India
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Kim H, Song E, Lee J, Gautam R, Shin S, Cho A, Kim Y, Yang S, Jo J, Acharya M, Maharjan A, Kim C, Heo Y, Kim H. Dysregulation of murine immune functions on inhalational exposure to ammonia, dimethyl disulfide, 3-methylindole, or propionic acid. Toxicol Ind Health 2021; 37:219-228. [PMID: 33663293 DOI: 10.1177/0748233721996559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Animal husbandry workers are exposed to various malodorous compounds in the workplace. Although these compounds cause severe nuisance, no systemic investigation of their effects on the immune system has been conducted. To address this issue, we evaluated the effects of inhalational exposure to ammonia, dimethyl disulfide, 3-methylindole (3-MI), and propionic acid (PA), representing four major groups of malodorous compounds, on humoral and cellular immunity in mice. Mice were exposed to the substances (low dose: 10 µL and high dose: 200 µL) for 10 min/day for 4 weeks in a modified standard mouse cage. Neutrophil% and splenic cytotoxic T cell% were significantly lower in the high-dose ammonia group than in the vehicle control. Exposure to ammonia and 3-MI increased immature thymic T lymphocyte% relative to control and concomitantly decreased both mature helper and cytotoxic T-cell populations in the thymus. In the ammonia exposure group, levels of serum immunoglobulin E and immunoglobulin A were elevated, and the IgG2a:IgG1 ratio in the serum was reduced in a dose-dependent manner. Splenic natural killer cell activity was significantly less in the PA exposure group than in the control. Overall, our findings suggest that inhalational exposure to these malodorous substances disturbs immune homeostasis in vivo.
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Affiliation(s)
- HyeonJi Kim
- Department of Occupational Health, College of Bio-Medical Sciences, 37981Daegu Catholic University, Gyeongbuk, Republic of Korea
| | - EunSeob Song
- Department of Occupational Health, College of Bio-Medical Sciences, 37981Daegu Catholic University, Gyeongbuk, Republic of Korea
| | - JaeHee Lee
- Department of Occupational Health, College of Bio-Medical Sciences, 37981Daegu Catholic University, Gyeongbuk, Republic of Korea
| | - Ravi Gautam
- Department of Occupational Health, College of Bio-Medical Sciences, 37981Daegu Catholic University, Gyeongbuk, Republic of Korea
| | - SoJung Shin
- Department of Occupational Health, College of Bio-Medical Sciences, 37981Daegu Catholic University, Gyeongbuk, Republic of Korea
| | - AhRang Cho
- Department of Occupational Health, College of Bio-Medical Sciences, 37981Daegu Catholic University, Gyeongbuk, Republic of Korea
| | - YeonGyeong Kim
- Department of Occupational Health, College of Bio-Medical Sciences, 37981Daegu Catholic University, Gyeongbuk, Republic of Korea
| | - SuJeong Yang
- Department of Occupational Health, College of Bio-Medical Sciences, 37981Daegu Catholic University, Gyeongbuk, Republic of Korea
| | - JiHun Jo
- Department of Occupational Health, College of Bio-Medical Sciences, 37981Daegu Catholic University, Gyeongbuk, Republic of Korea
| | - Manju Acharya
- Department of Occupational Health, College of Bio-Medical Sciences, 37981Daegu Catholic University, Gyeongbuk, Republic of Korea
| | - Anju Maharjan
- Department of Occupational Health, College of Bio-Medical Sciences, 37981Daegu Catholic University, Gyeongbuk, Republic of Korea
| | - ChangYul Kim
- Department of Occupational Health, College of Bio-Medical Sciences, 37981Daegu Catholic University, Gyeongbuk, Republic of Korea
| | - Yong Heo
- Department of Occupational Health, College of Bio-Medical Sciences, 37981Daegu Catholic University, Gyeongbuk, Republic of Korea.,Department of Toxicity Assessment, Graduate School of Medical Health and Science, 37981Daegu Catholic University, Gyeongbuk, Republic of Korea
| | - HyoungAh Kim
- Department of Preventive Medicine, 37128College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
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8
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Cognitive and Neurochemical Changes Following Polyphenol-Enriched Diet in Rats. Nutrients 2020; 13:nu13010059. [PMID: 33375450 PMCID: PMC7824548 DOI: 10.3390/nu13010059] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/20/2020] [Accepted: 12/24/2020] [Indexed: 12/11/2022] Open
Abstract
Dietary recommendations are frequently developed based on nutrient deficiency or prevention of disease, but less attention has been paid to the dietary guidelines to promote brain health. Active and healthy aging is a prerequisite for improving quality of life as people age, and evidence is establishing a relationship between diet and brain health. This work studied the effect of a diet based on foods rich in antioxidants, especially polyphenols, in rats, three days a week for 20 months starting at 14 months. Behavioral analysis testing working memory, spatial and episodic memory, as well as brain monoaminergic neurotransmitters involved in these processes but also in general brain health were analyzed. In addition, hippocampal SIRT1 protein which has an important role in regulating normal brain function was evaluated. The results show that long-term intake of polyphenol-enriched diet improves memory and learning, correlating with restoration of brain monoaminergic neurotransmitters and hippocampal SIRT1 levels in aged rats. These results agree with reports revealing a neuroprotective effect of different polyphenolic compounds on age-related brain decline, based on its antioxidant and anti-inflammatory properties; and demonstrate that consumption of antioxidant-rich foods, a few days a week, gives good long-term results in terms of brain health.
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9
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Pritchett-Corning KR. Environmental Complexity and Research Outcomes. ILAR J 2020; 60:239-251. [PMID: 32559304 DOI: 10.1093/ilar/ilaa007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 01/28/2020] [Accepted: 02/04/2020] [Indexed: 11/14/2022] Open
Abstract
Environmental complexity is an experimental paradigm as well as a potential part of animals' everyday housing experiences. In experimental uses, researchers add complexity to stimulate brain development, delay degenerative brain changes, elicit more naturalistic behaviors, and test learning and memory. Complexity can exacerbate or mitigate behavioral problems, give animals a sense of control, and allow for expression of highly driven, species-typical behaviors that can improve animal welfare. Complex environments should be designed thoughtfully with the animal's natural behaviors in mind, reported faithfully in the literature, and evaluated carefully for unexpected effects.
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Affiliation(s)
- Kathleen R Pritchett-Corning
- Office of Animal Resources, Faculty of Arts and Sciences, Harvard University, Cambridge, Massachusetts.,Department of Comparative Medicine, University of Washington, Seattle, Washington
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Zhou H, Wang X, Lin J, Zhao Z, Chang C. Distribution of Cadherin in the Parahippocampal Area of Developing Domestic Chicken Embryos. Exp Neurobiol 2020; 29:11-26. [PMID: 32122105 PMCID: PMC7075654 DOI: 10.5607/en.2020.29.1.11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 01/24/2020] [Accepted: 01/24/2020] [Indexed: 12/31/2022] Open
Abstract
Hippocampal formation is important in spatial learning and memory. Members of the cadherin superfamily are observed in the neural system with diverse spatial and temporal expression patterns and are involved in many biological processes. To date, the avian hippocampal formation is not well understood. In this study, we examined the expression of cadherin mRNA in chicken and mouse brains to investigate the morphological and cytoarchitectural bases of hippocampal formation. Profiles of the spatiotemporal expression of cadherin mRNAs in the developing chicken embryonic parahippocampal area (APH) are provided, and layer-specific expression and spatiotemporal expression were observed in different subdivisions of the APH. That fact that some cadherins (Cdh2, Cdh8, Pcdh8 and Pcdh10) showed conserved regional expression both in the hippocampus and entorhinal cortex of mice and the hippocampal formation of chickens partially confirmed the structural homology proposed by previous scientists. This study indicates that some cadherins can be used as special markers of the avian hippocampal formation.
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Affiliation(s)
- He Zhou
- School of Basic Medical Sciences, ZhengZhou University, Zhengzhou 450000, China.,Department of General and Visceral Surgery, Goethe-University Hospital, Frankfurt am Main 60596, Germany
| | - XiaoFan Wang
- School of Basic Medical Sciences, ZhengZhou University, Zhengzhou 450000, China
| | - JunTang Lin
- Henan Joint International Research Laboratory of Stem Cell Medicine, College of Biomedical Engineering, Xinxiang Medical University, Xinxiang 453000, China
| | - Ze Zhao
- School of Law, Shanghai University of Finance and Economics, Shanghai 200000, China
| | - Cheng Chang
- School of Basic Medical Sciences, ZhengZhou University, Zhengzhou 450000, China.,Birth Defect Prevention Key Laboratory, National Health Commission of the People's Republic of China, Zhengzhou 450000, China.,Center of Cerebral Palsy Surgical Research and Treatment, ZhengZhou University, Zhengzhou 450000, China
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