ABSTRACT
The increment of battery temperature during the operation caused by internal heat generation is one of the main issues to face in the management of storage systems for automotive and power generation applications. The temperature strongly affects the battery efficiency, granting the best performance in a limited range. The investigation and testing of materials for the improvement of heat dissipation are crucial for modern battery systems that must provide high power and energy density. This study presents an analysis of the thermal behavior of a lithium-polymer cell, which can be stacked in a battery pack for electric vehicles. The cell is sheltered with layers of two different materials: carbon and graphene, used in turn, to dissipate the heat generated during the operation in natural convection. Optical diagnostics in the infrared band is used to evaluate the battery surface temperature and the effect of the coatings. Experiments are performed in two operating conditions varying the current demand. Moreover, two theoretical correlations are used to estimate the thermal parameters of the battery with a reverse-logic approach. The convective heat transfer coefficient h and the specific heat capacity cp of the battery are evaluated and provided for the Li-ion battery under investigation for different coatings' conductivity. The results highlight the advantage of using a coating and the effect of the coating properties to reduce the battery temperature under operation. In particular, graphene is preferable because it provides the lowest battery temperature in the most intense operating condition.
ABSTRACT
Rhombomeres (r) contribute to brainstem auditory nuclei during development. Hox genes are determinants of rhombomere-derived fate and neuronal connectivity. Little is known about the contribution of individual rhombomeres and their associated Hox codes to auditory sensorimotor circuitry. Here, we show that r4 contributes to functionally linked sensory and motor components, including the ventral nucleus of lateral lemniscus, posterior ventral cochlear nuclei (VCN), and motor olivocochlear neurons. Assembly of the r4-derived auditory components is involved in sound perception and depends on regulatory interactions between Hoxb1 and Hoxb2. Indeed, in Hoxb1 and Hoxb2 mutant mice the transmission of low-level auditory stimuli is lost, resulting in hearing impairments. On the other hand, Hoxa2 regulates the Rig1 axon guidance receptor and controls contralateral projections from the anterior VCN to the medial nucleus of the trapezoid body, a circuit involved in sound localization. Thus, individual rhombomeres and their associated Hox codes control the assembly of distinct functionally segregated sub-circuits in the developing auditory brainstem.
Subject(s)
Brain Stem , Homeodomain Proteins , Transcription Factors , Animals , Auditory Pathways/metabolism , Auditory Pathways/physiology , Axons/metabolism , Brain Stem/growth & development , Brain Stem/metabolism , Cochlea/growth & development , Cochlea/metabolism , DEAD Box Protein 58 , DEAD-box RNA Helicases/genetics , DEAD-box RNA Helicases/metabolism , Gene Expression Regulation, Developmental , Gene Regulatory Networks , Homeodomain Proteins/genetics , Homeodomain Proteins/metabolism , Mice , Midline Thalamic Nuclei/growth & development , Midline Thalamic Nuclei/metabolism , Motor Neurons/cytology , Motor Neurons/metabolism , Olivary Nucleus/growth & development , Olivary Nucleus/metabolism , Sound Localization , Transcription Factors/genetics , Transcription Factors/metabolismABSTRACT
Noise over-stimulation will induce or influence molecular pathways in the cochlea; one approach to the identification of the components of these pathways in the cochlea is to examine genes and proteins that change following different types and levels of stress. Quantitative reverse transcription polymerase chain reaction provides a method to look at differential expression of genes in the acoustic stress response. By using this technique we have revealed a down-regulation of the level of otospiralin mRNA in the cochlea of guinea pigs after white noise over-stimulation for 2 h at 108 dB SPL. Otospiralin represents an inner ear specific protein found in fibrocytes of spiral limbus and spiral ligament in the cochlea, and some regions of the vestibule as the stroma underlying the utricle and crista sensory epithelia and the subepithelial layer of the walls of semicircular canals and maculae. It has been recently reported that transient down-regulation of otospiralin in guinea pigs causes vestibular syndrome and deafness. Our results suggest a possible role of this gene in response to acoustical stress, although the exact mechanism remains to be resolved.
Subject(s)
Cochlea/metabolism , Down-Regulation/physiology , Noise/adverse effects , Proteins/metabolism , RNA, Messenger/metabolism , Analysis of Variance , Animals , Case-Control Studies , Evoked Potentials, Auditory, Brain Stem , Female , Guinea Pigs , Proteins/genetics , Random Allocation , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
OBJECTIVE: To investigate brain morphology and function in patients with glycogen storage disease type I (GSDI). STUDY DESIGN: Nineteen patients (13 females and 6 males, aged 0.9-22.6 years) and 38 sex- and age-matched controls entered the study. Neurological examinations, psychometric tests (IQ, tests of performance and verbal abilities), standard electroencephalogram (EEG), somatosensory (SEPs), visual (VEPs), and brain-stem auditory evoked potentials (BAEPs), and brain magnetic resonance imaging (MRI) were performed. RESULTS: The results of tests of performance ability were lower in patients than in controls (P <.05). The prevalence of abnormal EEG findings (26.3% versus 2.6%), VEPs (38.4% versus 7.7%), SEPs (23.0% versus 0%), and BAEPs abnormalities (15.7% versus 0%) was higher in patients than in controls (P <.05). MRI pattern was altered in 57.1% of patients and was normal in all controls (P <.05). Both results of tests of performance ability and BAEPs abnormalities significantly correlated with the frequency of admissions for hypoglycemia, whereas EEG abnormalities correlated with dietary compliance (P <.05). CONCLUSIONS: Brain damage, probably caused by recurrent severe hypoglycemia, may be present in patients with GSDI.
Subject(s)
Brain Diseases, Metabolic/epidemiology , Glycogen Storage Disease Type I/complications , Adolescent , Adult , Brain Diseases, Metabolic/etiology , Brain Diseases, Metabolic/pathology , Case-Control Studies , Child , Child, Preschool , Electroencephalography , Evoked Potentials , Female , Humans , Hypoglycemia/complications , Infant , Italy/epidemiology , Magnetic Resonance Imaging , Male , Neurologic ExaminationABSTRACT
Temporary threshold shift (TTS) and permanent threshold shift (PTS) may follow prolonged noise exposure. Several reports suggest that noise-induced damage to the cochlea may be related to the activity of reactive oxygen species (ROS). Drugs that scavenge or block ROS formation also protect the cochlea. Guinea pigs, treated with allopurinol, were exposed to white noise (120 dB SPL) or impulse noise (114 dB SPL) for 2 and 5 h. The protective effect of allopurinol was confirmed, but, at these levels of sound, it was present only after noise exposure up to 2 h. This study also offers evidence suggesting that allopurinol does not influence the establishment of PTS.
