81,462 research outputs found
Acoustic Source Power Control and Global Noise Reduction by Arrangement of Absorptive Materials in Acoustically Small Enclosures
No full textThe possibility of global noise reduction by the sound power control is discussed. It is necessary to investigate the relation between the global sound energy in the field and the total sound power radiated by sources. In the previous work [1,2], the authors presented a useful design method to change boundary condition that reduces noise in acoustically small enclosures. Changing boundary condition is related to not only its geometrical shape but also acoustical treatment on walls; for example, attaching of impedance patches (ex: absorptive material). In many practical situations, we often meet a situation to change acoustical treatment on walls. A paper related to what we envisaged was presented at Inter-noise 2003 (S.-H. Cho, Y.-H. Kim, and K. Grosh, “The effect of impedance patch position on the sound field of an acoustically small cavity,” in Proc. Inter-noise 2003, N236). In this paper, the relation between acoustic source power control and global noise reduction are discussed. The possibility of total acoustic potential energy, which is global noise, reduction by acoustic source power control is examined for acoustically small cavity. Using acoustic energy balance equation, the relation between global noise control performance and absorptive material arrangement is deduced. Simulation is performed to investigate the theoretical possibility and the power control trend in terms of total acoustic potential energy reduction with respect to the frequency range of interest
CHO microRNA engineering is growing up : recent successes and future challenges
No full textmicroRNAs with their ability to regulate complex pathways that control cellular behavior and phenotype have been proposed as potential targets for cell engineering in the context of optimization of biopharmaceutical production cell lines, specifically of Chinese Hamster Ovary cells. However, until recently, research was limited by a lack of genomic sequence information on this industrially important cell line. With the publication of the genomic sequence and other relevant data sets for CHO cells since 2011, the doors have been opened for an improved understanding of CHO cell physiology and for the development of the necessary tools for novel engineering strategies. In the present review we discuss both knowledge on the regulatory mechanisms of microRNAs obtained from other biological models and proof of concepts already performed on CHO cells, thus providing an outlook of potential applications of microRNA engineering in production cell lines
The ALMA-PILS survey: First detection of the unsaturated 3-carbon molecules Propenal (CHCHO) and Propylene (CH) towards IRAS 162932422 B
No full textAccepted for publication in A&A. 24 pages, 17 figuresInternational audienceComplex organic molecules with three carbon atoms are found in the earliest stages of star formation. In particular, propenal (CHCHO) is a species of interest due to its implication in the formation of more complex species and even biotic molecules. This study aims to search for the presence of CHCHO and other three-carbon species such as propylene (CH) in the hot corino region of the low-mass protostellar binary IRAS 16293--2422 to understand their formation pathways. We use ALMA observations in Band 6 and 7 from various surveys to search for the presence of CH and CHCHO towards the protostar IRAS 16293--2422 B (IRAS 16293B). We report the detection of both CH and CHCHO towards IRAS 16293B, however, no unblended lines were found towards the other component of the binary system, IRAS 16293A. We derive column density upper limits for CH, HCCCHO, n-CHOH, i-CHOH, CO, and cis-HC(O)CHO towards IRAS 16293B. We then use a three-phase chemical model to simulate the formation of these species in a typical prestellar environment followed by its hydrodynamical collapse until the birth of the central protostar. Different formation paths, such as successive hydrogenation and radical-radical additions on grain surfaces, are tested and compared to the observational results. The simulations reproduce the abundances within one order of magnitude from those observed towards IRAS 16293B, with the best agreement found for a rate of cm s for the gas-phase reaction C + O C + CO. Successive hydrogenations of C, HC(O)CHO, and CHOCHO on grain surfaces are a major and crucial formation route of complex organics molecules, whereas both successive hydrogenation pathways and radical-radical addition reactions contribute to the formation of CHCHO
All-optical wavelength conversion with multicasting at 4 x 10 Gbits/s up and down using a Fabry-Perot laser diode
No full textWe demonstrate an all-optical wavelength converter with multicasting at 4 x 10 Gbits/s up and down conversion using gain modulation in an FP-LD. We also explain the gain modulation technique using the bistability behavior of the injection locked FP-LD. The wavelength converter shows the average power penalty of 1.5 dB at a bit error rate of 10(-9) and the extinction ratio of outputs over 12 dB, both for up and down conversions
Passive Control of Acoustic Potential Energy in a Rectangular Cavity by Means of Changing Boundary Condition
No full textWill eigenvalues and eigenfunctions be changed if the boundary surface is no longer rigid but has a specific acoustic admittance that may vary from point to point on surface? In this paper, the changes of eigenvalues and eigenfunctions are derived by using Kirchhoff-Helmholtz integral equation. Green’s function of which is composed by the sum of eigenfunctions is used in K-H integral equation. Acoustic potential energy is used to study the passive control performance that expresses an ability to make a quiet zone in the space of interest. Acoustic potential energy is found to have primary and secondary ones. Primary one is acoustic potential energy before changing boundary condition, and secondary one represents what can be gotten by changing boundary condition. Using these two terms, we attempt to see a control performance of each eigen mode when a boundary condition is changed. This index is defined by the ratio of acoustic potential energy after control to one before control in a quiet zone. Numerical simulations are carried out to illustrate and verify the proposed theory. One of highlights of this study is that it is possible to select or design a boundary condition if we do know what eigenfunctions we need, or vise versa
Development and growth of the foot lumbricalis muscle: a histological study using human foetuses
No full textBackground: Our group has shown early development of the hand lumbricalis and hypothesized that, at midterm, the lumbricalis (LU) bundles flexor tendons to provide a configuration of "one tendon per one finger" (Cho K.H. Folia Morphol. 2012; 71, 3: 154-163). However, the study concentrated on the hand and contained no sections of near-term foetuses.
Materials and methods: The present examination of paraffin-embedded tangential sections along the planta from 25 embryos and foetuses at 6-40 weeks (15-320 mm crown-rump length) demonstrated that, at 8 weeks, the initial foot LU appeared in the proximal side of the common tendinous plate of all five deep tendons.
Results: After midterm, a drastic three-phase change occurred at the muscle origin: 1) the LU originated from each of the flexor digitorum longus tendon (FDLT), but abundant tenocyte candidates separated the muscle fibre from the tendon collagen bundle; 2) the LU arose from the covering fascia depending on increased thickness of the muscle; and 3) the LU muscle fibres intermingled with tendon collagen bundles and partly surrounded the tendon. Simultaneously, a dividing site of the FDLT migrated distally to accelerate the changes at the LU origin. These phases did not always correspond to the size of foetus after 30 weeks.
Conclusions: Consequently, in contrast to the hand LU, the delayed changes in the foot were characterised by involvement of the LU origin into a single common part of the FDLT. The quadratus plantae muscle fibres did not attach to the LU at any phase, and connected with the fourth and fifth toe tendons.Depto. de Anatomía y EmbriologíaFac. de MedicinaTRUEpu
Effects of particle size distribution on the cake formation in crossflow microfiltration
No full textA WDM-PON with an 80 Gb/s capacity based on wavelength-locked polarisation independent Fabry-Perot laser diode
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