559 research outputs found

    Lipid Rafts: Keys to Sperm Maturation, Fertilization, and Early Embryogenesis

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    Cell membranes are composed of many different lipids and protein receptors, which are important for regulating intracellular functions and cell signaling. To orchestrate these activities, the cell membrane is compartmentalized into microdomains that are stably or transiently formed. These compartments are called “lipid rafts”. In gamete cells that lack gene transcription, distribution of lipids and proteins on these lipid rafts is focused during changes in their structure and functions such as starting flagella movement and membrane fusion. In this paper, we describe the role of lipid rafts in gamete maturation, fertilization, and early embryogenesis

    Sensitivity improvement of dual-comb spectroscopy using mode-filtering technique

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    In this study, we demonstrated an improvement in the detection sensitivity of dual-comb spectroscopy using the repetition rate multiplication of optical frequency combs. We compared the dual-comb signals in three dual-comb setups consisting of combinations of two combs with and without mode-filtering, and investigated how the repetition rate influences the signal-to-noise ratio (SNR) of dual-comb measurements. The dual-comb setups using high-repetition-rate combs enabled the absorption lines of HCN gas to be measured with a high SNR in a short averaging time, and real-time spectral data acquisition was realized using a low-sensitivity and low-resolution RF spectrum analyzer

    Current Status and Future Development of Cell Transplantation Therapy for Periodontal Tissue Regeneration

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    It has been shown that stem cell transplantation can regenerate periodontal tissue, and several clinical trials involving transplantation of stem cells into human patients have already begun or are in preparation. However, stem cell transplantation therapy is a new technology, and the events following transplantation are poorly understood. Several studies have reported side effects and potential risks associated with stem cell transplantation therapy. To protect patients from such risks, governments have placed regulations on stem cell transplantation therapies. It is important for the clinicians to understand the relevant risks and governmental regulations. This paper describes the ongoing clinical studies, basic research, risks, and governmental controls related to stem cell transplantation therapy. Then, one clinical study is introduced as an example of a government-approved periodontal cell transplantation therapy

    Dual-comb spectroscopy for rapid characterization of complex optical properties of solids

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    We demonstrate rapid characterization of complex optical properties of solids via dual-comb spectroscopy (DCS) in the near-infrared region. The fine spectral structures in the complex refractive index of an Er:YAG are successfully deduced using the developed system and Fourier analysis. Moreover, simultaneous determination of the refractive index and the thickness is demonstrated for a silicon semiconductor wafer through the use of multireflected echo signals. The results indicate the potential of DCS as a powerful measurement tool for the rapid and full characterization of solid materials

    Doppler-free dual-comb spectroscopy of Rb using optical-optical double resonance technique

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    We present a Doppler-free high-resolution dual-comb spectroscopy technique in which a dual-comb system is employed to perform optical-optical double-resonance (OODR) spectroscopy. In our experimental study, Doppler-free high-resolution and high-frequency-accuracy broadband measurements were realized using the proposed OODR dual-comb spectroscopic technique, which does not require high-power-per-mode frequency combs. We observed fully resolved hyperfine spectra of 5P3/2 - 4D5/2, 4D3/2 transitions of Rb at 1530 nm and precisely determined the absolute frequencies of the transitions, with an uncertainty of less than 1 MHz. The variations of the OODR spectral line shapes due to power broadening and alignment and the effects of polarization on the dual-comb OODR spectra were also analyzed. This study provides a widely applicable technique for Doppler-free dual-comb spectroscopy of various gaseous species

    Determination by ultrafiltration of the fraction of unbound estradiol and its variation in peritoneal fluid during the menstrual cycle.

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    An ultrafiltration method employing a Centrifree filter for determining the unbound fraction of estradiol was studied. Centrifugation was performed under conditions similar to those in vivo. Good correlation was recognized between this method and the equilibrium dialysis. This method was employed to determine the unbound fraction of estradiol in the serum and the peritoneal fluid of 26 infertility patients classified according to their menstrual dates. The total estradiol and progesterone contents in the peritoneal fluid were high after ovulation. There was no significant difference in the percentage of unbound estradiol in the serum among various groups. In the peritoneal fluid, however, the percentage of unbound estradiol for the day 12-14 patients was 4.5 +/- 0.2% in contrast with 3.8 +/- 0.4% for the day 15-18 group (p less than 0.05) and 3.5 +/- 0.1% (p less than 0.05) for the day 19-28 group. Moreover, the fraction (4.5%) of unbound estradiol in the peritoneal fluid of a patient with luteinized unruptured follicle (LUF) syndrome was comparable with that of patients in the follicular phase. The difference between the percentage of unbound estradiol in the peritoneal fluid before and after ovulation is considered to be due to the transudation of follicular estradiol in the follicular phase and the exudation of estradiol from the corpus luteum into the peritoneal cavity in the luteal phase.</p
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