Novel Gain Spectrum Control Method Employing Gain Clamping and Pump Power Adjustment in Thulium-Doped Fiber Amplifier

In this paper, we propose a novel method for controlling the gain spectrum of a thulium-doped fiber amplifier (TDFA) in the S-band. The conventional gain spectrum control method used for a silica erbium-doped fiber amplifier (EDFA) cannot be applied to TDFAs because of the complicated fluctuation of the TDFA gain spectrum. Our proposed method controls the gain spectrum by a combination of gain clamping and pump power adjustment. The algorithm for the method is as simple as that for the conventional EDFA gain spectrum control method. Furthermore, we describe a function for correcting the gain excursion generated by the incorporation of amplified spontaneous emission (ASE) at a signal monitoring photodiode (PD). We achieved a gain excursion of 0.35 dB against a total input signal power of 32 to 2 dBm.     

Modeling missing pedigree in single-step genomic BLUP

The objective was to compare methods of modeling missing pedigree in single-step genomic BLUP (ssGBLUP). Options for modeling missing pedigree included ignoring the missing pedigree, unknown parent groups (UPG) based on A (the numerator relationship matrix) or H (the unified pedigree and genomic relationship matrix), and metafounders. The assumptions for the distribution of estimated breeding values changed with the different models. We simulated data with heritabilities of 0.3 and 0.1 for dairy cattle populations that had more missing pedigrees for animals of lesser genetic merit. Predictions for the youngest generation and UPG solutions were compared with the true values for validation. For both traits, ssGBLUP with metafounders provided accurate and unbiased predictions for young animals while also appropriately accounting for genetic trend. Accuracy was least and bias was greatest for ssGBLUP with UPG for H for the trait with heritability of 0.3 and with UPG for A for the trait with heritability of 0.1. For the trait with heritability of 0.1 and UPG for H, the UPG accuracy (SD) was ?0.49 (0.12), suggesting poor estimates of genetic trend despite having little bias for validations on young, genotyped animals. Problems with UPG estimates were likely caused by the lesser amount of information available for the lower heritability trait. Hence, UPG need to be defined differently based on the trait and amount of information. More research is needed to investigate accounting for UPG in A₂₂ to better account for missing pedigrees for genotyped animals.     

硫酸氨基葡萄糖对口服透明质酸缓解小鼠佐剂性关节炎的增效作用

目的：探讨硫酸氨基葡萄糖（glucosamine sulfate,GS）对口服透明质酸（hyaluronic acid,HA）缓解小鼠佐剂性关节炎的增效作用。方法：将50 只8 周龄ICR雄性小鼠随机分成5 组：正常组、模型组、HA组、GS组和HA＋GS组。除正常组以外,其余4 组小鼠左后足注射弗氏完全佐剂（freund’s complete adjuvant,FCA）建立佐剂性关节炎模型,然后进行4 周的HA和GS口服给药,并分别对小鼠体质量、足跖肿胀度进行测定,同时采用酶联免疫吸附法（enzyme-linked immunosorbent assay,ELISA）检测小鼠血清中白细胞介素-1（interleukin-1,IL-1）及肿瘤坏死因子-α（tumor necrosis factor-α,TNF-α）的含量。结果：口服HA和GS都能够减轻小鼠的足跖肿胀度,而同时口服HA和GS能起到更好的消肿效果,血清中IL-1及TNF-α的含量也显著降低。结论：给予小鼠口服HA＋GS,比单独服用HA、GS能更有效、更快地缓解小鼠的足跖肿胀症状,同时能够降低血清中IL-1及TNF-α含量,进而对小鼠佐剂性关节炎起到更好的治愈效果。     

Small-scale hydrogen liquefaction with a two-stage Gifford–McMahon cycle refrigerator

We manufactured a small-scale hydrogen liquefier with a two-stage 10 K Gifford–McMahon cycle (GM) refrigerator. It had a hydrogen tank with the volume of 30 L that was surrounded by a radiation shield. This liquefier continuously liquefied gaseous hydrogen with the volumetric flow rate of 12.1 NL/min. It corresponds to the liquefaction rate of 19.9 L/day for liquid hydrogen. We proposed a simple estimation method for the liquefaction rate and confirmed that the estimation method well explained the experimental result. To evaluate the estimation method, we applied the estimation method to other liquefiers. In case of a liquefier with the GM refrigerator, we confirmed the estimation method was available for predicting the liquefaction rate. However, in case of a liquefier with the pulse tube refrigerator, the results of the estimation indicated small values as compared with the experimental data. We discuss the details about the estimation method of the liquefaction rate for the small-scale liquefiers.     

Synthesis and gas permeation properties of various Si-containing poly(diarylacetylene)s and their desilylated membranes

Diarylacetylene monomers having trimethylsilyl groups and other substituents (substituted biphenyl, 1a and 1b; trimethylsilylmethylphenyl, 1c-e) were synthesized and polymerized with TaCl₅-n-Bu₄Sn catalyst to produce the corresponding poly(diarylacetylene)s (2a-d). Polymers 2a-c had high molecular weights and were soluble in common organic solvents. Free-standing membranes of 2a-c as well as previously reported 2f-h were prepared by the solution-casting method. Desilylation of these Si-containing polymer membranes was carried out with trifluoroacetic acid to afford 3a, 3b, and 3f-h. Upon desilylation, biphenyl-containing membranes became less permeable (3a, b), whereas fluorene-containing membranes became more permeable (3f-h). In particular, 3h exhibited extremely high gas permeability (PO₂ = 9800 barrers), which is about the same as that of poly(1-trimethylsilyl-1-propyne). Desilylated membranes 3a and 3f-h showed different gas permeability from that of polymers 2i-k which have the identical chemical structures and obtained directly by the polymerization of the corresponding monomers.     

Investigation of Apatite Deposition onto Charged Surfaces in Aqueous Solutions Using a Quartz-Crystal Microbalance

Hydroxyapatite (HAp) deposition onto positively charged surfaces (i.e., self-assembled monolayers (SAMs) terminated with NH₂ head groups) and negatively charged surfaces (i.e., OH-SAMs (weak) and COOH-SAMs (strong)) soaked at 50°C in aqueous supersaturated solutions (1.5 SBF, pH 7.0–7.6; SBF = simulated body fluid) was investigated using a quartz-crystal microbalance. The results revealed that the solution conditions greatly influenced the formation of HAp on the charged surfaces. In a stable supersaturated solution of simulated body fluid (1.5 SBF, pH <7.4), more strongly negative surfaces had a more powerful induction capability for the heterogeneous nucleation of HAp (COOH > OH), whereas nucleation was obviously prohibited on a positive surface (NH₂-SAM). On the other hand, after the calcium phosphate particles had nucleated homogeneously in an unstable soaking solution (1.5 SBF, pH ≧7.4), adhesion of the HAp microparticles to the NH₂-SAM was observed. A two-step interaction is conceivable to describe the formation of HAp on the positive NH₂-SAM: At the first stage, electrostatic interaction dominates the adhesion of HAp microparticles; at the second stage, hydrogen bonds possibly form between the HAp microparticles and the amino head groups of the NH₂-SAM, for a firm bonding with the substrate, and the microparticles grow progressively into a thin film. The electrophoretic behaviors of the HAp microparticles confirmed this hypothesis.     

Biodegradation of sodium alkyl poly(oxyalkylene)sulfates

The biodegradability of sodium alkylpoly(oxyalkylene)sulfates was studied under aerobic conditions by oxygen consumption, total organic corbon (TOC) and methylene blue active substance (MBAS) measurements. MBAS of linear alkylpoly(oxyalkylene)sulfates with propylene oxide (APS) or ethylene oxide (AES) disappeared within 5 days, whereas AES with branched alkyl chains were degraded less than linear AES. APS with propylene oxide from 1 to 3 mol showed BOD/ThOD values of more than 40% after 6 days. Therefore, these surfactants are considered to be readily biodegradable. In comparison to the biodegradability of APS and AES, the existence of propylene oxide groups resulted in a slight decreasing in oxygen consumption and TOC removal. Linear APS with PO of 1~3 mol were degraded according to Swisher's distance principle up to a C₁₆ alkyl chain length. That is, increasing distance principle up to a C₁₆ alkyl chain length. That is, increasing distance between sulfate and chain end increased the rate of biodegradation of these surfactants. Furthermore, from the biodegradation test of³⁵S-C₁₂E₃S, it is suggested that the initial step of biodegradation is attack on the terminal methyl group.     

Solubilizing Trityl-Type Tag To Synthesize Asx/Glx-Containing Peptides

A novel solubilizing tag system for Asp/Asn/Glu/Gln-containing peptides is described. In this method, an Asp/Glu[Dbz-Cys-NH₂]-containing peptide (Dbz: 3,4-diaminobenzoic acid) is first synthesized through fluorenylmethyloxycarbonyl (Fmoc) solid-phase peptide synthesis. The solubilizing moiety containing an oligo-Lys group is then attached to the peptide in hexafluoroisopropanol through a trityl anchor to afford a hydrophilic tagged peptide. To detach the solubilizing tag, the Dbz moiety of the tagged peptide is activated with NaNO₂, and the Asp/Asn/Glu/Gln-containing peptide is obtained through hydrolysis or ammonolysis. This synthetic approach proved to be compatible with native chemical ligation, and amyloid β-protein 1–42 was successfully synthesized by the solubilizing-tag-aided native chemical ligation–desulfurization method.     

Dental Pulp-Derived Mesenchymal Stem Cells for Modeling Genetic Disorders

A subpopulation of mesenchymal stem cells, developmentally derived from multipotent neural crest cells that form multiple facial tissues, resides within the dental pulp of human teeth. These stem cells show high proliferative capacity in vitro and are multipotent, including adipogenic, myogenic, osteogenic, chondrogenic, and neurogenic potential. Teeth containing viable cells are harvested via minimally invasive procedures, based on various clinical diagnoses, but then usually discarded as medical waste, indicating the relatively low ethical considerations to reuse these cells for medical applications. Previous studies have demonstrated that stem cells derived from healthy subjects are an excellent source for cell-based medicine, tissue regeneration, and bioengineering. Furthermore, stem cells donated by patients affected by genetic disorders can serve as in vitro models of disease-specific genetic variants, indicating additional applications of these stem cells with high plasticity. This review discusses the benefits, limitations, and perspectives of patient-derived dental pulp stem cells as alternatives that may complement other excellent, yet incomplete stem cell models, such as induced pluripotent stem cells, together with our recent data.