Cavitation Characteristics of Restriction Orifices (Experiment for Shock Pressure Distribution by Cavitation on Restriction Orifices and Occurrence of Cavitation at Multiperforated Orifices Due to Interference of Butterfly Valve)

This paper presents two experimental investigations for cavitation characteristics of restriction orifices. The first experiment is about the spatial distribution of cavitation shock pressure in a pipe at the downstream of restriction orifices. The second experiment is the investigation of butterfly valve throttling to the cavitation in a multiperforated orifice installed piping. From the results of the experiment for the cavitation shock pressure, it is concluded the maximum shock pressure remarkably increases with the decrease of cavitation number regardless of the orifice types. The maximum shock pressure becomes smallest on cone type orifice, and largest on single hole orifice. Multiperforated orifice is between this two. The results of the experiment for occurrence of cavitation due to the interference of butterfly valve show that the cavitation occurs at a relatively high cavitation number when the multiperforated orifice is placed at 1D downstream of the butterfly valve. The butterfly valve throttling accelerates the cavitation at the multiperforated orifice because of the closed orifice installation

Lactobacillus casei 34143のニトロソグアニジン処理変異株による大豆乳での乳酸およびジアセチル生成

Production of acid and diacetyl by nitrosoguanidine mutants of Lactobacillus casei 34143 was evaluated in soymilk. Optimum temperature for growthof the five cultures varied between 34.5 and 35.9℃. However, the temperature required for maximum production of diacetyl in soymilk in the parent culture was 32.7℃ and mutants such as N-14, N-15 and N-25 required a temperature of 29.6℃, while another mutant, L-7 required 26.4℃ for production of diacetyl. Parent and mutant cultures were deficient in citrate permease and citritase synthetic mechanisms, although lactose-utilising mutants (N-25 and S-3-1) possessed both β-galactosidase and phospho-β-galactosidase.大豆乳の発酵に有効な乳酸菌株を検索する目的で、ラクトース非発酵性Lactobacillus casei 34143のニトロソグアニジン(NTG)処理変異株について、液体培地での生育性ならびに大豆乳培地での乳酸とジアセチル生成能を温度勾配培養法によって検討した。また、NTG処理変異株におけるクエン酸およびラクトースの取り込みと分解に関与する酵素の活性についても調べた。その結果、親株ならびに変異株の液体培地での生育至適温度はほぼ同じ値を示し、いずれも34.5℃から35.9℃の範囲であった。しかしながら、大豆乳培地での乳酸とジアセチル生生成能には違いを示す菌株があった。とくにジアセル生成の至適温度は親株が32.7℃であるのに対して、変異株(N-14株,N-15株およびN-25株)では29.6℃であり、そして変異株のL-7株では26.4℃であった。一方、供試した親株と変異株のはすべてクエン酸透過酵素ならびにクエン酸分解酵素活性を示さなかったが、ラクトース代謝能を獲得した変異株(N-25株とS-3-1株)はβ-ガラクトシダーゼとフォスフォ-β-ガラクトシダーゼの活性を示した

Studies on Chemical Properties of Milk and Milk Products Produced in Mongolia

モンゴルよりもち帰ることのできた乳汁試料2点,バター1点およびチーズ様製品5点について一般組成,窒素化合物および脂質構成脂肪酸組成を分析し,わが国における市販の乳製品の分析結果と比較検討した. 馬乳の一般組成は牛乳に比べ蛋白質含量が低く乳糖含量が高い. またモンゴル牛の乳汁組成はホルスタイン乳よりも全固形分含量が高い値であった. 一方チーズ様製品の一般組成は水分含量10.03～16.94%,蛋白質含量13.50～44.25%,脂肪含量12.62～54.94%であり種類によりかなりの変動がみられた. また市販のナチュラルチーズの分析結果とかなりの相違がみられたが,これは原料乳と製造方法が異なるためと考えられる. モンゴルチーズの全窒素含量は21.16～69.36mg/g,水溶性窒素含量は1.27～9.49mg/gであり,熟成指数は3.0～15.5の範囲にあった. これらは市販のゴーダチーズに比べ一般にかなり低い値であった. 一方脂質構成脂肪酸については,牛乳と馬乳で構成脂肪酸の種類に相違がみられ,馬乳脂質の脂肪酸組成は牛乳脂質のそれに比較してC4:0とC6:0酸が存在せず,C18:0酸含量が低く,C18:1,C18:2およびC18:3酸の不飽和脂肪酸含量が高い特徴を示した. またバターおよびチーズ様製品の脂質構成脂肪酸組成は牛乳脂質の脂肪酸組成と本質的なちがいはみられなかった

Symmetrically dimethylated histone H3R2 promotes global transcription during minor zygotic genome activation in mouse pronuclei

受精卵の発生に重要な因子を発見 --ヒストンのアルギニンジメチル化が重要--. 京都大学プレスリリース. 2021-05-13.Paternal genome reprogramming, such as protamine–histone exchange and global DNA demethylation, is crucial for the development of fertilised embryos. Previously, our study showed that one of histone arginine methylation, asymmetrically dimethylated histone H3R17 (H3R17me2a), is necessary for epigenetic reprogramming in the mouse paternal genome. However, roles of histone arginine methylation in reprogramming after fertilisation are still poorly understood. Here, we report that H3R2me2s promotes global transcription at the 1-cell stage, referred to as minor zygotic genome activation (ZGA). The inhibition of H3R2me2s by expressing a histone H3.3 mutant H3.3R2A prevented embryonic development from the 2-cell to 4-cell stages and significantly reduced global RNA synthesis and RNA polymerase II (Pol II) activity. Consistent with this result, the expression levels of MuERV-L as minor ZGA transcripts were decreased by forced expression of H3.3R2A. Furthermore, treatment with an inhibitor and co-injection of siRNA to PRMT5 and PRMT7 also resulted in the attenuation of transcriptional activities with reduction of H3R2me2s in the pronuclei of zygotes. Interestingly, impairment of H3K4 methylation by expression of H3.3K4M resulted in a decrease of H3R2me2s in male pronuclei. Our findings suggest that H3R2me2s together with H3K4 methylation is involved in global transcription during minor ZGA in mice

Millimeter-wave Wireless LAN and its Extension toward 5G Heterogeneous Networks

Millimeter-wave (mmw) frequency bands, especially 60 GHz unlicensed band, are considered as a promising solution for gigabit short range wireless communication systems. IEEE standard 802.11ad, also known as WiGig, is standardized for the usage of the 60 GHz unlicensed band for wireless local area networks (WLANs). By using this mmw WLAN, multi-Gbps rate can be achieved to support bandwidth-intensive multimedia applications. Exhaustive search along with beamforming (BF) is usually used to overcome 60 GHz channel propagation loss and accomplish data transmissions in such mmw WLANs. Because of its short range transmission with a high susceptibility to path blocking, multiple number of mmw access points (APs) should be used to fully cover a typical target environment for future high capacity multi-Gbps WLANs. Therefore, coordination among mmw APs is highly needed to overcome packet collisions resulting from un-coordinated exhaustive search BF and to increase the total capacity of mmw WLANs. In this paper, we firstly give the current status of mmw WLANs with our developed WiGig AP prototype. Then, we highlight the great need for coordinated transmissions among mmw APs as a key enabler for future high capacity mmw WLANs. Two different types of coordinated mmw WLAN architecture are introduced. One is the distributed antenna type architecture to realize centralized coordination, while the other is an autonomous coordination with the assistance of legacy Wi-Fi signaling. Moreover, two heterogeneous network (HetNet) architectures are also introduced to efficiently extend the coordinated mmw WLANs to be used for future 5th Generation (5G) cellular networks.Comment: 18 pages, 24 figures, accepted, invited paper

Occurrences of metamorphosed ultramafic rock and associating rocks in Howard Hills, Enderby Land, East Antarctica: Evidence of partial melting from geochemical and isotopic characteristics

Large blocks of metamorphic rocks with mafic to ultramafic compositions were discovered in felsic gneiss at the central part of northern Howard Hills in Enderby Land. The ultramafic core is separated from the felsic gneiss by a mantle of pyroxene granulite. We can recognize from mineral assemblages and chemical compositions that the metamorphic rocks experienced ultrahigh temperature (UHT) metamorphism. Rubidium-strontium and samarium neodymium analytical data from the metamorphic rocks yield apparent ages of about 2.65 Ga within analytical error on isochron diagrams. Metamorphic rocks with mafic to ultramafic compositions are enriched in incompatible elements and have high Sr isotope ratios, resulting in some samples in improbable Nd model ages. This is attributed to enrichment of compatible elements and/or depletion of incompatible elements during metamorphism. We conclude that these metamorphic rocks experienced partial melting during UHT metamorphism. Pyroxene granulite was produced as a residual material after partial melting of LILE-enriched protoliths with high Sr isotope ratios

On the Quality of Raw Milk Produced in Okayama Prefecture : Chemical Composition

1976年4月より1977年2月までの各月に,岡山県内10地区の原料乳,合計110個の試料を採取し,その化学的組成を調査した. その結果次のような結論を得た. 1)季節的にみると,脂肪は春と夏季が低く,秋と冬季が高い. 乳糖は一般に秋季に低い値であった. 蛋白質および無脂乳固形分は8月に最低値を示す. また無脂乳固形分においては8%未満のものが季節により若干みられた. 2)地域的にみると,特定地区の乳質が他地区に比較して全般的に劣るものがみられた. 3)成分的にみると,PHは6.70～6.90,酸度は0.13～0.15%,比重は1.0301～1.0338,脂肪は3.25～3.70%,蛋白質は2.95～3.35%,乳糖は4.20～4.45%,灰分は0.68～0.73%そして無脂乳固形分は8.15～8.75%の範固にあるものが多い. なおpH,酸度,比重,蛋白質,乳糖,灰分および無脂乳固形分の平均値はそれぞれ6.80,0.14%,1.0313,3.39%,3.13%,4.28%,0.68%および8.29%であった. 4)全般的にみると,全国平均と比較して脂肪はほぼ等しく,無脂乳固形分は若干高く,岡山県の原料乳の乳質は全国的にみて標準ないしはそれ以上のものと思われる

Altered Metabolism in Lactose-negative Mutants of Lactobacillus casei by Conjugation

ラクトース非発酵性Lactobacillus caseiはラクトース発酵能を欠くために,牛乳培地では酸生成がみられず,乳業用乳酸菌として応用する場合,ラタトース発酵性をこの菌株に付与する必要がある.そこで,Lactobacillus casei subsp. caseiのラクトース非発酵性(Lac-株である.34143S(ストレプトマイシン耐性,Strr)および34143P(ペニシリン耐性,Penr)株を分離し,それらを受容菌として液体培地中や寒天培地上での接合法によって,Lac+交配菌の作出を検討した.その結果,受容菌と供与菌Lactobacillus delbrueckii subsp. bulgaricus7235との交配で得られたLac+StrrやLac+Penrの交配菌,Lactobacillus rhamnosus IFO3245とのLac+StrrやLac+Penr株およびStreptococcus salivarius subsp. Thermophilus 18235とのLac+Penr株を3回の繰り返し試験で再現性高く得ることができた.それらの接合頻度は,供与菌当たり,1.1×10-5から1.6×10-2の範囲であり,比較的高い頻度でLac+交配菌の得られる組合せもあった. 得られた交配菌はほとんどが脱脂乳を凝固し,ラクトース発酵性は安定であった.また交配菌の糖類発酵性やその他の性状試験から,受容菌と供与菌にない性質を発現した交配菌や受容菌のもつ性質の一部を欠落した交配菌もあった.しかし形態はいずれも受容菌と同一であった.これらのラクトース発酵性交配菌の出現は,自然突然変異,形質導入および形質転換によるものではなく,受容菌と供与菌の細胞接合によりラクトース発酵性が発現したものと考えられた.またこのラクトース発酵性の発現は,プラスミドの伝達によるものではないと思われた.しかし詳細については今後さらに検討する必要がある