Search

Salivary cortisol concentration and its circadian variation were detected by optimizing the ionic concentration of a solution during the immobilization of aptamers on a field-effect transistor bios...

Field effect transistor (FET) biosensors are capable of detecting various biomolecules, although challenges remain in the detection of uncharged molecules. In this study, the detection of uncharged cortisol was demonstrated by interfacial design using a technique to immobilize target-bound aptamers. The target-bound aptamers, which formed a higher-order structure than target-unbound aptamers, expanded the distance between adjacent aptamers and reduced the steric hindrance to the conformational change. The density-controlled aptamers efficiently induced their conformational changes with the cortisol binding, which resulted in the improvement of the sensitivity of FET biosensors.

Nanostructure-induced L10-ordering of twinned single-crystals in CoPt ferromagnetic nanowires on Si/SiO2 substrates is demonstrated, where nanostructure-induced L10-ordering is driven by ultrasmall 10 nm-scale curvature radii of the nanowires.

L10-ordered CoPt with a large coercivity (H c) of 13 kOe was demonstrated on Si/SiO2 substrates by hydrogen annealing. Equiatomic 11.2 nm thick (Co/Pt)4 multilayer thin films were fabricated by electron-beam evaporation and were annealed at 500 °C–900 °C for 10–90 min under an Ar/H2 mixed gas atmosphere. The annealing temperature and time dependences of the crystal structures, magnetic properties, and surface morphologies of the films were systematically analyzed based on the experimental results obtained from grazing incidence X-ray diffraction (GI-XRD), vibrating sample magnetometer, and scanning electron microscope, respectively. Hydrogen annealing effectively promoted the out-of-plane c-axis orientation of L10-ordered CoPt compared to the vacuum annealing according to the GI-XRD patterns. A maximum H c of 13.3 kOe was obtained in L10-ordered CoPt with angular-outlined isolated grains by hydrogen annealing at 800 °C for 60 min, where the c-axis of L10-ordered CoPt was randomly distributed.

Single-electron transistors (SETs) represent a new generation of electronic devices with high charge sensitivity, high switching speed, and low power consumption. Here a simple and controlled fabrication of graphene quantum dot (GQD)-based SETs for photon detectors has been demonstrated. The plasma-synthesized GQDs exhibit stable photoluminescence and are successfully used as the Coulomb islands between heteroepitaxial spherical-gold/platinum (HS-Au/Pt) nanogap electrodes. The as-fabricated GQD-SETs enable photon detection with 410 nm excitation owing to the ability of GQDs to generate photoluminescence emission.

Introduction People have felt that their mind controls the body. Advances in immunology and neuroscience are scientifically elucidating this experience. For example, it has been clarified that the mechanism by which changes in the activity of the central nervous system due to stress regulate the immune response through sympathetic nerves. If these latest medical knowledge and electronic advances can be used to provide a simple monitoring system for stress-related substances, it is hoped that it will help prevent mental and physical diseases. Nevertheless, performing a blood draw to detect the stress hormones cortisol and catecholamine has the challenge that the act of drawing blood itself causes stress. Instead, cortisol concentration measurement from saliva has been developed as a non-invasive detection, but catecholamines cannot be detected from saliva. Salivary cortisol concentration measurements have been developed as an alternative non-invasive detection method, but catecholamines are unable to obtain the necessary information from saliva. Salivary α-amylase and chromogranin A (CgA) have also been studied and used in part as alternatives to catecholamines. Secretary immunoglobulin A (s-IgA) in saliva is also a good stress marker that reflects suppression of the immune system by stress. Simultaneous monitoring of the time-dependence of these stress markers of different origins is expected to help elucidate the complex mental stress mechanisms [1]. Sensor module platform Accurate and inexpensive biomaterial detectors are required for IoT biosensing systems and monitoring over time has not been realized until now. Field-effect transistor (FET) biosensors are small devices that detect various types of biomarkers at low power consumption without disturbing the system under test [2]. The biggest challenge of FET biosensors when used in electronics systems is instability due to current drift. We have succeeded in developing a method that minimizes drift using only the normal silicon fab process. This manufacturing process does not use tantalum pentoxide or other special materials. Figure 1 shows a picture of a newly developed four element FET sensor chip with extremely low instability. The electronics part of the developed biosensor module consists of this chip and a Bluetooth Low Energy (BLE)-type communication circuit. We selected four types of aptamers as sensor receptors on the gate insulator on the chip [3]. The aptamers can be stored and used at room temperature for a long period of time. They also have the advantages of being reversible to thermal denaturation and can be produced inexpensively and industrially. Finally, as a technique for producing biosensors with less variation, such as commercial physical sensors, we developed a tool for uniformly immobilizing the receptor monolayer in a narrow range of fixed positions on the chip. Simultaneous detection of multiple stress markers in saliva When n types of receptors are immobilized on n FET elements, n-1 types of independent signals can be extracted. The effects of non-specifically adsorbed substances and pH in saliva, temperature fluctuation, optical noise, and crosstalk between elements can be eliminated from the original signals of multiple FET elements. Using this technique, we succeeded in obtaining multiple stress marker concentrations such as cortisol, a-amylase, s-IgA, and CgA [4], at the same time just by dropping saliva on the sensor. The signal time constant is less than 1 minute, which indicates that a continuous monitor is realized substantially. Operability equivalent to physical sensor Internet of Things (IoT) systems require many low-cost sensors. FET sensor chips manufactured using only the conventional silicon fab process can achieve a low cost of about $1 per chip. However, even with such cheap biosensors, if they are disposable, the cost burden on the user will increase significantly in the long run. As a result, it becomes difficult to secure good customers as fixed users. In addition, disposable chips are not suitable for continuous monitoring required for medically important data. We are developing biosensors that are as easy to operate as conventional physical sensors by introducing reusable cleaning methods and recycled precision cleaning methods. References [1] L. Steinman, Annu. Rev. Immunol., 32, 257-281, (2014). [2] K. Ohashi, T. Osaka, ECS Transactions, 75, 39, 1-9, (2017). [3] N Kaneko, H Minagawa, J Akitomi, K Ohashi, S Kuroiwa, S Wustoni, S Hideshima, T Osaka, K Horii, I Waga, The 43rd International Symposium on Nucleic Acids Chemistry, 2P-55, (2016). [4] S. Kuroiwa, R. Takibuchi, A. Matsuzaka, S. Hideshima, N. Kaneko, H. Minagawa, K. Horii, I. Waga, T. Nakanishi, K. Ohashi, T. Momma, T. Osaka, 232nd ECS Meeting, 2115, (2017). Figure 1

L12-ordered CoPt3 and L10-ordered CoPt are formed in electron-beam-deposited (Co/Pt)4 multilayer thin films with and without a Ti underlayer, respectively, on Si/SiO2 substrates by rapid thermal annealing. The crystal structures, magnetic properties, and surface morphologies of the films are investigated by grazing incidence X-ray diffraction (GI-XRD), vibrating sample magnetometer (VSM), and scanning electron microscope (SEM), respectively. In the film without a Ti underlayer, L10-ordered CoPt with an isolated round grain structure is confirmed, showing an in-plane coercivity of 2.7 kOe. In contrast, in the film with a Ti underlayer, L12-ordered CoPt3 is confirmed together with Co-rich A1-disordered CoPt, showing an in-plane coercivity of 500 Oe, which exhibits an angular-outlined continuous film structure. The three sets of experimental results from GI-XRD, VSM, and SEM coincide well with each other.

Introduction People have felt that their mind controls the body. Advances in immunology and neuroscience are scientifically elucidating this experience. For example, it has been clarified that the mechanism by which changes in the activity of the central nervous system due to stress regulate the immune response through sympathetic nerves. If simple monitoring of stress-related substances is realized by utilizing such medical advances and advances in electronic devices, we can expect to help prevent many diseases. Nevertheless, the medically established technique of collecting blood for the detection of stress hormones, cortisol and catecholamine has the disadvantage of causing stress by the collecting action itself. Instead, cortisol concentration measurement from saliva has been developed as a non-invasive detection, but catecholamines cannot be detected from saliva. Salivary α-amylase and chromogranin A (CgA) have also been studied and used in part as alternatives to catecholamines. Secretary immunoglobulin A (s-IgA) in saliva is also a stress marker that reflects suppression of the immune system by stress. Simultaneous monitoring of time-dependent changes in these stress markers of different origins is expected to be an important technique for mental and physical health [1]. Biosensor module platform Precise but inexpensive biological material detectors are required for IoT biosensing system, and it has not been possible to monitor them over time. A field effect transistor (FET) biosensor is a compact device that detects many types of biomarkers with low power consumption without disturbing the system under test [2]. The biggest challenge of FET biosensors when used in electronics systems is instability due to current drift. We have succeeded in developing a method that minimizes drift using only the normal silicon fab process. This manufacturing process does not use tantalum pentoxide or other special materials. Figure 1 shows a photo of a newly developed four-element FET sensor chip with very low instability. The electronics part of the biosensor module consists of this chip and a Bluetooth Low Energy (BLE) type communication function. We selected aptamers as sensor receptors on the gate insulator film on the chip [3]. Aptamers can be stored and used at room temperature for a long period of time. They also have the advantages of being reversible to thermal denaturation, and can be produced inexpensively and industrially. Finally, as a technology for manufacturing biosensors with as little variation as semiconductor devices, we have developed a tool that uniformly immobilizes receptor monolayers in a narrow place at a fixed position on a chip. Simultaneous detection of stress markers in saliva When n types of receptors are immobilized on n FET elements, n − 1 types of independent signals can be extracted. The effects of non-specifically adsorbed substances and pH in saliva, temperature fluctuation, optical noise, and crosstalk between elements can be eliminated from the original signals of multiple FET elements. Using this technique, we succeeded in obtaining multiple stress marker concentrations such as cortisol, α-amylase, s-IgA, and CgA [4], at the same time just by dropping saliva on the sensor. The signal time constant is less than 1 minute, which indicates that a continuous monitor is realized substantially. Operability equivalent to physical sensor Internet of Things (IoT) systems require a large number of low-cost sensors. An FET sensor chip manufactured using only the normal silicon fab process achieves a low cost of about $ 1 per chip. However, if a biosensor is disposable, the cost burden on the user will increase significantly over the long term. As a result, it becomes difficult to secure good customers as fixed users. In addition, disposable chips are not suitable for continuous monitoring required for medically important data. We are developing an easy-to-reuse cleaning method and a recycling precision cleaning method with the aim of securing customers by realizing biosensor technology with the same operability as conventional physical sensors. References [1] L. Steinman, Annu. Rev. Immunol., 32, 257-281, (2014). [2] K. Ohashi, T. Osaka, ECS Transactions, 75, 39, 1-9, (2017). [3] N. Kaneko, H. Minagawa, J. Akitomi, K. Ohashi, S. Kuroiwa, S. Wustoni, S. Hideshima, T. Osaka, K. Horii, I. Waga, The 43rd International Symposium on Nucleic Acids Chemistry, 2P-55, (2016). [4] S. Kuroiwa, R. Takibuchi, A. Matsuzaka, S. Hideshima, N. Kaneko, H. Minagawa, K. Horii, I. Waga, T. Nakanishi, K. Ohashi, T. Momma, T. Osaka, 232nd ECS Meeting, 2115, (2017). Figure 1

Electroless Au plating (ELGP) on Pd thin films is performed. The ELGP time dependence on the surface morphology is investigated by a scanning electron microscope. Continuous nucleation and growth of hemispherical Au islands are observed as the plating time increases. Heteroepitaxial growth of the electroless plated Au on the Pd surface is confirmed by cross-sectional scanning transmission electron microscope images. Cross-sectional energy-dispersive X-ray spectroscopy reveals interdiffusion between the Pd atoms and the plated Au atoms at room temperature, which allows the formation of Au–Pd alloys. The heteroepitaxial Au growth on Pd is significant for reducing contact resistance of Au/Pd structures.

We present a controllable way of establishing a p-n junction in amorphous selenium (a-Se) using electrolysis. Amorphous selenium is used as an anode in the electrolysis of NaCl solution. By varying the duration of the electrolysis, we can make the contact to a-Se either Ohmic or rectifying and control the built-in potential and full depletion voltage of the contacts and junctions formed in the a-Se. I-V and C-V measurements show that after electrolysis rectification occurs and that as the duration of electrolysis increases, the direction of rectification changes, with the magnitudes of the built-in potential and the full depletion becoming higher. From the results, we present a model for the electrochemical process of forming the p-n junction and highlight the dependence on the duration of the electrolysis.

冷麺の官能検査項目とテンシプレッサーによる分析項目との関係について調べ以下の結果を得た.(1) 冷麺の官能検査項目と分析項目との相関行列をみた結果,官能検査項目内及び分析項目内での相関はかなり高い項目があったが,官能検査項目と分析項目間ではあまり高い相関はみられなかった.(2) 官能検査項目を従属変数(y)とし分析項目を独立変数(X)とする,2次曲線の当てはめを行った結果,相関係数が大幅に向上する項目が認められた.(3) 分析項目の因子分析を行った結果,分析項目は質的因子と強度因子の2つの因子が抽出された.質的因子とは分析項目の内応力の比率(100%圧縮応力/50%圧縮応力),プライアビリティ,破断応力,圧縮応力(100%圧縮応力),破断ひずみの相関が高く,強度因子とは50%圧縮応力,麺の太さ,圧縮エネルギー,破断エネルギーの相関が高かった.(4) 抽出した因子を軸とする散布図により,試験に使用した麺の太さ,でんぷんの配合量,押し出しスクリュ回転数が識別可能であった.(5) 抽出した2つの因子と相関の高い分析項目,あるいは抽出した因子そのものを独立変数(x1,x2)とし,官能検査項目を従属変数(y)とする2次重回帰モデル式への当てはめを行った結果,単相間の場合よりも重相関係数は更に向上した.(6)2次重回帰モデル式への当てはめにより導かれた回帰式による3次元曲面を検討した結果,細麺と太麺(それぞれ1.1mmと1.5mmの穴の経を持つダイを使用して製麺)とでは質的因子と強度因子との関係に差がみられ,細麺は質的因子に最適値を持ち,硬く且つ,ほど良く弾力性のある麺が好まれるが,太麺はこれと逆に強度因子に最適値を持ち,ほど良い硬さがあり且つ,弾力性の強い麺が好まれることが明らかとなった.

冷麺包装後の加熱殺菌処理並びに6ヶ月間保存中の色調の変化を調べ,以下の結果を得た.(1) 加熱殺菌温度が100℃を越えるとL*値は急激に低下し,a*,b*値は急激に増加し,褐変現象が見られることから,冷麺のレトルト殺菌温度での加熱は好ましくないことが分かった.(2) 保存温度が高いほど,冷麺の色調変化が激しく,時間の経過とともにL*値は低下し,a*値は増加する傾向を示した,b*値は2℃または20℃ではあまり変化しなかったが,30℃では増加傾向を示した.(3) 脱酸素剤を使用することにより色調の変化は大きくなり,保存温度が高いほどその効果は増幅された.脱酸素剤の使用による効果を色差(ΔE*ab)により比較すると,6ヶ月保存後では保存温度2℃, 20℃, 30℃の場合それぞれ,0.9, 2.1, 3.1倍であった.(4)L*a*b*が変化のパターンを比較することにより,加熱による変色と長期保存による変色は同一のメカニズムで起こるものと推測された.(5) 以上のことから,冷麺の色調は保存温度や酸素濃度により影響を受けるため,これらの条件を考慮した保存方法を採用する必要性が示された.

摩擦熱を利用して,生地を加熱する冷麺用押出し機の機械特性および熱特性を検討し次の結果を得た.1) 押出し機中の生地の粘性は塑性流動を示しf=k(γ)n+f0(f:ずり応力,k:コンシステンシー係数,γ:ずり速度,fn:降伏値,n:流動指数)で示された.コーンスターチ(40～60%)およびバレイショでんぷん(40～60%)配合生地ではk=1.45Pa・sn,fn=15kPa,n=0.4であった.2) 麺線の膨化率は生地の見掛けの粘性率の増加につれて,減少する傾向が見られた.バレイショでんぷん配合の方がコーンスターチ配合より高い膨化率を得た.また,両配合とも高でんぷん配合(60%)の方が膨化率は高かった.3) 容積流量はQ=KN(K:定数,N:スクリュ回転数)で表された.Kはコーンスターチ40%で1.52×10-5m3,バレイショでんぷん40%で1.239×10-6,バレイショでんぷん60%で1.084×10-5であった.4) スクリュ内の容積と流量から求めた見掛けの滞留時間tvと生地がニュートン流体と仮定したときの滞留時間tnはいずれも赤色マーカー法で求めた滞留時間tmより小さく,tm>tn>tvの関係があった.これは生地が準塑性流動することによるものと考えられ,tmはスクリュ回転数200rpmで284s,900rpmで38sであり,回転数の増加につれて減少した.5) 押出し機の理論エネルギーは,E1=1.801N2ηapで表され,実際のエネルギーは理論エネルギーの約83%であった.6) 圧力損失から求めた摩擦熱量は,実際の生地の熱量の約70%を占めていた.7) 押出し機の動力数Npはフルード数Fr,およびレイノルズ数Reの無次積で,つぎのように表すことができた.

We demonstrate an all-fiber Q-switched laser operation in the 2 µm region on the basis of a dynamic periodic microbend and pulsed-pump configuration. A single-mode thulium-doped silica fiber is pumped by 1.6 µm-band laser diodes, and the dynamic loss is introduced in the fiber ring resonator by the periodic microbend that is electrically controlled with a piezoelectric actuator. When the voltage-off period of the piezoelectric actuator is set at 20 µs for the pump power of 120 mW, the output pulse power is measured by 420 mW with a pulse width of 1.3 µs.

冷麺製造工程におけるエタノールの残存率及び残存エタノールと冷麺の保存性との関係について検討した.(1) 冷麺は製造時約100℃の加熱糊化工程を経ているにもかかわらず,製造原料に保存料として添加したエタノールの残存率はかなり高く,乾燥工程を経た段階で86.8%であった.(2) 乾燥工程でエタノールの減少率が低い原因を確認するため,冷麺を通風と無風の条件下で乾燥して比較したところ,無風乾燥では水分の減少とともにエタノール濃度も減少した.一方,通風乾燥では水分は急激に減少したが,工タノール濃度は逆に僅かに上昇した.(3) 以上のことから,冷麺製造時の通風乾燥は,エ夕ノールの残存率を高める上で有効であることが分かった.(4) エタノール残存率と保存性の関係を調べた結果,麺に1.94%のエタノールが残存する場合, 30℃, 14日間の保存でも微生物の増殖はほとんど見られなかった.エタノール含量が低下するにつれて保存性は低下するが,エタノール含量が1.26%と低くても保存温度が15℃であれば45日間経過しても微生物は全く検出されなかった.

キノコの加工適性を知る資料とするため,野生種を中心にキノコの種類,乾燥又は塩蔵条件,抽出条件による5'-Nt含量の差を検討した.(1) キノコ中の5'-Ntとしては5'-UMP, 5'-AMP,5'-GMPが最も広く存在し,また量的にも多かった.これら三成分の多少はほぼ並行的であった.次いで5'-CMPが比較的多く認められ,稀に5'-IMP, 5'-XMPも少量見出される場合もあった.(2) キノコの種類による5'-Nt含量の差は極めて大きく,供試試料のうちではハツタケ,シャカシメジ,マイタケに多く,次いでシイタケ,ナラタケに多く,サクラシメジ及びホウキタケには少なかった.(3) 塩蔵後脱塩をおこなった試料には5'-Ntは殆んど含まれていなかった.(4) 低温減圧乾燥と加熱通風乾燥との比較では5'-Nt含量は両者の問に大差は認められなかった.(5) 熱湯による10分間と30分間の抽出時間が5'-Nt含量にあたえる影響も少なかった.しかし3時間室温水に浸漬した後そのまま加熱し, 30分間抽出した場合は大幅に減少した.(6) 5'-GMPも5'-Nt全体の傾向とほぼ同一であった.

玄そば貯蔵中の品質変化におよぼす,温度,水分,および炭酸ガス充填の効果について発芽率および化学的指標により検討を加えた。(1) 温度および水分含量が高いほど品質の低下が著しく,30℃で貯蔵した場合には,水分含量で13.8%以上の試験区はすべて10ヶ月以内に品質の低下が見られた。(2) 30℃の条件下では炭酸ガスによる品質保持効果はほとんど認められなかった。(3) 脂肪酸度上昇の原因物質はほとんどが遊離脂肪酸であると考えられた。(4) 長期貯蔵した玄ソバの総脂肪酸と遊離脂肪酸の脂肪酸組成に差が見られ,前者と較べ後者では主としてC20以上の脂肪酸が少なく,リノール酸が多かった。

生めんを半ば乾燥させたいわゆる半生めんの保存に対するエタノール添加の有効性を確認するとともに,半生めん製造時におけるエタノールの残存率を高める条件を知る目的で試験を行った.(1) めんの乾燥を開始したのちエタノールは急速に揮散するが,見掛けの水分が30%以下になるとその速度は低下し水分20～25%ではほぼ一定の濃度で安定した.(2) 30℃ 14日間保存後,対照では水分17～18%以上の試料で生菌数の増加が認められるのに対して,3～5%エタノールを添加した場合,見掛けの水分が2～4%対照よりも高い試料で生菌数の増加が認められた.(3) エタノールの保存効果はエタノールによる水分活性の低下効果だけによるものではなく,その静菌作用が水分活性との相乗効果として現れたものと考えられた.(4) 乾燥温度が低く(20℃),湿度も低いほうが(65% RH)エタノールの残存量は多かった.(5) エタノールの揮散防止の目的でシュークロースやデキストリンを添加する方法に,効果が認められた.また,食塩含量を減らすことによりその効果は増大した.