20,205 research outputs found
養液配方及試藥等級對尖葉萵苣和小白菜生育之影響
No full textThis experiment uses Hogland and Shan Ch'i formula, respectively by the reagent level and the industry level raw material configuration, compared with it to influence pH value and the EC value change of culture solution, and influence to the growth in lettuce and pak-choi. Used Hoagland formula to culture lettuce and pak-choi, the daily pH value change is 0.08~0.66, in its average the climbing value and the climbing rate all significantly decrease 65% comparing the Shan Ch'i formula. The pH value of culture solution changes all to draw close significantly drops along with the cultivation number of days to is stable. Therefore its climbing rate significantly drops along with the cultivation number of days increase. The EC value of Hoagland formula is 1580~2080μS/cm, significantly higher than Shan Chi'i formula with 1015~1085μS/cm, and changes few during cultivation period. In leaf numbers, fresh weight, pH value of culture solution and the growth of lettuce and pak-choi, the use reagent level or the industry level raw material is not significantly. Therefore used Hoagland formula by the industry level raw material, the pH and the EC value compared the Shan Ch'i formula to be stable, and the growth of lettuce and pak-choi is better than Shan Ch'i formula, it is a worth reference for production.本試驗採用Hoagland及山崎培養液配方，分別以試藥級及工業級原料配製養液，比較其對水耕養液之pH值及EC值變化之影響，及對尖葉萵苣與小白菜生育之影響。Hoagland配方養液栽培尖葉萵苣及小白菜，其每日pH值變化為0.08~0.66，其平均上升值及上升率皆顯著較山崎配方減少65%。養液中的pH值變化皆隨栽培天數之增加而趨近於穩定，故其上升率隨栽培天數的增加而明顯下降。Hoagland養液之EC值1580~2080μS/cm，明顯較山崎配方之1015~1085μS/cm為高，但栽培期間之變化少。Hoagland養液對尖葉萵苣及小白菜之葉片數、鮮重、葉面積等生育性狀顯著高於山崎氏配方。使用試藥級或工業級藥品配製養液，對養液pH值及植株生育性狀則沒有顯著差異。因此即便以工業級藥品配製Hoagland配方，仍可使養液pH值及EC值較山崎配方穩定，且對尖葉萵苣及小白菜之生育有明顯促進效果，值得生產業者參考使用
Impact of Age and Body Site on Adult Female Skin Surface pH
No full textBackground: pH is known as an important parameter in epidermal barrier function and homeostasis. Aim: The impact of age and body site on skin surface pH (pH(SS)) of women was evaluated in vivo. Methods: Time domain dual lifetime referencing with luminescent sensor foils was used for pH(SS) measurements. pH(SS) was measured on the forehead, the temple, and the volar forearm of adult females (n = 97, 52.87 +/- 18.58 years, 20-97 years). Every single measurement contained 2,500 pH values due to the luminescence imaging technique used. Results: pH(SS) slightly increases with age on all three investigated body sites. There are no significant differences in pH(SS) between the three investigated body sites. Conclusion: Adult pH(SS) on the forehead, the temple and the volar forearm increases slightly with age. This knowledge is crucial for adapting medical skin care products. Copyright (C) 2012 S. Karger AG, Base
Dextran-b-poly(L-histidine) copolymer nanoparticles for pH-responsive drug delivery to tumor cells
No full textJong-Ho Hwang,1,2 Cheol Woong Choi,1 Hyung-Wook Kim,1 Do Hyung Kim,3 Tae Won Kwak,3 Hye Myeong Lee,3 Cy Hyun Kim,3 Chung Wook Chung,3 Young-Il Jeong,3 Dae Hwan Kang1,3 1Department of Internal Medicine, Medical Research Institute, Pusan National University School of Medicine, Yangsan, Republic of Korea; 2Department of Internal Medicine, Busan Medical Center, Yeonje-gu, Busan, Republic of Korea; 3National Research and Development Center for Hepatobiliary Disease, Pusan National University Yangsan Hospital, Yangsan, Republic of Korea Purpose: Nanoparticles based on stimuli-sensitive drug delivery have been extensively investigated for tumor targeting. Among them, pH-responsive drug targeting using pH-sensitive polymers has attracted attention because solid tumors have an acidic environment. A dextran-b-poly(L-histidine) (DexPHS) copolymer was synthesized and pH-responsive nanoparticles were fabricated for drug targeting. Methods and results: A DexPHS block copolymer was synthesized by attaching the reductive end of dextran to the amine groups of poly(L-histidine). pH-responsive nanoparticles incorporating doxorubicin were fabricated and studied in HuCC-T1 cholangiocarcinoma cells. Synthesis of DexPHS was confirmed by 1H nuclear magnetic resonance spectroscopy, with specific peaks of dextran and PHS observed at 2–5 ppm and 7.4–9.0 ppm, respectively. DexPHS nanoparticles showed changes in particle size with pH sensitivity, ie, the size of the nanoparticles increased at an acidic pH and decreased at a basic pH. DexPHS block copolymer nanoparticles incorporating doxorubicin were prepared using the nanoprecipitation dialysis method. The doxorubicin release rate was increased at acidic pH compared with basic pH, indicating that DexPHS nanoparticles have pH-sensitive properties and that drug release can be controlled by variations in pH. The antitumor activity of DexPHS nanoparticles incorporating doxorubicin were studied using HuCC-T1 cholangiocarcinoma cells. Viability was decreased in cells treated with nanoparticles at acidic pH, whereas cell viability in response to treatment with doxorubicin did not vary according to changes of pH. Conclusion: Our results indicated that DexPHS polymeric micelles are promising candidates for antitumor drug targeting. Keywords: pH-responsive drug targeting, nanoparticles, block copolymer, poly(L-histidine), dextra
Analysis and Comparison of rbcLXS and hupSL Gene Locus Nucletide and Amino Acid Sequences of the Taiwan Isolated Cyanobacterium
No full text利用從魚腥藻PCC 7120 rbcLS基因兩端高保留區設計兩條引子，篩選魚腥藻CH1 Rubisco基因rbcLXS，以CH1基因體組DNA為模版 (template)， 進行PCR反應，所得PCR產物經核酸定序得知，包含rbcL、rbcX及rbcS三個基因，其中rbcL基因含1428個鹼基對，可轉譯出476個胺基酸的蛋白，分子量52.9 kDa；rbcS基因含330個鹼基對，可轉譯出109個胺基酸，分子量12.9 kDa；rbcX基因含399個鹼基對，可轉譯出132個胺基酸的蛋白，分子量15.2 kDa。
依據Kellogg及Juliano (1997) 結果，推測魚腥藻CH1 RbcL活化區位於其α螺旋體與β平板所形成的C端loop處且胺基酸具有100%高保留特性。有關rbcX研究，截至目前為止，rbcX基因只在藍綠藻發現。
選殖魚腥藻CH2氫酵素基因hupSL過程，首先以魚腥藻CH1氫酵素基因hupSL為探針，經南方墨點分析結果，發現hupSL在魚腥藻CH2基因體組內為single copy。以魚腥藻CH2基因體組DNA切EcoR I 5.3 kb處構築而成的基因庫中篩選，將得到的選殖體核酸定序分析，包含完整的hupS基因963個鹼基對，可轉譯出320個胺基酸，分子量35.2 kDa；及hupL片段前端511個鹼基對；以及hupS前端未轉譯區2874個鹼基對；及hupL基因內插入片段841個鹼基對。將此片段進行基因庫比對，並無相似的片段存在，推論魚腥藻CH2 hupL基因具有基因重組現象。
魚腥藻CH1及CH2譜係關係分析，經由hupS、hupL核酸及胺基酸序列親緣關係比較，魚腥藻CH2與念珠藻PCC 73102親緣關係上較魚腥藻CH1、PCC 7120近，其可信度100%。與紫細菌親緣關係，由核酸及胺基酸序列比較，魚腥藻與紫細菌氫酵素基因差異很大。魚腥藻CH1譜係關係分析，經rbcL、X、S核酸及胺基酸序列親緣關係比較，所得結果，魚腥藻CH1與PCC 7120親緣關係較近，此結果與hupS、hupL核酸及胺基酸序列親緣關係分析結果一樣，藍綠藻親緣分析氫酵素基因hupS、hupL可以作為藍綠藻親緣分析上的研究。中文摘要 ------------------------------------------------- -01
前言 -------------------------------------------------------02
前人研究 ---------------------------------------------------03
一、 魚腥藻異型細胞分化之分子機制 --------------------------03
二、 魚腥藻Rubisco基因之研究 -------------------------------04
三、 魚腥藻氫酵素基因之研究 --------------------------------05
四、 藍綠藻親緣關係（phylogenetic analysis）之研究 ---------07
材料方法 ---------------------------------------------------10
一、 載體pCH1rbcLXS之來源 ----------------------------------10
二、 少量載體DNA之抽取 -------------------------------------10
三、 Exonuclease III單一方向刪減（deletion）反應 -----------10
1. 限制酵素作用 --------------------------------------------10
2. 刪減反應 ------------------------------------------------11
3. S1核酸酵素反應 ------------------------------------------11
4. DNA polymerase I（Klenow fragment）作用 -----------------11
四、 核酸序列分析 ------------------------------------------11
1. 雙股DNA之處理 -------------------------------------------11
2. 少量單股DNA之抽取 ---------------------------------------12
3. Autosequencing ------------------------------------------12
4. Manual Sequencing ---------------------------------------12
五、 魚腥藻之培養 ------------------------------------------13
六、 魚腥藻基因體組DNA（genomic DNA）之抽取 ----------------13
七、 南方墨點法 --------------------------------------------13
1. 限制酵素作用 --------------------------------------------13
2. DNA膠體電泳 ---------------------------------------------14
3. DNA轉印 -------------------------------------------------14
4. 探針之製備 ----------------------------------------------14
5. 雜交反應 ------------------------------------------------14
6. 自動放射顯影 --------------------------------------------15
八、 DNA片段之純化回收 -------------------------------------15
九、 基音體組（genomic clone）之篩選 -----------------------15
1. 基因庫之構築 --------------------------------------------15
2. 寄主細胞之培養 ------------------------------------------15
3. 基因庫噬菌體之培養 --------------------------------------16
4. 溶菌斑之轉印 --------------------------------------------16
5. 溶菌斑之篩選 --------------------------------------------16
十、 載体（phagemid）之跳脫（excision） --------------------17
十一、 載体之構築 ------------------------------------------17
十二、 數據分析 --------------------------------------------17
1. 序列比較 ------------------------------------------------17
2. 譜系分析（phylogenetic analysis） -----------------------17
結果--------------------------------------------------------18
一、 魚腥藻CH1 Rubisco 基因定序及分析 ----------------------18
1. 魚腥藻CH1 rbcLXS核酸定序分析 ----------------------------19
2. 魚腥藻CH1 rbcL、rbcX、rbcS胺基酸序列分析 ----------------19
3. 魚腥藻CH1 rbcL、rbcX、 rbcS三基因其親源關係 ------------20
（1） 魚腥藻CH1 rbcL核酸及胺基酸序列親源關係----------------20
（2） 魚腥藻CH1 rbcX核酸及胺基酸序列親源關係 ---------------20
（3） 魚腥藻CH1 rbcS核酸及胺基酸序列親源關係 ---------------21
4. 魚腥藻CH1 rbcL、rbcX、rbcS 核酸及胺基酸序列相似性之比較 -21
（1） 魚腥藻CH1 rbcL核酸及胺基酸序列相似性之比較 -----------21
(2)魚腥藻CH1 rbcX核酸及胺基酸序列相似性之比較 -------------22
(3)魚腥藻CH1 rbcS核酸及胺基酸序列相似性之比較 -------------22
二、 魚腥藻CH2 氫酵素基因選殖係篩選及其胺基酸序列分析,
親源關係之比較-----------------------------------------23
1. 魚腥藻CH2 氫酵素基因之選殖及核酸序定序分析 --------------23
2. 魚腥藻CH2氫酵素基因 hupS、hupL胺基酸序列分析-------------24
3. 魚腥藻CH2氫酵素基因 hupS、hupL基因親源關係分析 ----------24
4. 魚腥藻CH2氫酵素基因 hupS核酸及胺基酸序列相似性之比較-----24
討論 -------------------------------------------------------26
一、 台灣分離株魚腥藻CH1及CH2譜系關係分析-------------------26
二、 魚腥藻CH2 氫酵素基因hupL基因重組 ----------------------26
三、 魚腥藻CH2 氫酵素基因hupS、hupL譜系關係研究 ------------27
四、 rbcLXS及hupSL親緣關係上核酸及胺基酸序列取代速率的意義--27
參考文獻 ---------------------------------------------------28
圖表 -------------------------------------------------------34
附錄--------------------------------------------------------7
The Fermentation of Low-Starch Yam Liquid with Lactic Cultures
No full text山藥塊莖富含多種必需胺基酸、蛋白質及澱粉，另具有黏液質及多種維生素與礦物質，可提供人體多種必需的營養。在塊莖中亦富含澱粉質，但由於黏質液（醣蛋白結構）的存在，使澱粉不易分離。本研究之目的即是利用酵素之添加及其他化學方式，試圖降低山藥黏度並以簡易而有效之步驟分離澱粉，以期提高澱粉之回收。此外，利用乳酸菌產酸之特性，添加於山藥中進行發酵以助澱粉的分離，並探討其發酵之條件。經分離澱粉過之低澱粉含量山藥黏質液，具有高營養、保健功用，以乳酸菌再行第二次發酵，在其山藥本身可提供乳酸菌發酵用之基質條件限制下，添加果寡醣以增加乳酸菌數並做簡單之調味，製備成山藥乳酸液。同時發酵液也進行酸度、總醣含量、乳酸菌菌量、嗜好性試驗，及貯藏試驗。
結果顯示，山藥澱粉回收的情形，不論添加果膠酵素、添加綜合型醣類分解酵素或以酸降低pH值至3及4，與山藥直接打漿後進行分離相比，均可達良好的回收增加率（約125∼172％）；以乳酸菌8％之S. thermophilus添加於25％山藥濃度，於37℃下發酵12小時後，可達pH 值約為3.75之低酸，其澱粉之回收情形，與山藥直接打漿後進行分離相比，亦增加約54∼63％。
經初次乳酸發酵分離澱粉過之山藥黏質液有部分澱粉存在，以混合菌株（L. bulgaricus＋S. thermophilus）進行發酵之風味較佳，有其特殊的香味。當添加5％之果寡醣於低澱粉含量山藥液中時，乳酸菌之產酸較佳，但就乳酸菌生長情形，則以添加量為7.5％時較佳，添加果寡糖與否，對乳酸菌之生長確有助益。從嗜好性試驗及貯藏試驗結果顯示，添加果寡糖後製成之發酵品，去除了山藥原有的苦澀味，且其在4℃下貯藏8日後仍具高量的活性乳酸菌，實為一具有潛力可開發之產品。The tuber of yam is an abundant supply of amino acids, proteins, mucin, vitamins and mineral elements. It is a good source for human nutrition. The starch content is special rich in the tuber. However it is difficult to isolate yam starch from yam tuber because the present of the viscous mucin is a carbohydrate moiety firmly associated with protein (glycoprotein). This study is trying to modify yam tuber extract by adding enzymes and chemicals during preparation procedure to decrease the viscosity of the mucin for further yam starch isolation and its liquid separation so as to increase their recovery. Besides, the lactic acid bacteria are inoculated into the yam liquid to reduce its pH and in order to recover yam starch alone from its liquid. After the separate yam liquid being sterilized, the lactic acid bacteria are inoculated twice for secondary fermentation. Another objective of this investigation was to study whether yam liquid can be a good substrate for lactic acid bacteria with or without adding fructooligosaccharides. The characteristics of the low-starch fermentative yam liquid were examined including pH, titratable acidity, total sugar, microbiological analysis, flavor analysis, and storage analysis.
Results showed that better recovery of yam starch can be obtained by adding enzymes (Pectinex® Ultra SP-L, and Viscozyme® L) or acids to adjust pH to 3 or 4. In comparison with the original isolation method, the yam starch recovery rate increased about 125~172%. By inoculating 8% S. thermophilus to 25% yam substrate at 37℃ for 12 hours (the pH can drop to 3.75), the recovery of yam starch is increased but not as good as directly adjusting its pH to 3 or 4 by adding acid.
With the addition 5% fructooligosaccharides to low-starch yam liquid, the lactic acid bacteria produced more acids. The lactic acid bacteria also grew well when 7.5% fructooligosaccharides was added. This result showed that fructooligosaccharides were good for the lactic acid bacteria growth. The fermentative (L. bulgaricus and S. thermophlius) mixed cultures generated a better flavor than their individual cultures alone. Results for taste preference and storage analysis showed that with the addition of 7.5% fructooligosaccharides, the fermentative low-starch yam liquid remove its original bitter taste, and high lactic acid bacteria counts lasted after 8 days storage at 4℃.目錄
英文摘要………………………………………………………….1
中文摘要………………………………………………………….3
壹、前言…………………………………………………………..5
貳、文獻整理……………………………………………………..7
一、山藥簡介..…………………………………..……………...7
（一）概說………..…………………………..……………...7
（二）成分…………………………………………………...8
（三）栽培種類及品種………………………..….………..12
（四）採收及貯藏………………………………………….15
（五）營養價值……………………………………..……...17
（六）黏質液之研究……………………………………….19
二、乳酸菌之簡介…..………………………………………...20
三、乳酸菌發酵食品之簡介…………………………………21
（一）米奶之乳酸發酵…………………………………….24
（二）豆奶之乳酸發酵…………………………………….25
（三）甘藷之乳酸發酵…………………………………….26
（四）樹薯之乳酸發酵…………………………………….27
（五）芋頭之乳酸發酵……………………………...……..27
（六）胡蘿蔔之乳酸發酵…………………………….……28
（七）香蕉之乳酸發酵.…………………………….……...29
（八）蓮霧之乳酸發酵………………………..…………...30
（九）甜瓜之乳酸發酵………………………..…………...31
（十）芥菜汁之乳酸發酵……………….……….………...31
（十一）澱粉原料之乳酸發酵……………………….……32
四、澱粉之分離………………………………………………33
參、實驗架構……………………………………………….……35
肆、材料與方法………………………………………….………36
一、實驗材料………………………………………….………36
（一）山藥…………….……………………………………36
（二）酵素…………….……………………………………36
（三）試驗菌種……….……………………………………37
（四）藥品…………….……………………………………37
（五）儀器…………….……………………………………40
二、實驗方法…………………………………………….…...42
（一）山藥漿之製備………………………………….……42
（二）酵素性水解…………………………………….……42
1.蛋白質分解酵素………………..……..……………42
2.澱粉分解酵素…………………..……..……………43
3.醣類分解酵素……………...…..……..………….…43
（三）加酸、電解質………………………………….……43
（四）接種源之製備………………………………….……43
（五）菌種之選擇與發酵條件之探討……………….……44
1.發酵基質固形量………………..……..……………44
2.發酵溫度………………………..……..……………44
3.菌株之初步篩選.………………...…..……..………44
4.菌量之篩選…………….. …...…..……..…………..45
（六）山藥澱粉之分離...…………………………………..45
（七）低澱粉含量山藥液之取得………………………….45
（八）低澱粉含量山藥液之利用...………………………..46
三、發酵液分析.……………………………………………...46
（一）pH值……….………………………………………..46
（二）可滴定酸度………………………………………….46
（三）總醣含量……………….……..……………………..46
（四）乳酸菌菌數之測定及乳酸菌之世代時間………….47
（五）嗜好性試驗………………………………….………47
（六）貯藏試驗…………………...……………….……….48
伍、結果與討論………………………………………………….49
第一部份：山藥澱粉之分離………………………………...49
一、添加蛋白質分解酵素…………………………………….49
二、添加澱粉分解酵素…………………………….………...51
三、添加果膠酵素及綜合型醣類分解酵素...…….………….52
四、添加酸……………..……………………………………...53
五、添加電解質鹽類…..……………………………………...54
第二部份：山藥黏質液之再利用….………………………..57
一、最適乳酸菌產酸條件之探討………….……………….57
（一）山藥發酵基質濃度對乳酸菌產酸之影響..………...57
（二）發酵溫度對乳酸菌產酸之影響………..….………..61
（三）不同菌株對乳酸菌產酸之影響……..……………...64
（四）不同菌量乳酸菌對山藥基質產酸之影響..………...65
（五）以乳酸菌發酵產酸後其山藥澱粉之回收情形……68
二、低澱粉含量山藥液之製備….……………..…………….71
三、低澱粉含量山藥液之再利用………......…………….…..72
（一）乳酸菌於低澱粉含量山藥液中產酸的情形…….....72
（二）果寡醣對乳酸菌於低澱粉含量山藥液中
產酸的情形………………………………………..73
（三）發酵期間其總醣量之變化…………..……………...80
（四）發酵液嗜好性試驗響..…………………….………..85
（五）貯藏試驗…..…………..…………………..………..86
陸、結論………………………………………………………….91
柒、參考文獻………………………………………………..…...94
圖目錄
圖一 山藥粘質物中甘露糖可能結構式…………………….... 11
圖二 常見山藥之種類………………………………………...16
圖三 L. bulgaricus 和S. thermophilus於牛乳中之
生長情形. …………..……………………………..…….23
圖四 添加酵素及調降pH值對山藥澱粉與黏質液
分層之影響. . …………..…………………………….…55
圖五 L. bulgaricus 在各種不同山藥基質中，於40℃下，24小時培養期間之pH及可滴定酸度之變化情形...……..60
圖六 L. bulgaricus 在25％之山藥基質於四種不同溫度，12小時培養期間之pH及可滴定酸度之變化情形…….…62
圖七 S. thermophilius 在25％之山藥基質於三種不同溫度，12小時培養期間之pH及可滴定酸度之變化情形…….63
圖八 不同菌在25％之山藥基質於其最適產酸溫度，12小時培養期間之pH及可滴定酸度之變化情形…………….66
圖九 不同菌量在25％之山藥基質於37℃，24小時培養期間之pH及可滴定酸度之變化情形……………………….67
圖十 不同菌在低澱粉含量山藥液中其pH及可滴定酸度之變化情形…………………….……………………..………74
圖十一 添加5％及7.5％之果寡醣對乳酸菌於低澱粉含量山藥液中其pH及可滴定酸度之變化情形………….....77
圖十二 添加5％及7.5％之果寡醣對乳酸菌於低澱粉含量山藥液生長之情形……………………………………...78
圖十三 山藥漿在處理過程中，其總醣含量之變化情形…….81
圖十四 低澱粉含量山藥液在乳酸發酵過程中總醣糖變化情形……………………………………………………...85
表目錄
表一 山藥粘質物的胺基酸組成……………………………...10
表二 應用於發酵食品之主要乳酸菌………………………...22
表三 世界不同地區生產以乳酸發酵澱粉原料之例子……...34
表四 本試驗中所採用蛋白質分解酵素之一般性質………...38
表五 本試驗中所採用澱粉分解酵素及綜合型醣類分解酵素之一般性質……………………………………...……..39
表六 果寡糖中所含各種糖類之比例………………………...41
表七 不同山藥澱粉回收之情形………………...……………50
表八 L. bulgaricus 接種於各種不同山藥基質中，於40℃下，發酵2、6、12、24小時之pH值及可滴定酸度………....59
表九 添加不同菌量之乳酸菌對山藥澱粉回收之影響…...…70
表十 乳酸菌在低澱粉含量山藥液中之生長情形…………...79
表十一 山藥漿在各處理中，其總醣含量之變化情形……….82
表十二 低澱粉含量山藥發酵液之嗜好性試驗……………...87
表十二 低澱粉含量山藥發酵液於4℃下貯存期間之乳酸菌菌數變化情形…………………………………….……88
表十三 低澱粉含量山藥發酵液於4℃下貯存期間其pH值及可滴定酸度之變化情形…………………………….8
Microplasma Band Structure Engineering in Graphene Quantum Dots for Sensitive and Wide-Range pH Sensing
No full textpH sensing using active nanomaterials is promising in many fields ranging from chemical reactions to biochemistry, biomedicine, and environmental safety especially in the nanoscale. However, it is still challenging to achieve nanotechnology-enhanced rapid, sensitive, and quantitative pH detection with stable, biocompatible, and cost-effective materials. Here, we report a rational design of nitrogen-doped graphene quantum dot (NGQD)-based pH sensors by boosting the NGQD pH sensing properties via microplasma-enabled band-structure engineering. Effectively and economically, the emission-tunable NGQDs can be synthesized from earth-abundant chitosan biomass precursor by controlling the microplasma chemistry under ambient conditions. Advanced spectroscopy measurements and density functional theory (DFT) calculations reveal that functionality-tuned NGQDs with enriched -OH functional groups and stable and large Stokes shift along the variations of pH value can achieve rapid, label-free, and ionic-stable pH sensing with a wide sensing range from pH 1.8 to 13.6. The underlying mechanism of pH sensing is related to the protonation/deprotonation of -OH group of NGQDs, leading to the maximum pH-dependent luminescence peak shift along with the bandgap broadening or narrowing. In just 1 h, a single microplasma jet can produce a stable colloidal NGQD dispersion with 10 mg/mL concentration lasting for at least 100 pH detections, and the process is scalable. This approach is generic and opens new avenues for nanographene-based materials synthesis for applications in sensing, nanocatalysis, energy generation and conversion, quantum optoelectronics, bioimaging, and drug delivery.No Full Tex
An intracellular pH gradient in the anammox bacterium Kuenenia stuttgartiensis as evaluated by (31)P NMR
No full textThe cytoplasm of anaerobic ammonium oxidizing (anammox) bacteria consists of three compartments separated by membranes. It has been suggested that a proton motive force may be generated over the membrane of the innermost compartment, the “anammoxosome”. 31P nuclear magnetic resonance (NMR) spectroscopy was employed to investigate intracellular pH differences in the anammox bacterium Kuenenia stuttgartiensis. With in vivo NMR, spectra were recorded of active, highly concentrated suspensions of K. stuttgartiensis in a wide-bore NMR tube. At different external pH values, two stable and distinct phosphate peaks were apparent in the recorded spectra. These peaks were equivalent with pH values of 7.3 and 6.3 and suggested the presence of a proton motive force over an intracytoplasmic membrane in K.stuttgartiensis. This study provides for the second time—after discovery of acidocalcisome-like compartments in Agrobacterium tumefaciens—evidence for an intracytoplasmic pH gradient in a chemotrophic prokaryotic cell.BiotechnologyApplied Science
Discretization and solution of elliptic PDEs--a transform domain approach
No full textIncludes bibliographies.Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1987.by Chung-Chieh Kuo.Ph.D
Syntheses of chorismate analogs for investigation of structural requirements for chorismate mutase
No full textThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1994.Includes bibliographical references.by Chang-Chung Cheng.Ph.D
Symmetric function generalizations of graph polynomials
No full textThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 1995.Includes bibliographical references (p. 67-70).by Timothy Yi-Chung Chow.Ph.D
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