STD Awareness Month PSA (:30)

Centers for Disease Control (CDC) Podcasts

2011-04-19

April is National STD Awareness Month. STDs can affect anyone. Many STDs don't have symptoms so it's important to get tested.  Created: 4/19/2011 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention.   Date Released: 4/19/2011.

STD Training in Canadian Medical Schools

Directory of Open Access Journals (Sweden)

Jo-Anne A Doherty

1992-01-01

Full Text Available OBJECTIVE: The emergence of the acquired immune deficiency syndrome in 1981 and the consequent publicity surrounding sexual behaviour has increased the likelihood that patients will seek medical advice. Sexually transmitted disease (STD teaching and postgraduate medical programs in Canadian schools of medicine have not been adequately documented. Accordingly, the Laboratory Centre for Disease Control. Department of National Health and Welfare, sought to determine the magnitude and scope of STD training in these schools. DESIGN: A four page questionnaire sought information on preclinical, clinical and residency training in terms of the number of classroom and laboratory hours of instruction, the subspecialty responsible for providing the training, and the clinical ‘hands on’ experience of the teachers: each respondent was also asked to assess the quality and scope of instruction provided at his/her medical school. SETTING/PARTICIPANTS: The questionnaire was mailed to the Dean of each of the 16 schools of medicine in Canada: it was requested that the questionnaire be forwarded to and completed by the person responsible for STD training at the university. RESULTS: Thirteen schools (81% completed the questionnaire. Each school indicated that some STD instruction was provided at the undergraduate level: the mean number of hours of classroom instruction was 6.1. Physicians with STD clinical ‘hands on’ experience were responsible for teaching in 12 schools. Infectious disease residents spent 4 to 80 h on STDs, while those from other residency programs where STD was not an elective spent 2 to 8 h. Each medical school was asked to provide an evaluation of its program. Only three respondents considered their STD training program adequate. The majority of schools responded that infectious disease residents received sufficient training but the training offered medical students and residents in other programs was less than adequate. The quality

HIV and STD status among MSM and attitudes about Internet partner notification for STD exposure.

Science.gov (United States)

Mimiaga, Matthew J; Tetu, Ashley M; Gortmaker, Steven; Koenen, Karestan C; Fair, Andrew D; Novak, David S; Vanderwarker, Rodney; Bertrand, Thomas; Adelson, Stephan; Mayer, Kenneth H

2008-02-01

This study assessed the acceptability and perceived utility of Internet-based partner notification (PN) of sexually transmitted disease (STD) exposure for men who have sex with men (MSM) by human immunodeficiency virus (HIV) serostatus. We recruited 1848 US MSM via a banner advertisement posted on an MSM website for meeting sexual partners between October and November 2005. Even though there was broad acceptance of a PN e-mail across HIV serostatus groups, HIV-infected men rated the importance of each component (e.g., information about where to get tested/treated, additional education regarding the STD exposed to, a mechanism for verifying the authenticity of the PN e-mail) lower than HIV-uninfected or status-unknown participants (all P's e-mail (if they were to receive an e-mail notifying them of possible STD exposure in the future), and were less likely to inform their partners of possible STD exposure via an Internet notification system in the future (all P's e-mail. If public health officials consider using Internet notification services, they may need to anticipate and address concerns of HIV-infected MSM, and will need to use a culturally-sensitive, social marketing campaign to ensure that those who may benefit from these services are willing to use this modality for PN. Internet PN should be considered as a tool to decrease rising STD and HIV rates among MSM who use the Internet to meet sexual partners.

HIV/STD pattern and its associated risk factors among male STD clinic attendees in China: a foci for HIV intervention

Directory of Open Access Journals (Sweden)

Wang Qian-Qiu

2011-12-01

Full Text Available Abstract Background Previous studies suggested a high prevalence of STDs including HIV among female sex workers and men who have sex with men in China, but little was known about the prevalence in male patients attending public STD clinics. The aim of this study was to investigate STD patterns and HIV prevalence among male STD clinic attendees in different areas in China and the associated risk factors. The feasibility of Provider-initiated HIV testing and counseling (PITC was evaluated as well. Methods A cross-sectional study was conducted at 46 public STD clinics in 4 provinces in China. Between July 2009 and September 2009, a total of 3243 eligible subjects were invited to participate in an interview with a structured-questionnaire for collecting socio-demographic characteristics and sexual behavioral information. They also were asked to provide venous blood samples for serological determinations of HIV and syphilis infection, and first void urine specimens for detecting Chlamydia trachomatis and Neisseria gonorrhoeae infections, Results Out of the 3243 eligible patients, 2951(91% men agreed to take part in the HIV and syphilis testing. The overall prevalence rate of HIV infection was 0.7% while the rates of syphilis, N. gonorrhoeae, C. trachomatis infections were 10.7%, 4.3% and 6.9%, respectively, with the highest syphilis and N. gonorrhoeae rates in Jiangsu Province. Patients from Guangxi province, homosexual/bisexual practices and intravenous drug use were significantly associated with HIV infection in multivariate logistic regression analyses. Provider-initiated HIV testing and counseling (PITC was well accepted by attendees, with 91% of eligible attendees agreeing to undergo HIV testing and counseling. All HIV positive patients were properly managed accordingly. Conclusions A modest prevalence of HIV infection and substantial prevalence of other STD infections were found among male patients attending public STD clinics in China. The

Extracting protein dynamics information from overlapped NMR signals using relaxation dispersion difference NMR spectroscopy.

Science.gov (United States)

Konuma, Tsuyoshi; Harada, Erisa; Sugase, Kenji

2015-12-01

Protein dynamics plays important roles in many biological events, such as ligand binding and enzyme reactions. NMR is mostly used for investigating such protein dynamics in a site-specific manner. Recently, NMR has been actively applied to large proteins and intrinsically disordered proteins, which are attractive research targets. However, signal overlap, which is often observed for such proteins, hampers accurate analysis of NMR data. In this study, we have developed a new methodology called relaxation dispersion difference that can extract conformational exchange parameters from overlapped NMR signals measured using relaxation dispersion spectroscopy. In relaxation dispersion measurements, the signal intensities of fluctuating residues vary according to the Carr-Purcell-Meiboon-Gill pulsing interval, whereas those of non-fluctuating residues are constant. Therefore, subtraction of each relaxation dispersion spectrum from that with the highest signal intensities, measured at the shortest pulsing interval, leaves only the signals of the fluctuating residues. This is the principle of the relaxation dispersion difference method. This new method enabled us to extract exchange parameters from overlapped signals of heme oxygenase-1, which is a relatively large protein. The results indicate that the structural flexibility of a kink in the heme-binding site is important for efficient heme binding. Relaxation dispersion difference requires neither selectively labeled samples nor modification of pulse programs; thus it will have wide applications in protein dynamics analysis.

Extracting protein dynamics information from overlapped NMR signals using relaxation dispersion difference NMR spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Konuma, Tsuyoshi [Icahn School of Medicine at Mount Sinai, Department of Structural and Chemical Biology (United States); Harada, Erisa [Suntory Foundation for Life Sciences, Bioorganic Research Institute (Japan); Sugase, Kenji, E-mail: sugase@sunbor.or.jp, E-mail: sugase@moleng.kyoto-u.ac.jp [Kyoto University, Department of Molecular Engineering, Graduate School of Engineering (Japan)

2015-12-15

Protein dynamics plays important roles in many biological events, such as ligand binding and enzyme reactions. NMR is mostly used for investigating such protein dynamics in a site-specific manner. Recently, NMR has been actively applied to large proteins and intrinsically disordered proteins, which are attractive research targets. However, signal overlap, which is often observed for such proteins, hampers accurate analysis of NMR data. In this study, we have developed a new methodology called relaxation dispersion difference that can extract conformational exchange parameters from overlapped NMR signals measured using relaxation dispersion spectroscopy. In relaxation dispersion measurements, the signal intensities of fluctuating residues vary according to the Carr-Purcell-Meiboon-Gill pulsing interval, whereas those of non-fluctuating residues are constant. Therefore, subtraction of each relaxation dispersion spectrum from that with the highest signal intensities, measured at the shortest pulsing interval, leaves only the signals of the fluctuating residues. This is the principle of the relaxation dispersion difference method. This new method enabled us to extract exchange parameters from overlapped signals of heme oxygenase-1, which is a relatively large protein. The results indicate that the structural flexibility of a kink in the heme-binding site is important for efficient heme binding. Relaxation dispersion difference requires neither selectively labeled samples nor modification of pulse programs; thus it will have wide applications in protein dynamics analysis.

A ten year study of STD Cases in an urban clinic in Calcutta

Directory of Open Access Journals (Sweden)

Ghosh Sadhana

1994-01-01

Full Text Available Total 16440 patients attended the STD clinic during the 10 years period of study from 1984 to 1993. From 1988 number of STD caes were gradually decreasing probably due to less promiscuity in fear of AIDS and different measures taken to prevent transmission of HIV infection. But it does not lessen the importance of STD control, because syphilis is still prevalent (8% with congenital syphilis. Peak in the incidence of chancroid (15% is alarming as this may lead to increased transmission of HIV infection in near future. Male unmarried constituted the bulk of STD sufferers (44% and married males (34%, while female unmarried and married patients were 1% and 20% respectively, 5.7% of antenatal mothers were strongly seroreactive for syphilis. Therefore all antenatal mothers should be screened for STD and routine serological test for syphilis should be done.

Nondestructive NMR technique for moisture determination in radioactive materials

International Nuclear Information System (INIS)

Aumeier, S.; Gerald, R.E. II; Growney, E.; Nunez, L.; Kaminski, M.

1998-01-01

This progress report focuses on experimental and computational studies used to evaluate nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) for detecting, quantifying, and monitoring hydrogen and other magnetically active nuclei ( 3 H, 3 He, 239 Pu, 241 Pu) in Spent nuclear fuels and packaging materials. The detection of moisture by using a toroid cavity NMR imager has been demonstrated in SiO 2 and UO 2 systems. The total moisture was quantified by means of 1 H NMR detection of H 2 O with a sensitivity of 100 ppm. In addition, an MRI technique that was used to determine the moisture distribution also enabled investigators to discriminate between bulk and stationary water sorbed on the particles. This imaging feature is unavailable in any other nondestructive assay (NDA) technique. Following the initial success of this program, the NMR detector volume was scaled up from the original design by a factor of 2000. The capacity of this detector exceeds the size specified by DOE-STD-3013-96

Insights into molecular recognition of LewisX mimics by DC-SIGN using NMR and molecular modelling

International Nuclear Information System (INIS)

Guzzi, C.; Angulo, J.; Rojo, J.; Nieto, P.M.; Doro, F.; Bernardi, A.; Thepaut, M.; Fieschi, F.; Thepaut, M.; Fieschi, F.

2011-01-01

In this work, we have studied in detail the binding of two α-fucosyl-amide-based mimics of Lewis X to DC-SIGN ECD (ECD = extracellular domain) using STD NMR and docking. We have concluded that the binding mode occurs mainly through the fucose moiety, in the same way as Lewis X . Similarly to other mimics containing mannose or fucose previously studied, we have shown that both compounds bind to DC-SIGN ECD in a multimodal fashion. In this case, the main contact is the interaction of two hydroxyl groups one equatorial and the other one axial (O3 and O4) of the fucose with the Ca 2+ as Lewis X and similarly to mannose-containing mimics (in this case the interacting groups are both in the equatorial position). Finally, we have measured the K D of one mimic that was 0.4 mM. Competitive STD NMR experiments indicate that the aromatic moiety provides additional binding contacts that increase the affinity. (authors)

STD Awareness – Reaching Youth

Centers for Disease Control (CDC) Podcasts

2012-04-16

In this podcast, Dr. Gail Bolan, Director of CDC's Division of STD Prevention, discusses the problem of STDs in young people, 15-24, and what providers can do.  Created: 4/16/2012 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 4/16/2012.

Sexual Risk Behavior: HIV, STD, & Teen Pregnancy Prevention

Science.gov (United States)

... A-Glance Project Connect Sexual Health STD Teen Pregnancy Sexual Risk Behaviors: HIV, STD, & Teen Pregnancy Prevention Recommend on Facebook Tweet ... their risk for HIV , other STDs , and unintended pregnancy . The National HIV/AIDS Strategy calls for all Americans to be ...

Compact, Low-Overhead, MIL-STD-1553B Controller

Science.gov (United States)

Katz, Richard; Barto, Rod

2009-01-01

A compact and flexible controller has been developed to provide MIL-STD- 1553B Remote Terminal (RT) communications and supporting and related functions with minimal demand on the resources of the system in which the controller is to be installed. (MIL-STD-1553B is a military standard that encompasses a method of communication and electrical-interface requirements for digital electronic subsystems connected to a data bus. MIL-STD-1553B is commonly used in defense and space applications.) Many other MIL-STD-1553B RT controllers are complicated, and to enable them to function, it is necessary to provide software and to use such ancillary separate hardware devices as microprocessors and dual-port memories. The present controller functions without need for software and any ancillary hardware. In addition, it contains a flexible system interface and extensive support hardware while including on-chip error-checking and diagnostic support circuitry. This controller is implemented within part of a modern field-programmable gate array.

Qualification test of Class 1E equipment based on IEEE323 Std 2003

International Nuclear Information System (INIS)

Kim, J. S.; Jung, S. C.; Kim, T. R.

2004-01-01

IEEE Standard for Qualifying Class 1E Equipment has been updated to 2003 edition since the issue of IEEE Std 323-1971, 1974, 1983. NRC approved the IEEE Std 323-1974 as Qualification standard of Class 1E Equipment in domestic nuclear power plant. IEEE Std 323-2003 was issued in September of 2003 and utility is waiting the approval of NRC. IEEE Std 323-2003 suggest a new qualification technique which adopts the condition monitoring. Performance of two transient during DBA test is no longer recommended in IEEE Std 323-2003. IEEE323 Std 2003 included a chapter of ''extension of Qualified life'' to make available the life extension of components during plant life extension. For the efficient control of preserving EQ in domestic nuclear power plant, IEEE323 Std 2003 is strongly recommended

Sensitivity of NMR spectra properties to different inversion algorithms. Abstract 97

International Nuclear Information System (INIS)

Bryan, J.; Wang, G.; Vargas, S.; Kantzas, A.

2004-01-01

'Full text:' Low field NMR technology has many applications in the petroleum industry. NMR spectra obtained from logging tools or laboratory instruments can be used to provide an incredible wealth of useful information for formation evaluation and reservoir fluid characterization purposes. In recent years, research performed at the University of Calgary has been instrumental in developing this technology for heavy oil and bitumen related problems. Specifically, low field NMR has been used in several niche applications: in-situ viscosity estimates of heavy oil and bitumen, water-in-oil emulsion and solvent-bitumen mixture viscosity, water cut in produced fluid streams, and oil-water-solids content in oil sands mining samples. The majority of all NMR analyses are based on the interpretation of NMR spectra. These spectra are inverted numerically from the measured NMR decay data. The mathematics of the inversion is generally assumed to be correct, and the analyses revolve around interpretations of how the spectra relate to physical properties of the samples. However, when measuring high viscosity fluids or clay-bound water, the NMR signal relaxes very quickly and it becomes extremely important to ensure that the spectrum obtained is accurate before relating its properties to physics. This work investigates the effect of different inversion algorithms on the generated spectra, and attempts to quantify the magnitude of the errors that can be associated with the mathematics of inversion. This leads to a better understanding of the accuracy of NMR estimates of rock and fluid properties. (author)

A High-Resolution Magic Angle Spinning NMR Study of the Enantiodiscrimination of 3,4-Methylenedioxymethamphetamine (MDMA by an Immobilized Polysaccharide-Based Chiral Phase.

Directory of Open Access Journals (Sweden)

Juliana C Barreiro

Full Text Available This paper reports the investigation of the chiral interaction between 3,4-methylenedioxy-methamphetamine (MDMA enantiomers and an immobilized polysaccharide-based chiral phase. For that, suspended-state high-resolution magic angle spinning nuclear magnetic resonance spectroscopy (1H HR-MAS NMR was used. 1H HR-MAS longitudinal relaxation time and Saturation Transfer Difference (STD NMR titration experiments were carried out yielding information at the molecular level of the transient diastereoisomeric complexes of MDMA enantiomers and the chiral stationary phase. The interaction of the enantiomers takes place through the aromatic moiety of MDMA and the aromatic group of the chiral selector by π-π stacking for both enantiomers; however, a stronger interaction was observed for the (R-enantiomer, which is the second one to elute at the chromatographic conditions.

Exposure to Different Types of Violence and Subsequent Sexual Risk Behavior among Female STD Clinic Patients: A Latent Class Analysis

Science.gov (United States)

Walsh, Jennifer L.; Senn, Theresa E.; Carey, Michael P.

2013-01-01

Objective Diverse forms of violence, including childhood maltreatment (CM), intimate partner violence (IPV), and exposure to community violence (ECV), have been linked separately with sexual risk behaviors. However, few studies have explored multiple experiences of violence simultaneously in relation to sexual risk-taking, especially in women who are most vulnerable to violent experiences. Methods Participants were 481 women (66% African American, Mage = 27 years) attending a publicly-funded STD clinic who reported on their past and current experiences with violence and their current sexual risk behavior. We identified patterns of experience with violence using latent class analysis (LCA) and investigated which combinations of experiences were associated with the riskiest sexual outcomes. Results Four classes of women with different experiences of violence were identified: Low Violence (39%), Predominantly ECV (20%), Predominantly CM (23%), and Multiply Victimized (18%). Women in the Multiply Victimized and Predominantly ECV classes reported the highest levels of sexual risk behavior, including more lifetime sexual partners and a greater likelihood of receiving STD treatment and using substances before sex. Conclusions Women with different patterns of violent experiences differed in their sexual risk behavior. Interventions to reduce sexual risk should address violence against women, focusing on experiences with multiple types of violence and experiences specifically with ECV. Additional research is needed to determine the best ways to address violence in sexual risk reduction interventions. PMID:23626921

Internet and Email Use Among STD Clinic Patients

Science.gov (United States)

Mark, Karen E.; Wald, Anna; Drolette, Linda; Golden, Matthew R.

2009-01-01

Background Little data exist on Internet and email use among STD clinic patients for research and clinical care communication. Methods An anonymous cross-sectional survey of STD clinic patients aged ≥ 18 years in Seattle, Washington, March 13–22, 2006. Results Of 489 study period patients, 251 (51%) completed the questionnaire. Participants had a median age of 30 (range 18–66) years and were 69% male, 56% White, 19% African-American, 9% Hispanic, and 7% Asian/Pacific Islander. 75% had some post-secondary education but half reported an annual income of email that they check at least 3 times a week, and 144 (57%) were willing to receive an email reminding them to come back for a follow-up appointment if diagnosed with an STD. MSM were more likely than women and heterosexual men to be regular Internet and email users (92% versus 70%, p = 0.001) and to have met a sex partner over the Internet during the past year (69% versus 11%, p email use, as was racial/ethnic background (86% of Whites, 48% of African-Americans, 73% of Hispanics, 100% of Asians/Pacific Islanders, and 57% of others, p email use are common and acceptable to many STD clinic patients for research and clinical purposes. PMID:18685548

Estimating the Size and Cost of the STD Prevention Services Safety Net.

Science.gov (United States)

Gift, Thomas L; Haderxhanaj, Laura T; Torrone, Elizabeth A; Behl, Ajay S; Romaguera, Raul A; Leichliter, Jami S

2015-01-01

The Patient Protection and Affordable Care Act is expected to reduce the number of uninsured people in the United States during the next eight years, but more than 10% are expected to remain uninsured. Uninsured people are one of the main populations using publicly funded safety net sexually transmitted disease (STD) prevention services. Estimating the proportion of the uninsured population expected to need STD services could help identify the potential demand for safety net STD services and improve program planning. In 2013, an estimated 8.27 million people met the criteria for being in need of STD services. In 2023, 4.70 million uninsured people are expected to meet the criteria for being in need of STD services. As an example, the cost in 2014 U.S. dollars of providing chlamydia screening to these people was an estimated $271.1 million in 2013 and is estimated to be $153.8 million in 2023. A substantial need will continue to exist for safety net STD prevention services in coming years.

Assessing STD Partner Services in State and Local Health Departments.

Science.gov (United States)

Cuffe, Kendra M; Leichliter, Jami S; Gift, Thomas L

2018-02-07

State and local health department STD programs provide several partner services to reduce disease transmission. Budget cuts and temporary staff reassignments for public health emergencies may affect the provision of partner services. Determining the impact of staffing reductions on STD rates and public health response should be further assessed.

Fast and Efficient Fragment-Based Lead Generation by Fully Automated Processing and Analysis of Ligand-Observed NMR Binding Data.

Science.gov (United States)

Peng, Chen; Frommlet, Alexandra; Perez, Manuel; Cobas, Carlos; Blechschmidt, Anke; Dominguez, Santiago; Lingel, Andreas

2016-04-14

NMR binding assays are routinely applied in hit finding and validation during early stages of drug discovery, particularly for fragment-based lead generation. To this end, compound libraries are screened by ligand-observed NMR experiments such as STD, T1ρ, and CPMG to identify molecules interacting with a target. The analysis of a high number of complex spectra is performed largely manually and therefore represents a limiting step in hit generation campaigns. Here we report a novel integrated computational procedure that processes and analyzes ligand-observed proton and fluorine NMR binding data in a fully automated fashion. A performance evaluation comparing automated and manual analysis results on (19)F- and (1)H-detected data sets shows that the program delivers robust, high-confidence hit lists in a fraction of the time needed for manual analysis and greatly facilitates visual inspection of the associated NMR spectra. These features enable considerably higher throughput, the assessment of larger libraries, and shorter turn-around times.

Developing a Motion Comic for HIV/STD Prevention for Young People Ages 15-24, Part 2: Evaluation of a Pilot Intervention.

Science.gov (United States)

Willis, Leigh A; Kachur, Rachel; Castellanos, Ted J; Nichols, Kristen; Mendoza, Maria C B; Gaul, Zaneta J; Spikes, Pilgrim; Gamayo, Ashley C; Durham, Marcus D; LaPlace, Lisa; Straw, Julie; Staatz, Colleen; Buge, Hadiza; Hogben, Matthew; Robinson, Susan; Brooks, John; Sutton, Madeline Y

2018-03-01

In the United States, young people (ages 15-24 years) are disproportionately affected by human immunodeficiency virus (HIV) and other sexually transmitted diseases (STDs), due at least in part to inadequate or incorrect HIV/STD-related knowledge, attitudes, beliefs, and behavioral intentions (KABI). Comic book narratives are a proven method of HIV/STD prevention communication to strengthen KABI for HIV/STD prevention. Motion comics, a new type of comic media, are an engaging and low-cost means of narrative storytelling. The objective of this study was to quantitatively evaluate the effectiveness of a pilot six-episode HIV/STD-focused motion comic series to improve HIV/STD-related KABI among young people. We assessed change in HIV/STD knowledge, HIV stigma, condom attitudes, HIV/STD testing attitudes, and behavioral intentions among 138 participants in 15 focus groups immediately before and after viewing the motion comic series. We used paired t-tests and indicators of overall improvement to assess differences between surveys. We found a significant decrease in HIV stigma (p comic intervention improved HIV/STD-related KABI of young adult viewers by reducing HIV stigma and increasing behavioral intentions to engage in safer sex. Our results demonstrate the promise of this novel intervention and support its use to deliver health messages to young people.

HIV Services Provided by STD Programs in State and Local Health Departments - United States, 2013-2014.

Science.gov (United States)

Cuffe, Kendra M; Esie, Precious; Leichliter, Jami S; Gift, Thomas L

2017-04-07

The incidence of human immunodeficiency virus (HIV) infection in the United States is higher among persons with other sexually transmitted diseases (STDs), and the incidence of other STDs is increased among persons with HIV infection (1). Because infection with an STD increases the risk for HIV acquisition and transmission (1-4), successfully treating STDs might help reduce the spread of HIV among persons at high risk (1-4). Because health department STD programs provide services to populations who are at risk for HIV, ensuring service integration and coordination could potentially reduce the incidence of STDs and HIV. Program integration refers to the combining of STD and HIV prevention programs through structural, service, or policy-related changes such as combining funding streams, performing STD and HIV case matching, or integrating staff members (5). Some STD programs in U.S. health departments are partially or fully integrated with an HIV program (STD/HIV program), whereas other STD programs are completely separate. To assess the extent of provision of HIV services by state and local health department STD programs, CDC analyzed data from a sample of 311 local health departments and 56 state and directly funded city health departments derived from a national survey of STD programs. CDC found variation in the provision of HIV services by STD programs at the state and local levels. Overall, 73.1% of state health departments and 16.1% of local health departments matched STD case report data with HIV data to analyze possible syndemics (co-occurring epidemics that exacerbate the negative health effects of any of the diseases) and overlaps. Similarly, 94.1% of state health departments and 46.7% of local health departments performed site visits to HIV care providers to provide STD information or public health updates. One fourth of state health departments and 39.4% of local health departments provided HIV testing in nonclinical settings (field testing) for STD

An audit of Colposcopy referrals from a GU/STD clinic.

LENUS (Irish Health Repository)

O'Connor, Catherine

2008-01-01

BACKGROUND: Cervical cancer is increasing at 1.5% per year in Ireland with 50% mortality giving 2.2% of all cancer deaths. In the Mid-West region a pilot screening programme has begun to screen all women 25-60 years. 66% of Genitourinary\\/Sexually transmitted disease (GU\\/STD) clinics\\' abnormal smears are <25 years. Requests to abandon "opportunistic" screening prompted this GU\\/STD clinic audit. METHODS: 221(8.4%) patients referred to colposcopy over 4 years were audited. Retrospective analysis was carried out on GU\\/STD clinic files, hospital files and computer records for biopsy reports. Ethical approval was prospectively granted. RESULTS: 2637 smears were carried out from November 1999 - September 2003.221 patients referred to colposcopy were audited.1%, 3%, 5% had severe, moderate and, mild dyskaryosis, respectively, on cervical screening while 0.8%, 1.2%, 1.5% had CIN3, CIN2, CIN1 abnormalities, respectively, on biopsy with 3.5% having no abnormality (Cervical Intraepithelial Neoplasia = CIN).53% referred to colposcopy were <25 years. CONCLUSION: 2% had high grade lesions. 37% of high grade lesions are <25 years.Of the high grade lesions 13% had Chlamydia trachomatis (27% of CIN3) and 44% had HPV despite Relative Risks (RR) being 0.75 and 1.09 respectively. Older women had higher grade changes. No statistical difference was found for progression, regression and persistence in those over and under 25.

National STD Awareness Month and GYT: Get Yourself Tested PSA (:60)

Centers for Disease Control (CDC) Podcasts

2011-03-03

April is National STD Awareness Month. In this PSA, native communities, especially adolescents and young adults, are encouraged to get educated, tested, and treated by visiting gytnow.org.  Created: 3/3/2011 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention.   Date Released: 3/3/2011.

Small Explorer Data System MIL-STD-1773 fiber optic bus

Science.gov (United States)

Flanegan, Mark; Label, Ken

1992-01-01

The MIL-STD-1773 Fiber Optic Data Bus as implemented in the GSFC Small Explorer Data System (SEDS) for the Small Explorer Program is described. It provides an overview of the SEDS MIL-STD-1773 bus components system design considerations, reliability figures, acceptance and qualification testing requirements, radiation requirements and tests, error handling considerations, and component heritage. The first mission using the bus will be launched in June of 1992.

Net Weight Issue LLNL DOE-STD-3013 Containers

International Nuclear Information System (INIS)

Wilk, P

2008-01-01

The following position paper will describe DOE-STD-3013 container sets No.L000072 and No.L000076, and how they are compliant with DOE-STD-3013-2004. All masses of accountable nuclear materials are measured on LLNL certified balances maintained under an MC and A Program approved by DOE/NNSA LSO. All accountability balances are recalibrated annually and checked to be within calibration on each day that the balance is used for accountability purposes. A statistical analysis of the historical calibration checks from the last seven years indicates that the full-range Limit of Error (LoE, 95% confidence level) for the balance used to measure the mass of the contents of the above indicated 3013 containers is 0.185 g. If this error envelope, at the 95% confidence level, were to be used to generate an upper-limit to the measured weight of the containers No.L000072 and No.L000076, the error-envelope would extend beyond the 5.0 kg 3013-standard limit on the package contents by less than 0.3 g. However, this is still well within the intended safety bounds of DOE-STD-3013-2004

HIV and STD testing in prisons: perspectives of in-prison service providers.

Science.gov (United States)

Grinstead, Olga; Seal, David W; Wolitski, Richard; Flanigan, Timothy; Fitzgerald, Christine; Nealey-Moore, Jill; Askew, John

2003-12-01

Because individuals at risk for HIV and STDs are concentrated in prisons and jails, incarceration is an opportunity to provide HIV and STD testing. We interviewed 72 service providers working in U.S. prisons in four states about their experiences with and perceptions regarding HIV and STD testing in prison. Providers' job duties represented administration, education, security, counseling, and medical care. Providers' knowledge of prison procedures and programs related to HIV and STD testing was narrowly limited to their specific job duties, resulting in many missed opportunities for prevention counseling and referral. Suggestions include increasing health care and counseling staff so posttest counseling can be provided for those with negative as well as positive test results, providing additional prevention programs for incarcerated persons, improving staff training about HIV and STD testing, and improving communication among in-prison providers as well as between corrections and public health staff.

Telling Your Partner You Have an STD

Science.gov (United States)

... STD after a confirmed diagnosis may be a criminal offense in some states. Some STDs can affect ... to make decisions about sex or your relationship right away. It's normal to want acceptance and reassurance ...

CDC WONDER: Sexually Transmitted Disease (STD) morbidity

Data.gov (United States)

U.S. Department of Health & Human Services — The Sexually Transmitted Disease (STD) Morbidity online databases on CDC WONDER contain case reports reported from the 50 United States and D.C., Puerto Rico, Virgin...

CDC WONDER: Sexually Transmitted Disease (STD) Morbidity

Data.gov (United States)

U.S. Department of Health & Human Services — The Sexually Transmitted Disease (STD) Morbidity online databases on CDC WONDER contain case reports reported from the 50 United States and D.C., Puerto Rico, Virgin...

STD Prevention Policies in the United States: Evidence and Opportunities

OpenAIRE

Leichliter, Jami S.; Seiler, Naomi; Wohlfeiler, Dan

2016-01-01

Policies are an important part of public health interventions, including in the area of STD prevention. Similar to other tools used in public health, policies are often evaluated to determine their usefulness. Therefore, we conducted a non-systematic review of policy evidence for sexually transmitted disease prevention. Our review considers assessments or evaluations of STD prevention-specific policies, health care system policies, and other, broader policies that have the potential to impact...

NMR data-driven structure determination using NMR-I-TASSER in the CASD-NMR experiment

Energy Technology Data Exchange (ETDEWEB)

Jang, Richard [Huazhong University of Science and Technology, School of Software Engineering (China); Wang, Yan [Huazhong University of Science and Technology, School of Life Science and Technology (China); Xue, Zhidong, E-mail: zdxue@hust.edu.cn [Huazhong University of Science and Technology, School of Software Engineering (China); Zhang, Yang, E-mail: zhng@umich.edu [University of Michigan, Department of Computational Medicine and Bioinformatics (United States)

2015-08-15

NMR-I-TASSER, an adaption of the I-TASSER algorithm combining NMR data for protein structure determination, recently joined the second round of the CASD-NMR experiment. Unlike many molecular dynamics-based methods, NMR-I-TASSER takes a molecular replacement-like approach to the problem by first threading the target through the PDB to identify structural templates which are then used for iterative NOE assignments and fragment structure assembly refinements. The employment of multiple templates allows NMR-I-TASSER to sample different topologies while convergence to a single structure is not required. Retroactive and blind tests of the CASD-NMR targets from Rounds 1 and 2 demonstrate that even without using NOE peak lists I-TASSER can generate correct structure topology with 15 of 20 targets having a TM-score above 0.5. With the addition of NOE-based distance restraints, NMR-I-TASSER significantly improved the I-TASSER models with all models having the TM-score above 0.5. The average RMSD was reduced from 5.29 to 2.14 Å in Round 1 and 3.18 to 1.71 Å in Round 2. There is no obvious difference in the modeling results with using raw and refined peak lists, indicating robustness of the pipeline to the NOE assignment errors. Overall, despite the low-resolution modeling the current NMR-I-TASSER pipeline provides a coarse-grained structure folding approach complementary to traditional molecular dynamics simulations, which can produce fast near-native frameworks for atomic-level structural refinement.

Complete relaxation and conformational exchange matrix (CORCEMA) analysis of intermolecular saturation transfer effects in reversibly forming ligand-receptor complexes.

Science.gov (United States)

Jayalakshmi, V; Krishna, N Rama

2002-03-01

A couple of recent applications of intermolecular NOE (INOE) experiments as applied to biomolecular systems involve the (i) saturation transfer difference NMR (STD-NMR) method and (ii) the intermolecular cross-saturation NMR (ICS-NMR) experiment. STD-NMR is a promising tool for rapid screening of a large library of compounds to identify bioactive ligands binding to a target protein. Additionally, it is also useful in mapping the binding epitopes presented by a bioactive ligand to its target protein. In this latter application, the STD-NMR technique is essentially similar to the ICS-NMR experiment, which is used to map protein-protein or protein-nucleic acid contact surfaces in complexes. In this work, we present a complete relaxation and conformational exchange matrix (CORCEMA) theory (H. N. B. Moseley et al., J. Magn. Reson. B 108, 243-261 (1995)) applicable for these two closely related experiments. As in our previous work, we show that when exchange is fast on the relaxation rate scale, a simplified CORCEMA theory can be formulated using a generalized average relaxation rate matrix. Its range of validity is established by comparing its predictions with those of the exact CORCEMA theory which is valid for all exchange rates. Using some ideal model systems we have analyzed the factors that influence the ligand proton intensity changes when the resonances from some protons on the receptor protein are saturated. The results show that the intensity changes in the ligand signals in an intermolecular NOE experiment are very much dependent upon: (1) the saturation time, (2) the location of the saturated receptor protons with respect to the ligand protons, (3) the conformation of the ligand-receptor interface, (4) the rotational correlation times for the molecular species, (5) the kinetics of the reversibly forming complex, and (6) the ligand/receptor ratio. As an example of a typical application of the STD-NMR experiment we have also simulated the STD effects for a

NMR studies of chemical structural variation of insoluble organic matter from different carbonaceous chondrite groups

Science.gov (United States)

Cody, George D.; Alexander, Conel M. O.'D.

2005-02-01

Solid-state 1H and 13C Nuclear Magnetic Resonance (NMR) spectroscopic experiments have been performed on isolated meteoritic Insoluble Organic Matter (IOM) spanning four different carbonaceous chondrite meteorite groups; a CR2 (EET92042), a CI1 (Orgueil), a CM2 (Murchison), and the unique C2 meteorite, Tagish Lake. These solid state NMR experiments reveal considerable variation in bulk organic composition across the different meteorite group's IOM. The fraction of aromatic carbon increases as CR2 meteorite groups. Single pulse (SP) 13C magic angle spinning (MAS) NMR experiments reveal the presence of nanodiamonds with an apparent concentration ranking in the IOM of CR2 IOM of all four meteoritic IOM fractions are highly substituted. Fast spinning SP 1H MAS NMR spectral data combined with other NMR experimental data reveal that the average hydrogen content of sp 3 bonded carbon functional groups is low, requiring a high degree of aliphatic chain branching in each IOM fraction. The variation in chemistry across the meteorite groups is consistent with alteration by low temperature chemical oxidation. It is concluded that such chemistry principally affected the aliphatic moieties whereas the aromatic moieties and nanodiamonds may have been largely unaffected.

Prevalence of Hepatitis C Virus Antibody in Patients With Sexually Transmitted Diseases Attending a Harrisburg, PA, STD Clinic

Directory of Open Access Journals (Sweden)

Robert L. Sautter

1994-01-01

Full Text Available Objective: The prevalence of hepatitis B and hepatitis C in a sexually transmitted disease (STD clinic population was studied, along with the prevalence of various STD agents, in an attempt to identify possible STD markers for the hepatitis C virus and help delineate the role of hepatitis C as an STD. The hepatitis C antibody rates found in the STD clinic were also compared with those found among patients attending a local OB/GYN clinic and those enrolled in a blood donor program, all from the same geographical area.

"Something of an adventure": postwar NIH research ethos and the Guatemala STD experiments.

Science.gov (United States)

Spector-Bagdady, Kayte; Lombardo, Paul A

2013-01-01

The STD experiments in Guatemala from 1946-1948 have earned a place of infamy in the history of medical ethics. But if the Guatemala STD experiments were so "ethically impossible," how did the U.S. government approve their funding? Although much of the literature has targeted the failings of Dr. John Cutler, we focus on the institutional context and research ethos that shaped the outcome of the research. After the end of WWII, Dr. Cassius Van Slyke reconstructed the federal research contracts process into a grant program. The inaugural NIH study section recommended approval of the Guatemala STD experiments at its first meeting. The funding and oversight process of the Guatemala research was marked with serious conflicts of interest and a lack of oversight, and it was this structure, as opposed to merely a maleficent individual, that allowed the Guatemala STD experiments to proceed. We conclude that while current research regulations are designed to prevent the abuses perpetrated on the subjects of the Guatemala STD experiments, it takes a comprehensive understanding of research ethics through professional education to achieve the longstanding ideal of the responsible investigator, and ensure ethical research under any regulatory scheme. © 2013 American Society of Law, Medicine & Ethics, Inc.

Return of IEEE Std 627 and its Value to Equipment Qualification Programs

International Nuclear Information System (INIS)

Horvath, D.A.

2012-01-01

IEEE Std 627 ''Design Qualification of Safety Systems Equipment Used in Nuclear Power Generating Stations'' was issued to more generically establish qualification requirements in the form of a high level umbrella document. Efforts on this standard began in late 1975 at the request of the IEEE Nuclear Standards Management Board. In 1977 a joint ASME/IEEE agreement established responsibility for qualification and quality assurance standards preparation. ASME accepted responsibility for Quality Assurance and IEEE for qualification. In accordance with that agreement, IEEE completed the generic qualification standard in 1980. This document provided high level approaches, criteria, guidance, and principles for qualification of both electrical and mechanical equipment that at that time appeared in no other industry standard. IEEE Std 627-1980 was later reaffirmed in 1996. In 1986, ASME's Board on Nuclear Codes and Standards directed its Committee on Qualification of Mechanical Equipment (QME) to develop a standard for qualifying mechanical equipment. This task was completed in several parts during the time frame from 1992 to 1994. Partly in response to this activity, IEEE Std 627 was withdrawn in 2002. Later although withdrawn, it was found that IEEE Std 627 was continuing to be used and referenced by many entities both in the US and other countries including in ASME's QME-1-2002 ''Qualification of Active Mechanical Equipment Used in Nuclear Power Plants'', US NRC's NUREG-0800 Standard Review Plan Section 3.11, at least one reactor vendor's Design Certification Document (DCD), several international licensing documents, and elsewhere. As a result, in 2007, the IEEE Standards Board authorized Working Group 2.10 of Subcommittee 2 (Qualification) of the Power and Energy Society's Nuclear Power Engineering Committee to resurrect and update IEEE Std 627-1980 (Reaff 1996). The result was the culmination IEEE Std 627 in 2010. This paper will report on the eight improvements made

Charting a Path to Location Intelligence for STD Control.

Science.gov (United States)

Gerber, Todd M; Du, Ping; Armstrong-Brown, Janelle; McNutt, Louise-Anne; Coles, F Bruce

2009-01-01

This article describes the New York State Department of Health's GeoDatabase project, which developed new methods and techniques for designing and building a geocoding and mapping data repository for sexually transmitted disease (STD) control. The GeoDatabase development was supported through the Centers for Disease Control and Prevention's Outcome Assessment through Systems of Integrated Surveillance workgroup. The design and operation of the GeoDatabase relied upon commercial-off-the-shelf tools that other public health programs may also use for disease-control systems. This article provides a blueprint of the structure and software used to build the GeoDatabase and integrate location data from multiple data sources into the everyday activities of STD control programs.

Lawrence Livermore National Laboratory Measurements of Plutonium-bearing Oxide in DOE-STD-3013-2000 Containers Using Calorimetry and Gamma Isotopic Analyses

International Nuclear Information System (INIS)

Dearborn, D M; Keeton, S C

2004-01-01

Lawrence Livermore National Laboratory (LLNL) routinely uses calorimetry and gamma isotopic analyses (Cal/Iso) for the accountability measurement of plutonium (Pu) bearing items. In the past 15 years, the vast majority of those items measured by Cal/Iso were contained in a thin-walled convenience can enclosed in another thin-walled outer container. However, LLNL has recently begun to use DOE-STD-3013-2000 containers as well. These DOE-STD-3013-2000 containers are comprised of a stainless steel convenience can enclosed in welded stainless steel primary and secondary containers. In addition to the fact that the wall thickness of the DOE-STD-3013-2000 containers is much greater than that of other containers in our experience, the DOE-STD-3013-2000 containers appear to have larger thermal insulation characteristics. To date, we have derived Pu-mass values from Cal/Iso measurements of 74 different DOE-STD-3013-2000 containers filled with Pu-bearing oxide or mixed uranium-plutonium (U-Pu) oxide material. Both water-bath and air-bath calorimeters were used for these measurements and both use software to predict when thermal equilibrium is attained. Our experience has shown that after apparent equilibrium has been attained, at least one more complete cycle, and sometimes two or three more complete cycles, is required to gain a measure of true thermal equilibrium. Otherwise, the derived Pu-mass values are less than would be expected from a combination of previously measured Pu-bearing items and would contribute to increased loss in our inventory difference determinations. Conclusions and recommendations drawn from LLNL experience with measurements of Pu mass in Pu-bearing oxide or mixed U-Pu oxide in DOE-STD-3013-2000 containers using the Cal/Iso technique are included

A versatile electrical penetration design qualified to IEEE Std. 317-1983

International Nuclear Information System (INIS)

Lankenau, W.; Wetherill, T.M.

1994-01-01

Although worldwide demand for new construction of nuclear power stations has been on a decline, the available opportunities for the design and construction of qualified electrical penetrations continues to offer challenges, requiring a highly versatile design. Versatility is necessary in order to meet unique customer requirements within the constraints of a design basis qualified to IEEE Std. 317-1983. This paper summarizes such a versatile electrical penetration designed, built and tested to IEEE Std. 317-1983. The principal features are described including major materials of construction. Some of the design constraints such as sealing requirements, and conductor density (including numerical example) are discussed. The requirements for qualification testing of the penetration assembly to IEEE Std. 317-1983 are delineated in a general sense, and some typical test ranges for preconditioning, radiation exposure, and LOCA are provided. The paper concludes by describing ways in which this versatile design has been adapted to meet unique customer requirements in a variety of nuclear power plants

Unlike twins: an NMR comparison of two α-synuclein polymorphs featuring different toxicity.

Directory of Open Access Journals (Sweden)

Julia Gath

Full Text Available We structurally compare, using solid-state NMR, two different polymorphs of α-synuclein which, as established recently, display contrasting biochemical properties, toxicity, and tropism for cells. We show that both forms, which can each be produced as a pure polymorph, are greatly different in secondary structure. While β-sheets are the dominating secondary structure elements for both polymorphs, they are markedly divergent in terms of number of elements, as well as their distribution. We demonstrate that all identified β-sheets feature an in-register parallel stacking for both polymorphs. The two forms show a different molecular arrangement in the unit cell and distinct dynamic features, while sharing a highly flexible C-terminal domain. The use of reproducible, well-identified conditions for sample preparation and the recording of identical NMR experiments allows for a direct comparison of the results.

Salmonella enterica serotype Typhimurium Std fimbriae bind terminal α (1,2)fucose residues in the cecal mucosa

Science.gov (United States)

Chessa, Daniela; Winter, Maria G.; Jakomin, Marcello; Bäumler, Andreas J.

2013-01-01

SUMMARY The std operon encodes a fimbrial adhesin of Salmonella enterica serotype Typhimurium that is required for attachment to intestinal epithelial cells and for cecal colonization in the mouse. To study the mechanism by which this virulence factor contributes to colonization we characterized its binding specificity. Std-mediated binding to human colonic epithelial (Caco-2) cells could be abrogated by removing N-linked glycans. Adherence of Std fimbriated S. Typhimurium to Caco-2 cells could be blocked by co-incubation with H type 2 oligosaccharide (Fucα1-2Galβ1-4GlcNAc) or by pretreatment of cells with α1-2 fucosidase. In contrast, pretreatment of Caco-2 cells with neuraminidase or co-incubation with the type 2 disaccharide precursor (Galβ1-4GlcNAc) did not reduce adherence of Std fimbriated S. Typhimurium. Binding of purified Std fimbriae to Fucα1-2Galβ1-4GlcNAc in a solid phase binding assay was competitively inhibited by Ulex europaeus agglutinin-I (UEA-I), a lectin specific for Fucα1-2 moieties. Purified Std fimbriae and UEA both bound to a receptor localized in the mucus layer of the murine cecum. These data suggest that the std operon encodes an adhesin that binds an α1-2 fucosylated receptor(s) present in the cecal mucosa. PMID:19183274

A study on the present scenario of STD management in an urban clinic in Kolkata

Directory of Open Access Journals (Sweden)

Ghosh Sadhan Kumar

2002-01-01

Full Text Available A total of 4129 patients attended the STD clinic from 1996 to 1999. Of those 25.75% were STD cases. Male and female cases comprised 86% and 14% respectively. Majority were in the age group between 18 to 38 years. Choncroid was the commonest STD (37. 7%. Other STDs in order were syphilis (30. 66%, NGU (15.71%, gonorrhoea (7%, venereal wart (3.57%, candidiasis (2.53%, trichomonal vaginitis (1.6%, herpes genitalis (0.65% and LGV (0.47%. No case of Donovanosis or HIV was detected. 13.7% of STD cases were reactive for VDRL test and 8% of the antenatal attendents were strongly VDRL test reactive. The urethral discharge on gram staining was positive for gonococcus, in 29%. 68% of the clinic attendents were given safer sex education and served condom.

NMR measurement of bitumen at different temperatures.

Science.gov (United States)

Yang, Zheng; Hirasaki, George J

2008-06-01

Heavy oil (bitumen) is characterized by its high viscosity and density, which is a major obstacle to both well logging and recovery. Due to the lost information of T2 relaxation time shorter than echo spacing (TE) and interference of water signal, estimation of heavy oil properties from NMR T2 measurements is usually problematic. In this work, a new method has been developed to overcome the echo spacing restriction of NMR spectrometer during the application to heavy oil (bitumen). A FID measurement supplemented the start of CPMG. Constrained by its initial magnetization (M0) estimated from the FID and assuming log normal distribution for bitumen, the corrected T2 relaxation time of bitumen sample can be obtained from the interpretation of CPMG data. This new method successfully overcomes the TE restriction of the NMR spectrometer and is nearly independent on the TE applied in the measurement. This method was applied to the measurement at elevated temperatures (8-90 degrees C). Due to the significant signal-loss within the dead time of FID, the directly extrapolated M0 of bitumen at relatively lower temperatures (viscosity, the extrapolated M0 of bitumen at over 60 degrees C can be reasonably assumed to be the real value. In this manner, based on the extrapolation at higher temperatures (> or = 60 degrees C), the M0 value of bitumen at lower temperatures (index (HI), fluid content and viscosity were evaluated by using corrected T2.

NATO Pallet with Javelin Missiles, MIL-STD-1660 Tests

National Research Council Canada - National Science Library

2004-01-01

The U.S. Army Defense Ammunition Center (DAC), Validation Engineering Division (SJMAC-DEV) conducted tests in accordance with MIL-STD-1660, "Design Criteria for Ammunition Unit Loads" on the NATO pallet with Javelin missiles...

Metabolomic differentiation of maca (Lepidium meyenii) accessions cultivated under different conditions using NMR and chemometric analysis.

Science.gov (United States)

Zhao, Jianping; Avula, Bharathi; Chan, Michael; Clément, Céline; Kreuzer, Michael; Khan, Ikhlas A

2012-01-01

To gain insights on the effects of color type, cultivation history, and growing site on the composition alterations of maca (Lepidium meyenii Walpers) hypocotyls, NMR profiling combined with chemometric analysis was applied to investigate the metabolite variability in different maca accessions. Maca hypocotyls with different colors (yellow, pink, violet, and lead-colored) cultivated at different geographic sites and different areas were examined for differences in metabolite expression. Differentiations of the maca accessions grown under the different cultivation conditions were determined by principle component analyses (PCAs) which were performed on the datasets derived from their ¹H NMR spectra. A total of 16 metabolites were identified by NMR analysis, and the changes in metabolite levels in relation to the color types and growing conditions of maca hypocotyls were evaluated using univariate statistical analysis. In addition, the changes of the correlation pattern among the metabolites identified in the maca accessions planted at the two different sites were examined. The results from both multivariate and univariate analysis indicated that the planting site was the major determining factor with regards to metabolite variations in maca hypocotyls, while the color of maca accession seems to be of minor importance in this respect. © Georg Thieme Verlag KG Stuttgart · New York.

Evaluation of the Positive Prevention HIV/STD Curriculum

Science.gov (United States)

LaChausse, Robert G.

2006-01-01

This study evaluated the effectiveness of Positive Prevention, a theory-based, HIV/STD prevention education curriculum for high school youth. Three hundred fifty-three students participated in a longitudinal experimental design to determine the impact of the curriculum on HIV/AIDS knowledge, self-efficacy to abstain from sex, self-efficacy of…

Clinic-based intervention projects: STD and family planning programs get involved. Intervention model.

Science.gov (United States)

Finger, W R

1991-06-01

The sexually transmitted disease (STD) program in Udorn, a popular Thai tourist city, has worked closely with 750 prostitutes for 15 years, incorporating the concerns of brothel managers and prostitutes into service delivery. The program in Udorn is part of a nationwide network of STD clinics. The level of person-to-person interaction was increased once it was determined by 1989 that HIV had infected 6% of prostitutes in the city's brothels. Outreach educators were recruited and trained to ensure that all prostitutes in Udorn had the basic facts about HIV and AIDS. Over the last 2 years, the STD program has trained outreach educators to work in 8 brothels, started a local AIDS prevention foundation supported by local businessmen, and taken other steps to incorporate AIDS prevention into its clinic structure. Such clinic-based programs are an important way of targeting groups at high risk of HIV transmission.

NMR imaging

International Nuclear Information System (INIS)

Andrew, E.R.

1983-01-01

Since hydrogen is the most abundant element in all living organisms, proton NMR lends itself well as a method of investigation in biology and medicine. NMR imaging has some special advantages as a diagnostic tool: no ionizing radiation is used, it is noninvasive; it provides a safer means of imaging than the use of x-rays, gamma rays, positrons, or heavy ions. In contrast with ultrasound, the radiation penetrates the bony structures without attenuation. In additional to morphological information, NMR imaging provides additional diagnostic insights through relaxation parameters, which are not available from other imaging methods. In the decade since the first primitive NMR images were obtained, the quality of images now obtained approaches those from CT x-ray scanners. Prototype instruments are being constructed for clinical evaluation and the first whole-body scanners are beginning to appear on the market at costs comparable to CT scanners. Primary differences in equipment for conventional NMR and NMR imaging are the much larger aperture magnets that are required for the examination of human subjects and the addition of coils to generate field gradients and facilities for manipulating the gradients. Early results from clinical trials in many parts of the world are encouraging, and in a few years, the usefuleness of this modality of medical imaging to the medical profession in diagnosis and treatment of disease will be defined. 10 figures

Adherence to CDC Recommendations for the Treatment of Uncomplicated Gonorrhea - STD Surveillance Network, United States, 2016.

Science.gov (United States)

Weston, Emily J; Workowski, Kimberly; Torrone, Elizabeth; Weinstock, Hillard; Stenger, Mark R

2018-04-27

Gonorrhea, the sexually transmitted disease (STD) caused by Neisseria gonorrhoeae, is the second most common notifiable disease in the United States after chlamydia; 468,514 cases were reported to state and local health departments in 2016, an increase of 18.5% from 2015 (1). N. gonorrhoeae has progressively developed resistance to most antimicrobials used to treat the infection (2). As a result, CDC recommends two antimicrobials (250 mg of ceftriaxone [IM] plus 1 g of azithromycin [PO]) for treating uncomplicated gonorrhea to improve treatment efficacy and, potentially, to slow the emergence and spread of antimicrobial resistance. To monitor adherence to the current CDC-recommended regimen for uncomplicated gonorrhea, CDC reviewed enhanced data collected on a random sample of reported cases of gonorrhea in seven jurisdictions participating in the STD Surveillance Network (SSuN) and estimated the proportion of patients who received the CDC-recommended regimen for uncomplicated gonorrhea, by patient characteristics and diagnosing facility type. In 2016, the majority of reported patients with gonorrhea (81%) received the recommended regimen. There were no differences in the proportion of patients receiving the recommended regimen by age or race/ethnicity; however, patients diagnosed with gonorrhea in STD (91%) or family planning/reproductive health (94%) clinics were more likely to receive this regimen than were patients diagnosed in other provider settings (80%). These data document high provider adherence to CDC gonorrhea treatment recommendations in specialty STD clinics, indicating high quality of care provided in those settings. Local and state health departments should monitor adherence with recommendations in their jurisdictions and consider implementing interventions to improve provider and patient compliance with gonorrhea treatment recommendations where indicated.

An audit of Colposcopy referrals from a GU/STD clinic

Directory of Open Access Journals (Sweden)

Ryan Ailis

2008-06-01

Full Text Available Abstract Background Cervical cancer is increasing at 1.5% per year in Ireland with 50% mortality giving 2.2% of all cancer deaths. In the Mid-West region a pilot screening programme has begun to screen all women 25–60 years. 66% of Genitourinary/Sexually transmitted disease (GU/STD clinics' abnormal smears are Methods 221(8.4% patients referred to colposcopy over 4 years were audited. Retrospective analysis was carried out on GU/STD clinic files, hospital files and computer records for biopsy reports. Ethical approval was prospectively granted. Results 2637 smears were carried out from November 1999 – September 2003. 221 patients referred to colposcopy were audited. 1%, 3%, 5% had severe, moderate and, mild dyskaryosis, respectively, on cervical screening while 0.8%, 1.2%, 1.5% had CIN3, CIN2, CIN1 abnormalities, respectively, on biopsy with 3.5% having no abnormality (Cervical Intraepithelial Neoplasia = CIN. 53% referred to colposcopy were Conclusion 2% had high grade lesions. 37% of high grade lesions are Of the high grade lesions 13% had Chlamydia trachomatis (27% of CIN3 and 44% had HPV despite Relative Risks (RR being 0.75 and 1.09 respectively. Older women had higher grade changes. No statistical difference was found for progression, regression and persistence in those over and under 25.

77 FR 66469 - CDC/HRSA Advisory Committee on HIV, Viral Hepatitis and STD Prevention and Treatment

Science.gov (United States)

2012-11-05

... Advisory Committee on HIV, Viral Hepatitis and STD Prevention and Treatment In accordance with section 10(a...--Treatment as Prevention; (2) Ryan White HIV/AIDS Program Client Level Data Update; (3) Viral Hepatitis... Person for More Information: Margie Scott-Cseh, National Center for HIV/AIDS, Viral Hepatitis, STD, and...

NMR and Chemometric Characterization of Vacuum Residues and Vacuum Gas Oils from Crude Oils of Different Origin

Directory of Open Access Journals (Sweden)

Jelena Parlov Vuković

2015-03-01

Full Text Available NMR spectroscopy in combination with statistical methods was used to study vacuum residues and vacuum gas oils from 32 crude oils of different origin. Two chemometric metodes were applied. Firstly, principal component analysis on complete spectra was used to perform classification of samples and clear distinction between vacuum residues and vacuum light and heavy gas oils were obtained. To quantitatively predict the composition of asphaltenes, principal component regression models using areas of resonance signals spaned by 11 frequency bins of the 1H NMR spectra were build. The first 5 principal components accounted for more than 94 % of variations in the input data set and coefficient of determination for correlation between measured and predicted values was R2 = 0.7421. Although this value is not significant, it shows the underlying linear dependence in the data. Pseudo two-dimensional DOSY NMR experiments were used to assess the composition and structural properties of asphaltenes in a selected crude oil and its vacuum residue on the basis of their different hydrodynamic behavior and translational diffusion coefficients. DOSY spectra showed the presence of several asphaltene aggregates differing in size and interactions they formed. The obtained results have shown that NMR techniques in combination with chemometrics are very useful to analyze vacuum residues and vacuum gas oils. Furthermore, we expect that our ongoing investigation of asphaltenes from crude oils of different origin will elucidate in more details composition, structure and properties of these complex molecular systems.

Simultaneous use of solution NMR and X-ray data in REFMAC5 for joint refinement/detection of structural differences

Energy Technology Data Exchange (ETDEWEB)

Rinaldelli, Mauro; Ravera, Enrico; Calderone, Vito; Parigi, Giacomo [University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino (Finland) (Italy); University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (Finland) (Italy); Murshudov, Garib N., E-mail: garib@mrc-lmb.cam.ac.uk [MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH (United Kingdom); Luchinat, Claudio, E-mail: garib@mrc-lmb.cam.ac.uk [University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino (Finland) (Italy); University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (Finland) (Italy)

2014-04-01

Paramagnetic NMR data (pseudocontact shifts and self-orientation residual dipolar couplings) and diamagnetic residual dipolar couplings can now be used in the program REFMAC5 from CCP4 as structural restraints together with X-ray crystallographic data. These NMR restraints can reveal differences between solid state and solution conformations of molecules or, in their absence, can be used together with X-ray crystallographic data for structural refinement. The program REFMAC5 from CCP4 was modified to allow the simultaneous use of X-ray crystallographic data and paramagnetic NMR data (pseudocontact shifts and self-orientation residual dipolar couplings) and/or diamagnetic residual dipolar couplings. Incorporation of these long-range NMR restraints in REFMAC5 can reveal differences between solid-state and solution conformations of molecules or, in their absence, can be used together with X-ray crystallographic data for structural refinement. Since NMR and X-ray data are complementary, when a single structure is consistent with both sets of data and still maintains reasonably ‘ideal’ geometries, the reliability of the derived atomic model is expected to increase. The program was tested on five different proteins: the catalytic domain of matrix metalloproteinase 1, GB3, ubiquitin, free calmodulin and calmodulin complexed with a peptide. In some cases the joint refinement produced a single model consistent with both sets of observations, while in other cases it indicated, outside the experimental uncertainty, the presence of different protein conformations in solution and in the solid state.

Simultaneous use of solution NMR and X-ray data in REFMAC5 for joint refinement/detection of structural differences

International Nuclear Information System (INIS)

Rinaldelli, Mauro; Ravera, Enrico; Calderone, Vito; Parigi, Giacomo; Murshudov, Garib N.; Luchinat, Claudio

2014-01-01

Paramagnetic NMR data (pseudocontact shifts and self-orientation residual dipolar couplings) and diamagnetic residual dipolar couplings can now be used in the program REFMAC5 from CCP4 as structural restraints together with X-ray crystallographic data. These NMR restraints can reveal differences between solid state and solution conformations of molecules or, in their absence, can be used together with X-ray crystallographic data for structural refinement. The program REFMAC5 from CCP4 was modified to allow the simultaneous use of X-ray crystallographic data and paramagnetic NMR data (pseudocontact shifts and self-orientation residual dipolar couplings) and/or diamagnetic residual dipolar couplings. Incorporation of these long-range NMR restraints in REFMAC5 can reveal differences between solid-state and solution conformations of molecules or, in their absence, can be used together with X-ray crystallographic data for structural refinement. Since NMR and X-ray data are complementary, when a single structure is consistent with both sets of data and still maintains reasonably ‘ideal’ geometries, the reliability of the derived atomic model is expected to increase. The program was tested on five different proteins: the catalytic domain of matrix metalloproteinase 1, GB3, ubiquitin, free calmodulin and calmodulin complexed with a peptide. In some cases the joint refinement produced a single model consistent with both sets of observations, while in other cases it indicated, outside the experimental uncertainty, the presence of different protein conformations in solution and in the solid state

31P NMR spectroscopy studies of phospholipid metabolism in human melanoma xenograft lines differing in rate of tumour cell proliferation.

Science.gov (United States)

Lyng, H; Olsen, D R; Petersen, S B; Rofstad, E K

1995-04-01

The concentration of phospholipid metabolites in tumours has been hypothesized to be related to rate of cell membrane turnover and may reflect rate of cell proliferation. The purpose of the study reported here was to investigate whether 31P NMR resonance ratios involving the phosphomonoester (PME) or phosphodiester (PDE) resonance are correlated to fraction of cells in S-phase or volume-doubling time in experimental tumours. Four human melanoma xenograft lines (BEX-t, HUX-t, SAX-t, WIX-t) were included in the study. The tumours were grown subcutaneously in male BALB/c-nu/nu mice. 31P NMR spectroscopy was performed at a magnetic field strength of 4.7 T. Fraction of cells in S-phase was measured by flow cytometry. Tumour volume-doubling time was determined by Gompertzian analysis of volumetric growth data. BEX-t and SAX-t tumours differed in fraction of cells in S-phase and volume-doubling time, but showed similar 31P NMR resonance ratios. BEX-t and WIX-t tumours showed significantly different 31P NMR resonance ratios but similar fractions of cells in S-phase. The 31P NMR resonance ratios were significantly different for small and large HUX-t tumours even though fraction of cells in S-phase and volume-doubling time did not differ with tumour volume. None of the 31P NMR resonance ratios showed significant increase with increasing fraction of cells in S-phase or significant decrease with increasing tumour volume-doubling time across the four xenograft lines.(ABSTRACT TRUNCATED AT 250 WORDS)

Overview - Be Smart. Be Well. STD Videos

Centers for Disease Control (CDC) Podcasts

2010-03-15

This video, produced by Be Smart. Be Well., raises awareness of Sexually Transmitted Diseases (STDs): 1) What are they? 2) Why they matter? and, 3) What can I do about them? Footage courtesy of Be Smart. Be Well., featuring CDC's Dr. John Douglas, Division of Sexually Transmitted Disease Prevention.  Created: 3/15/2010 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 3/15/2010.

Nitrogen Use Efficiency and Carbon Isotope Discrimination Study on NMR151 and NMR152 Mutant Lines Rice at Field Under Different Nitrogen Rates and Water Potentials

International Nuclear Information System (INIS)

Ahmad Nazrul Abdul Wahid; Shyful Azizi Abdul Rahman; Abdul Rahim Harun; Latiffah Nordin; Abdul Razak Ruslan; Hazlina Abdullah; Khairuddin Abdul Rahim

2016-01-01

This study was conducted to evaluate the nitrogen use efficiency and "1"3C isotope discrimination of rice mutant lines viz. NMR151 and NMR152. Both cultivars are developed under rice radiation mutagenesis programme for adaptability to aerobic conditions. In the present study, NMR151 and NMR152 were grown under conditions of varying water potentials and nitrogen levels in a field. Two water potentials and three nitrogen rates in a completely randomized design with three replications were carried out. The rice mutants were grown for 110 days under two water potentials, (i) Field capacity from 0 to 110 DAS [FC], and (ii) Field capacity from 0 to 40 DAS and 30 % dry of field capacity from 41 to 110 DAS [SS] and three nitrogen rates, (i) 0 kg N/ ha (0N), (ii) 60 kg N/ ha (60N), and (iii) 120 kg N/ ha (120N). "1"5N isotopic tracer technique was used in this study, whereby the "1"5N labeled urea fertilizer 5.20 % atom excess (a.e) was utilized as a tracer for nitrogen use efficiency (NUE) study. "1"5N isotope presence in the samples was determined using emission spectrometry and percentage of total nitrogen was determined by the Kjeldahl method. "1"5N a.e values of the samples were used in the determination of the NUE. The value of "1"3C isotope discrimination (Δ"1"3C) in the sample was determined using isotope ratio mass spectrometry (IRMS). The "1"3C isotope discrimination technique was used as a tool to identify drought resistance rice cultivars with improves water use efficiency. The growth and agronomy data, viz. plant height, number of tillers, grain yield, straw yield, and 1000 grain weight also were recorded. Results from this study showed nitrogen rates imparted significant effects on yield (grain and straw) plant height, number of tillers and 1000 grain weight. Water potentials had significant effects only on 1000 grain weight and Δ"1"3C. The NUE for both mutant lines rice showed no significant different between treatments. Both Rice mutant lines rice NMR151

NMR spectroscopy of coal pyrolysis products

Energy Technology Data Exchange (ETDEWEB)

Polonov, V.M.; Kalabin, G.A.; Kushnarev, D.F.; Shevchenko, G.G.

1985-12-01

The authors consider the scope for using H 1 and C 13 NMR spectroscopy to describe the products from coal pyrolysis and hydrogenization. The accuracy of the structural information provided by the best NMR methods is also considered. The stuctural parameters derived from H 1 and C 13 NMR spectra are presented. Results demonstrate the high accuracy and sensitivity of the structural information provided by H 1 AND C 13 NMR spectra for coal products. There are substantial structural differences between the soluble products from medium-temperature coking of Cheremkhov coal and high-speed pyrolysis of Kan-Acha coal, and also differences in behavior during hydrogenation. These differences are related to the structure of the organic matter in the initial coal and to differences in the pyrolysis mechanisms.

Street Stories - Be Smart. Be Well. STD Videos

Centers for Disease Control (CDC) Podcasts

2010-03-15

This video, produced by Be Smart. Be Well., raises awareness of Sexually Transmitted Diseases (STDs): 1) What are they? 2) Why they matter? and, 3) What can I do about them? Footage courtesy of Be Smart. Be Well.  Created: 3/15/2010 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 3/15/2010.

Molly's Story - Be Smart. Be Well. STD Videos

Centers for Disease Control (CDC) Podcasts

2010-03-15

This video, produced by Be Smart. Be Well., raises awareness of Sexually Transmitted Diseases (STDs): 1) What are they? 2) Why they matter? and, 3) What can I do about them? Footage courtesy of Be Smart. Be Well.  Created: 3/15/2010 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 3/15/2010.

Comparison of Fruits of Forsythia suspensa at Two Different Maturation Stages by NMR-Based Metabolomics

Directory of Open Access Journals (Sweden)

Jinping Jia

2015-05-01

Full Text Available Forsythiae Fructus (FF, the dried fruit of Forsythia suspensa, has been widely used as a heat-clearing and detoxifying herbal medicine in China. Green FF (GF and ripe FF (RF are fruits of Forsythia suspensa at different maturity stages collected about a month apart. FF undergoes a complex series of physical and biochemical changes during fruit ripening. However, the clinical uses of GF and RF have not been distinguished to date. In order to comprehensively compare the chemical compositions of GF and RF, NMR-based metabolomics coupled with HPLC and UV spectrophotometry methods were adopted in this study. Furthermore, the in vitro antioxidant and antibacterial activities of 50% methanol extracts of GF and RF were also evaluated. A total of 27 metabolites were identified based on NMR data, and eight of them were found to be different between the GF and RF groups. The GF group contained higher levels of forsythoside A, forsythoside C, cornoside, rutin, phillyrin and gallic acid and lower levels of rengyol and β-glucose compared with the RF group. The antioxidant activity of GF was higher than that of RF, but no significant difference was observed between the antibacterial activities of GF and RF. Given our results showing their distinct chemical compositions, we propose that NMR-based metabolic profiling can be used to discriminate between GF and RF. Differences in the chemical and biological activities of GF and RF, as well as their clinical efficacies in traditional Chinese medicine should be systematically investigated in future studies.

Developing a Motion Comic for HIV/STD Prevention for Young People Ages 15-24, Part 1: Listening to Your Target Audience.

Science.gov (United States)

Willis, Leigh A; Kachur, Rachel; Castellanos, Ted J; Spikes, Pilgrim; Gaul, Zaneta J; Gamayo, Ashley C; Durham, Marcus; Jones, Sandra; Nichols, Kristen; Han Barthelemy, Solange; LaPlace, Lisa; Staatz, Colleen; Hogben, Matthew; Robinson, Susan; Brooks, John T; Sutton, Madeline Y

2018-02-01

Young people (15-24 years) in the United States are disproportionately affected by infection with human immunodeficiency virus (HIV) and sexually transmitted diseases (STD). Shortfalls in HIV/STD-related knowledge, attitudes, beliefs, and behavioral intentions (KABI) likely contribute to this discrepancy. In this report we describe our experience developing a novel means of health communication combining entertainment-education theory and recent technological advances to create a HIV/STD-focused "motion comic." We also report the audience satisfaction and acceptance of the intervention. We used the Health Belief Model (HBM), entertainment-education (EE) principles, and the Sabido Method (SM) and conducted three rounds of focus groups to develop a 38-minute HIV/STD focused motion comic for young people between the ages 15 and 24 years. Participants indicated that motion comics were an acceptable method of delivering HIV/STD prevention messages. They also expressed satisfaction with motion comics plot, story settings, the tone of humor, and drama. Our results suggest that motion comics are a viable new method of delivering health communication messages about HIV/STD and other public health issues, and warrant further development and broader evaluation.

A study on sexually transmitted diseases in patients in a STD clinic in a district hospital in North India

Directory of Open Access Journals (Sweden)

Neerja Puri

2014-07-01

Full Text Available Introduction: The Sexually transmitted diseases (STDs are a global health problem of great magnitude. The pattern of STDs differs from country to country and from region to region. The increased risk of the transmission of HIV is known to be associated with the presence of sexually transmitted diseases (STDs and despite the presence of the National STD Control Program in India the number of people with STDs remains high. Aim: The aim of our study was to study the profile of patients in a STD clinic in North India and to study various sexually transmitted infections in both male and female patients. Material and Methods: A prospective study of the patients attending STD clinic in a district hospital in North India from December 2009 to December 2012 was done. A total of 2700 patients attending the STDclinic in three years from December 2009 to December 2012 were taken up for the study. Results: The commonest sexually transmitted infection in males was herpes genitalis (30% followed by 20% cases of genital warts. 10% patients had gonorrhoea, genital molluscum contagiosum, syphilis and genital scabies each and 5% patients had nongonococcal urethritis. Only 5% of the total patients had chancroid, donovanosis and LGV. The commonest sexually transmitted infection in females was vaginal discharge seen in 40% patients, lower abdominal pain in 20% patients, herpes genitalis in 15% patients followed by 20% cases of genital warts and syphilis each. Genital molluscum contagiosum was seen in 5% patients only. Conclusions: The treatment of STD’s is important as both non-ulcerative and ulcerative STDs increase the susceptibility to or transmissibility of HIV infection and as such, an increase in STD prevalence as revealed by clinic attendance in this study was bound to facilitate the spread of HIV/AIDS. Perhaps it is high time health planners adopted a more aggressive and result oriented HIV/AIDS/STD awareness campaign strategy.

IEEE Std 535-1979: IEEE standard for qualification of Class 1E lead storage batteries for nuclear power generating stations

International Nuclear Information System (INIS)

Anon.

1992-01-01

This document describes qualification methods for Class 1E lead storage batteries and racks to be used in nuclear power generating stations outside of primary containment. Qualification required in ANSI/IEEE Std 279-1971 and IEE Std 308-1978, can be demonstrated by using the procedures provided in this standard in accordance with IEEE Std 323-1974. Battery sizing, maintenance, capacity testing, installation, charging equipment and consideration of other type batteries are beyond the scope of this standard

NMR

International Nuclear Information System (INIS)

Kneeland, J.B.; Lee, B.C.P.; Whalen, J.P.; Knowles, R.J.R.; Cahill, P.T.

1984-01-01

Although still quite new, NMR imaging has already emerged as a safe, noninvasive, painless, and effective diagnostic modality requiring no ionizing radiation. Also, NMR appears already to have established itself as the method of choice for the examination of the brain spinal cord (excluding herniated disks). Another area in which NMR excels is in the examination of the pelvis. The use of surface coils offers the promise of visualizing structures with resolution unobtainable by any other means. In addition, NMR, with its superb visualization of vascular structures and potential ability to measure flow, may soon revolutionize the diagnosis of cardiovascular disease. Finally, NMR, through biochemically and physiologically based T/sub 1/ and T/sub 2/ indices or through spectroscopy, may provide a means of monitoring therapeutic response so as to permit tailoring of treatment to the individual patient. In short, NMR is today probably at the same stage as the x-ray was in Roentgen's day

An assessment of care provided by a public sector STD clinic in Cape Town.

Science.gov (United States)

Mathews, C; van Rensburg, A; Schierhout, G; Coetzee, N; Lombard, C J; Fehler, H G; Ballard, R C

1998-11-01

A study was undertaken in a Cape Town public sector STD clinic to evaluate the content and quality of care provided since it has been recognized that appropriate improvements in the management of conventional sexually transmitted diseases (STDs), including provision of correct therapy, health education, condom promotion and partner notification, could result in a reduced incidence of HIV infection. Our objectives were to assess patients' needs for health education and to assess the quality of STD management in terms of health education, condom promotion, partner notification, the validity of the clinical diagnoses and the adequacy of the treatments prescribed. The study subjects were sampled systematically, according to their gender. Patients included in the study were given a standardized interview and their clinical records reviewed. Specimens were collected for laboratory investigations. For each STD detected, the treatment was defined as adequate if drugs currently known to be active against that infection were prescribed. One hundred and seventy men and 161 women were included in the study (median age: females 22 years, males 26 years). While almost all patients believed their STD may have been caused by unprotected sexual intercourse, many also believed it may have been caused by other factors, such as bewitchment with traditional medicine. Only 21% of male and 37% of female patients received any education about STD transmission during the clinic visit, and only 25% of male and 36% of female patients received education about condom use. As a result of the low sensitivity of the clinicians' diagnoses, 16% of men and 61% of women left the clinic with at least one infection inadequately treated. The majority of patients were not receiving education for the prevention of STDs including HIV. Many were not receiving adequate treatment for their infections. The introduction of a syndromic management protocol in this setting would substantially reduce the proportion

NMR measurement of dynamic nuclear polarization: a technique to test the quality of its volume average obtained with different NMR coil configurations

International Nuclear Information System (INIS)

Zhao, W.H.; Cox, S.F.J.

1980-07-01

In the NMR measurement of dynamic nuclear polarization, a volume average is obtained where the contribution from different parts of the sample is weighted according to the local intensity of the RF field component perpendicular to the large static field. A method of mapping this quantity is described. A small metallic object whose geometry is chosen to perturb the appropriate RF component is scanned through the region to be occupied by the sample. The response of the phase angle of the impedance of a tuned circuit comprising the NMR coil gives a direct measurement of the local weighting factor. The correlation between theory and experiment was obtained by using a circular coil. The measuring method, checked in this way, was then used to investigate the field profiles of practical coils which are required to be rectangular for a proposed experimental neutron polarizing filter. This method can be used to evaluate other practical RF coils. (author)

Ida's Story - Be Smart. Be Well. STD Videos

Centers for Disease Control (CDC) Podcasts

2010-03-15

This video, produced by Be Smart. Be Well., raises awareness of Sexually Transmitted Diseases (STDs): 1) What are they? 2) Why they matter? and, 3) What can I do about them? Footage courtesy of Be Smart. Be Well., featuring CDC's Dr. John Douglas, Division of Sexually Transmitted Disease Prevention.  Created: 3/15/2010 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 3/15/2010.

NMR in structure-based drug design.

Science.gov (United States)

Carneiro, Marta G; Ab, Eiso; Theisgen, Stephan; Siegal, Gregg

2017-11-08

NMR spectroscopy is a powerful technique that can provide valuable structural information for drug discovery endeavors. Here, we discuss the strengths (and limitations) of NMR applications to structure-based drug discovery, highlighting the different levels of resolution and throughput obtainable. Additionally, the emerging field of paramagnetic NMR in drug discovery and recent developments in approaches to speed up and automate protein-observed NMR data collection and analysis are discussed. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

DOE Handbook: Supplementary guidance and design experience for the fusion safety standards DOE-STD-6002-96 and DOE-STD-6003-96

International Nuclear Information System (INIS)

1999-01-01

Two standards have been developed that pertain to the safety of fusion facilities. These are DOE- STD-6002-96, Safety of Magnetic Fusion Facilities: Requirements, and DOE-STD-6003-96, Safety of Magnetic Fusion Facilities: Guidance. The first of these standards identifies requirements that subscribers to that standard must meet to achieve safety in fusion facilities. The second standard contains guidance to assist in meeting the requirements identified inthefirst This handbook provides additional documentation on good operations and design practices as well as lessons learned from the experiences of designers and operators of previous fusion facilities and related systems. It is intended to capture the experience gained in the various fields and pass it on to designers of future fusion facilities as a means of enhancing success and safeiy. The sections of this document are presented according to the physical location of the major systems of a t%sion facility, beginning with the vacuum vessel and proceeding to those systems and components outside the vacuum vessel (the ''Ex-vessel Systems''). The last section describes administrative procedures that cannot be localized to specific components. It has been tacitly assumed that the general structure of the fusion facilities addressed is that of a tokamak though the same principles would apply to other magnetic confinement options

DOE Handbook: Supplementary guidance and design experience for the fusion safety standards DOE-STD-6002-96 and DOE-STD-6003-96

Energy Technology Data Exchange (ETDEWEB)

None

1999-01-01

Two standards have been developed that pertain to the safety of fusion facilities. These are DOE- STD-6002-96, Safety of Magnetic Fusion Facilities: Requirements, and DOE-STD-6003-96, Safety of Magnetic Fusion Facilities: Guidance. The first of these standards identifies requirements that subscribers to that standard must meet to achieve safety in fusion facilities. The second standard contains guidance to assist in meeting the requirements identified in the first This handbook provides additional documentation on good operations and design practices as well as lessons learned from the experiences of designers and operators of previous fusion facilities and related systems. It is intended to capture the experience gained in the various fields and pass it on to designers of future fusion facilities as a means of enhancing success and safety. The sections of this document are presented according to the physical location of the major systems of a fusion facility, beginning with the vacuum vessel and proceeding to those systems and components outside the vacuum vessel (the "Ex-vessel Systems"). The last section describes administrative procedures that cannot be localized to specific components. It has been tacitly assumed that the general structure of the fusion facilities addressed is that of a tokamak though the same principles would apply to other magnetic confinement options.

Characterisation of different polymorphs of tris(8-hydroxyquinolinatoaluminium(III using solid-state NMR and DFT calculations

Directory of Open Access Journals (Sweden)

Periasamy N

2009-11-01

Full Text Available Abstract Background Organic light emitting devices (OLED are becoming important and characterisation of them, in terms of structure, charge distribution, and intermolecular interactions, is important. Tris(8-hydroxyquinolinato-aluminium(III, known as Alq3, an organomettalic complex has become a reference material of great importance in OLED. It is important to elucidate the structural details of Alq3 in its various isomeric and solvated forms. Solid-state nuclear magnetic resonance (NMR is a useful tool for this which can also complement the information obtained with X-ray diffraction studies. Results We report here 27Al one-dimensional (1D and two-dimensional (2D multiple-quantum magic-angle spinning (MQMAS NMR studies of the meridional (α-phase and the facial (δ-phase isomeric forms of Alq3. Quadrupolar parameters are estimated from the 1D spectra under MAS and anisotropic slices of the 2D spectra and also calculated using DFT (density functional theory quantum-chemical calculations. We have also studied solvated phase of Alq3 containing ethanol in its lattice. We show that both the XRD patterns and the quadrupolar parameters of the solvated phase are different from both the α-phase and the δ-phase, although the fluorescence emission shows no substantial difference between the α-phase and the solvated phase. Moreover, we have shown that after the removal of ethanol from the matrix the solvated Alq3 has similar XRD patterns and quadrupolar parameters to that of the α-phase. Conclusion The 2D MQMAS experiments have shown that all the different modifications of Alq3 have 27Al in single unique crystallographic site. The quadrupolar parameters predicted using the DFT calculation under the isodensity polarisable continuum model resemble closely the experimentally obtained values. The solvated phase of Alq3 containing ethanol has structural difference from the α-phase of Alq3 (containing meridional isomer from the solid-state NMR studies

STD/AIDS prevention in Portuguese-speaking Africa: a review of the recent literature in the social sciences and health.

Science.gov (United States)

Monteiro, Simone

2009-03-01

The article reviews academic literature in the social sciences and health on the problems and challenges of STD/AIDS prevention in Portuguese-speaking African countries. Based on a bibliographic survey of the SciELO, PubMed, and Sociological Abstracts databases between 1997 and 2007, the research under review was organized into two groups, according to content. The first group of studies sought to understand STD/AIDS vulnerability among social groups by examining local cultural and socioeconomic factors as related to gender dynamics, sexuality, color/race, religion and health care. The second group encompassed critical assessments of shortcomings in the STD/AIDS educational messages delivered by governments and international agencies. Attention is called to the way in which the presence of traditional medicine systems and the occurrence of civil wars in the post-colonial period impact the STD/AIDS epidemic in the African countries under study.

Influence of carbohydrates on the interaction of procyanidin B3 with trypsin.

Science.gov (United States)

Gonçalves, Rui; Mateus, Nuno; De Freitas, Victor

2011-11-09

The biological properties of procyanidins, in particular their inhibition of digestive enzymes, have received much attention in the past few years. Dietary carbohydrates are an environmental factor that is known to affect the interaction of procyanidins with proteins. This work aimed at understanding the effect of ionic food carbohydrates (polygalacturonic acid, arabic gum, pectin, and xanthan gum) on the interaction between procyanidins and trypsin. Physical-chemical techniques such as saturation transfer difference-NMR (STD-NMR) spectroscopy, fluorescence quenching, and nephelometry were used to evaluate the interaction process. Using STD-NMR, it was possible to identify the binding of procyanidin B3 to trypsin. The tested carbohydrates prevented the association of procyanidin B3 and trypsin by a competition mechanism in which the ionic character of carbohydrates and their ability to encapsulate procyanidins seem crucial leading to a reduction in STD signal and light scattering and to a recovery of the proteins intrinsic fluorescence. On the basis of these results, it was possible to grade the carbohydrates in their aggregation inhibition ability: XG > PA > AG ≫ PC. These effects may be relevant since the coingestion of procyanidins and ionic carbohydrates are frequent and furthermore since these might negatively affect the antinutritional properties ascribed to procyanidins in the past.

Incidence of herpes simplex virus type 2 infection in 5 sexually transmitted disease (STD) clinics and the effect of HIV/STD risk-reduction counseling.

Science.gov (United States)

Gottlieb, Sami L; Douglas, John M; Foster, Mark; Schmid, D Scott; Newman, Daniel R; Baron, Anna E; Bolan, Gail; Iatesta, Michael; Malotte, C Kevin; Zenilman, Jonathan; Fishbein, Martin; Peterman, Thomas A; Kamb, Mary L

2004-09-15

The seroincidence of herpes simplex virus type 2 (HSV-2) infection was determined among 1766 patients attending sexually transmitted disease (STD) clinics and enrolled in a randomized, controlled trial of human immunodeficiency virus (HIV)/STD risk-reduction counseling (RRC). Arm 1 received enhanced RRC (4 sessions); arm 2, brief RRC (2 sessions); and arm 3, the control arm, brief informational messages. The overall incidence rate was 11.7 cases/100 person-years (py). Independent predictors of incidence of HSV-2 infection included female sex; black race; residence in Newark, New Jersey; new HSV-2 infections were diagnosed clinically. Incidence rates were 12.9 cases/100 py in the control arm, 11.8 cases/100 py in arm 2, and 10.3 cases/100 py in arm 1 (hazard ratio, 0.8 [95% confidence interval, 0.6-1.1], vs. controls). The possible benefit of RRC in preventing acquisition of HSV-2 infection offers encouragement that interventions more specifically tailored to genital herpes may be useful and should be an important focus of future studies.

Solid-state NMR of inorganic semiconductors.

Science.gov (United States)

Yesinowski, James P

2012-01-01

Studies of inorganic semiconductors by solid-state NMR vary widely in terms of the nature of the samples investigated, the techniques employed to observe the NMR signal, and the types of information obtained. Compared with the NMR of diamagnetic non-semiconducting substances, important differences often result from the presence of electron or hole carriers that are the hallmark of semiconductors, and whose theoretical interpretation can be involved. This review aims to provide a broad perspective on the topic for the non-expert by providing: (1) a basic introduction to semiconductor physical concepts relevant to NMR, including common crystal structures and the various methods of making samples; (2) discussions of the NMR spin Hamiltonian, details of some of the NMR techniques and strategies used to make measurements and theoretically predict NMR parameters, and examples of how each of the terms in the Hamiltonian has provided useful information in bulk semiconductors; (3) a discussion of the additional considerations needed to interpret the NMR of nanoscale semiconductors, with selected examples. The area of semiconductor NMR is being revitalized by this interest in nanoscale semiconductors, the great improvements in NMR detection sensitivity and resolution that have occurred, and the current interest in optical pumping and spintronics-related studies. Promising directions for future research will be noted throughout.

Application of Solid-State NMR to Reveal Structural Differences in Cefazolin Sodium Pentahydrate from Different Manufacturing Processes

Science.gov (United States)

Tian, Ye; Wang, Wei D.; Zou, Wen-Bo; Qian, Jian-Qin; Hu, Chang-Qin

2018-04-01

The solid form of an active pharmaceutical ingredient is important when developing a new chemical entity. A solid understanding of the crystal structure and morphology that affect the mechanical and physical characteristics of pharmaceutical powders determines the manufacturing process. Solid-state NMR, thermogravimetric analysis, X-ray diffraction, and Fourier-transform infrared spectroscopy were combined with theoretical calculation to investigate different crystal packings of α-cefazolin sodium from three different vendors and conformational polymorphism was identified to exist in the α-cefazolin sodium. Marginal differences observed among CEZ-Na pentahydrate 1, 2, and 3 were speculated as the proportion of conformation 2. Understanding the differences in the polymorphic structure of α-cefazolin sodium may help with making modifications to incorporate new knowledge with a product’s development.

NASA-STD-7009 Guidance Document for Human Health and Performance Models and Simulations

Science.gov (United States)

Walton, Marlei; Mulugeta, Lealem; Nelson, Emily S.; Myers, Jerry G.

2014-01-01

Rigorous verification, validation, and credibility (VVC) processes are imperative to ensure that models and simulations (MS) are sufficiently reliable to address issues within their intended scope. The NASA standard for MS, NASA-STD-7009 (7009) [1] was a resultant outcome of the Columbia Accident Investigation Board (CAIB) to ensure MS are developed, applied, and interpreted appropriately for making decisions that may impact crew or mission safety. Because the 7009 focus is engineering systems, a NASA-STD-7009 Guidance Document is being developed to augment the 7009 and provide information, tools, and techniques applicable to the probabilistic and deterministic biological MS more prevalent in human health and performance (HHP) and space biomedical research and operations.

Compositional differences among Chinese soy sauce types studied by (13)C NMR spectroscopy coupled with multivariate statistical analysis.

Science.gov (United States)

Kamal, Ghulam Mustafa; Wang, Xiaohua; Bin Yuan; Wang, Jie; Sun, Peng; Zhang, Xu; Liu, Maili

2016-09-01

Soy sauce a well known seasoning all over the world, especially in Asia, is available in global market in a wide range of types based on its purpose and the processing methods. Its composition varies with respect to the fermentation processes and addition of additives, preservatives and flavor enhancers. A comprehensive (1)H NMR based study regarding the metabonomic variations of soy sauce to differentiate among different types of soy sauce available on the global market has been limited due to the complexity of the mixture. In present study, (13)C NMR spectroscopy coupled with multivariate statistical data analysis like principle component analysis (PCA), and orthogonal partial least square-discriminant analysis (OPLS-DA) was applied to investigate metabonomic variations among different types of soy sauce, namely super light, super dark, red cooking and mushroom soy sauce. The main additives in soy sauce like glutamate, sucrose and glucose were easily distinguished and quantified using (13)C NMR spectroscopy which were otherwise difficult to be assigned and quantified due to serious signal overlaps in (1)H NMR spectra. The significantly higher concentration of sucrose in dark, red cooking and mushroom flavored soy sauce can directly be linked to the addition of caramel in soy sauce. Similarly, significantly higher level of glutamate in super light as compared to super dark and mushroom flavored soy sauce may come from the addition of monosodium glutamate. The study highlights the potentiality of (13)C NMR based metabonomics coupled with multivariate statistical data analysis in differentiating between the types of soy sauce on the basis of level of additives, raw materials and fermentation procedures. Copyright © 2016 Elsevier B.V. All rights reserved.

NMR-based metabolic study of fruits of Physalis peruviana L. grown in eight different Peruvian ecosystems.

Science.gov (United States)

Maruenda, Helena; Cabrera, Rodrigo; Cañari-Chumpitaz, Cristhian; Lopez, Juan M; Toubiana, David

2018-10-01

The berry of Physalis peruviana L. (Solanaceae) represents an important socio-economical commodity for Latin America. The absence of a clear phenotype renders it difficult to trace its place of origin. In this study, Cape gooseberries from eight different regions within the Peruvian Andes were profiled for their metabolism implementing a NMR platform. Twenty-four compounds could be unequivocally identified and sixteen quantified. One-way ANOVA and post-hoc Tukey test revealed that all of the quantified metabolites changed significantly among regions: Bambamarca I showed the most accumulated significant differences. The coefficient of variation demonstrated high phenotypic plasticity for amino acids, while sugars displayed low phenotypic plasticity. Correlation analysis highlighted the closely coordinated behavior of the amino acid profile. Finally, PLS-DA revealed a clear separation among the regions based on their metabolic profiles, accentuating the discriminatory capacity of NMR in establishing significant phytochemical differences between producing regions of the fruit of P. peruviana L. Copyright © 2018 Elsevier Ltd. All rights reserved.

Sexual Lifestyle, Risk Factors and Socioeconomic Status of the STD Patients in Bangladesh.

Science.gov (United States)

Nandi, A K; Hossain, K J; Islam, A S

2017-01-01

Sexually transmitted diseases (STDs) are increasing alarmingly with time among the young-adults in Bangladesh. The objective of the study was to investigate Sexual lifestyle, Risk Factors and Socioeconomic Status of the STD Patients. A total of 205 STD patients were selected following convenient method of sampling consistent with defined selection criteria from outpatient department of Skin and Venereal Disease of Mymensingh Medical College Hospital, Mymensingh. Period of data collection was from July 2014 to June 2015. The research instrument was an interviewer questionnaire and laboratory investigation reports. Results showed that the mean age of the respondents was 27±5.9 years of which 104(50.7%) unmarried and 95(46.3%) married. Level of education, 168(82.0%) of the STD patients were literate. Occupation of the STD patients, 201(98.0%) had specific occupation of which 74(36.1%) were businessmen, 48(23.4%) student, 24(11.7%) technical jobs, 20(9.8%) day labourer, 15(7.3%) household workers, 14(6.8%) service holders and 6(2.9%) were transport workers. Their average monthly income was Tk. 7892±6763. Majority of the STD patients 115((56.1%) expressed that they enjoyed extra-marital sex or illegal sex out of curiosity, 32(15.6%) habitual, 24(11.7%) to test sexual performance, 18(8.8%) inadequate response of the legal sex partners, 8(3.9%) hyper-sexuality and 8(3.9%) family disharmony. Most of the patients 200(97.6%) were heterosexual of which 165(80.5%) visited 1-10 sex partners, 18(8.8%) 11-20 sex partners and 22(10.7%) visited 21-100 sex partners in lifetime. In category of sex partners, 60(29.3%) were hotel-based sex partners, 111(54.1%) brothel-based, 20(9.8%) friends sex partners, 10(4.9%) street sex sellers and 4(2.0%) were residential sex partners respectively. Of them, 132(64.4%) did not use condom during sex, 65(31.7%) use it occasionally and only 8(3.9%) use condom regularly. Most of them 170((82.8%) had been suffering from gonococcal urethritis, 19

Dynamic combinatorial chemistry to identify binders of ThiT, an S-component of the energy-coupling factor transporter for thiamine

NARCIS (Netherlands)

Monjas, Leticia; Swier, Lotteke J Y M; Setyawati, Inda; Slotboom, Dirk Jan; Hirsch, Anna Katharina Herta

2017-01-01

We applied dynamic combinatorial chemistry (DCC) to identify ligands of ThiT, the S-component of the energy-coupling factor (ECF) transporter for thiamine in Lactococcus lactis. We used a pre-equilibrated dynamic combinatorial library (DCL) and saturation-transfer difference (STD) NMR spectroscopy

Study by 31P NMR spectroscopy of the triacylglycerol degradation processes in olive oil with different heat-transfer mechanisms.

OpenAIRE

Lucas Torres, Covadonga; Pérez Martínez, Angel; Cabañas Galán, Beatriz; Moreno Moreno, Andrés

2014-01-01

The thermal degradation of olive oil using conventional and microwave heating under the same experimental conditions were compared. A powerful identification and quantification technique based on 31P NMR has been developed to characterise the differences between the minor components including diacylglycerol and free fatty acids in the heated samples. The 31P NMR spectra of the degraded olive oils, which contain single bondOH groups derivatised with a phosphorus reagent, showed that convention...

Application of 13C NMR spectroscopy to characterize organic chemical components of decomposing coarse woody debris from different climatic regions

Directory of Open Access Journals (Sweden)

Takuya Hishinuma

2015-04-01

Full Text Available Solid-state 13C nuclear magnetic resonance (NMR spectroscopy was applied to coarse woody debris (CWD in different stages of decomposition and collected from forest floor of a subtropical, a cool temperate, and a subalpine forest in Japan. The purpose was to test its applicability to characterize organic chemical composition of CWD of broad-leaved and coniferous trees from different climatic conditions. O-alkyl-C, mainly representing carbohydrates, was the predominant component of CWD at the three sites, accounting for 43.5-58.1% of the NMR spectra. Generally, the relative area under the signals for aromatic-C and phenolic-C, mainly representing lignin, increased, whereas the relative area for O-alkyl-C decreased, as the decay class advanced. The relative area under NMR chemical shift regions was significantly correlated with the chemical properties examined with proximate analyses. That is, O-alkyl-C and di-O-alkyl-C NMR signal areas were positively correlated with the volumetric density of CWD and the content of total carbohydrates. Methoxyl-C, aromatic-C, phenolic-C, carboxyl-C, and carbonyl-C were positively correlated with the contents of acid-unhydrolyzable residues (lignin, tannins, and cutin and nitrogen. Lignin-C calculated from NMR signals increased, and polysaccharide-C decreased, with the decay class of CWD at the three study sites. A review of previous studies on 13C NMR spectroscopy for decomposing CWD suggested further needs of its application to broad-leaved trees from tropical and subtropical regions.

A novel integration effort to reduce the risk for alcohol-exposed pregnancy among women attending urban STD clinics.

Science.gov (United States)

Hutton, Heidi E; Chander, Geetanjali; Green, Patricia P; Hutsell, Catherine A; Weingarten, Kimberly; Peterson, Karen L

2014-01-01

Alcohol-exposed pregnancy (AEP) is a significant public health problem in the United States. Sexually transmitted disease (STD) clinics serve female clients with a high prevalence of heavy alcohol consumption coupled with ineffective contraceptive use. Project CHOICES (Changing High-Risk AlcOhol Use and Increasing Contraception Effectiveness) is an evidence-based, brief intervention to lower risk of AEP by targeting alcohol and contraceptive behaviors through motivational interviewing and individualized feedback. We describe our experience integrating and implementing CHOICES in STD clinics. This endeavor aligns with CDC's National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention's program collaboration and service integration strategic priority to strengthen collaborative work across disease areas and integrate services provided by related programs at the client level.

Charting a Path to Location Intelligence for STD Control

OpenAIRE

Gerber, Todd M.; Du, Ping; Armstrong-Brown, Janelle; McNutt, Louise-Anne; Coles, F. Bruce

2009-01-01

This article describes the New York State Department of Health's GeoDatabase project, which developed new methods and techniques for designing and building a geocoding and mapping data repository for sexually transmitted disease (STD) control. The GeoDatabase development was supported through the Centers for Disease Control and Prevention's Outcome Assessment through Systems of Integrated Surveillance workgroup. The design and operation of the GeoDatabase relied upon commercial-off-the-shelf ...

Characterisation of different polymorphs of tris(8-hydroxyquinolinato)aluminium(III) using solid-state NMR and DFT calculations.

Science.gov (United States)

Goswami, Mithun; Nayak, Pabitra K; Periasamy, N; Madhu, P K

2009-11-09

Organic light emitting devices (OLED) are becoming important and characterisation of them, in terms of structure, charge distribution, and intermolecular interactions, is important. Tris(8-hydroxyquinolinato)-aluminium(III), known as Alq3, an organomettalic complex has become a reference material of great importance in OLED. It is important to elucidate the structural details of Alq3 in its various isomeric and solvated forms. Solid-state nuclear magnetic resonance (NMR) is a useful tool for this which can also complement the information obtained with X-ray diffraction studies. We report here 27Al one-dimensional (1D) and two-dimensional (2D) multiple-quantum magic-angle spinning (MQMAS) NMR studies of the meridional (alpha-phase) and the facial (delta-phase) isomeric forms of Alq3. Quadrupolar parameters are estimated from the 1D spectra under MAS and anisotropic slices of the 2D spectra and also calculated using DFT (density functional theory) quantum-chemical calculations. We have also studied solvated phase of Alq3 containing ethanol in its lattice. We show that both the XRD patterns and the quadrupolar parameters of the solvated phase are different from both the alpha-phase and the delta-phase, although the fluorescence emission shows no substantial difference between the alpha-phase and the solvated phase. Moreover, we have shown that after the removal of ethanol from the matrix the solvated Alq3 has similar XRD patterns and quadrupolar parameters to that of the alpha-phase. The 2D MQMAS experiments have shown that all the different modifications of Alq3 have 27Al in single unique crystallographic site. The quadrupolar parameters predicted using the DFT calculation under the isodensity polarisable continuum model resemble closely the experimentally obtained values. The solvated phase of Alq3 containing ethanol has structural difference from the alpha-phase of Alq3 (containing meridional isomer) from the solid-state NMR studies. Solid-state NMR can hence be

Intimate Partner Violence, Sexual Autonomy and Postpartum STD Prevention Among Young Couples: A Mediation Analysis.

Science.gov (United States)

Willie, Tiara C; Callands, Tamora A; Kershaw, Trace S

2018-03-01

The transition to parenthood is a stressful time for young couples and can put them at risk for acquiring STDs. Mechanisms underlying this risk-particularly, intimate partner violence (IPV) and sexual autonomy-have not been well studied. Between 2007 and 2011, a prospective cohort study of the relationships and health of pregnant adolescents and their male partners recruited 296 couples at four hospital-based obstetrics and gynecology clinics in the U.S. Northeast; participants were followed up six and 12 months after the birth. Structural equation modeling identified associations among IPV at baseline and six months, sexual autonomy at six months and STD acquisition at 12 months. Mediating effects of sexual autonomy were tested via bootstrapping. Females were aged 14-21, and male partners were 14 or older. For females, IPV victimization at baseline was positively associated with the likelihood of acquiring a postpartum STD (coefficient, 0.4); level of sexual autonomy was inversely associated with the likelihood of acquiring an STD and of having a male partner who acquired one by the 12-month follow-up (-0.4 for each). For males, IPV victimization at baseline was negatively correlated with a female partner's sexual autonomy (-0.3) and likelihood of acquiring an STD (-0.7); victimization at six months was positively related to a partner's sexual autonomy (0.2). Sexual autonomy did not mediate these relationships. Females' sexual autonomy appears to protect against postpartum STDs for both partners. Future research should explore the efficacy of IPV-informed approaches to improving women's sexual and reproductive health. Copyright © 2018 by the Guttmacher Institute.

Value of NMR logging for heavy oil characterization

Energy Technology Data Exchange (ETDEWEB)

Chen, S.; Chen, J.; Georgi, D. [Baker Hughes, Calgary, AB (Canada); Sun, B. [Chevron Energy Technology Co., Calgary, AB (Canada)

2008-07-01

Non-conventional, heavy oil fields are becoming increasingly important to the security of energy supplies and are becoming economically profitable to produce. Heavy oil reservoirs are difficult to evaluate since they are typically shallow and the connate waters are very fresh. Other heavy oil reservoirs are oil-wet where the resistivities are not indicative of saturation. Nuclear magnetic resonance (NMR) detects molecular level interactions. As such, it responds distinctively to different hydrocarbon molecules, thereby opening a new avenue for constituent analysis. This feature makes NMR a more powerful technique than bulk oil density or viscosity measurements for characterizing oils, and is the basis for detecting gas in heavy oil fields. NMR logging, which measures fluid in pore space directly, is capable of separating oil from water. It is possible to discern movable from bound water by analyzing NMR logs. The oil viscosity can be also quantified from NMR logs, NMR relaxation time and diffusivity estimates. The unique challenges for heavy oil reservoir characterization for the NMR technique were discussed with reference to the extra-fast decay of the NMR signal in response to extra-heavy oil/tars, and the lack of sensitivity in measuring very slow diffusion of heavy oil molecules. This paper presented various methods for analyzing heavy oil reservoirs in different viscosity ranges. Heavy oil fields in Venezuela, Kazakhstan, Canada, Alaska and the Middle East were analyzed using different data interpretation approaches based on the reservoir formation characteristics and the heavy oil type. NMR direct fluid typing was adequate for clean sands and carbonate reservoirs while integrated approaches were used to interpret extra heavy oils and tars. It was concluded that NMR logs can provide quantitative measures for heavy oil saturation, identify sweet spots or tar streaks, and quantify heavy oil viscosity within reasonable accuracy. 14 refs., 16 figs.

Analysis of the hydrolysis of inulin using real time 1H NMR spectroscopy

Science.gov (United States)

Barclay, Thomas; Ginic-Markovic, Milena; Johnston, Martin R.; Cooper, Peter D.; Petrovsky, Nikolai

2012-01-01

The hydrolysis of various carbohydrates was investigated under acidic conditions in real time by 1H NMR spectroscopy, with a focus on the polysaccharide inulin. Sucrose was used as a model compound to illustrate the applicability of this technique. The hydrolysis of sucrose was shown to follow pseudo first order kinetics and have an activation energy of 107.0 kJ.mol−1 (s.d. 1.7 kJ.mol−1). Inulin, pullulan and glycogen also all followed pseudo first order kinetics, but had an initiation phase at least partially generated by the protonation of the glycosidic bonds. It was also demonstrated that polysaccharide chain length has an effect on the hydrolysis of inulin. For short chain inulin (DPn 18, s.d. 0.70) the activation energy calculated for the hydrolytic cleavage of glucose was similar to sucrose at 108.5 kJ.mol−1 (std. dev. 0.60). For long chain inulin (DPn 30, s.d. 1.3) the activation energy for the hydrolytic cleavage of glucose was reduced to 80.5 kJ.mol−1 (s.d. 2.3 kJ.mol−1). This anomaly has been attributed to varied conformations for the two different lengths of inulin chain in solution. PMID:22464225

Knowledge, Beliefs and Behaviours Related to STD Risk, Prevention, and Screening among a Sample of African American Men and Women

Science.gov (United States)

Uhrig, Jennifer D.; Friedman, Allison; Poehlman, Jon; Scales, Monica; Forsythe, Ann

2014-01-01

Objective: Current data on sexually transmitted disease (STD) among African Americans show significant racial/ethnic disparities. The purpose of this study was to explore knowledge, attitudes, beliefs, and behaviours related to STD risk, prevention, and testing among African American adults to help inform the development of a health communication…

Club Drugs and HIV/STD Infection: An Exploratory Analysis among Men Who Have Sex with Men in Changsha, China

Science.gov (United States)

Zheng, Jun; Zhao, Junshi; He, Jianmei; Zhang, Guoqiang; Tang, Xuemin

2015-01-01

Objective To evaluate current club drug use and its potential association with the transmission of HIV/STD among Changsha men who have sex with men (MSM). Method A cross-sectional survey was conducted by using self-administered questionnaires including information regarding socio-demographics, club drug use, high-risk behaviors, and HIV/STD infections. Multiple methods including venue-based, peer referral using “snowball” techniques, and internet advertisements were used to recruit study participants. Results Of the 826 participants, 177 (21.4%) reported that they had used club drugs at some time before or during sex in the past six months. MSM with young age, low education level, and seeking partners through the internet or bars were the main population who used drugs. Poppers were the most common drug used among Changsha MSM. The prevalence of HIV, syphilis, and herpes simplex virus-2 were higher among drug users. There were no significant differences in unprotected sexual intercourse and condom use between drug users and non-users. Compared with non-users, risk behaviors such as group sex, multiple sex partners, and sex with foreigners were more frequent among drug users. Conclusion Club drug use is common among Changsha MSM, and is related to unsafe sex activities and HIV/STD infection. It is necessary to build novel targeted HIV prevention strategies to monitor and reduce club drug use among MSM. PMID:25950912

Club Drugs and HIV/STD Infection: An Exploratory Analysis among Men Who Have Sex with Men in Changsha, China.

Directory of Open Access Journals (Sweden)

Xi Chen

Full Text Available To evaluate current club drug use and its potential association with the transmission of HIV/STD among Changsha men who have sex with men (MSM.A cross-sectional survey was conducted by using self-administered questionnaires including information regarding socio-demographics, club drug use, high-risk behaviors, and HIV/STD infections. Multiple methods including venue-based, peer referral using "snowball" techniques, and internet advertisements were used to recruit study participants.Of the 826 participants, 177 (21.4% reported that they had used club drugs at some time before or during sex in the past six months. MSM with young age, low education level, and seeking partners through the internet or bars were the main population who used drugs. Poppers were the most common drug used among Changsha MSM. The prevalence of HIV, syphilis, and herpes simplex virus-2 were higher among drug users. There were no significant differences in unprotected sexual intercourse and condom use between drug users and non-users. Compared with non-users, risk behaviors such as group sex, multiple sex partners, and sex with foreigners were more frequent among drug users.Club drug use is common among Changsha MSM, and is related to unsafe sex activities and HIV/STD infection. It is necessary to build novel targeted HIV prevention strategies to monitor and reduce club drug use among MSM.

What Is It? - Be Smart. Be Well. STD Videos

Centers for Disease Control (CDC) Podcasts

2010-03-15

This video, produced by Be Smart. Be Well., raises awareness of Sexually Transmitted Diseases (STDs): 1) What are they? 2) Why they matter? and, 3) What can I do about them? Footage courtesy of Be Smart. Be Well., featuring CDC's Dr. John Douglas, Division of Sexually Transmitted Disease Prevention.  Created: 3/15/2010 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 3/15/2010.

Quality of sour cherry juice of different clones and cultivars (Prunus cerasus L.) determined by a combined sensory and NMR spectroscopic approach

DEFF Research Database (Denmark)

Clausen, Morten Rahr; Pedersen, Bjarne Hjelmsted; Bertram, Hanne Christine S.

2011-01-01

Juice was manufactured from seven different sour cherry clones/cultivars and evaluated by quantitative descriptive sensory analysis and 1H NMR spectroscopy. The sensory evaluation showed a large variation in several sensory attributes between the sour cherry clones/cultivars, which could be divided...... into two groups on the basis of both the sensory data and the NMR spectroscopic data. These groups were closely related to the genetic background of the clones. Kelleris clones were distinctly different from Stevnsberry and Fanal clones. Hence, 1H NMR spectroscopic data seem to correlate with sensory...... quality of different sour cherry clones. In addition, malic acid was the most important metabolite for modeling the two highly correlated sensory attributes sweetness and sourness, whereas the glucose content had a slight effect and the fructose content had no impact on sweetness/sourness. Other...

Cell-free expressed bacteriorhodopsin in different soluble membrane mimetics: biophysical properties and NMR accessibility.

Science.gov (United States)

Etzkorn, Manuel; Raschle, Thomas; Hagn, Franz; Gelev, Vladimir; Rice, Amanda J; Walz, Thomas; Wagner, Gerhard

2013-03-05

Selecting a suitable membrane-mimicking environment is of fundamental importance for the investigation of membrane proteins. Nonconventional surfactants, such as amphipathic polymers (amphipols) and lipid bilayer nanodiscs, have been introduced as promising environments that may overcome intrinsic disadvantages of detergent micelle systems. However, structural insights into the effects of different environments on the embedded protein are limited. Here, we present a comparative study of the heptahelical membrane protein bacteriorhodopsin in detergent micelles, amphipols, and nanodiscs. Our results confirm that nonconventional environments can increase stability of functional bacteriorhodopsin, and demonstrate that well-folded heptahelical membrane proteins are, in principle, accessible by solution-NMR methods in amphipols and phospholipid nanodiscs. Our data distinguish regions of bacteriorhodopsin that mediate membrane/solvent contacts in the tested environments, whereas the protein's functional inner core remains almost unperturbed. The presented data allow comparing the investigated membrane mimetics in terms of NMR spectral quality and thermal stability required for structural studies. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Factors associated with condom use and knowledge about STD/AIDS among teenagers in public and private schools in São Paulo, Brazil].

Science.gov (United States)

Martins, Laura B Motta; da Costa-Paiva, Lúcia Helena S; Osis, Maria José D; de Sousa, Maria Helena; Pinto-Neto, Aarão M; Tadini, Valdir

2006-02-01

This study aimed to compare knowledge about STD/AIDS and identify the factors associated with adequate knowledge and consistent use of male condoms in teenagers from public and private schools in the city of São Paulo, Brazil. We selected 1,594 adolescents ranging 12 to 19 years of age in 13 public schools and 5 private schools to complete a questionnaire on knowledge of STD/AIDS and use of male condoms. Prevalence ratios were computed with a 95% confidence interval. The score on STD knowledge used a cutoff point corresponding to 50% of correct answers. Statistical tests were chi-square and Poisson multiple regression. Consistent use of male condoms was 60% in private and 57.1% in public schools (p > 0.05) and was associated with male gender and lower socioeconomic status. Female gender, higher schooling, enrollment in private school, Caucasian race, and being single were associated with higher knowledge of STDs. Teenagers from public and private schools have adequate knowledge of STD prevention, however this does not include the adoption of effective prevention. Educational programs and STD/AIDS awareness-raising should be expanded in order to minimize vulnerability.

Development of a micro flow-through cell for high field NMR spectroscopy.

Energy Technology Data Exchange (ETDEWEB)

Alam, Todd Michael; McIntyre, Sarah K.

2011-05-01

A highly transportable micro flow-through detection cell for nuclear magnetic resonance (NMR) spectroscopy has been designed, fabricated and tested. This flow-through cell allows for the direct coupling between liquid chromatography (LC) and gel permeation chromatography (GPC) resulting in the possibility of hyphenated LC-NMR and GPC-NMR. The advantage of the present flow cell design is that it is independent and unconnected to the detection probe electronics, is compatible with existing commercial high resolution NMR probes, and as such can be easily implemented at any NMR facility. Two different volumes were fabricated corresponding to between {approx}3.8 and 10 {micro}L detection volume. Examples of the performance of the cell on different NMR instruments, and using different NMR detection probes were demonstrated.

Characterization of natural bentonite by NMR

International Nuclear Information System (INIS)

Leite, Sidnei Q.M.; Dieguez, Lidia C.; Menezes, Sonia M.C.; San Gil, Rosane A.S.

1993-01-01

Solid state NMR as well as several other instrumental chemical analysis techniques were used in order to characterize two natural occurring bentonite. The methodology is described. The NMR spectra, together with the other used techniques suggest that the observed differences are due to iron inclusions in tetrahedral and octahedral sites

Organic matter characterization during the anaerobic digestion of different biomasses by means of CPMAS 13C NMR spectroscopy

International Nuclear Information System (INIS)

Tambone, Fulvia; Adani, Fabrizio; Gigliotti, Giovanni; Volpe, Daniela; Fabbri, Claudio; Provenzano, Maria Rosaria

2013-01-01

The aim of this work was to characterize ingestates and their corresponding digestates obtained in two full-scale biogas production plants processing a) mixtures of organic wastes in co-digestion, and b) pig slurry in order to assess the organic matter transformation during anaerobic digestion by means of chemical analysis and 13 CPMAS-NMR spectroscopy. Results proved that digestates obtained by different organic substrates exhibited significant chemical differences related to the different initial composition of substrates. We proposed the use of the aliphaticity index in order to highlight the different chemical nature of ingestates and their corresponding digestates. In order to verify whether the AD process leads to stabilized final products regardless the initial composition of biomass in view of a possible agronomical use of digestate, a comparison of CPMAS 13 C NMR data of a number of ingestates and digestates available in literature was carried out. Results indicated that most of the aromatic structures present in the substrate tend to degrade during the process and that anaerobic digestion proceeds through preferential degradation of carbohydrates such as cellulose and hemicellulose and, as a consequence, concentration of more chemically recalcitrant aliphatic molecules occurs. -- Highlights: ► We studied anaerobic digestion by means of chemical analysis and 13 CPMAS-NMR spectroscopy. ► Significant chemical differences in digestates were highlighted. ► We proposed the use of the aliphaticity index in order to differentiate digestates. ► Most of the aromatic structures tend to degrade. ► Carbohydrates are degraded and recalcitrant aliphatic molecules concentrate

Metabolic characterization of natural and cultured Ophicordyceps sinensis from different origins by 1H NMR spectroscopy.

Science.gov (United States)

Zhang, Jianshuang; Zhong, Xin; Li, Shaosong; Zhang, Guren; Liu, Xin

2015-11-10

Ophicordyceps sinensis is a well-known traditional Chinese medicine and cultured mycelium is a substitute for wild O. sinensis. Metabolic profiles of wild O. sinensis from three geographical locations and cultivated mycelia derived from three origins were investigated using (1)H nuclear magnetic resonance (NMR) analysis combined with multivariate statistical analysis. A total of 56 primary metabolites were identified and quantified from O. sinensis samples. The principle component analysis (PCA) showed significant differences between natural O. sinensis and fermentation mycelia. Seven metabolites responsible for differentiation were screened out by orthogonal partial least squares discriminant analysis (OPLS-DA). The concentrations of mannitol, trehalose, arginine, trans-4-hydroxyproline, alanine and glucitol were significantly different between wild and cultured groups. The variation in metabolic profiling among artificial mycelia was greater than that among wild O. sinensis. Furthermore, wild samples from different origins were clearly distinguished by the levels of mannitol, trehalose and some amino acids. This study indicates that (1)H NMR-based metabolomics is useful for fingerprinting and discriminating O. sinensis of different geographical regions and cultivated mycelia of different strains. The present study provided an efficient approach for investigating chemical compositions and evaluating the quality of medicine and health food derived from O. sinensis. Copyright © 2015 Elsevier B.V. All rights reserved.

Interactions of poly(amidoamine) dendrimers with human serum albumin: binding constants and mechanisms.

Science.gov (United States)

Giri, Jyotsnendu; Diallo, Mamadou S; Simpson, André J; Liu, Yi; Goddard, William A; Kumar, Rajeev; Woods, Gwen C

2011-05-24

The interactions of nanomaterials with plasma proteins have a significant impact on their in vivo transport and fate in biological fluids. This article discusses the binding of human serum albumin (HSA) to poly(amidoamine) [PAMAM] dendrimers. We use protein-coated silica particles to measure the HSA binding constants (K(b)) of a homologous series of 19 PAMAM dendrimers in aqueous solutions at physiological pH (7.4) as a function of dendrimer generation, terminal group, and core chemistry. To gain insight into the mechanisms of HSA binding to PAMAM dendrimers, we combined (1)H NMR, saturation transfer difference (STD) NMR, and NMR diffusion ordered spectroscopy (DOSY) of dendrimer-HSA complexes with atomistic molecular dynamics (MD) simulations of dendrimer conformation in aqueous solutions. The binding measurements show that the HSA binding constants (K(b)) of PAMAM dendrimers depend on dendrimer size and terminal group chemistry. The NMR (1)H and DOSY experiments indicate that the interactions between HSA and PAMAM dendrimers are relatively weak. The (1)H NMR STD experiments and MD simulations suggest that the inner shell protons of the dendrimers groups interact more strongly with HSA proteins. These interactions, which are consistently observed for different dendrimer generations (G0-NH(2)vs G4-NH(2)) and terminal groups (G4-NH(2)vs G4-OH with amidoethanol groups), suggest that PAMAM dendrimers adopt backfolded configurations as they form weak complexes with HSA proteins in aqueous solutions at physiological pH (7.4).

The effect of target's physical attractiveness and dominance on STD-risk perceptions

NARCIS (Netherlands)

Dijkstra, P; Buunk, BP; Blanton, H

Utilizing a 2 x 2 design, the present study examined the effect of a female's physical attractiveness and dominance on men's sexual motivation and sexually transmitted disease (STD) risk perceptions in a sample of 72 heterosexual male college students. As predicted, participants a ere more motivated

Technical basis for storage of elastomer-sealed produce cans in the DOE-STD-3013-94 package

International Nuclear Information System (INIS)

Horrell, D.R.; Stakebake, J.L.; Szempruch, R.W.

1996-11-01

Department of Energy standard DOE-STD-3013-94 establishes criteria for the long-term packaging of plutonium metal and oxide. The inclusion of organic materials in sealed packages of plutonium may produce gases that contribute to container pressurization. To expedite processing, it would be desirable to permit, within the DOE-outlined criteria, limited amounts of organic materials to be used as a sealing gasket in some packaging containers. This paper presents a technical basis for allowing elastomer-sealed cans to be packaged inside the sealed inner container of a double weld-sealed DOE-STD-3013-94 container system

Direct 13C NMR Detection in HPLC Hyphenation Mode

DEFF Research Database (Denmark)

Wubshet, Sileshi Gizachew; Johansen, Kenneth; Nyberg, Nils

2012-01-01

Solid phase extraction (SPE) was introduced as a crucial step in the HPLC-SPE-NMR technique to enable online analyte enrichment from which proton-detected NMR experiments on submicrogram amounts from complex mixtures were possible. However, the significance of direct-detected (13)C NMR experiments...... application of HPLC-SPE-NMR analysis using direct-detected (13)C NMR spectra. HPLC column loading, accumulative SPE trappings, and the effect of different elution solvents were evaluated and optimized. A column loading of approximately 600 mug of a prefractionated triterpenoid mixture, six trappings...

Optical pumping and xenon NMR

International Nuclear Information System (INIS)

Raftery, M.D.

1991-11-01

Nuclear Magnetic Resonance (NMR) spectroscopy of xenon has become an important tool for investigating a wide variety of materials, especially those with high surface area. The sensitivity of its chemical shift to environment, and its chemical inertness and adsorption properties make xenon a particularly useful NMR probe. This work discusses the application of optical pumping to enhance the sensitivity of xenon NMR experiments, thereby allowing them to be used in the study of systems with lower surface area. A novel method of optically-pumping 129 Xe in low magnetic field below an NMR spectrometer and subsequent transfer of the gas to high magnetic field is described. NMR studies of the highly polarized gas adsorbed onto powdered samples with low to moderate surface areas are now possible. For instance, NMR studies of optically-pumped xenon adsorbed onto polyacrylic acid show that xenon has a large interaction with the surface. By modeling the low temperature data in terms of a sticking probability and the gas phase xenon-xenon interaction, the diffusion coefficient for xenon at the surface of the polymer is determined. The sensitivity enhancement afforded by optical pumping also allows the NMR observation of xenon thin films frozen onto the inner surfaces of different sample cells. The geometry of the thin films results in interesting line shapes that are due to the bulk magnetic susceptibility of xenon. Experiments are also described that combine optical pumping with optical detection for high sensitivity in low magnetic field to observe the quadrupoler evolution of 131 Xe spins at the surface of the pumping cells. In cells with macroscopic asymmetry, a residual quadrupolar interaction causes a splitting in the 131 Xe NMR frequencies in bare Pyrex glass cells and cells with added hydrogen

Rapid prediction of multi-dimensional NMR data sets

International Nuclear Information System (INIS)

Gradmann, Sabine; Ader, Christian; Heinrich, Ines; Nand, Deepak; Dittmann, Marc; Cukkemane, Abhishek; Dijk, Marc van; Bonvin, Alexandre M. J. J.; Engelhard, Martin; Baldus, Marc

2012-01-01

We present a computational environment for Fast Analysis of multidimensional NMR DAta Sets (FANDAS) that allows assembling multidimensional data sets from a variety of input parameters and facilitates comparing and modifying such “in silico” data sets during the various stages of the NMR data analysis. The input parameters can vary from (partial) NMR assignments directly obtained from experiments to values retrieved from in silico prediction programs. The resulting predicted data sets enable a rapid evaluation of sample labeling in light of spectral resolution and structural content, using standard NMR software such as Sparky. In addition, direct comparison to experimental data sets can be used to validate NMR assignments, distinguish different molecular components, refine structural models or other parameters derived from NMR data. The method is demonstrated in the context of solid-state NMR data obtained for the cyclic nucleotide binding domain of a bacterial cyclic nucleotide-gated channel and on membrane-embedded sensory rhodopsin II. FANDAS is freely available as web portal under WeNMR (http://www.wenmr.eu/services/FANDAShttp://www.wenmr.eu/services/FANDAS).

Rapid prediction of multi-dimensional NMR data sets

Energy Technology Data Exchange (ETDEWEB)

Gradmann, Sabine; Ader, Christian [Utrecht University, Faculty of Science, Bijvoet Center for Biomolecular Research (Netherlands); Heinrich, Ines [Max Planck Institute for Molecular Physiology, Department of Physical Biochemistry (Germany); Nand, Deepak [Utrecht University, Faculty of Science, Bijvoet Center for Biomolecular Research (Netherlands); Dittmann, Marc [Max Planck Institute for Molecular Physiology, Department of Physical Biochemistry (Germany); Cukkemane, Abhishek; Dijk, Marc van; Bonvin, Alexandre M. J. J. [Utrecht University, Faculty of Science, Bijvoet Center for Biomolecular Research (Netherlands); Engelhard, Martin [Max Planck Institute for Molecular Physiology, Department of Physical Biochemistry (Germany); Baldus, Marc, E-mail: m.baldus@uu.nl [Utrecht University, Faculty of Science, Bijvoet Center for Biomolecular Research (Netherlands)

2012-12-15

We present a computational environment for Fast Analysis of multidimensional NMR DAta Sets (FANDAS) that allows assembling multidimensional data sets from a variety of input parameters and facilitates comparing and modifying such 'in silico' data sets during the various stages of the NMR data analysis. The input parameters can vary from (partial) NMR assignments directly obtained from experiments to values retrieved from in silico prediction programs. The resulting predicted data sets enable a rapid evaluation of sample labeling in light of spectral resolution and structural content, using standard NMR software such as Sparky. In addition, direct comparison to experimental data sets can be used to validate NMR assignments, distinguish different molecular components, refine structural models or other parameters derived from NMR data. The method is demonstrated in the context of solid-state NMR data obtained for the cyclic nucleotide binding domain of a bacterial cyclic nucleotide-gated channel and on membrane-embedded sensory rhodopsin II. FANDAS is freely available as web portal under WeNMR (http://www.wenmr.eu/services/FANDAShttp://www.wenmr.eu/services/FANDAS).

Design and implementation of STD32-BUS based reactor protection trip unit on FPGA imbaby

International Nuclear Information System (INIS)

Mahmoud, I.; Elnokity, O.A.; Refai, M.K.

2007-01-01

This paper presents a way to design and implement the Trip Unit of a Reactor Protection System (RPS) using a Field Programmable Gate Arrays (FPGA). Instead of the traditional embedded Microprocessor based interface design method, a proposed tailor made FPGA based circuit is built to substitute the Trip Unit (TL1) existing in Egypt's 2' ' Research reactor ETRR-2. The existing embedded system is built around the STD32 field Computer Bus which used in industrial and process control applications. It is modular, rugged, reliable, and easy-to-use and is able to support a large mix of I/O cards and to easily change its configuration in the future. Therefore, the state machine of this bus is extracted from its timing diagrams and implemented in VHDL to interface the designed TU circuit. The proposed designed circuit implemented using ALTERA EPF10K10LC84-3 chip replaces the Single Board Computer which have the embedded SAY program of the TU providing the same integrated HAV and SAV functions implemented in FPGA Chip housed in an printed circuit board, which uses the same shape and specifications of STD32 boards. H/W implementation of both TU and STD32 Bus in VHDL addresses the issues of safety and reusability

Software Test Description (STD) for the Globally Relocatable Navy Tide/Atmospheric Modeling System (PCTides)

National Research Council Canada - National Science Library

Posey, Pamela

2002-01-01

The purpose of this Software Test Description (STD) is to establish formal test cases to be used by personnel tasked with the installation and verification of the Globally Relocatable Navy Tide/Atmospheric Modeling System (PCTides...

The Use of Technology for STD Partner Services in the United States: A Structured Review.

Science.gov (United States)

Kachur, Rachel; Hall, Wendasha; Coor, Alexandra; Kinsey, Jennine; Collins, Dayne; Strona, F V

2018-05-01

Since the late 1990s, health departments and STD programs throughout the U.S. have used technologies, such as the internet and mobile phones, to provide services to persons with a sexually transmitted infection, including HIV, and their sex partners, also known as partner services. This study reviewed the published literature to assess and compare partner services outcomes as a result of using technology and to calculate cost savings through cases averted. We conducted a structured literature review of all U.S. studies that examined the use of technology to notify persons exposed to an STD (syphilis, chlamydia, gonorrhea), including HIV, by health care professionals in the U.S. from 2000 to 2017. Outcome measures, including the number of the number of partners notified, screened or tested; and new positives identified, were captured and cost savings were calculated, when data were available. Seven studies were identified. Methods used for partner services differed across studies, although email was the primary mode in 6 (83%) of the 7 studies. Only 2 of the 7 studies compared use of technology for partner services to traditional partner services. Between 10% and 97% of partners were successfully notified of their exposure through the use of technology and between 34% and 81% were screened or tested. Five studies reported on new infections identified, which ranged from 3-19. Use of technology for partner serves saved programs between $22,795 and $45,362 in direct and indirect medical costs. Use of technology for partner services increased the number of partners notified, screened or tested, and new infections found. Importantly, the use of technology allowed programs to reach partners who otherwise would not have been notified of their exposure to an STD or HIV. Improved response times and time to treatment were also seen as was re-engagement into care for previous HIV positive patients. Data and outcome measures across the studies were not standardized, making it

Application of 1H NMR for the characterisation of cocoa beans of different geographical origins and fermentation levels.

Science.gov (United States)

Caligiani, Augusta; Palla, Luigi; Acquotti, Domenico; Marseglia, Angela; Palla, Gerardo

2014-08-15

This study reports for the first time the use of (1)H NMR technique combined with chemometrics to study the metabolic profile of cocoa (Theobroma cacao L.) beans of different varieties, origin and fermentation levels. Results of PCA applied to cocoa bean (1)H NMR dataset showed that the main factor influencing the cocoa bean metabolic profile is the fermentation level. In fact well fermented brown beans form a group clearly separated from unfermented, slaty, and underfermented, violet, beans, independently of the variety or geographical origin. Considering only well fermented beans, the metabolic profile obtained by (1)H NMR permitted to discriminate between some classes of samples. The National cocoa of Ecuador, known as Arriba, showed the most peculiar characteristics, while the samples coming from the African region showed some similar traits. The dataset obtained, representative of all the classes of soluble compounds of cocoa, was therefore useful to characterise fermented cocoa beans as a function of their origin and fermentation level. Copyright © 2014 Elsevier Ltd. All rights reserved.

New dereplication method applied to NMR-Based metabolomics on different fusarium species isolated from Rhizosphere of Senna spectabilis

International Nuclear Information System (INIS)

Selegato, Denise M.; Castro-Gamboa, Ian; Freire, Rafael T.; Tannús, Alberto

2016-01-01

The search for new sources of natural products steadily increased the use of bioinformatics tools that enabled efficient analysis of complex matrices. In this context, dereplication methods emerged as a fast way of identifying known compounds, accelerating the identification of bioactive chemotypes. Although 1 H NMR is widely used as an analytical technique, few studies have been reported using it as a dereplication tool, primarily because of the spectral complexity. This work aims to create a new computational method that analyses 1 H NMR data from Fusarium solani and F. oxysporum isolated from Senna spectabilis' srhizosphere through principal component analysis (PCA). The algorithm uses loading values to select important peaks that distinguish both species in PCA, allowing compound dereplication, even in highly similar profiles. As a result, the method, associated with other NMR experiments and information from an in-house Fusarium's metabolite library was able to distinguish different mycotoxins produced by both fungi, identifying fusaric acid and beauvericin for F. oxysporum and the depsipeptide HA23 from F. solani. (author)

New dereplication method applied to NMR-Based metabolomics on different fusarium species isolated from Rhizosphere of Senna spectabilis

Energy Technology Data Exchange (ETDEWEB)

Selegato, Denise M.; Castro-Gamboa, Ian, E-mail: ian.castro@gmail.com [Universidade Estadual Paulista Júlio de Mesquita Filho (NuBBE/UNESP), Araraquara, SP (Brazil). Núcleo de Bioensaios, Biossíntese e Ecofisiologia de Produtos Naturais; Freire, Rafael T.; Tannús, Alberto [Universidade de São Paulo (CIERMag/USP), São Carlos, SP (Brazil). Centro de Imagens e Espectroscopia in Vivo por Ressonância Magnética

2016-07-01

The search for new sources of natural products steadily increased the use of bioinformatics tools that enabled efficient analysis of complex matrices. In this context, dereplication methods emerged as a fast way of identifying known compounds, accelerating the identification of bioactive chemotypes. Although {sup 1}H NMR is widely used as an analytical technique, few studies have been reported using it as a dereplication tool, primarily because of the spectral complexity. This work aims to create a new computational method that analyses {sup 1}H NMR data from Fusarium solani and F. oxysporum isolated from Senna spectabilis' srhizosphere through principal component analysis (PCA). The algorithm uses loading values to select important peaks that distinguish both species in PCA, allowing compound dereplication, even in highly similar profiles. As a result, the method, associated with other NMR experiments and information from an in-house Fusarium's metabolite library was able to distinguish different mycotoxins produced by both fungi, identifying fusaric acid and beauvericin for F. oxysporum and the depsipeptide HA23 from F. solani. (author)

NMR Characterization of Flavanone Naringenin 7-O-Glycoside Diastereomer

Directory of Open Access Journals (Sweden)

SUN Li-juan

2017-12-01

Full Text Available To discriminate R and S flavanone glycoside using NMR, the mixture of R and S naringenin 7-O-glycoside was first isolated from Gleditsia sinensis. 1H and 13C NMR data of the mixture were recorded with 1H NMR, 13C NMR, 1H-1H COSY, 1H-13C HSQC and 1H-13C HMBC in DMSO-d6 solution. The two diastereomers were then separated with chiral chromatographic isolation, with their absolute configurations determined by circular dichroism. To avoid the disturbance of protons from glucose residues to dihydroflavonoid, 1H NMR spectra were acquired for pure R and S naringenin 7-O-glycoside and their mixture in CD3CN. The two diastereomers showed the largest proton chemical shift differences at the end group of glucose residue (H-1" with a chemical shift difference of 9.4 Hz. The OH-5 proton showed a chemical shift difference of 5.8 Hz. The chemical shift of the three protons on ring C were all influenced by configuration.

Rational Design of Glycomimetic Compounds Targeting the Saccharomyces cerevisiae Transglycosylase Gas2.

Science.gov (United States)

Delso, Ignacio; Valero-González, Jessika; Marca, Eduardo; Tejero, Tomás; Hurtado-Guerrero, Ramón; Merino, Pedro

2016-02-01

The transglycosylase Saccharomyces cerevisiae Gas2 (ScGas2) belongs to a large family of enzymes that are key players in yeast cell wall remodeling. Despite its biologic importance, no studies on the synthesis of substrate-based compounds as potential inhibitors have been reported. We have synthesized a series of docking-guided glycomimetics that were evaluated by fluorescence spectroscopy and saturation-transfer difference (STD) NMR experiments, revealing that a minimum of three glucose units linked via a β-(1,3) linkage are required for achieving molecular recognition at the binding donor site. The binding mode of our compounds is further supported by STD-NMR experiments using the active site-mutants Y107Q and Y244Q. Our results are important for both understanding of ScGas2-substrate interactions and setting up the basis for future design of glycomimetics as new antifungal agents. © 2015 John Wiley & Sons A/S.

Comparison of Chemical Compositions in Pseudostellariae Radix from Different Cultivated Fields and Germplasms by NMR-Based Metabolomics

Directory of Open Access Journals (Sweden)

Yujiao Hua

2016-11-01

Full Text Available Pseudostellariae Radix (PR is an important traditional Chinese medicine (TCM, which is consumed commonly for its positive health effects. However, the chemical differences of PR from different cultivated fields and germplasms are still unknown. In order to comprehensively compare the chemical compositions of PR from different cultivated fields, in this study, 1H-NMR-based metabolomics coupled with high performance liquid chromatography (HPLC were used to investigate the different metabolites in PR from five germplasms (jr, zs1, zs2, sb, and xc cultivated in traditional fields (Jurong, Jiangsu, JSJR and cultivated fields (Zherong, Fujian, FJZR. A total of 34 metabolites were identified based on 1H-NMR data, and fourteen of them were found to be different in PR from JSJR and FJZR. The relative contents of alanine, lactate, lysine, taurine, sucrose, tyrosine, linolenic acid, γ-aminobutyrate, and hyperoside in PR from JSJR were higher than that in PR from FJZR, while PR from FJZR contained higher levels of glutamine, raffinose, xylose, unsaturated fatty acid, and formic acid. The contents of Heterophyllin A and Heterophyllin B were higher in PR from FJZR. This study will provide the basic information for exploring the influence law of ecological environment and germplasm genetic variation on metabolite biosynthesis of PR and its quality formation mechanism.

Quartz Crystal Temperature Sensor for MAS NMR

Science.gov (United States)

Simon, Gerald

1997-10-01

Quartz crystal temperature sensors (QCTS) were tested for the first time as wireless thermometers in NMR MAS rotors utilizing the NMR RF technique itself for exiting and receiving electro-mechanical quartz resonances. This new tool in MAS NMR has a high sensitivity, linearity, and precision. When compared to the frequently used calibration of the variable temperature in the NMR system by a solid state NMR chemical shift thermometer (CST), such as lead nitrate, QCTS shows a number of advantages. It is an inert thermometer in close contact with solid samples operating parallel to the NMR experiment. QCTS can be manufactured for any frequency to be near a NMR frequency of interest (typically 1 to 2 MHz below or above). Due to the strong response of the crystal, signal detection is possible without changing the tuning of the MAS probe. The NMR signal is not influenced due to the relative sharp crystal resonance, restricted excitation by finite pulses, high probeQvalues, and commonly used audio filters. The quadratic dependence of the temperature increase on spinning speed is the same for the QCTS and for the CST lead nitrate and is discussed in terms of frictional heat in accordance with the literature about lead nitrate and with the results of a simple rotor speed jump experiment with differently radial located lead nitrate in the rotor.

Seismic design and evaluation criteria for DOE facilities (DOE-STD-1020-XX)

International Nuclear Information System (INIS)

Short, S.A.; Kennedy, R.P.; Murray, R.C.

1993-01-01

Seismic design and evaluation criteria for DOE facilities are provided in DOE-STD-1020-XX. The criteria include selection of design/evaluation seismic input from probabilistic seismic hazard curves combined with commonly practiced deterministic response evaluation methods and acceptance criteria with controlled levels of conservatism. Conservatism is intentionally introduced in specification of material strengths and capacities, in the allowance of limited inelastic behavior and by a seismic load factor. These criteria are based on the performance or risk goals specified in DOE 5480.28. Criteria have been developed following a graded approach for several performance goals ranging from that appropriate for normal-use facilities to that appropriate for facilities involving hazardous or critical operations. Performance goals are comprised of desired behavior and of the probability of not achieving that behavior. Following the seismic design/evaluation criteria of DOE-STD-1020-XX is sufficient to demonstrate that the probabilistic performance or risk goals are achieved. The criteria are simple procedures but with a sound, rigorous basis for the achievement of goals

Solid state NMR of spin-1/2 nuclei

International Nuclear Information System (INIS)

Wind, R.A.

1991-01-01

The detection of nuclear magnetic resonance by Bloch et al. and Purcell and co-workers in 1946 has led to the development of one of the most powerful spectroscopic techniques known today. The reason is that, besides the applied external magnetic field, a nuclear spin also experiences extra local magnetic fields, which are due to surrounding electron clouds (the chemical shift) and other spins. These local fields differ for nuclei located at chemically different positions in a molecule. The result is that an NMR spectrum often consists of several lines, which can be considered to be a fingerprint of the material under investigation an can assist the clarifying its molecular structure. NMR has been especially successful in liquids and liquid like materials, where fast molecular tumblings average out the anisotropies in the local fields, resulting in well-resolved NMR spectra. This paper reports that initially the development of solid-state NMR was less dramatic. Originally, for reasons of sensitivity, attention was focused mainly on 1 H NMR. The result is that the NMR spectrum usually consists of single, broad, featureless line, which, except for special cases such as more or less isolated spin pairs or methyl groups, does not provide much information

Metabolite profiling of Clinacanthus nutans leaves extracts obtained from different drying methods by 1H NMR-based metabolomics

Science.gov (United States)

Hashim, Noor Haslinda Noor; Latip, Jalifah; Khatib, Alfi

2016-11-01

The metabolites of Clinacanthus nutans leaves extracts and their dependence on drying process were systematically characterized using 1H nuclear magnetic resonance spectroscopy (NMR) multivariate data analysis. Principal component analysis (PCA) and partial least square-discriminant analysis (PLS-DA) were able to distinguish the leaves extracts obtained from different drying methods. The identified metabolites were carbohydrates, amino acid, flavonoids and sulfur glucoside compounds. The major metabolites responsible for the separation in PLS-DA loading plots were lupeol, cycloclinacosides, betulin, cerebrosides and choline. The results showed that the combination of 1H NMR spectroscopy and multivariate data analyses could act as an efficient technique to understand the C. nutans composition and its variation.

MIL-STD-1553B Marconi LSI chip set in a remote terminal application

Science.gov (United States)

Dimarino, A.

1982-11-01

Marconi Avionics is utilizing the MIL-STD-1553B LSI Chip Set in the SCADC Air Data Computer application to perform all of the required remote terminal MIL-STD-1553B protocol functions. Basic components of the RTU are the dual redundant chip set, CT3231 Transceivers, 256 x 16 RAM and a Z8002 microprocessor. Basic transfers are to/from the RAM command of the bus controller or Z8002 processor. During transfers from the processor to the RAM, the chip set busy bit is set for a period not exceeding 250 microseconds. When the transfer is complete, the busy bit is released and transfers to the data bus occur on command. The LSI Chip Set word count lines are used to locate each data word in the local memory and 4 mode codes are used in the application: reset remote terminal, transmit status word, transmitter shut-down, and override transmitter shutdown.

PSYCHE Pure Shift NMR Spectroscopy.

Science.gov (United States)

Foroozandeh, Mohammadali; Morris, Gareth; Nilsson, Mathias

2018-03-13

Broadband homodecoupling techniques in NMR, also known as "pure shift" methods, aim to enhance spectral resolution by suppressing the effects of homonuclear coupling interactions to turn multiplet signals into singlets. Such techniques typically work by selecting a subset of "active" nuclear spins to observe, and selectively inverting the remaining, "passive", spins to reverse the effects of coupling. Pure Shift Yielded by Chirp Excitation (PSYCHE) is one such method; it is relatively recent, but has already been successfully implemented in a range of different NMR experiments. Paradoxically, PSYCHE is one of the trickiest of pure shift NMR techniques to understand but one of the easiest to use. Here we offer some insights into theoretical and practical aspects of the method, and into the effects and importance of the experimental parameters. Some recent improvements that enhance the spectral purity of PSYCHE spectra will be presented, and some experimental frameworks including examples in 1D and 2D NMR spectroscopy, for the implementation of PSYCHE will be introduced. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

NMR-CT scanner

International Nuclear Information System (INIS)

Kose, Katsumi; Sato, Kozo; Sugimoto, Hiroshi; Sato, Masataka.

1983-01-01

A brief explanation is made on the imaging methods for a practical diagnostic NMR-CT scanner : A whole-body NMR-CT scanner utilizing a resistive magnet has been developed by Toshiba in cooperation with the Institute for Solid State Physics, the University of Tokyo. Typical NMR-CT images of volunteers and patients obtained in the clinical experiments using this device are presented. Detailed specifications are also shown about the practical NMR-CTs which are to be put on the market after obtaining the government approval. (author)

Unified integration intervals for the structural characterization of oil, coal or fractions there of by 1h NMR and 13c NMR

International Nuclear Information System (INIS)

Avella, Eliseo; Fierro, Ricardo

2010-01-01

Based on an analysis of publications reported between 1972 and 2006, it became clear that there are inaccuracies in the limits of the ranges of integration that the authors assigned to signals in nuclear magnetic resonance (NMR) to the structural characterization of petroleum, coals and their derived fractions, from their hydrogen (1H NMR) and carbon (13C NMR) spectra. Consequently, consolidated limits were determined for the integration of 1H NMR spectra and 13C NMR of these samples using a statistical treatment applied to the limits of integration intervals already published. With these unified limits, correlation NMR charts were developed that are useful for the allocation of the integral at such intervals, and at smaller intervals defined in terms of the intersection between different assignments. Also raised equations needed to establish the integral attributable to specific fragments in an attempt to make a more accurate structural characterization from NMR spectra of oil, coal or fractions derived.

Study on the Effects of Oligo chitosan and Bioliquifert on Two Rice Mutants, NMR 151 and NMR 152

International Nuclear Information System (INIS)

Shakinah Salleh; Faiz Ahmad; Sobri Hussein

2016-01-01

Nuclear Malaysia has successfully developed two new rice mutants namely NMR 151 and NMR 152. In addition, Nuclear Malaysia has also successfully developed Oligo chitosan and liquid bio fertilizer (Bioliquifert). Oligo chitosan acts as elicitor that has been proven to be very effective in controlling disease infections and improving yield productivity. Bioliquifert on the other hand is a mixture of microbes containing major nutrient-providing microorganisms. The objective of this study is to observe the effects of Oligo chitosan and Bioliquifert on rice mutants, NMR 151 and NMR 152. The treatment was applied on 14 day old seedlings of MR 219, NMR 151 and NMR 152 sowed in 20 cm pots containing silty clay from the paddy soil of Tanjung Karang, Selangor. The seedlings were then placed in the greenhouse at Nuclear Malaysia until it reaches 110 days old. Study was conducted in a Complete Randomized Design (CRD) with 3 replications was used and each replication consisted of three plants. All treatments received compound and single dressing fertilizer as recommended by National Rice Production Package except for Treatment 2 and 3, in which Treatment 2 received Oligo chitosan and Bioliquifert while Treatment 3 only received Bioliquifert. Results on plant height, number of tiller and plant fresh weight are not significantly different for all cultivar except for seed dry weight of NMR 152 and MR 219. (author)

NMR of lignins

Science.gov (United States)

John Ralph; Larry L. Landucci

2010-01-01

This chapter will consider the basic aspects and findings of several forms of NMR spectroscopy, including separate discussions of proton, carbon, heteronuclear, and multidimensional NMR. Enhanced focus will be on 13C NMR, because of its qualitative and quantitative importance, followed by NMR’s contributions to our understanding of lignin...

IEEE Std 535-1986: IEEE standard for qualification of Class 1E lead storage batteries for nuclear power generating stations

International Nuclear Information System (INIS)

Anon.

1992-01-01

This document describes qualification methods for Class 1E lead storage batteries and racks to be used in nuclear power generating stations outside of primary containment. Qualification required in ANSI/IEEE Std 308-1980 can be demonstrated by using the procedures provided in this standard in accordance with ANSI/IEEE Std 323-1983. Battery sizing, maintenance, capacity testing, installation, charging equipment, and consideration of other type batteries are beyond the scope of this standard

Using community-based participatory research to develop an intervention to reduce HIV and STD infections among Latino men.

Science.gov (United States)

Rhodes, Scott D; Hergenrather, Kenneth C; Montaño, Jaime; Remnitz, Ivan M; Arceo, Ramiro; Bloom, Fred R; Leichliter, Jami S; Bowden, W Patrick

2006-10-01

Although the Latino community living in the United States has been disproportionately affected by the intersecting epidemics of HIV and sexually transmitted diseases (STDs), the development, implementation, and evaluation of HIV and STD prevention interventions designed to reduce infection among Latinos lags behind prevention efforts targeting other communities. HoMBReS: Hombres Manteniendo Bienestar y Relaciones Saludables is a sexual risk reduction intervention designed to reduce HIV and STD infection among recently arrived, non-English-speaking Latino men who are members of a multicounty Latino soccer league in central North Carolina, a region of the United States with both the fastest growing Latino population and disproportionate HIV and STD infection rates. HoMBReS was developed in partnership with the local Latino community using community-based participatory research (CBPR). We describe (a) the CBPR partnership history and further expansion; (b) the development of the intervention through the integration of collected formative data, theoretical considerations, and findings from the scientific literature; and (c) lessons learned while using a CBPR approach to develop HoMBReS.

Medical applications of NMR imaging and NMR spectroscopy with stable isotopes. Summary

International Nuclear Information System (INIS)

Matwiyoff, N.A.

1983-01-01

The current status of NMR imaging and NMR spectroscopy are summarized. For the most part examples from the March 1983 Puerto Rico symposium are used to illustrate the utility of NMR in medicine. 18 refs., 5 figs

Medical applications of NMR imaging and NMR spectroscopy with stable isotopes. Summary

Energy Technology Data Exchange (ETDEWEB)

Matwiyoff, N.A.

1983-01-01

The current status of NMR imaging and NMR spectroscopy are summarized. For the most part examples from the March 1983 Puerto Rico symposium are used to illustrate the utility of NMR in medicine. 18 refs., 5 figs.

NMR structure of temporin-1 ta in lipopolysaccharide micelles: mechanistic insight into inactivation by outer membrane.

Directory of Open Access Journals (Sweden)

Rathi Saravanan

Full Text Available BACKGROUND: Antimicrobial peptides (AMPs play important roles in the innate defense mechanism. The broad spectrum of activity of AMPs requires an efficient permeabilization of the bacterial outer and inner membranes. The outer leaflet of the outer membrane of Gram negative bacteria is made of a specialized lipid called lipopolysaccharide (LPS. The LPS layer is an efficient permeability barrier against anti-bacterial agents including AMPs. As a mode of protection, LPS can induce self associations of AMPs rendering them inactive. Temporins are a group of short-sized AMPs isolated from frog skin, and many of them are inactive against Gram negative bacteria as a result of their self-association in the LPS-outer membrane. PRINCIPAL FINDINGS: Using NMR spectroscopy, we have determined atomic resolution structure and characterized localization of temporin-1Ta or TA (FLPLIGRVLSGIL-amide in LPS micelles. In LPS micelles, TA adopts helical conformation for residues L4-I12, while residues F1-L3 are found to be in extended conformations. The aromatic sidechain of residue F1 is involved in extensive packing interactions with the sidechains of residues P3, L4 and I5. Interestingly, a number of long-range NOE contacts have been detected between the N-terminal residues F1, P3 with the C-terminal residues S10, I12, L13 of TA in LPS micelles. Saturation transfer difference (STD NMR studies demonstrate close proximity of residues including F1, L2, P3, R7, S10 and L13 with the LPS micelles. Notably, the LPS bound structure of TA shows differences with the structures of TA determined in DPC and SDS detergent micelles. SIGNIFICANCE: We propose that TA, in LPS lipids, forms helical oligomeric structures employing N- and C-termini residues. Such oligomeric structures may not be translocated across the outer membrane; resulting in the inactivation of the AMP. Importantly, the results of our studies will be useful for the development of antimicrobial agents with a

Identification of B. anthracis N(5)-carboxyaminoimidazole ribonucleotide mutase (PurE) active site binding compounds via fragment library screening.

Science.gov (United States)

Lei, Hao; Jones, Christopher; Zhu, Tian; Patel, Kavankumar; Wolf, Nina M; Fung, Leslie W-M; Lee, Hyun; Johnson, Michael E

2016-02-15

The de novo purine biosynthesis pathway is an attractive target for antibacterial drug design, and PurE from this pathway has been identified to be crucial for Bacillus anthracis survival in serum. In this study we adopted a fragment-based hit discovery approach, using three screening methods-saturation transfer difference nucleus magnetic resonance (STD-NMR), water-ligand observed via gradient spectroscopy (WaterLOGSY) NMR, and surface plasmon resonance (SPR), against B. anthracis PurE (BaPurE) to identify active site binding fragments by initially testing 352 compounds in a Zenobia fragment library. Competition STD NMR with the BaPurE product effectively eliminated non-active site binding hits from the primary hits, selecting active site binders only. Binding affinities (dissociation constant, KD) of these compounds varied between 234 and 301μM. Based on test results from the Zenobia compounds, we subsequently developed and applied a streamlined fragment screening strategy to screen a much larger library consisting of 3000 computationally pre-selected fragments. Thirteen final fragment hits were confirmed to exhibit binding affinities varying from 14μM to 700μM, which were categorized into five different basic scaffolds. All thirteen fragment hits have ligand efficiencies higher than 0.30. We demonstrated that at least two fragments from two different scaffolds exhibit inhibitory activity against the BaPurE enzyme. Published by Elsevier Ltd.

Nuclear magnetic resonance (NMR) imaging in the diagnosis of liver disease. Differential diagnosis of hepatic tumors and correlation between NMR imaging and histological findings

Energy Technology Data Exchange (ETDEWEB)

Ebara, Masaaki; Oto, Masao; Sugiura, Nobuyuki; Kimura, Kunio; Okuda, Kunio; Hirooka, Noboru; Ikehira, Hiroo; Fukuda, Nobuo; Tateno, Yukio

1984-06-01

Characteristics of nuclear magnetic resonance (NMR) images for various liver diseases were examined using a 0.1 T resistive NMR imaging unit on 26 patients with liver disease and 10 normal volunteers. Hepatic tumors, including small hepatocellular carcinoma 1.5 cm in diameter, were detected on NMR imaging. Ring sign characteristic of nodular type hepatocellular carcinoma was shown on NMR-CT in 60 % of patients. T/sub 1/ values allowed differential diagnosis of hepatic tumors. There was close correlation between NMR images and histopathological findings. The T/sub 1/ in the liver and spleen was more prolonged in patients with liver cirrhosis than in normal volunteers, with significant differences. (Namekawa, K.).

75 FR 39264 - CDC/HRSA Advisory Committee on HIV and STD Prevention and Treatment

Science.gov (United States)

2010-07-08

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention Health Resources and Services Administration CDC/HRSA Advisory Committee on HIV and STD Prevention and Treatment In... disparities through programs, policy, and research and public health ethics; (2) To provide information to...

Spectroscopic approaches to resolving ambiguities of hyper-polarized NMR signals from different reaction cascades

DEFF Research Database (Denmark)

Jensen, Pernille Rose; Meier, Sebastian

2016-01-01

The influx of exogenous substrates into cellular reaction cascades on the seconds time scale is directly observable by NMR spectroscopy when using nuclear spin polarization enhancement. Conventional NMR assignment spectra for the identification of reaction intermediates are not applicable...... in these experiments due to the non-equilibrium nature of the nuclear spin polarization enhancement. We show that ambiguities in the intracellular identification of transient reaction intermediates can be resolved by experimental schemes using site-specific isotope labelling, optimised referencing and response...

SEDS MIL-STD-1773 fiber optic data bus: Proton irradiation test results and spaceflight SEU data

Energy Technology Data Exchange (ETDEWEB)

LaBel, K.A.; Stassinopoulos, E.G.; Miller, J.T. (NASA/GSFC, Greenbelt, MD (United States)); Marshall, P. (NRL/SFA, Washington, DC (United States)); Dale, C. (NRL, Washington, DC (United States)); Crabtree, C.M. (Hughes/ST Systems Corp., Seabrook, MD (United States)); Gates, M.M. (Jackson and Tull, Seabrook, MD (United States))

1993-12-01

The Small Explorer Data System (SEDS) was launched in July of 1992 as part of the Solar Anomalous Magnetospheric Particle Explorer (SAMPEX) mission. The SEDS utilizes NASA's first MIL-STD-1773 Fiber Optic Multiplexed Data Bus (or 1773 bus) to communicate with other spacecraft subsystems in the space environment. The 1773 bus is the fiber optic version of the MIL-STD-1553 Data Bus, a electronic wire bus used in many avionics applications. The authors present proton test and space flight single event effect data for NASA's first fiber optic data bus. Bit error rate predictions based on a new proton direct ionization model agree well with flight data for proton belt and solar flare effects.

NMR-Based Metabolomic Study on Isatis tinctoria: Comparison of Different Accessions, Harvesting Dates, and the Effect of Repeated Harvesting.

Science.gov (United States)

Guldbrandsen, Niels; Kostidis, Sarantos; Schäfer, Hartmut; De Mieri, Maria; Spraul, Manfred; Skaltsounis, Alexios-Leandros; Mikros, Emmanuel; Hamburger, Matthias

2015-05-22

Isatis tinctoria is an ancient dye and medicinal plant with potent anti-inflammatory and antiallergic properties. Metabolic differences were investigated by NMR spectroscopy of accessions from different origins that were grown under identical conditions on experimental plots. For these accessions, metabolite profiles at different harvesting dates were analyzed, and single and repeatedly harvested plants were compared. Leaf samples were shock-frozen in liquid N2 immediately after being harvested, freeze-dried, and cryomilled prior to extraction. Extracts were prepared by pressurized liquid extraction with ethyl acetate and 70% aqueous methanol. NMR spectra were analyzed using a combination of different methods of multivariate data analysis such as principal component analysis (PCA), canonical analysis (CA), and k-nearest neighbor concept (k-NN). Accessions and harvesting dates were well separated in the PCA/CA/k-NN analysis in both extracts. Pairwise statistical total correlation spectroscopy (STOCSY) revealed unsaturated fatty acids, porphyrins, carbohydrates, indole derivatives, isoprenoids, phenylpropanoids, and minor aromatic compounds as the cause of these differences. In addition, the metabolite profile was affected by the repeated harvest regime, causing a decrease of 1,5-anhydroglucitol, sucrose, unsaturated fatty acids, porphyrins, isoprenoids, and a flavonoid.

NMR imaging and pharmaceutical sciences

International Nuclear Information System (INIS)

Beall, P.T.; Good, W.R.

1986-01-01

Described is the technique of NMR-imaging in diagnostic medicine. Proton and phosphorus NMR in diagnosis of abnormal tissue pathology. Discussed is the value of NMR to the pharmaceutical sciences. NMR may play an important role in monitoring the response of tissues to drugs, determining the localization of drugs, performing real time pharmacokinetics and testing the use of NMR contrast pharmaceuticals

The proposal of permanent education in the formation of dentists in std/hiv/aids

Directory of Open Access Journals (Sweden)

Maria de Fátima Nunes

2008-01-01

Full Text Available The objective of this work is to report the experience of the "Project for the formation of dentists as facilitators of Permanent Education in Health in the area of STD/HIV/AIDS" developed in partnerships with the National Program of STD/AIDS, the Technical Area of Oral Health of the Ministry of Health, Public Universities and Municipal and State Secretaries of Health. The objective of the program was to capacitate dentists of the public health system in Brazilian states and cities to provide integral and humanized attendance for people living with HIV/AIDS. The methodology of choice for the form of teams of facilitators was Permanent Education in Health through semi-presential courses focusing on the problematization of local and professional realities. Thus, seeking to construct a process of education to modify and reorient the hegemonic dental practice, strengthening the process of attendance and management and the partnerships, guaranteeing the sustainability of the actions in the states and cities.

Intermodal Storage and Transport Frame (ISTF) MIL-STD-1660 Design Criteria for Ammunition Unit Loads Tests

National Research Council Canada - National Science Library

Barickman, Philip

2004-01-01

.... The ISTF was evaluated by the testing procedures set forth in MIL-STD-1660. Stacking, vibration, edgewise rotational drop, incline impact, sling compatibility, forklifting, and disassembly testing were conducted on the ISTF units...

NMR imaging of the brain: initial impressions

International Nuclear Information System (INIS)

Spencer, D.H.; Bydder, G.M.

1983-01-01

An NMR imaging system designed and built by Thorn-EMI Ltd was installed at Hammersmith Hospital in March 1981. In the first year of operation 180 patients and 40 volunteers have had cranial examinations and initial impressions bases on this experience are presented. Patients with a wide variety of neurological diseases have been studied to provide a basis for diagnostic interpretation, to define distinctive features, and to evaluate different types of scanning sequences. NMR imaging appears to be of considerable value in neurological diagnosis and has a number of advantages over CT. The detailed evaluation of NMR imaging will require much more work but the initial results are very promising

Graphical programming for pulse automated NMR experiments

International Nuclear Information System (INIS)

Belmonte, S.B.; Oliveira, I.S.; Guimaraes, A.P.

1999-01-01

We describe a software program designed to control a broadband pulse Nuclear Magnetic Resonance (NMR) spectrometer used in zero-field NMR studies of magnetic metals. The software is written in the graphical language LabVIEW. This type of programming allows modifications and the inclusion of new routines to be easily made by the non-specialist, without changing the basic structure of the program. The program corrects for differences in the gain of the two acquisition channels [U (phase) and V (quadrature)], and automatic baseline subtraction. We present examples of measurements of NMR spectra, spin-echo decay (T 2 ), and quadrupolar oscillations, performed in magnetic intermetallic compounds. (author)

Theory of NMR probe design

International Nuclear Information System (INIS)

Schnall, M.D.

1988-01-01

The NMR probe is the intrinsic part of the NMR system which allows transmission of a stimulus to a sample and the reception of a resulting signal from a sample. NMR probes are used in both imaging and spectroscopy. Optimal probe design is important to the production of adequate signal/moise. It is important for anyone using NMR techniques to understand how NMR probes work and how to optimize probe design

Obtaining aluminas from the thermal decomposition of their different precursors: An {sup 27}Al MAS NMR and X-ray powder diffraction studies

Energy Technology Data Exchange (ETDEWEB)

Chagas, L.H.; De Carvalho, G.S.G. [Universidade Federal de Juiz de Fora, Departamento de Química, Grupo de Físico-Química de Sólidos e Interfaces, 36036-330 Juiz de Fora, MG (Brazil); San Gil, R.A.S. [Universidade Federal do Rio de Janeiro, Instituto de Química, 21949-900 Rio de Janeiro, RJ (Brazil); Chiaro, S.S.X. [PETROBRAS-CENPES, 21941-915 Rio de Janeiro, RJ (Brazil); Leitão, A.A. [Universidade Federal de Juiz de Fora, Departamento de Química, Grupo de Físico-Química de Sólidos e Interfaces, 36036-330 Juiz de Fora, MG (Brazil); Diniz, R., E-mail: renata.diniz@ufjf.edu.br [Universidade Federal de Juiz de Fora, Departamento de Química, Grupo de Físico-Química de Sólidos e Interfaces, 36036-330 Juiz de Fora, MG (Brazil)

2014-01-01

Graphical abstract: - Highlights: • We synthesized three precursors of alumina from different methods. • The calcination of the precursors generated several alumina polymorphs. • XRD and NMR were used for structural investigation of the polymorphs. • The synthesis route determines the structural and textural properties of the solids. - Abstract: A commercial sample of Boehmite was used as precursor of alumina polymorphs. For comparison, three other precursors were synthesized from different methods. Particularly, the use of excess of urea promoted a very crystalline form of basic aluminum carbonate. The characteristics of the four precursors were investigated by thermal, vibrational and X-ray powder diffraction (XRD) analysis. Additionally, the nuclear magnetic resonance, with magic angle spinning ({sup 27}Al MAS NMR), was used to verify the coordination of aluminum cations. Each precursor was calcined at various temperatures generating alumina polymorphs, which were structurally analyzed by XRD and {sup 27}Al MAS NMR. Due to interest in catalysis supports, special attention was given to the γ-Al{sub 2}O{sub 3} phase, which in addition to structural investigation was subjected to textural analysis. The results showed that, from different synthesis procedures and common route of calcination, one can obtain materials with the same composition but with different structural and textural properties, which in turn can significantly influence the performance of a supported catalyst.

Influence of Professional Preparation and Class Structure on HIV, STD, and Pregnancy Prevention Education

Science.gov (United States)

Rhodes, Darson L.; Jozkowski, Kristen N.; Hammig, Bart J.; Ogletree, Roberta J.; Fogarty, Erin C.

2014-01-01

Objective: The purpose of this study was to determine if education about human immunodeficiency virus (HIV)/sexually transmitted disease (STD) and pregnancy prevention is dependent on professional preparation and/or class structure. Design: A secondary data analysis of the 2006 School Health Policies and Programmes Study (SHPPS) was conducted.…

76 FR 66721 - CDC/HRSA Advisory Committee on HIV and STD Prevention and Treatment

Science.gov (United States)

2011-10-27

... Advisory Committee on HIV and STD Prevention and Treatment In accordance with section l0(a)(2) of the... the Administrator, HRSA, regarding activities related to prevention and control of HIV/AIDS and other STDs, the support of health care services to persons living with HIV/AIDS, and education of health...

Investigation of zeolites by solid state quadrapole NMR

International Nuclear Information System (INIS)

Janssen, R.

1990-01-01

The subject of this thesis is the NMR investigation of zeolites. The nature and properties of zeolites are discussed. Some of the basic priniples of NMR techniques on quadrupole nuclei are presented. A special technique, namely a two-dimensional nutation experiment is discussed in detail. The theory of the nutation experiment for quadrupole spin species with spin quantum number 3/2 as well as 5/2 is presented. For both spin spcies the theoretical spectra are compared with experimental results. It is also shown that the nutation expeirment can be performed with several pulse schemes. It is shown how phase-sensitive pure-absorption nutation spectra can be obtained and an NMR-probe is presented that is capable of performing NMR experiments at high (up to 500 degree C) temperatures. The two-dimensional nutation NMR technique has been applied to sodium cations in zeolite NaA. For this purpose a numbre of zeolite samples were prepared that contained different amounts of water. With the aid of nutation NMR the hydration of the zeolite can be studied and conclusions can be drawn about the symmetry of the surrounding of the sodium cations. With the aid of an extension of the nutation NMR experiment: Rotary Echo Nutation NMR, it is shown that in zeolite NaA, in various stages of hydration, the sodium cations or water molecules are mobile. Proof is given by means of high-temperature 23 Na-NMR that dehydrates zeolite NaA undergoes a phase transition at ca. 120 degree C. In a high-temperature NMR investigation of zeolite ZSM-5 it is shown that the sodium ions start to execute motions when the temperature is increased. (author). 198 refs.; 72 figs.; 6 tabs

Knowns and unknowns in metabolomics identified by multidimensional NMR and hybrid MS/NMR methods

Energy Technology Data Exchange (ETDEWEB)

Bingol, Kerem; Brüschweiler, Rafael

2017-02-01

Metabolomics continues to make rapid progress through the development of new and better methods and their applications to gain insight into the metabolism of a wide range of different biological systems from a systems biology perspective. Customization of NMR databases and search tools allows the faster and more accurate identification of known metabolites, whereas the identification of unknowns, without a need for extensive purification, requires new strategies to integrate NMR with mass spectrometry, cheminformatics, and computational methods. For some applications, the use of covalent and non-covalent attachments in the form of labeled tags or nanoparticles can significantly reduce the complexity of these tasks.

nmrML: A Community Supported Open Data Standard for the Description, Storage, and Exchange of NMR Data.

Science.gov (United States)

Schober, Daniel; Jacob, Daniel; Wilson, Michael; Cruz, Joseph A; Marcu, Ana; Grant, Jason R; Moing, Annick; Deborde, Catherine; de Figueiredo, Luis F; Haug, Kenneth; Rocca-Serra, Philippe; Easton, John; Ebbels, Timothy M D; Hao, Jie; Ludwig, Christian; Günther, Ulrich L; Rosato, Antonio; Klein, Matthias S; Lewis, Ian A; Luchinat, Claudio; Jones, Andrew R; Grauslys, Arturas; Larralde, Martin; Yokochi, Masashi; Kobayashi, Naohiro; Porzel, Andrea; Griffin, Julian L; Viant, Mark R; Wishart, David S; Steinbeck, Christoph; Salek, Reza M; Neumann, Steffen

2018-01-02

NMR is a widely used analytical technique with a growing number of repositories available. As a result, demands for a vendor-agnostic, open data format for long-term archiving of NMR data have emerged with the aim to ease and encourage sharing, comparison, and reuse of NMR data. Here we present nmrML, an open XML-based exchange and storage format for NMR spectral data. The nmrML format is intended to be fully compatible with existing NMR data for chemical, biochemical, and metabolomics experiments. nmrML can capture raw NMR data, spectral data acquisition parameters, and where available spectral metadata, such as chemical structures associated with spectral assignments. The nmrML format is compatible with pure-compound NMR data for reference spectral libraries as well as NMR data from complex biomixtures, i.e., metabolomics experiments. To facilitate format conversions, we provide nmrML converters for Bruker, JEOL and Agilent/Varian vendor formats. In addition, easy-to-use Web-based spectral viewing, processing, and spectral assignment tools that read and write nmrML have been developed. Software libraries and Web services for data validation are available for tool developers and end-users. The nmrML format has already been adopted for capturing and disseminating NMR data for small molecules by several open source data processing tools and metabolomics reference spectral libraries, e.g., serving as storage format for the MetaboLights data repository. The nmrML open access data standard has been endorsed by the Metabolomics Standards Initiative (MSI), and we here encourage user participation and feedback to increase usability and make it a successful standard.

Performance of the WeNMR CS-Rosetta3 web server in CASD-NMR.

Science.gov (United States)

van der Schot, Gijs; Bonvin, Alexandre M J J

2015-08-01

We present here the performance of the WeNMR CS-Rosetta3 web server in CASD-NMR, the critical assessment of automated structure determination by NMR. The CS-Rosetta server uses only chemical shifts for structure prediction, in combination, when available, with a post-scoring procedure based on unassigned NOE lists (Huang et al. in J Am Chem Soc 127:1665-1674, 2005b, doi: 10.1021/ja047109h). We compare the original submissions using a previous version of the server based on Rosetta version 2.6 with recalculated targets using the new R3FP fragment picker for fragment selection and implementing a new annotation of prediction reliability (van der Schot et al. in J Biomol NMR 57:27-35, 2013, doi: 10.1007/s10858-013-9762-6), both implemented in the CS-Rosetta3 WeNMR server. In this second round of CASD-NMR, the WeNMR CS-Rosetta server has demonstrated a much better performance than in the first round since only converged targets were submitted. Further, recalculation of all CASD-NMR targets using the new version of the server demonstrates that our new annotation of prediction quality is giving reliable results. Predictions annotated as weak are often found to provide useful models, but only for a fraction of the sequence, and should therefore only be used with caution.

11B NMR study of calcium-hexaborides

International Nuclear Information System (INIS)

Mean, B.J.; Lee, K.H.; Kang, K.H.; Lee, Moohee; Rhee, J.S.; Cho, B.K.

2005-01-01

We have performed 11 B nuclear magnetic resonance (NMR) measurements to look for microscopic evidence of the ferromagnetic state in several CaB 6 single crystals. A number of 11 B NMR resonance peaks are observed with the frequency and intensity of those peaks distinctively changing depending on the angle between the crystalline axis and a magnetic field. Analyzing this behavior, we find that the electric field gradient tensor at the boron has its principal axis perpendicular to the six cubic faces with a quadrupole resonance frequency ν Q ∼600kHz. However, the satellite resonances are found to be made of two peaks. Detailed analysis of the four composite satellite peaks confirms that there are two different boron sites with slightly different ν Q 's. This suggests that the boron octahedron cages are locally distorted. However, this distortion is not directly related to ferromagnetism. Even though the magnetization data highlight the ferromagnetic hysteresis, 11 B NMR linewidth and shift data show no clear microscopic evidence of the ferromagnetic state in several different compositions of CaB 6 single crystals

LC-NMR coupling technology: recent advancements and applications in natural products analysis

NARCIS (Netherlands)

Exarchou, V.; Krucker, M.; Beek, van T.A.; Vervoort, J.J.M.; Gerothanassis, I.P.; Albert, K.

2005-01-01

An overview of recent advances in nuclear magnetic resonance (NMR) coupled with separation technologies and their application in natural product analysis is given and discussed. The different modes of LC-NMR operation are described, as well as how technical improvements assist in establishing LC-NMR

Determination of solid fat content by NMR

International Nuclear Information System (INIS)

Kawada, Tsukasa; Kato, Chihiro; Suzuki, Kazuaki

1984-01-01

To establish a standard method for determing solid fat content, the NMR method was tested at six laboratories and the results were examined for collaboration. Two types of instruments, pulse NMR and wide-line NMR were used. Standard deviation in results at six laboratories was less than 1.5 for the step wise method, but more than 1.5 for the rapid method. The standard deviation in results at a single laboratory was much less than either of these cases. No significant difference could be observed in the values obtained using both instruments. Solid fat content values measured for a mixture of fully hydrogenated rapeseed and rapeseed oil agreed well with the percentage of solid by weight. (author)

Identification of different oxygen species in oxide nanostructures with 17O solid-state NMR spectroscopy

Science.gov (United States)

Wang, Meng; Wu, Xin-Ping; Zheng, Sujuan; Zhao, Li; Li, Lei; Shen, Li; Gao, Yuxian; Xue, Nianhua; Guo, Xuefeng; Huang, Weixin; Gan, Zhehong; Blanc, Frédéric; Yu, Zhiwu; Ke, Xiaokang; Ding, Weiping; Gong, Xue-Qing; Grey, Clare P.; Peng, Luming

2015-01-01

Nanostructured oxides find multiple uses in a diverse range of applications including catalysis, energy storage, and environmental management, their higher surface areas, and, in some cases, electronic properties resulting in different physical properties from their bulk counterparts. Developing structure-property relations for these materials requires a determination of surface and subsurface structure. Although microscopy plays a critical role owing to the fact that the volumes sampled by such techniques may not be representative of the whole sample, complementary characterization methods are urgently required. We develop a simple nuclear magnetic resonance (NMR) strategy to detect the first few layers of a nanomaterial, demonstrating the approach with technologically relevant ceria nanoparticles. We show that the 17O resonances arising from the first to third surface layer oxygen ions, hydroxyl sites, and oxygen species near vacancies can be distinguished from the oxygen ions in the bulk, with higher-frequency 17O chemical shifts being observed for the lower coordinated surface sites. H217O can be used to selectively enrich surface sites, allowing only these particular active sites to be monitored in a chemical process. 17O NMR spectra of thermally treated nanosized ceria clearly show how different oxygen species interconvert at elevated temperature. Density functional theory calculations confirm the assignments and reveal a strong dependence of chemical shift on the nature of the surface. These results open up new strategies for characterizing nanostructured oxides and their applications. PMID:26601133

NMR spectroscopy

International Nuclear Information System (INIS)

Gruenert, J.

1989-01-01

The book reviews the applications of NMR-spectroscopy in medicine and biology. The first chapter of about 40 pages summarizes the history of development and explains the chemical and physical fundamentals of this new and non-invasive method in an easily comprehensible manner. The other chapters summarize diagnostic results obtained with this method in organs and tissues, so that the reader will find a systematic overview of the available findings obtained in the various organ systems. It must be noted, however, that ongoing research work and new insight quite naturally will necessitate corrections to be done, as is the case here with some biochemical interpretations which would need adjustment to latest research results. NMR-spectroscopy is able to measure very fine energy differences on the molecular level, and thus offers insight into metabolic processes, with the advantage that there is no need of applying ionizing radiation in order to qualitatively or quantitatively analyse the metabolic processes in the various organ systems. (orig./DG) With 40 figs., 4 tabs [de

77 FR 23733 - CDC/HRSA Advisory Committee on HIV and STD Prevention and Treatment

Science.gov (United States)

2012-04-20

... Resources and Services Administration CDC/HRSA Advisory Committee on HIV and STD Prevention and Treatment In... and control of HIV/AIDS and other STDs, the support of health care services to persons living with HIV/AIDS, and education of health professionals and the public about HIV/AIDS and other STDs. Matters To Be...

Performance of the WeNMR CS-Rosetta3 web server in CASD-NMR

NARCIS (Netherlands)

Van Der Schot, Gijs; Bonvin, Alexandre M J J

We present here the performance of the WeNMR CS-Rosetta3 web server in CASD-NMR, the critical assessment of automated structure determination by NMR. The CS-Rosetta server uses only chemical shifts for structure prediction, in combination, when available, with a post-scoring procedure based on

Current socioclinical trend of sexually transmitted diseases and relevance of STD clinic: A comparative study from referral tertiary care center of Gwalior, India

Directory of Open Access Journals (Sweden)

Sandeep Singh

2014-01-01

Full Text Available Objective: Sexually transmitted infections (STIs are the major public health concern in both developed and developing countries regulated by the cultural pattern of gender expression in their society. Thus, it demanded a necessary action to review the changing pattern in (Gwalior, central India where health condition is not in a good fashion with poor socioeconomic status and awareness. Materials and Methods: This is a hospital based cross sectional questionnaire study with a sample size of 222 respondents attending sexually transmitted disease (STD clinic at JAH Gwalior from December 2011 to March 2012 using a random sampling method. Results: Most of the cases among females were in the age group of 20-40 years (152, 84.44% and males were in 18-40 years age group (35, 83.33%. Out of 180, 22 (12.22% females were having non-regular sexual partners. Out of 22 females frequency of consistent, non-consistent, and no condom use with non-regular sexual partners was three (13.63%, two (9.09%, and 17 (77.27%, respectively. Out of 42 males, 22 (52.38% reported having sex with non-regular sexual partners. None of the 15 (100% male subjects having friends or relatives as non-regular sexual partner were using condoms. Statistically significant differences were found as compared to a previous study from same STD clinic are discharge, lower abdominal pain, painful micturition, nodules in genitals as 106 (58.88%; P = 0.0001, 59 (32.77%; P = 0.0007, 25 (13.88%; P = 0.001, and one (0.5%; P = 0.005, respectively and in males with absence of abdominal pain and nodules in genitals as P = 0.016 and 0.03, respectively. Preferred place of treatment of STIs was government facility in both male and females with statistically significant 15.76% (P = 0.0001 of the population seeking no treatment. Discussions: Study suggests a changing trend of the STDs owing to the difference in the clinical presentation of the disease to a previous study from the same STD clinic few years

Evolution of organic matter during composting of different organic wastes assessed by CPMAS 13C NMR spectroscopy

International Nuclear Information System (INIS)

Caricasole, P.; Provenzano, M.R.; Hatcher, P.G.; Senesi, N.

2011-01-01

In this paper, the evolution of organic matter (OM) during composting of different mixtures of various organic wastes was assessed by means of chemical analyses and CPMAS 13 C NMR spectroscopy measured during composting. The trends of temperatures and C/N ratios supported the correct evolution of the processes. The CPMAS 13 C NMR spectra of all composting substrates indicated a reduction in carbohydrates and an increase in aromatic, phenolic, carboxylic and carbonylic C which suggested a preference by microorganisms for easily degradable C molecules. The presence of hardly degradable pine needles in one of the substrates accounted for the lowest increase in alkyl C and the lowest reduction in carbohydrates and carboxyl C as opposite to another substrate characterized by the presence of a highly degradable material such as spent yeast from beer production, which showed the highest increase of the alkyl C/O-alkyl C ratio. The highest increase of COOH deriving by the oxidative degradation of cellulose was shown by a substrate composed by about 50% of plant residues. The smallest increases in alkyl C/O-alkyl C ratio and in polysaccharides were associated to the degradation of proteins and lipids which are major components of sewage sludge. Results obtained were related to the different composition of fresh organic substrates and provided evidence of different OM evolution patterns as a function of the initial substrate composition.

Performance of the WeNMR CS-Rosetta3 web server in CASD-NMR

Energy Technology Data Exchange (ETDEWEB)

Schot, Gijs van der [Uppsala University, Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology (Sweden); Bonvin, Alexandre M. J. J., E-mail: a.m.j.j.bonvin@uu.nl [Utrecht University, Faculty of Science – Chemistry, Bijvoet Center for Biomolecular Research (Netherlands)

2015-08-15

We present here the performance of the WeNMR CS-Rosetta3 web server in CASD-NMR, the critical assessment of automated structure determination by NMR. The CS-Rosetta server uses only chemical shifts for structure prediction, in combination, when available, with a post-scoring procedure based on unassigned NOE lists (Huang et al. in J Am Chem Soc 127:1665–1674, 2005b, doi: 10.1021/ja047109h 10.1021/ja047109h ). We compare the original submissions using a previous version of the server based on Rosetta version 2.6 with recalculated targets using the new R3FP fragment picker for fragment selection and implementing a new annotation of prediction reliability (van der Schot et al. in J Biomol NMR 57:27–35, 2013, doi: 10.1007/s10858-013-9762-6 10.1007/s10858-013-9762-6 ), both implemented in the CS-Rosetta3 WeNMR server. In this second round of CASD-NMR, the WeNMR CS-Rosetta server has demonstrated a much better performance than in the first round since only converged targets were submitted. Further, recalculation of all CASD-NMR targets using the new version of the server demonstrates that our new annotation of prediction quality is giving reliable results. Predictions annotated as weak are often found to provide useful models, but only for a fraction of the sequence, and should therefore only be used with caution.

Performance of the WeNMR CS-Rosetta3 web server in CASD-NMR

International Nuclear Information System (INIS)

Schot, Gijs van der; Bonvin, Alexandre M. J. J.

2015-01-01

We present here the performance of the WeNMR CS-Rosetta3 web server in CASD-NMR, the critical assessment of automated structure determination by NMR. The CS-Rosetta server uses only chemical shifts for structure prediction, in combination, when available, with a post-scoring procedure based on unassigned NOE lists (Huang et al. in J Am Chem Soc 127:1665–1674, 2005b, doi: 10.1021/ja047109h 10.1021/ja047109h ). We compare the original submissions using a previous version of the server based on Rosetta version 2.6 with recalculated targets using the new R3FP fragment picker for fragment selection and implementing a new annotation of prediction reliability (van der Schot et al. in J Biomol NMR 57:27–35, 2013, doi: 10.1007/s10858-013-9762-6 10.1007/s10858-013-9762-6 ), both implemented in the CS-Rosetta3 WeNMR server. In this second round of CASD-NMR, the WeNMR CS-Rosetta server has demonstrated a much better performance than in the first round since only converged targets were submitted. Further, recalculation of all CASD-NMR targets using the new version of the server demonstrates that our new annotation of prediction quality is giving reliable results. Predictions annotated as weak are often found to provide useful models, but only for a fraction of the sequence, and should therefore only be used with caution

Direct Comparison of 19F qNMR and 1H qNMR by Characterizing Atorvastatin Calcium Content

Directory of Open Access Journals (Sweden)

Yang Liu

2016-01-01

Full Text Available Quantitative nuclear magnetic resonance (qNMR is a powerful tool in measuring drug content because of its high speed, sensitivity, and precision. Most of the reports were based on proton qNMR (1H qNMR and only a few fluorine qNMR (19F qNMR were reported. No research has been conducted to directly compare the advantage and disadvantage between these two methods. In the present study, both 19F and 1H qNMR were performed to characterize the content of atorvastatin calcium with the same internal standard. Linearity, precision, and results from two methods were compared. Results showed that 19F qNMR has similar precision and sensitivity to 1H qNMR. Both methods generate similar results compared to mass balance method. Major advantage from 19F qNMR is that the analyte signal is with less or no interference from impurities. 19F qNMR is an excellent approach to quantify fluorine-containing analytes.

Dynamic pulsed-field-gradient NMR

CERN Document Server

Sørland, Geir Humborstad

2014-01-01

Dealing with the basics, theory and applications of dynamic pulsed-field-gradient NMR NMR (PFG NMR), this book describes the essential theory behind diffusion in heterogeneous media that can be combined with NMR measurements to extract important information of the system being investigated. This information could be the surface to volume ratio, droplet size distribution in emulsions, brine profiles, fat content in food stuff, permeability/connectivity in porous materials and medical applications currently being developed. Besides theory and applications it will provide the readers with background knowledge on the experimental set-ups, and most important, deal with the pitfalls that are numerously present in work with PFG-NMR. How to analyze the NMR data and some important basic knowledge on the hardware will be explained, too.

Masculinity, vulnerability and prevention of STD/HIV/AIDS among male adolescents: social representations in a land reform settlement

Directory of Open Access Journals (Sweden)

Camila de Oliveira Arraes

2013-12-01

Full Text Available OBJECTIVE: to analyze the relationship of masculinity, vulnerability and prevention of STD / HIV / AIDS among adolescent males of a land reform settlement in central Brazil. METHOD: a qualitative study using as precepts the strands of social representations with teenagers between 12 to 24 years. RESULTS: three categories emerged - Perception of vulnerability; Gender and vulnerability; and, Prevention and vulnerability to STD / HIV / AIDS. Adolescents felt invulnerable to sexually transmitted diseases anchored in the social representations in favor of the male hegemony. An ignorance about forms of prevention for STD / HIV / AIDS was demonstrated in their statements. It is believed that institutional projects such as the School Health Program and the Men's Health Care Program constitute essential tools to minimize factors of vulnerability in this population, since the school is recognized as a social facility that promotes socialization of experiences and contributes to the construction of the identity of the adolescent. CONCLUSION: the social representations of masculinity collaborate for the vulnerable behavior of the adolescents for the acquisition of sexually transmitted diseases. One hopes that this study can contribute to the production of knowledge and technical-scientific improvement of the professionals, especially the nurse, in order to discuss issues related to male sexuality of adolescents in the situation of the land reform settlement.

Masculinity, vulnerability and prevention of STD/HIV/AIDS among male adolescents: social representations in a land reform settlement.

Science.gov (United States)

Arraes, Camila de Oliveira; Palos, Marinésia Aparecida Prado; Barbosa, Maria Alves; Teles, Sheila Araujo; Souza, Márcia Maria de; Matos, Marcos André de

2013-01-01

to analyze the relationship of masculinity, vulnerability and prevention of STD / HIV / AIDS among adolescent males of a land reform settlement in central Brazil. a qualitative study using as precepts the strands of social representations with teenagers between 12 to 24 years. three categories emerged - Perception of vulnerability; Gender and vulnerability; and, Prevention and vulnerability to STD / HIV / AIDS. Adolescents felt invulnerable to sexually transmitted diseases anchored in the social representations in favor of the male hegemony. An ignorance about forms of prevention for STD / HIV / AIDS was demonstrated in their statements. It is believed that institutional projects such as the School Health Program and the Men's Health Care Program constitute essential tools to minimize factors of vulnerability in this population, since the school is recognized as a social facility that promotes socialization of experiences and contributes to the construction of the identity of the adolescent. the social representations of masculinity collaborate for the vulnerable behavior of the adolescents for the acquisition of sexually transmitted diseases. One hopes that this study can contribute to the production of knowledge and technical-scientific improvement of the professionals, especially the nurse, in order to discuss issues related to male sexuality of adolescents in the situation of the land reform settlement.

The NMR Probe of High-T$_{c}$ Materials

CERN Document Server

Walstedt, Russell E

2008-01-01

The NMR probe has yielded a vast array of data for the high-Tc materials, corresponding to different compounds, ionic sites, and nuclear species, as well as to a wide variety of experimental conditions. Over the twenty years, since the discovery of superconducting cuprates, ongoing analysis and discussion of cuprate NMR data have resulted in a wealth of important insights into the physics of these exotic systems. The aims of this monograph are threefold. First, it reviews NMR methodology as it has been applied to the cuprate studies. This is addressed to NMR practitioners and to physics laypersons alike. Next, it presents a review of cuprate NMR measurements and the wide variety of phenomena which they represent. The third phase is to recount the theoretical model calculations and other proposals which have been put forward to account for these data. Parts two and three are presented in parallel, as there are many aspects to both topics, each with its own interesting history. There is, even twenty years on, a...

1H NMR spectroscopy-based interventional metabolic phenotyping

DEFF Research Database (Denmark)

Lauridsen, Michael B; Bliddal, Henning; Christensen, Robin

2010-01-01

1H NMR spectroscopy-based metabolic phenotyping was used to identify biomarkers in the plasma of patients with rheumatoid arthritis (RA). Forty-seven patients with RA (23 with active disease at baseline and 24 in remission) and 51 healthy subjects were evaluated during a one-year follow-up with a......1H NMR spectroscopy-based metabolic phenotyping was used to identify biomarkers in the plasma of patients with rheumatoid arthritis (RA). Forty-seven patients with RA (23 with active disease at baseline and 24 in remission) and 51 healthy subjects were evaluated during a one-year follow......-up with assessments of disease activity (DAS-28) and 1H NMR spectroscopy of plasma samples. Discriminant analysis provided evidence that the metabolic profiles predicted disease severity. Cholesterol, lactate, acetylated glycoprotein, and lipid signatures were found to be candidate biomarkers for disease severity.......0007). However, after 31 days of optimized therapy, the two patient groups were not significantly different (P=0.91). The metabolic profiles of both groups of RA patients were different from the healthy subjects. 1H NMR-based metabolic phenotyping of plasma samples in patients with RA is well suited...

CcpNmr AnalysisAssign: a flexible platform for integrated NMR analysis

International Nuclear Information System (INIS)

Skinner, Simon P.; Fogh, Rasmus H.; Boucher, Wayne; Ragan, Timothy J.; Mureddu, Luca G.; Vuister, Geerten W.

2016-01-01

NMR spectroscopy is an indispensably powerful technique for the analysis of biomolecules under ambient conditions, both for structural- and functional studies. However, in practice the complexity of the technique has often frustrated its application by non-specialists. In this paper, we present CcpNmr version-3, the latest software release from the Collaborative Computational Project for NMR, for all aspects of NMR data analysis, including liquid- and solid-state NMR data. This software has been designed to be simple, functional and flexible, and aims to ensure that routine tasks can be performed in a straightforward manner. We have designed the software according to modern software engineering principles and leveraged the capabilities of modern graphics libraries to simplify a variety of data analysis tasks. We describe the process of backbone assignment as an example of the flexibility and simplicity of implementing workflows, as well as the toolkit used to create the necessary graphics for this workflow. The package can be downloaded from www.ccpn.ac.uk/v3-software/downloads http://www.ccpn.ac.uk/v3-software/downloads and is freely available to all non-profit organisations.

CcpNmr AnalysisAssign: a flexible platform for integrated NMR analysis

Energy Technology Data Exchange (ETDEWEB)

Skinner, Simon P.; Fogh, Rasmus H. [University of Leicester, Department of Molecular and Cell Biology, Leicester Institute for Structural- and Chemical Biology (United Kingdom); Boucher, Wayne [University of Cambridge, Department of Biochemistry (United Kingdom); Ragan, Timothy J.; Mureddu, Luca G.; Vuister, Geerten W., E-mail: gv29@le.ac.uk [University of Leicester, Department of Molecular and Cell Biology, Leicester Institute for Structural- and Chemical Biology (United Kingdom)

2016-10-15

NMR spectroscopy is an indispensably powerful technique for the analysis of biomolecules under ambient conditions, both for structural- and functional studies. However, in practice the complexity of the technique has often frustrated its application by non-specialists. In this paper, we present CcpNmr version-3, the latest software release from the Collaborative Computational Project for NMR, for all aspects of NMR data analysis, including liquid- and solid-state NMR data. This software has been designed to be simple, functional and flexible, and aims to ensure that routine tasks can be performed in a straightforward manner. We have designed the software according to modern software engineering principles and leveraged the capabilities of modern graphics libraries to simplify a variety of data analysis tasks. We describe the process of backbone assignment as an example of the flexibility and simplicity of implementing workflows, as well as the toolkit used to create the necessary graphics for this workflow. The package can be downloaded from www.ccpn.ac.uk/v3-software/downloads http://www.ccpn.ac.uk/v3-software/downloads and is freely available to all non-profit organisations.

Simplification of lipase design in the enzymatic kinetic resolution of amines by saturation transfer difference NMR

Energy Technology Data Exchange (ETDEWEB)

Silva, Marcio S.; Pietrobom, Daniel, E-mail: s.marcio@ufabc.edu.br [Universidade Federal do ABC (CCNH/UFABC), Santo André, SP (Brazil). Centro de Ciências Naturais e Humanas

2016-07-01

In this work, we demonstrate a nuclear magnetic resonance (NMR) method for racemic amide and lipase interaction as a first-pass design method in the enzymatic kinetic resolution of amines. As a novel adaptation of commonly used protein-ligand screening NMR methodologies, this approach relies upon a lipase-amide interaction wherein the time-consuming is reduced drastically and new insights are produced during the development of biocatalysis reactions. (author)

HIV, other STD, and pregnancy prevention education in public secondary schools -- 45 states, 2008-2010.

Science.gov (United States)

2012-04-06

In the United States, 46% of high school students have had sexual intercourse and potentially are at risk for human immunodeficiency virus (HIV) infection, other sexually transmitted diseases (STDs), and pregnancy. The National HIV/AIDS Strategy for the United States recommends educating young persons about HIV before they begin engaging in behaviors that place them at risk for HIV infection. The Community Preventive Services Task Force (CPSTF) also recommends risk reduction interventions to prevent HIV, other STDs, and pregnancy among adolescents. To estimate changes in the percentage of secondary schools that teach specific HIV, other STD, and pregnancy risk reduction topics, a key intervention consistent with those supported by the National HIV/AIDS Strategy and CPSTF, CDC analyzed 2008 and 2010 School Health Profiles data for public secondary schools in 45 states. This report summarizes the results of those analyses, which indicated that in 2010, compared with 2008, the percentage of secondary schools teaching 11 topics on HIV, other STD, and pregnancy prevention in a required course in grades 6, 7, or 8 was significantly lower in 11 states and significantly higher in none; the percentage of secondary schools teaching eight topics in a required course in grades 9, 10, 11, or 12 was significantly lower in one state and significantly higher in two states; and the percentage of secondary schools teaching three condom-related topics in a required course in grades 9, 10, 11, or 12 was significantly lower in eight states and significantly higher in three states. Secondary schools can increase efforts to teach all age-appropriate HIV, other STD, and pregnancy prevention topics to help reduce risk behaviors among students.

A comparison of four sampling methods among men having sex with men in China: implications for HIV/STD surveillance and prevention

Science.gov (United States)

Guo, Yan; Li, Xiaoming; Fang, Xiaoyi; Lin, Xiuyun; Song, Yan; Jiang, Shuling; Stanton, Bonita

2011-01-01

Sample representativeness remains one of the challenges in effective HIV/STD surveillance and prevention targeting MSM worldwide. Although convenience samples are widely used in studies of MSM, previous studies suggested that these samples might not be representative of the broader MSM population. This issue becomes even more critical in many developing countries where needed resources for conducting probability sampling are limited. We examined variations in HIV and Syphilis infections and sociodemographic and behavioral factors among 307 young migrant MSM recruited using four different convenience sampling methods (peer outreach, informal social network, Internet, and venue-based) in Beijing, China in 2009. The participants completed a self-administered survey and provided blood specimens for HIV/STD testing. Among the four MSM samples using different recruitment methods, rates of HIV infections were 5.1%, 5.8%, 7.8%, and 3.4%; rates of Syphilis infection were 21.8%, 36.2%, 11.8%, and 13.8%; rates of inconsistent condom use were 57%, 52%, 58%, and 38%. Significant differences were found in various sociodemographic characteristics (e.g., age, migration history, education, income, places of employment) and risk behaviors (e.g., age at first sex, number of sex partners, involvement in commercial sex, and substance use) among samples recruited by different sampling methods. The results confirmed the challenges of obtaining representative MSM samples and underscored the importance of using multiple sampling methods to reach MSM from diverse backgrounds and in different social segments and to improve the representativeness of the MSM samples when the use of probability sampling approach is not feasible. PMID:21711162

Structural investigation of e-beam cured epoxy resins through solid state NMR

International Nuclear Information System (INIS)

Alessi, Sabina; Spinella, Alberto; Caponetti, Eugenio; Dispenza, Clelia; Spadaro, Giuseppe

2012-01-01

In this paper the network structure of e-beam cured DGEBF based epoxy resins is investigated. Two epoxy systems, having different reactivity and cured in different process conditions, were analyzed through solid state NMR spectroscopy. The analysis shows that the more reactive system has higher cross-linking density and higher uniformity of network distribution. Similar information were obtained, in a previous work, on the same systems through dynamic mechanical thermal analysis. It is worth noting that unlike DMTA tests, which interfere with the molecular structure of the analyzed material, due to the heating during the analysis itself, more reliable information, without any artefact, are obtained by solid state NMR, carried out at constant room temperature. - Highlights: ► The structure of two e-beam cured epoxy systems is investigated through solid state NMR. ► The aim is to have direct information about the structure without inducing modifications. ► The different molecular structures are able to emphasize the response of solid state NMR. ► T 1 H, T 1ρ H and T CH measurements indicate different cross-linking degrees. ► The NMR results are in agreement with DMTA analysis performed in a previous paper.

Quality control of antibiotics before the implementation of an STD program in Northern Myanmar.

Science.gov (United States)

Prazuck, Thierry; Falconi, Isabelle; Morineau, Guy; Bricard-Pacaud, Véronique; Lecomte, Antoine; Ballereau, Francoise

2002-11-01

The ready availability of poor-quality drugs in developing countries leads to treatment failure and, consequently, excess mortality and morbidity. Moreover, the widespread availability of substandard drugs plays a key role in increasing the resistance to antimicrobial drugs.GOAL As a prerequisite to the establishment of a sexually transmitted disease (STD) control program, this study aimed to evaluate the quality of antibiotics recommended for treatment of STDs that were locally available in the capital of a province of Northern Myanmar. In addition to the hospital pharmacy, we selected at random 5 of the 41 drug sellers and 5 of the 40 general practitioners who sell antibiotics in the city of Myitkyina. Twenty-one marketing products corresponding to nine different antibiotics used for STD treatment were purchased (benzathine benzylpenicillin, benzylpenicillin, ceftriaxone, chlortetracycline, ciprofloxacin, clotrimazole, co-trimoxazole, doxycycline, and erythromycin). Drugs were sent to France, where they were analyzed according to the WHO guidelines. Drugs were considered to be standard if their dosage remained in the 10% range of the expected value. Among the 21 different specialty products, only three displayed the official "registered" label. Three drugs were expired and the expiration date was not available for six others. One product did not contain the active drug declared (chlortetracycline; Lombisin, Unicorn, China) and did not show any in vitro activity against bacteria. Seven of 21 products (33%) did not contain the stated dosage (1, more than stated dosage; 6, less than stated dosage). The highest deficit observed was 48% in two products (co-trimoxazole, Yong Fong, Myanmar; benzylpenicillin, China [city and manufacturer unknown]). The dosage was not available for five drugs. As a result, only 8 of 21 products (38%) did not contain the stated dosage of active drug. These findings suggest that public health policies based on national treatment guidelines

HPLC-NMR revisited: Using time-slice HPLC-SPE-NMR with database assisted dereplication

DEFF Research Database (Denmark)

Johansen, Kenneth; Wubshet, Sileshi Gizachew; Nyberg, Nils

2013-01-01

Time based trapping of chromatographically separated compounds on to solid-phase extraction cartridges (SPE) and subsequent elution to NMR-tubes was done to emulate the function of HPLC–NMR for dereplication purposes. Sufficient mass sensitivity was obtained by the use of a state-of-the-art HPLC......–SPE–NMR-system with a cryogenically cooled probe head, designed for 1.7 mm NMR-tubes. The resulting 1H NMR spectra (600 MHz) were evaluated against a database of previously acquired and prepared spectra. The in-house developed matching algorithm, based on partitioning of the spectra and allowing for changes in the chemical shifts......, is described and the code included as Supplementary Information. Two mixtures of natural products was used to test the approach; one extract of Carthamus oxyacantha (wild safflower) containing an array of spiro compounds and one extract of the endophytic fungus Penicillum namyslowski containing griseofulvin...

NMR for chemists and biologists

CERN Document Server

Carbajo, Rodrigo J

2013-01-01

This book offers a concise introduction to the field of nuclear magnetic resonance or NMR. It presents the basic foundations of NMR in a non-mathematical way and provides an overview of both recent and important biological applications of NMR.

Compact NMR

Energy Technology Data Exchange (ETDEWEB)

Bluemich, Bernhard; Haber-Pohlmeier, Sabina; Zia, Wasif [RWTH Aachen Univ. (Germany). Inst. fuer Technische und Makromolekulare Chemie (ITMC)

2014-06-01

Nuclear Magnetic Resonance (NMR) spectroscopy is the most popular method for chemists to analyze molecular structures, while Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic tool for medical doctors that provides high-contrast images of biological tissue. In both applications, the sample (or patient) is positioned inside a large, superconducting magnet to magnetize the atomic nuclei. Interrogating radio-frequency pulses result in frequency spectra that provide the chemist with molecular information, the medical doctor with anatomic images, and materials scientist with NMR relaxation parameters. Recent advances in magnet technology have led to a variety of small permanent magnets to allow compact and low-cost instruments. The goal of this book is to provide an introduction to the practical use of compact NMR at a level nearly as basic as the operation of a smart phone.

Optimized slice-selective 1H NMR experiments combined with highly accurate quantitative 13C NMR using an internal reference method

Science.gov (United States)

Jézéquel, Tangi; Silvestre, Virginie; Dinis, Katy; Giraudeau, Patrick; Akoka, Serge

2018-04-01

Isotope ratio monitoring by 13C NMR spectrometry (irm-13C NMR) provides the complete 13C intramolecular position-specific composition at natural abundance. It represents a powerful tool to track the (bio)chemical pathway which has led to the synthesis of targeted molecules, since it allows Position-specific Isotope Analysis (PSIA). Due to the very small composition range (which represents the range of variation of the isotopic composition of a given nuclei) of 13C natural abundance values (50‰), irm-13C NMR requires a 1‰ accuracy and thus highly quantitative analysis by 13C NMR. Until now, the conventional strategy to determine the position-specific abundance xi relies on the combination of irm-MS (isotopic ratio monitoring Mass Spectrometry) and 13C quantitative NMR. However this approach presents a serious drawback since it relies on two different techniques and requires to measure separately the signal of all the carbons of the analyzed compound, which is not always possible. To circumvent this constraint, we recently proposed a new methodology to perform 13C isotopic analysis using an internal reference method and relying on NMR only. The method combines a highly quantitative 1H NMR pulse sequence (named DWET) with a 13C isotopic NMR measurement. However, the recently published DWET sequence is unsuited for samples with short T1, which forms a serious limitation for irm-13C NMR experiments where a relaxing agent is added. In this context, we suggest two variants of the DWET called Multi-WET and Profiled-WET, developed and optimized to reach the same accuracy of 1‰ with a better immunity towards T1 variations. Their performance is evaluated on the determination of the 13C isotopic profile of vanillin. Both pulse sequences show a 1‰ accuracy with an increased robustness to pulse miscalibrations compared to the initial DWET method. This constitutes a major advance in the context of irm-13C NMR since it is now possible to perform isotopic analysis with high

HIV and STD Knowledge, Sexual Behaviors and Drug Taking Behaviors of Adolescents in Southern Russia

Science.gov (United States)

Kelley, R. Mark; Ball, Marcia; Cerullo, Jennie; Trunova, Elena

2004-01-01

For several years, HIV infection has increasing rapidly in Eastern Europe and Russia (UNAIDS, 2000, 2003). The purpose of the study was to investigate the HIV and STD knowledge, sexual behaviors and drug taking behaviors of adolescents in southern Russia. The instrument was compiled by the authors, professionally translated, and pilot tested. Most…

Moessbauer and NMR study of novel Tin(IV)-lactames

Energy Technology Data Exchange (ETDEWEB)

Kuzmann, Erno; Szalay, Roland; Homonnay, Zoltan, E-mail: homonnay@ludens.elte.hu; Nagy, Sandor [Eoetvoes Lorand University, Institute of Chemistry (Hungary)

2012-03-15

N-tributylstannylated 2-pyrrolidinone was reacted with tributyltin triflate in different molar ratios and the complex formation monitored using {sup 1}H-NMR, {sup 13}C-NMR and {sup 119}Sn Moessbauer spectroscopy. Comparing the carbon NMR and tin Moessbauer results, a reaction scheme is suggested for the complexation which assumes the formation of a simultaneously O- and N-tributylstannylated pyrrolidinone cation. The formation of the only O-stannylated pyrrolidinone is also assumed to account for the non-constant Moessbauer parameters of the two tin environments in the distannylated pyrrolidinone cation when the ratio of tributyltin triflate is increased in the reaction.

IEEE Std 101-1987: IEEE guide for the statistical analysis of thermal life test data

International Nuclear Information System (INIS)

Anon.

1992-01-01

This revision of IEEE Std 101-1972 describes statistical analyses for data from thermally accelerated aging tests. It explains the basis and use of statistical calculations for an engineer or scientist. Accelerated test procedures usually call for a number of specimens to be aged at each of several temperatures appreciably above normal operating temperatures. High temperatures are chosen to produce specimen failures (according to specified failure criteria) in typically one week to one year. The test objective is to determine the dependence of median life on temperature from the data, and to estimate, by extrapolation, the median life to be expected at service temperature. This guide presents methods for analyzing such data and for comparing test data on different materials

Characterization of Two Distinct Amorphous Forms of Valsartan by Solid-State NMR.

Science.gov (United States)

Skotnicki, Marcin; Apperley, David C; Aguilar, Juan A; Milanowski, Bartłomiej; Pyda, Marek; Hodgkinson, Paul

2016-01-04

Valsartan (VAL) is an antihypertensive drug marketed in an amorphous form. Amorphous materials can have different physicochemical properties depending on preparation method, thermal history, etc., but the nature of such materials is difficult to study by diffraction techniques. This study characterizes two different amorphous forms of valsartan (AR and AM) using solid-state NMR (SSNMR) as a primary investigation tool, supported by solution-state NMR, FT-IR, TMDSC, and dissolution tests. The two forms are found to be clearly distinct, with a significantly higher level of structural arrangement in the AR form, as observed in (13)C, (15)N, and (1)H SSNMR. (13)C and (15)N NMR indicates that the fully amorphous material (AM) contains an approximately equal ratio of cis-trans conformers about the amide bond, whereas the AR form exists mainly as one conformer, with minor conformational "defects". (1)H ultrafast MAS NMR shows significant differences in the hydrogen bonding involving the tetrazole and acid hydrogens between the two materials, while (15)N NMR shows that both forms exist as a 1,2,3,4-tetrazole tautomer. NMR relaxation times show subtle differences in local and bulk molecular mobility, which can be connected with the glass transition, the stability of the glassy material, and its response to aging. Counterintuitively the fully amorphous material is found to have a significantly lower dissolution rate than the apparently more ordered AR material.

HIV/STD risk behaviors and perceptions among rural-to-urban migrants in China.

Science.gov (United States)

Li, Xiaoming; Fang, Xiaoyi; Lin, Danhua; Mao, Rong; Wang, Jing; Cottrell, Lesley; Harris, Carole; Stanton, Bonita

2004-12-01

Data from 2,153 sexually active rural-to-urban migrants in China were analyzed to examine the relationship between the movement of rural-to-urban migration and increased HIV/STD (sexually transmitted disease) risk and the applicability of constructs of a Western-based theory of behavioral change to the study population. Measurements included migrant mobility, sexual risk, and the seven constructs of the protection motivation theory (PMT). Data in the current study suggest that high mobility among rural-to-urban migrants was associated with increased sexual risk. The PMT constructs are applicable in identifying perceptions and attitudes associated with sexual risk behaviors in this culturally distinct population. Increased sexual risk was associated with increased perceptions of extrinsic rewards, intrinsic rewards, and response cost. Also consistent with PMT, increased sexual risk was associated with perceptions of decreased severity, vulnerability, response efficacy, and self-efficacy. After controlling for a number of key confounding factors, all seven PMT constructs were associated with sexual risk in the manner posited by the theory. The association between mobility and sexual risk underscores the importance of effective HIV/STD prevention efforts among this vulnerable population. The social cognitive theories including the PMT may form a logical base for prevention intervention programs targeting rural-to-urban migrants in China.

Structural Biology: Practical NMR Applications

CERN Document Server

Teng, Quincy

2005-01-01

This textbook begins with an overview of NMR development and applications in biological systems. It describes recent developments in instrument hardware and methodology. Chapters highlight the scope and limitation of NMR methods. While detailed math and quantum mechanics dealing with NMR theory have been addressed in several well-known NMR volumes, chapter two of this volume illustrates the fundamental principles and concepts of NMR spectroscopy in a more descriptive manner. Topics such as instrument setup, data acquisition, and data processing using a variety of offline software are discussed. Chapters further discuss several routine stategies for preparing samples, especially for macromolecules and complexes. The target market for such a volume includes researchers in the field of biochemistry, chemistry, structural biology and biophysics.

78 FR 32392 - CDC/HRSA Advisory Committee on HIV, Viral Hepatitis and STD Prevention and Treatment

Science.gov (United States)

2013-05-30

... Resources and Services Administration CDC/HRSA Advisory Committee on HIV, Viral Hepatitis and STD Prevention.../AIDS, Viral Hepatitis and other STDs, the support of health care services to persons living with HIV/AIDS, and education of health professionals and the public about HIV/AIDS, Viral Hepatitis and other...

Real-life IT architecture design reports and their relation to IEEE Std 1471 stakeholders and concerns

NARCIS (Netherlands)

van Vliet, H.; Koning, H.

2006-01-01

Architectural designs are an important means to manage the development and deployment of information technology (IT). Much debate has been going on about a proper definition of architecture in IT and about how to describe it. In 2000, the IEEE Std 1471 proposed a model of an architecture description

Two dimensional solid state NMR

International Nuclear Information System (INIS)

Kentgens, A.P.M.

1987-01-01

This thesis illustrates, by discussing some existing and newly developed 2D solid state experiments, that two-dimensional NMR of solids is a useful and important extension of NMR techniques. Chapter 1 gives an overview of spin interactions and averaging techniques important in solid state NMR. As 2D NMR is already an established technique in solutions, only the basics of two dimensional NMR are presented in chapter 2, with an emphasis on the aspects important for solid spectra. The following chapters discuss the theoretical background and applications of specific 2D solid state experiments. An application of 2D-J resolved NMR, analogous to J-resolved spectroscopy in solutions, to natural rubber is given in chapter 3. In chapter 4 the anisotropic chemical shift is mapped out against the heteronuclear dipolar interaction to obtain information about the orientation of the shielding tensor in poly-(oxymethylene). Chapter 5 concentrates on the study of super-slow molecular motions in polymers using a variant of the 2D exchange experiment developed by us. Finally chapter 6 discusses a new experiment, 2D nutation NMR, which makes it possible to study the quadrupole interaction of half-integer spins. 230 refs.; 48 figs.; 8 tabs

Introduction to IEEE Std. 7-4.3.2 Annex D -- ''Qualification of existing commercial computers''

International Nuclear Information System (INIS)

Holmstrom, K.J.

1995-01-01

On September 15th of 1993 the IEEE standards board approved IEEE Std. 7-4.3.2-1993, IEEE Standard for Digital Computers in Safety Systems of Nuclear Power Generating Stations. This paper is an introduction to Annex D of this document which concerns the commercial grade dedication of existing computers or new non-1E computers

Advanced NMR technology for bioscience and biotechnology

Energy Technology Data Exchange (ETDEWEB)

Hammel, P.C.; Hernandez, G.; Trewhella, J.; Unkefer, C.J. [Los Alamos National Lab., NM (US); Boumenthal, D.K. [Univ. of Utah, Salt Lake City, UT (US); Kennedy, M.A. [Pacific Northwest National Lab., Richland, WA (US); Moore, G.J. [Wayne State Univ., Detroit, MI (US)

1998-11-01

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). NMR plays critical roles in bioscience and biotechnology in both imaging and structure determination. NMR is limited, however, by the inherent low sensitivity of the NMR experiment and the demands for spectral resolution required to study biomolecules. The authors addressed both of these issues by working on the development of NMR force microscopy for molecular imaging, and high field NMR with isotope labeling to overcome limitations in the size of biomolecules that can be studied using NMR. A novel rf coil design for NMR force microscopy was developed that increases the limits of sensitivity in magnetic resonance detection for imaging, and the authors demonstrated sub-surface spatial imaging capabilities. The authors also made advances in the miniaturization of two critical NMR force microscope components. They completed high field NMR and isotope labeling studies of a muscle protein complex which is responsible for regulating muscle contraction and is too large for study using conventional NMR approaches.

Functional studies using NMR

International Nuclear Information System (INIS)

McCready, V.R.; Leach, M.O.; Sutton; Ell, P.

1986-01-01

The object of this book is to discuss and evaluate an area of Nuclear Magnetic Resonance which to date has been less emphasized than it might be, namely the use of NMR for functional studies. The book commences with a discussion of the areas in which the NMR techniques might be needed due to deficiencies in other techniques. The physics of NMR especially relating to functional measurement are then explained. Technical factors in producing functional images are discussed and the use of paramagnetic substances for carrying out flow studies are detailed. Particular attention is paid to specific studies in the various organs. The book ends with a survey of imaging in each organ and the relation of NMR images to other techniques such as ultrasound, nuclear medicine and X-rays

11B nutation NMR study of powdered borosilicates

International Nuclear Information System (INIS)

Woo, Ae Ja; Yang, Kyung Hwa; Han, Duk Young

1998-01-01

In this work, we applied the 1D 11 B nutation NMR method for the analysis of the local structural environments in powdered borosilicates (SiO 2 -B 2 O 3 ). Spin dynamics during a rf irradiation for spin I=3/2 was analytically calculated with a density matrix formalism. Spectral simulation programs were written in MATLAB on a PC. Two borosilicates prepared by the sol-gel process at different stabilization temperature were used for the 1D 11 B nutation NMR experiment. The 11 B NMR parameters, quadrupole coupling constants (e 2 qQ/h) and asymmetry parameters (η), for each borosilicate were extracted from the nonlinear least-squares fitting. The effects of heat treatments on the local structures of boron sites in borosilicates were discussed

NMR analog of Bell's inequalities violation test

International Nuclear Information System (INIS)

Souza, A M; Oliveira, I S; Sarthour, R S; Magalhaes, A; Teles, J; Azevedo, E R de; Bonagamba, T J

2008-01-01

In this paper, we present an analog of Bell's inequalities violation test for N qubits to be performed in a nuclear magnetic resonance (NMR) quantum computer. This can be used to simulate or predict the results for different Bell's inequality tests, with distinct configurations and a larger number of qubits. To demonstrate our scheme, we implemented a simulation of the violation of the Clauser, Horne, Shimony and Holt (CHSH) inequality using a two-qubit NMR system and compared the results to those of a photon experiment. The experimental results are well described by the quantum mechanics theory and a local realistic hidden variables model (LRHVM) that was specifically developed for NMR. That is why we refer to this experiment as a simulation of Bell's inequality violation. Our result shows explicitly how the two theories can be compatible with each other due to the detection loophole. In the last part of this work, we discuss the possibility of testing some fundamental features of quantum mechanics using NMR with highly polarized spins, where a strong discrepancy between quantum mechanics and hidden variables models can be expected

Applications of 1H-NMR relaxometry in experimental liver studies

International Nuclear Information System (INIS)

Holzmueller, P.

1992-01-01

Purpose of this study was to investigate applications of proton nuclear magnetic resonance ( 1 H-NMR) relaxometry in experimental medicine. Relaxometry was performed by measurements of spin-lattice (T 1 ) and spin-spin (T 2 ) relaxation time parameters on liver biopsies up to four hours after biopsy excision. Variations of relaxation times due to species and strain, different sample handling and different liver damage models, ethionine fatty liver and paracetamol liver necrosis, were investigated. Cell integrity effects were studied on homogenized liver samples. Relaxation time parameters, especially 'main' components T 1A and T 2A of biexponential model fit, were identified to react very sensitive after tissue damages as well as to cell viability. Thus, investigation of stored liver grafts was performed in order to evaluate the possibility of a rapid liver graft viability testing method for human liver transplantation surgery by 1 H-NMR relaxometry. Another series of measurements was performed to investigate the applicability of isoflurane anesthesia for in vivo NMR experiments. This study proved the good appropriateness of isoflurane for that purpose provided that physiological monitoring and individual adjustment of anesthesia are performed. In these investigations it could be revealed that mainly T 1A and T 2A are influenced by tissue condition and that different information is inherent in these two parameters, with T 2A reflecting tissue viability and changes of tissue conditions very sensitively but rather unspecifically in respect to the damage applied. Based on these results the following future applications of 1 H-NMR relaxometry are suggested : (1) model investigations, (2) investigation of given pathologies, (3) investigation of basic requirements for in vivo NMR and (4) application in a liver graft viability testing protocol, which seems to be the most important future application of 1 H-NMR relaxometry in medicine. (author)

Recent Advances in Targeted and Untargeted Metabolomics by NMR and MS/NMR Methods

Energy Technology Data Exchange (ETDEWEB)

Bingol, Kerem

2018-04-18

Metabolomics has made significant progress in multiple fronts in the last 18 months. This minireview aimed to give an overview of these advancements in the light of their contribution to targeted and untargeted metabolomics. New computational approaches have emerged to overcome manual absolute quantitation step of metabolites in 1D 1H NMR spectra. This provides more consistency between inter-laboratory comparisons. Integration of 2D NMR metabolomics databases under a unified web server allowed very accurate identification of the metabolites that have been catalogued in these databases. For the remaining uncatalogued and unknown metabolites, new cheminformatics approaches have been developed by combining NMR and mass spectrometry. These hybrid NMR/MS approaches accelerated the identification of unknowns in untargeted studies, and now they are allowing to profile ever larger number of metabolites in application studies.

Magic Angle Spinning NMR Metabolomics

Energy Technology Data Exchange (ETDEWEB)

Zhi Hu, Jian

2016-01-01

Nuclear Magnetic Resonance (NMR) spectroscopy is a non-destructive, quantitative, reproducible, untargeted and unbiased method that requires no or minimal sample preparation, and is one of the leading analytical tools for metabonomics research [1-3]. The easy quantification and the no need of prior knowledge about compounds present in a sample associated with NMR are advantageous over other techniques [1,4]. 1H NMR is especially attractive because protons are present in virtually all metabolites and its NMR sensitivity is high, enabling the simultaneous identification and monitoring of a wide range of low molecular weight metabolites.

Calibration of the Lawrence Livermore National Laboratory Passive-Active Neutron Drum Shuffler for Measurement of Highly Enriched Uranium in Oxides within DOE-STD-3013-2000 Containers

International Nuclear Information System (INIS)

Mount, M E; O'Connell, W J

2005-01-01

Lawrence Livermore National Laboratory (LLNL) uses the LLNL passive-active neutron drum (PAN) shuffler (Canberra Model JCC-92) for accountability measurement of highly enriched uranium (HEU) oxide and HEU in mixed uranium-plutonium (U-Pu) oxide. In June 2002, at the 43rd Annual Meeting of the Institute of Nuclear Material Management, LLNL reported on an extensive effort to calibrate this shuffler, based on standards measurements and extensive simulations, for HEU oxides and mixed U-Pu oxides in thin-walled primary and secondary containers. In August 2002, LLNL began to also use DOE-STD-3013-2000 containers for HEU oxide and mixed U-Pu oxide. These DOE-STD-3013-2000 containers are comprised of a stainless steel convenience can enclosed in welded stainless steel primary and secondary containers. Compared to the double thin-walled containers, the DOE-STD-3013-2000 containers have substantially thicker walls, and the density of materials in these containers was found to extend over a greater range (1.35 g/cm 3 to 4.62 g/cm 3 ) than foreseen for the double thin-walled containers. Further, the DOE-STD-3013-2000 Standard allows for oxides containing at least 30 wt% Pu plus U whereas the calibration algorithms for thin-walled containers were derived for virtually pure HEU or mixed U-Pu oxides. An initial series of Monte Carlo simulations of the PAN shuffler response to given quantities of HEU oxide and mixed U-Pu oxide in DOE-STD-3013-2000 containers was generated and compared with the response predicted by the calibration algorithms for thin-walled containers. Results showed a decrease on the order of 10% in the count rate, and hence a decrease in the calculated U mass for measured unknowns, with some varying trends versus U mass. Therefore a decision was made to develop a calibration algorithm for the PAN shuffler unique to the DOE-STD-3013-2000 container. This paper describes that effort and selected unknown item measurement results

An NMR-Guided Screening Method for Selective Fragment Docking and Synthesis of a Warhead Inhibitor

Directory of Open Access Journals (Sweden)

Ram B. Khattri

2016-07-01

Full Text Available Selective hits for the glutaredoxin ortholog of Brucella melitensis are determined using STD NMR and verified by trNOE and 15N-HSQC titration. The most promising hit, RK207, was docked into the target molecule using a scoring function to compare simulated poses to experimental data. After elucidating possible poses, the hit was further optimized into the lead compound by extension with an electrophilic acrylamide warhead. We believe that focusing on selectivity in this early stage of drug discovery will limit cross-reactivity that might occur with the human ortholog as the lead compound is optimized. Kinetics studies revealed that lead compound 5 modified with an ester group results in higher reactivity than an acrylamide control; however, after modification this compound shows little selectivity for bacterial protein versus the human ortholog. In contrast, hydrolysis of compound 5 to the acid form results in a decrease in the activity of the compound. Together these results suggest that more optimization is warranted for this simple chemical scaffold, and opens the door for discovery of drugs targeted against glutaredoxin proteins—a heretofore untapped reservoir for antibiotic agents.

An NMR-Guided Screening Method for Selective Fragment Docking and Synthesis of a Warhead Inhibitor.

Science.gov (United States)

Khattri, Ram B; Morris, Daniel L; Davis, Caroline M; Bilinovich, Stephanie M; Caras, Andrew J; Panzner, Matthew J; Debord, Michael A; Leeper, Thomas C

2016-07-16

Selective hits for the glutaredoxin ortholog of Brucella melitensis are determined using STD NMR and verified by trNOE and (15)N-HSQC titration. The most promising hit, RK207, was docked into the target molecule using a scoring function to compare simulated poses to experimental data. After elucidating possible poses, the hit was further optimized into the lead compound by extension with an electrophilic acrylamide warhead. We believe that focusing on selectivity in this early stage of drug discovery will limit cross-reactivity that might occur with the human ortholog as the lead compound is optimized. Kinetics studies revealed that lead compound 5 modified with an ester group results in higher reactivity than an acrylamide control; however, after modification this compound shows little selectivity for bacterial protein versus the human ortholog. In contrast, hydrolysis of compound 5 to the acid form results in a decrease in the activity of the compound. Together these results suggest that more optimization is warranted for this simple chemical scaffold, and opens the door for discovery of drugs targeted against glutaredoxin proteins-a heretofore untapped reservoir for antibiotic agents.

Molecular recognition of epothilones by microtubules and tubulin dimers revealed by biochemical and NMR approaches.

Science.gov (United States)

Canales, Angeles; Nieto, Lidia; Rodríguez-Salarichs, Javier; Sánchez-Murcia, Pedro A; Coderch, Claire; Cortés-Cabrera, Alvaro; Paterson, Ian; Carlomagno, Teresa; Gago, Federico; Andreu, José M; Altmann, Karl-Heinz; Jiménez-Barbero, Jesús; Díaz, J Fernando

2014-04-18

The binding of epothilones to dimeric tubulin and to microtubules has been studied by means of biochemical and NMR techniques. We have determined the binding constants of epothilone A (EpoA) and B (EpoB) to dimeric tubulin, which are 4 orders of magnitude lower than those for microtubules, and we have elucidated the conformation and binding epitopes of EpoA and EpoB when bound to tubulin dimers and microtubules in solution. The determined conformation of epothilones when bound to dimeric tubulin is similar to that found by X-ray crystallographic techniques for the binding of EpoA to the Tubulin/RB3/TTL complex; it is markedly different from that reported for EpoA bound to zinc-induced sheets obtained by electron crystallography. Likewise, only the X-ray structure of EpoA bound to the Tubulin/RB3/TTL complex at the luminal site, but not the electron crystallography structure, is compatible with the results obtained by STD on the binding epitope of EpoA bound to dimeric tubulin, thus confirming that the allosteric change (structuring of the M-loop) is the biochemical mechanism of induction of tubulin assembly by epothilones. TR-NOESY signals of EpoA bound to microtubules have been obtained, supporting the interaction with a transient binding site with a fast exchange rate (pore site), consistent with the notion that epothilones access the luminal site through the pore site, as has also been observed for taxanes. Finally, the differences in the tubulin binding affinities of a series of epothilone analogues has been quantitatively explained using the newly determined binding pose and the COMBINE methodology.

Biosynthetic origin of acetic acid using SNIF-NMR

International Nuclear Information System (INIS)

Boffo, Elisangela Fabiana; Ferreira, Antonio Gilberto

2006-01-01

The main purpose of this work is to describe the use of the technique Site-Specific Natural Isotopic Fractionation of hydrogen (SNIF-NMR), using 2 H and 1 H NMR spectroscopy, to investigate the biosynthetic origin of acetic acid in commercial samples of Brazilian vinegar. This method is based on the deuterium to hydrogen ratio at a specific position (methyl group) of acetic acid obtained by fermentation, through different biosynthetic mechanisms, which result in different isotopic ratios. We measured the isotopic ratio of vinegars obtained through C 3 , C 4 , and CAM biosynthetic mechanisms, blends of C 3 and C 4 (agrins) and synthetic acetic acid. (author)

NMR-based milk metabolomics

DEFF Research Database (Denmark)

Sundekilde, Ulrik; Larsen, Lotte Bach; Bertram, Hanne Christine S.

2013-01-01

and processing capabilities of bovine milk is closely associated to milk composition. Metabolomics is ideal in the study of the low-molecular-weight compounds in milk, and this review focuses on the recent nuclear magnetic resonance (NMR)-based metabolomics trends in milk research, including applications linking...... compounds. Furthermore, metabolomics applications elucidating how the differential regulated genes affects milk composition are also reported. This review will highlight the recent advances in NMR-based metabolomics on milk, as well as give a brief summary of when NMR spectroscopy can be useful for gaining...

Exploring high-resolution magic angle spinning (HR-MAS) NMR spectroscopy for metabonomic analysis of apples.

Science.gov (United States)

Vermathen, Martina; Marzorati, Mattia; Vermathen, Peter

2012-01-01

Classical liquid-state high-resolution (HR) NMR spectroscopy has proved a powerful tool in the metabonomic analysis of liquid food samples like fruit juices. In this paper the application of (1)H high-resolution magic angle spinning (HR-MAS) NMR spectroscopy to apple tissue is presented probing its potential for metabonomic studies. The (1)H HR-MAS NMR spectra are discussed in terms of the chemical composition of apple tissue and compared to liquid-state NMR spectra of apple juice. Differences indicate that specific metabolic changes are induced by juice preparation. The feasibility of HR-MAS NMR-based multivariate analysis is demonstrated by a study distinguishing three different apple cultivars by principal component analysis (PCA). Preliminary results are shown from subsequent studies comparing three different cultivation methods by means of PCA and partial least squares discriminant analysis (PLS-DA) of the HR-MAS NMR data. The compounds responsible for discriminating organically grown apples are discussed. Finally, an outlook of our ongoing work is given including a longitudinal study on apples.

Methods of NMR structure refinement: molecular dynamics simulations improve the agreement with measured NMR data of a C-terminal peptide of GCN4-p1

International Nuclear Information System (INIS)

Dolenc, Jozica; Missimer, John H.; Steinmetz, Michel O.; Gunsteren, Wilfred F. van

2010-01-01

The C-terminal trigger sequence is essential in the coiled-coil formation of GCN4-p1; its conformational properties are thus of importance for understanding this process at the atomic level. A solution NMR model structure of a peptide, GCN4p16-31, encompassing the GCN4-p1 trigger sequence was proposed a few years ago. Derived using a standard single-structure refinement protocol based on 172 nuclear Overhauser effect (NOE) distance restraints, 14 hydrogen-bond and 11 φ torsional-angle restraints, the resulting set of 20 NMR model structures exhibits regular α-helical structure. However, the set slightly violates some measured NOE bounds and does not reproduce all 15 measured 3 J(H N -H Cα )-coupling constants, indicating that different conformers of GCN4p16-31 might be present in solution. With the aim to resolve structures compatible with all NOE upper distance bounds and 3 J-coupling constants, we executed several structure refinement protocols employing unrestrained and restrained molecular dynamics (MD) simulations with two force fields. We find that only configurational ensembles obtained by applying simultaneously time-averaged NOE distance and 3 J-coupling constant restraining with either force field reproduce all the experimental data. Additionally, analyses of the simulated ensembles show that the conformational variability of GCN4p16-31 in solution admitted by the available set of 187 measured NMR data is larger than represented by the set of the NMR model structures. The conformations of GCN4p16-31 in solution differ in the orientation not only of the side-chains but also of the backbone. The inconsistencies between the NMR model structures and the measured NMR data are due to the neglect of averaging effects and the inclusion of hydrogen-bond and torsional-angle restraints that have little basis in the primary, i.e. measured NMR data.

Methods of NMR structure refinement: molecular dynamics simulations improve the agreement with measured NMR data of a C-terminal peptide of GCN4-p1.

Science.gov (United States)

Dolenc, Jozica; Missimer, John H; Steinmetz, Michel O; van Gunsteren, Wilfred F

2010-07-01

The C-terminal trigger sequence is essential in the coiled-coil formation of GCN4-p1; its conformational properties are thus of importance for understanding this process at the atomic level. A solution NMR model structure of a peptide, GCN4p16-31, encompassing the GCN4-p1 trigger sequence was proposed a few years ago. Derived using a standard single-structure refinement protocol based on 172 nuclear Overhauser effect (NOE) distance restraints, 14 hydrogen-bond and 11 phi torsional-angle restraints, the resulting set of 20 NMR model structures exhibits regular alpha-helical structure. However, the set slightly violates some measured NOE bounds and does not reproduce all 15 measured (3)J(H(N)-H(Calpha))-coupling constants, indicating that different conformers of GCN4p16-31 might be present in solution. With the aim to resolve structures compatible with all NOE upper distance bounds and (3)J-coupling constants, we executed several structure refinement protocols employing unrestrained and restrained molecular dynamics (MD) simulations with two force fields. We find that only configurational ensembles obtained by applying simultaneously time-averaged NOE distance and (3)J-coupling constant restraining with either force field reproduce all the experimental data. Additionally, analyses of the simulated ensembles show that the conformational variability of GCN4p16-31 in solution admitted by the available set of 187 measured NMR data is larger than represented by the set of the NMR model structures. The conformations of GCN4p16-31 in solution differ in the orientation not only of the side-chains but also of the backbone. The inconsistencies between the NMR model structures and the measured NMR data are due to the neglect of averaging effects and the inclusion of hydrogen-bond and torsional-angle restraints that have little basis in the primary, i.e. measured NMR data.

NMR imaging of cerebral infarction

International Nuclear Information System (INIS)

Takusagawa, Yoshihiko; Yamaoka, Naoki; Doi, Kazuaki; Okada, Keisei

1987-01-01

One hundred and five patients with cerebral infarction were studied by nuclear magnetic resonance (NMR) CT (resistive type of magnet with strength of 0.1 tesla) and X-ray CT. Pulse sequences used saturation recovery (Tr = 600 mSec), Inversion recovery (Tr = 500 mSec, Td = 300 mSec) and spin echo (Tr = 1500 mSec, Te = 40, 80, 120, 160 mSec). Fifteen cases were examined by NMR-CT within 24 hours from onset. Proton NMR imaging could not detect cerebral ischemia as early as 2 hours after onset, but except could detect the lesions in Se image the area of cerebral infarct 3 hours after onset. After 5 hours from onset image changes in SE were evident and corresponded to the area of cerebral infarct, but image changes in IR could not fully delineate the infarcted area. NMR images of 41 year-old woman with cerebral embolism by MCA trunck occlusion associated with mitral stenosis were presented, and NMR-CT was examined 10 hours, 9th and 43th days after episode of MCA occlusion. Sixty patents (64 times) with lacunar infarction were studied by NMR-CT and X-ray CT. The inversion recovery images were used mainly for detection of lesions and comparison with X-ray CT. In 160 lesions which were detected by NMR-CT or X-ray CT, could 156 lesions be detected by NMR-CT and 78 lesions by X-ray CT. Inversion recovery images were more useful for detection of lacunes than X-ray CT. Calculated T1 and T2 values prolonged with time course from onset. (author)

Analysis of porous media and objects of cultural heritage by mobile NMR

International Nuclear Information System (INIS)

Haber, Agnes

2012-01-01

Low-field NMR techniques are used to study porous system, from simple to complex structures, and objects of cultural heritage. It is shown that NMR relaxometry can be used to study the fluid dynamics inside a porous system. A simple theoretical model for multi-site relaxation exchange NMR is used to extract exchange kinetic parameters when applied on a model porous systems. It provides a first step towards the study of more complex systems, where continuous relaxation distributions are present, such as soil systems or building materials. Moisture migration is observed in the soil systems with the help of 1D and 2D NMR relaxometry methods. In case of the concrete samples, the difference in composition makes a significant difference in the ability of water uptake. The single-sided NMR sensor proves to be a useful tool for on-site measurements. This is very important also in the case of the cultural heritage objects, as most of the objects can not be moved out of their environment. Mobile NMR turns out to be a simple but reliable and powerful tool to investigate moisture distributions and pore structures in porous media as well as the conservation state and history of objects of cultural heritage.

Mössbauer and NMR study of novel Tin(IV)-lactames

International Nuclear Information System (INIS)

Kuzmann, Erno; Szalay, Roland; Homonnay, Zoltan; Nagy, Sandor

2012-01-01

N-tributylstannylated 2-pyrrolidinone was reacted with tributyltin triflate in different molar ratios and the complex formation monitored using 1 H-NMR, 13 C-NMR and 119 Sn Mössbauer spectroscopy. Comparing the carbon NMR and tin Mössbauer results, a reaction scheme is suggested for the complexation which assumes the formation of a simultaneously O- and N-tributylstannylated pyrrolidinone cation. The formation of the only O-stannylated pyrrolidinone is also assumed to account for the non-constant Mössbauer parameters of the two tin environments in the distannylated pyrrolidinone cation when the ratio of tributyltin triflate is increased in the reaction.

Short-Term Impact of Safer Choices: A Multicomponent, School-Based HIV, Other STD, and Pregnancy Prevention Program.

Science.gov (United States)

Coyle, Karin; Basen-Engquist, Karen; Kirby, Douglas; Parcel, Guy; Banspach, Stephen; Harrist, Ronald; Baumler, Elizabeth; Weil, Marsha

1999-01-01

Evaluated the effectiveness of the first year of "Safer Choices," a two-year, multicomponent HIV, STD, and pregnancy-prevention program for high school students based on social theory. Student self-report surveys indicated that "Safer Choices" succeeded in reducing selected risk behaviors and in enhancing selected protective…

Reducing offensiveness of STD prevention advertisements in China.

Science.gov (United States)

Waller, David S; Fam, Kim-Shyan

2011-01-01

The issue of sexually transmitted diseases is a socially sensitive one in Asian communities, with governments being criticized for not doing enough to reduce AIDS transmission, and the advertising of such issues potentially causing offense to people. This article surveys 630 people in China to determine their level of offense toward the advertising of condoms and STD prevention and analyzes the qualitative responses to how they would reduce the offensiveness of such advertising. The results found that generally women are more offended by the advertising of these products than men, and in terms of creative execution, women prefer implicit, prevention or effects messages, whereas men suggested a scientific message, or a focus on the creative strategy or media/location of the advertisement. It is recommended that traditional Chinese Confucian values are important for public policy makers to keep in mind when wanting to advertise socially sensitive issues in China and wider Asia.

Overcoming the solubility limit with solubility-enhancement tags: successful applications in biomolecular NMR studies

International Nuclear Information System (INIS)

Zhou Pei; Wagner, Gerhard

2010-01-01

Although the rapid progress of NMR technology has significantly expanded the range of NMR-trackable systems, preparation of NMR-suitable samples that are highly soluble and stable remains a bottleneck for studies of many biological systems. The application of solubility-enhancement tags (SETs) has been highly effective in overcoming solubility and sample stability issues and has enabled structural studies of important biological systems previously deemed unapproachable by solution NMR techniques. In this review, we provide a brief survey of the development and successful applications of the SET strategy in biomolecular NMR. We also comment on the criteria for choosing optimal SETs, such as for differently charged target proteins, and recent new developments on NMR-invisible SETs.

Comparing pharmacophore models derived from crystallography and NMR ensembles

Science.gov (United States)

Ghanakota, Phani; Carlson, Heather A.

2017-11-01

NMR and X-ray crystallography are the two most widely used methods for determining protein structures. Our previous study examining NMR versus X-Ray sources of protein conformations showed improved performance with NMR structures when used in our Multiple Protein Structures (MPS) method for receptor-based pharmacophores (Damm, Carlson, J Am Chem Soc 129:8225-8235, 2007). However, that work was based on a single test case, HIV-1 protease, because of the rich data available for that system. New data for more systems are available now, which calls for further examination of the effect of different sources of protein conformations. The MPS technique was applied to Growth factor receptor bound protein 2 (Grb2), Src SH2 homology domain (Src-SH2), FK506-binding protein 1A (FKBP12), and Peroxisome proliferator-activated receptor-γ (PPAR-γ). Pharmacophore models from both crystal and NMR ensembles were able to discriminate between high-affinity, low-affinity, and decoy molecules. As we found in our original study, NMR models showed optimal performance when all elements were used. The crystal models had more pharmacophore elements compared to their NMR counterparts. The crystal-based models exhibited optimum performance only when pharmacophore elements were dropped. This supports our assertion that the higher flexibility in NMR ensembles helps focus the models on the most essential interactions with the protein. Our studies suggest that the "extra" pharmacophore elements seen at the periphery in X-ray models arise as a result of decreased protein flexibility and make very little contribution to model performance.

NMR-Metabolic Methodology in the Study of GM Foods

Directory of Open Access Journals (Sweden)

Irene D’Amico

2010-01-01

Full Text Available The 1H-NMR methodology used in the study of genetically modified (GM foods is discussed. Transgenic lettuce (Lactuca sativa cv "Luxor" over-expressing the Arabidopsis KNAT1 gene is presented as a case study. Twenty-two water-soluble metabolites (amino acids, organic acids, sugars present in leaves of conventional and GM lettuce were monitored by NMR and quantified at two developmental stages. The NMR spectra did not reveal any difference in metabolite composition between the GM lettuce and the wild type counterpart. Statistical analyses of metabolite variables highlighted metabolism variation as a function of leaf development as well as the transgene. A main effect of the transgene was in altering sugar metabolism.

STD screening, testing, case reporting, and clinical and partner notification practices: a national survey of US physicians.

Science.gov (United States)

St Lawrence, Janet S; Montaño, Daniel E; Kasprzyk, Danuta; Phillips, William R; Armstrong, Keira; Leichliter, Jami S

2002-11-01

This study presents results from a national survey of US physicians that assessed screening, case reporting, partner management, and clinical practices for syphilis, gonorrhea, chlamydia, and HIV infection. Surveys were mailed to a random sample of 7300 physicians to assess screening, testing, reporting, and partner notification for syphilis, gonorrhea, chlamydia, and HIV. Fewer than one third of physicians routinely screened men or women (pregnant or nonpregnant) for STDs. Case reporting was lowest for chlamydia (37 percent), intermediate for gonorrhea (44 percent), and higher for syphilis, HIV, and AIDS (53 percent-57 percent). Physicians instructed patients to notify their partners (82 percent-89 percent) or the health department (25 percent-34 percent) rather than doing so themselves. STD screening levels are well below practice guidelines for women and virtually nonexistent for men. Case reporting levels are below those legally mandated; physicians rely instead on patients for partner notification. Health departments must increase collaboration with private physicians to improve the quality of STD care.

Fluorine dynamics in BaF2 superionic conductors investigated by NMR

OpenAIRE

Gumann, Patryk

2008-01-01

In this work the dynamics of fluorine in solid-state electrolytes having BaF2-structure was investigated using three different NMR-methods: field cycling relaxometry, lineshape analysis, and static field gradient NMR. For this purpose a pure BaF2 crystal, as well as crystals doped with trivalent impurities (LaF3), were studied as a function of temperature. The main goal of this investigation was to utilize the structure information provided by neutron scattering and MAS NMR data in order to s...

β-NMR sample optimization

CERN Document Server

Zakoucka, Eva

2013-01-01

During my summer student programme I was working on sample optimization for a new β-NMR project at the ISOLDE facility. The β-NMR technique is well-established in solid-state physics and just recently it is being introduced for applications in biochemistry and life sciences. The β-NMR collaboration will be applying for beam time to the INTC committee in September for three nuclei: Cu, Zn and Mg. Sample optimization for Mg was already performed last year during the summer student programme. Therefore sample optimization for Cu and Zn had to be completed as well for the project proposal. My part in the project was to perform thorough literature research on techniques studying Cu and Zn complexes in native conditions, search for relevant binding candidates for Cu and Zn applicable for ß-NMR and eventually evaluate selected binding candidates using UV-VIS spectrometry.

Microprocessorized NMR measurement

International Nuclear Information System (INIS)

Rijllart, A.

1984-01-01

An MC68000 CAMAC microprocessor system for fast and accurate NMR signal measurement will be presented. A stand-alone CAMAC microprocessor system (MC68000 STAC) with a special purpose interface sweeps a digital frequency synthesizer and digitizes the NMR signal with a 16-bit ADC of 17 μs conversion time. It averages the NMR signal data over many sweeps and then transfers it through CAMAC to a computer for calculation of the signal parameters. The computer has full software control over the timing and sweep settings of this signal averager, and thus allows optimization of noise suppression. Several of these processor systems can be installed in the same crate for parallel processing, and the flexibility of the STAC also allows easy adaptation to other applications such as transient recording or phase-sensitive detection. (orig.)

Anticipated Notification of Sexual Partners following STD Diagnosis among Men Who Have Sex with Men and Transgender Women in Lima, Peru: A Mixed Methods Analysis

Science.gov (United States)

Clark, Jesse L.; Perez-Brumer, Amaya G.; Segura, Eddy R.; Salvatierra, Hector J.; Sanchez, Jorge; Lama, Javier R.

2016-01-01

Background New strategies to support partner notification (PN) are critical for STD control and require detailed understanding of how specific individual and partnership characteristics guide notification decisions. Methods From 2011 to 2012, 397 MSM and TW recently diagnosed with HIV, syphilis, or another STD completed a survey on anticipated notification of recent sexual partners and associated factors. Qualitative interviews were conducted with a subset of participants to provide further depth to quantitative findings. Prevalence ratios and generalized estimating equation (GEE) models were used to analyze participant- and partner-level factors associated with anticipated PN. Results Among all partners reported, 52.5% were described as “Very Likely” or “Somewhat Likely” to be notified. Anticipated notification was more likely for main partners than casual (adjusted Prevalence Ratio [aPR], 95% CI: 0.63, 0.54–0.75) or commercial (aPR, 95% CI: 0.44, 0.31–0.62) partners. Other factors associated with likely notification included perception of the partner as an STD source (aPR, 95% CI: 1.27, 1.10–1.48) and anticipated future sexual contact with the partner (aPR, 95% CI: 1.30, 1.11–1.52). An HIV diagnosis was associated with a lower likelihood of notification than non-HIV STDs (aPR: 0.68, 0.55–0.86). Qualitative discussion of the barriers and incentives to PN reflected a similar differentiation of anticipated notification according to partnership type and type of HIV/STD diagnosis. Discussion Detailed attention to how partnership characteristics guide notification outcomes is essential to the development of new PN strategies. By accurately and thoroughly assessing the diversity of partnership interactions among individuals with HIV/STD, new notification techniques can be tailored to partner-specific circumstances. PMID:27685158

Fourier transform n.m.r. spectroscopy

International Nuclear Information System (INIS)

Shaw, D.

1976-01-01

This book is orientated to techniques rather than applications. The basic theory of n.m.r. is dealt with in a unified approach to the Fourier theory. The middle section of the book concentrates on the practical aspects of Fourier n.m.r., both instrumental and experimental. The final chapters briefly cover general application of n.m.r., but concentrate strongly on those areas where Fourier n.m.r. can give information which is not available by conventional techniques

Fundamentals of Protein NMR Spectroscopy

CERN Document Server

Rule, Gordon S

2006-01-01

NMR spectroscopy has proven to be a powerful technique to study the structure and dynamics of biological macromolecules. Fundamentals of Protein NMR Spectroscopy is a comprehensive textbook that guides the reader from a basic understanding of the phenomenological properties of magnetic resonance to the application and interpretation of modern multi-dimensional NMR experiments on 15N/13C-labeled proteins. Beginning with elementary quantum mechanics, a set of practical rules is presented and used to describe many commonly employed multi-dimensional, multi-nuclear NMR pulse sequences. A modular analysis of NMR pulse sequence building blocks also provides a basis for understanding and developing novel pulse programs. This text not only covers topics from chemical shift assignment to protein structure refinement, as well as the analysis of protein dynamics and chemical kinetics, but also provides a practical guide to many aspects of modern spectrometer hardware, sample preparation, experimental set-up, and data pr...

An introduction to biological NMR spectroscopy

International Nuclear Information System (INIS)

Marion, Dominique

2013-01-01

NMR spectroscopy is a powerful tool for biologists interested in the structure, dynamics, and interactions of biological macromolecules. This review aims at presenting in an accessible manner the requirements and limitations of this technique. As an introduction, the history of NMR will highlight how the method evolved from physics to chemistry and finally to biology over several decades. We then introduce the NMR spectral parameters used in structural biology, namely the chemical shift, the J-coupling, nuclear Overhauser effects, and residual dipolar couplings. Resonance assignment, the required step for any further NMR study, bears a resemblance to jigsaw puzzle strategy. The NMR spectral parameters are then converted into angle and distances and used as input using restrained molecular dynamics to compute a bundle of structures. When interpreting a NMR-derived structure, the biologist has to judge its quality on the basis of the statistics provided. When the 3D structure is a priori known by other means, the molecular interaction with a partner can be mapped by NMR: information on the binding interface as well as on kinetic and thermodynamic constants can be gathered. NMR is suitable to monitor, over a wide range of frequencies, protein fluctuations that play a crucial role in their biological function. In the last section of this review, intrinsically disordered proteins, which have escaped the attention of classical structural biology, are discussed in the perspective of NMR, one of the rare available techniques able to describe structural ensembles. This Tutorial is part of the International Proteomics Tutorial Programme (IPTP 16 MCP). (authors)

Recent Advances in Multinuclear NMR Spectroscopy for Chiral Recognition of Organic Compounds

Directory of Open Access Journals (Sweden)

Márcio S. Silva

2017-02-01

Full Text Available Nuclear magnetic resonance (NMR is a powerful tool for the elucidation of chemical structure and chiral recognition. In the last decade, the number of probes, media, and experiments to analyze chiral environments has rapidly increased. The evaluation of chiral molecules and systems has become a routine task in almost all NMR laboratories, allowing for the determination of molecular connectivities and the construction of spatial relationships. Among the features that improve the chiral recognition abilities by NMR is the application of different nuclei. The simplicity of the multinuclear NMR spectra relative to 1H, the minimal influence of the experimental conditions, and the larger shift dispersion make these nuclei especially suitable for NMR analysis. Herein, the recent advances in multinuclear (19F, 31P, 13C, and 77Se NMR spectroscopy for chiral recognition of organic compounds are presented. The review describes new chiral derivatizing agents and chiral solvating agents used for stereodiscrimination and the assignment of the absolute configuration of small organic compounds.

PA171 Containers on a Wood Pallet with Metal Top Adapter, Air Pressure Tests During MIL-STD-1660 Tests

National Research Council Canada - National Science Library

2004-01-01

... (PM-MAS) to conduct Air Pressure Tests during MIL-STD-1660, "Design Criteria for Ammunition Unit Loads" testing on the PA171 containers on a wood pallet with metal top adapter as manufactured by Alliant Tech...

Functional studies using NMR

International Nuclear Information System (INIS)

McCready, V.R.; Leach, M.; Ell, P.J.

1987-01-01

This volume is based on a series of lectures delivered at a one-day teaching symposium on functional and metabolic aspects of NMR measurements held at the Middlesex Hospital Medical School on 1st September 1985 as a part of the European Nuclear Medicine Society Congress. Currently the major emphasis in medical NMR in vivo is on its potential to image and display abnormalities in conventional radiological images, providing increased contrast between normal and abnormal tissue, improved definition of vasculature, and possibly an increased potential for differential diagnosis. Although these areas are undeniably of major importance, it is probable that NMR will continue to complement conventional measurement methods. The major potential benefits to be derived from in vivo NMR measurements are likely to arise from its use as an instrument for functional and metabolic studies in both clinical research and in the everyday management of patients. It is to this area that this volume is directed

NMR quantification of diffusional exchange in cell suspensions with relaxation rate differences between intra and extracellular compartments.

Science.gov (United States)

Eriksson, Stefanie; Elbing, Karin; Söderman, Olle; Lindkvist-Petersson, Karin; Topgaard, Daniel; Lasič, Samo

2017-01-01

Water transport across cell membranes can be measured non-invasively with diffusion NMR. We present a method to quantify the intracellular lifetime of water in cell suspensions with short transverse relaxation times, T2, and also circumvent the confounding effect of different T2 values in the intra- and extracellular compartments. Filter exchange spectroscopy (FEXSY) is specifically sensitive to exchange between compartments with different apparent diffusivities. Our investigation shows that FEXSY could yield significantly biased results if differences in T2 are not accounted for. To mitigate this problem, we propose combining FEXSY with diffusion-relaxation correlation experiment, which can quantify differences in T2 values in compartments with different diffusivities. Our analysis uses a joint constrained fitting of the two datasets and considers the effects of diffusion, relaxation and exchange in both experiments. The method is demonstrated on yeast cells with and without human aquaporins.

NMR detected metabolites in complex natural fluids. Quinic acid in apple juice

Directory of Open Access Journals (Sweden)

Ailiesei Gabriela Liliana

2015-12-01

Full Text Available Different types of 1D and 2D NMR experiments were used to completely characterize quinic acid and demonstrate its presence in complex mixtures. The identification of quinic acid in apple juice was done without any separation step. The NMR experiments presented in this study can be used to analyze other metabolites in different complex natural fluids, of vegetal or biological origin.

Structure determination of helical filaments by solid-state NMR spectroscopy

Science.gov (United States)

Ahmed, Mumdooh; Spehr, Johannes; König, Renate; Lünsdorf, Heinrich; Rand, Ulfert; Lührs, Thorsten; Ritter, Christiane

2016-01-01

The controlled formation of filamentous protein complexes plays a crucial role in many biological systems and represents an emerging paradigm in signal transduction. The mitochondrial antiviral signaling protein (MAVS) is a central signal transduction hub in innate immunity that is activated by a receptor-induced conversion into helical superstructures (filaments) assembled from its globular caspase activation and recruitment domain. Solid-state NMR (ssNMR) spectroscopy has become one of the most powerful techniques for atomic resolution structures of protein fibrils. However, for helical filaments, the determination of the correct symmetry parameters has remained a significant hurdle for any structural technique and could thus far not be precisely derived from ssNMR data. Here, we solved the atomic resolution structure of helical MAVSCARD filaments exclusively from ssNMR data. We present a generally applicable approach that systematically explores the helical symmetry space by efficient modeling of the helical structure restrained by interprotomer ssNMR distance restraints. Together with classical automated NMR structure calculation, this allowed us to faithfully determine the symmetry that defines the entire assembly. To validate our structure, we probed the protomer arrangement by solvent paramagnetic resonance enhancement, analysis of chemical shift differences relative to the solution NMR structure of the monomer, and mutagenesis. We provide detailed information on the atomic contacts that determine filament stability and describe mechanistic details on the formation of signaling-competent MAVS filaments from inactive monomers. PMID:26733681

NMR structure of the protein NP-247299.1: comparison with the crystal structure

International Nuclear Information System (INIS)

Jaudzems, Kristaps; Geralt, Michael; Serrano, Pedro; Mohanty, Biswaranjan; Horst, Reto; Pedrini, Bill; Elsliger, Marc-André; Wilson, Ian A.; Wüthrich, Kurt

2010-01-01

Comparison of the NMR and crystal structures of a protein determined using largely automated methods has enabled the interpretation of local differences in the highly similar structures. These differences are found in segments of higher B values in the crystal and correlate with dynamic processes on the NMR chemical shift timescale observed in solution. The NMR structure of the protein NP-247299.1 in solution at 313 K has been determined and is compared with the X-ray crystal structure, which was also solved in the Joint Center for Structural Genomics (JCSG) at 100 K and at 1.7 Å resolution. Both structures were obtained using the current largely automated crystallographic and solution NMR methods used by the JCSG. This paper assesses the accuracy and precision of the results from these recently established automated approaches, aiming for quantitative statements about the location of structure variations that may arise from either one of the methods used or from the different environments in solution and in the crystal. To evaluate the possible impact of the different software used for the crystallographic and the NMR structure determinations and analysis, the concept is introduced of reference structures, which are computed using the NMR software with input of upper-limit distance constraints derived from the molecular models representing the results of the two structure determinations. The use of this new approach is explored to quantify global differences that arise from the different methods of structure determination and analysis versus those that represent interesting local variations or dynamics. The near-identity of the protein core in the NMR and crystal structures thus provided a basis for the identification of complementary information from the two different methods. It was thus observed that locally increased crystallographic B values correlate with dynamic structural polymorphisms in solution, including that the solution state of the protein involves

Lectures on pulsed NMR

International Nuclear Information System (INIS)

Pines, A.

1986-09-01

These lectures discuss some recent developments in pulsed NMR, emphasizing fundamental principles with selected illustrative applications. Major topics covered include multiple-quantum spectroscopy, spin decoupling, the interaction of spins with a quantized field, adiabatic rapid passage, spin temperature and statistics of cross-polarization, coherent averaging, and zero field NMR. 55 figs

NMR spectroscopy using liquid crystal solvents

CERN Document Server

Emsley, JW

2013-01-01

NMR Spectroscopy using Liquid Crystal Solvents covers the importance of using a liquid crystal solvent in NMR to derive nuclear dipolar spin-spin coupling constants. This book is composed of ten chapters, and begins with a brief description of the features and benefits of liquid crystal in NMR spectroscopic analysis. The succeeding chapters deal with the mode of operation of nuclear spin Hamiltonian for partially oriented molecules and the analysis of NMR spectra of partially oriented molecules, as well as the determination of rigid molecule structure. These topics are followed by discussions

NMR studies of isotopically labeled RNA

Energy Technology Data Exchange (ETDEWEB)

Pardi, A. [Univ. of Colorado, Boulder, CO (United States)

1994-12-01

In summary, the ability to generate NMR quantities of {sup 15}N and {sup 13}C-labeled RNAs has led to the development of heteronuclear multi-dimensional NMR techniques for simplifying the resonance assignment and structure determination of RNAs. These methods for synthesizing isotopically labeled RNAs are only several years old, and thus there are still relatively few applications of heteronuclear multi-dimensional NMR techniques to RNA. However, given the critical role that RNAs play in cellular function, one can expect to see an increasing number of NMR structural studies of biologically active RNAs.

1H-NMR, 1H-NMR T2-edited, and 2D-NMR in bipolar disorder metabolic profiling.

Science.gov (United States)

Sethi, Sumit; Pedrini, Mariana; Rizzo, Lucas B; Zeni-Graiff, Maiara; Mas, Caroline Dal; Cassinelli, Ana Cláudia; Noto, Mariane N; Asevedo, Elson; Cordeiro, Quirino; Pontes, João G M; Brasil, Antonio J M; Lacerda, Acioly; Hayashi, Mirian A F; Poppi, Ronei; Tasic, Ljubica; Brietzke, Elisa

2017-12-01

The objective of this study was to identify molecular alterations in the human blood serum related to bipolar disorder, using nuclear magnetic resonance (NMR) spectroscopy and chemometrics. Metabolomic profiling, employing 1 H-NMR, 1 H-NMR T 2 -edited, and 2D-NMR spectroscopy and chemometrics of human blood serum samples from patients with bipolar disorder (n = 26) compared with healthy volunteers (n = 50) was performed. The investigated groups presented distinct metabolic profiles, in which the main differential metabolites found in the serum sample of bipolar disorder patients compared with those from controls were lipids, lipid metabolism-related molecules (choline, myo-inositol), and some amino acids (N-acetyl-L-phenyl alanine, N-acetyl-L-aspartyl-L-glutamic acid, L-glutamine). In addition, amygdalin, α-ketoglutaric acid, and lipoamide, among other compounds, were also present or were significantly altered in the serum of bipolar disorder patients. The data presented herein suggest that some of these metabolites differentially distributed between the groups studied may be directly related to the bipolar disorder pathophysiology. The strategy employed here showed significant potential for exploring pathophysiological features and molecular pathways involved in bipolar disorder. Thus, our findings may contribute to pave the way for future studies aiming at identifying important potential biomarkers for bipolar disorder diagnosis or progression follow-up.

Quantitative analysis of protein-ligand interactions by NMR.

Science.gov (United States)

Furukawa, Ayako; Konuma, Tsuyoshi; Yanaka, Saeko; Sugase, Kenji

2016-08-01

Protein-ligand interactions have been commonly studied through static structures of the protein-ligand complex. Recently, however, there has been increasing interest in investigating the dynamics of protein-ligand interactions both for fundamental understanding of the underlying mechanisms and for drug development. NMR is a versatile and powerful tool, especially because it provides site-specific quantitative information. NMR has widely been used to determine the dissociation constant (KD), in particular, for relatively weak interactions. The simplest NMR method is a chemical-shift titration experiment, in which the chemical-shift changes of a protein in response to ligand titration are measured. There are other quantitative NMR methods, but they mostly apply only to interactions in the fast-exchange regime. These methods derive the dissociation constant from population-averaged NMR quantities of the free and bound states of a protein or ligand. In contrast, the recent advent of new relaxation-based experiments, including R2 relaxation dispersion and ZZ-exchange, has enabled us to obtain kinetic information on protein-ligand interactions in the intermediate- and slow-exchange regimes. Based on R2 dispersion or ZZ-exchange, methods that can determine the association rate, kon, dissociation rate, koff, and KD have been developed. In these approaches, R2 dispersion or ZZ-exchange curves are measured for multiple samples with different protein and/or ligand concentration ratios, and the relaxation data are fitted to theoretical kinetic models. It is critical to choose an appropriate kinetic model, such as the two- or three-state exchange model, to derive the correct kinetic information. The R2 dispersion and ZZ-exchange methods are suitable for the analysis of protein-ligand interactions with a micromolar or sub-micromolar dissociation constant but not for very weak interactions, which are typical in very fast exchange. This contrasts with the NMR methods that are used

Lectures on pulsed NMR

International Nuclear Information System (INIS)

Pines, A.

1988-08-01

These lectures discuss some recent developments in pulsed NMR, emphasizing fundamental principles with selected illustrative applications. Major topics covered include multiple-quantum spectroscopy, spin decoupling, the interaction of spins with a quantized field, adiabatic rapid passage, spin temperature and statistics of cross-polarization, coherent averaging, and zero field NMR. 32 refs., 56 figs

Efficient cellular solid-state NMR of membrane proteins by targeted protein labeling

Energy Technology Data Exchange (ETDEWEB)

Baker, Lindsay A. [University of Oxford, Oxford Particle Imaging Centre, The Wellcome Trust Centre for Human Genetics, Division of Structural Biology, Nuffield Department of Medicine (United Kingdom); Daniëls, Mark; Cruijsen, Elwin A. W. van der; Folkers, Gert E.; Baldus, Marc, E-mail: m.baldus@uu.nl [Utrecht University, NMR Spectroscopy, Department of Chemistry, Faculty of Science, Bijvoet Center for Biomolecular Research (Netherlands)

2015-06-15

Solid-state NMR spectroscopy (ssNMR) has made significant progress towards the study of membrane proteins in their native cellular membranes. However, reduced spectroscopic sensitivity and high background signal levels can complicate these experiments. Here, we describe a method for ssNMR to specifically label a single protein by repressing endogenous protein expression with rifampicin. Our results demonstrate that treatment of E. coli with rifampicin during induction of recombinant membrane protein expression reduces background signals for different expression levels and improves sensitivity in cellular membrane samples. Further, the method reduces the amount of time and resources needed to produce membrane protein samples, enabling new strategies for studying challenging membrane proteins by ssNMR.

Efficient cellular solid-state NMR of membrane proteins by targeted protein labeling

International Nuclear Information System (INIS)

Baker, Lindsay A.; Daniëls, Mark; Cruijsen, Elwin A. W. van der; Folkers, Gert E.; Baldus, Marc

2015-01-01

Solid-state NMR spectroscopy (ssNMR) has made significant progress towards the study of membrane proteins in their native cellular membranes. However, reduced spectroscopic sensitivity and high background signal levels can complicate these experiments. Here, we describe a method for ssNMR to specifically label a single protein by repressing endogenous protein expression with rifampicin. Our results demonstrate that treatment of E. coli with rifampicin during induction of recombinant membrane protein expression reduces background signals for different expression levels and improves sensitivity in cellular membrane samples. Further, the method reduces the amount of time and resources needed to produce membrane protein samples, enabling new strategies for studying challenging membrane proteins by ssNMR

Solid-state NMR basic principles and practice

CERN Document Server

Apperley, David C; Hodgkinson, Paul

2014-01-01

Nuclear Magnetic Resonance (NMR) has proved to be a uniquely powerful and versatile tool for analyzing and characterizing chemicals and materials of all kinds. This book focuses on the latest developments and applications for "solid-state" NMR, which has found new uses from archaeology to crystallography to biomaterials and pharmaceutical science research. The book will provide materials engineers, analytical chemists, and physicists, in and out of lab, a survey of the techniques and the essential tools of solid-state NMR, together with a practical guide on applications. In this concise introduction to the growing field of solid-state nuclear magnetic resonance spectroscopy The reader will find: * Basic NMR concepts for solids, including guidance on the spin-1/2 nuclei concept * Coverage of the quantum mechanics aspects of solid state NMR and an introduction to the concept of quadrupolar nuclei * An understanding relaxation, exchange and quantitation in NMR * An analysis and interpretation of NMR data, with e...

High resolution NMR theory and chemical applications

CERN Document Server

Becker, Edwin D

1999-01-01

High Resolution NMR provides a broad treatment of the principles and theory of nuclear magnetic resonance (NMR) as it is used in the chemical sciences. It is written at an "intermediate" level, with mathematics used to augment, rather than replace, clear verbal descriptions of the phenomena. The book is intended to allow a graduate student, advanced undergraduate, or researcher to understand NMR at a fundamental level, and to see illustrations of the applications of NMR to the determination of the structure of small organic molecules and macromolecules, including proteins. Emphasis is on the study of NMR in liquids, but the treatment also includes high resolution NMR in the solid state and the principles of NMR imaging and localized spectroscopy. Careful attention is given to developing and interrelating four approaches - steady state energy levels, the rotating vector picture, the density matrix, and the product operator formalism. The presentation is based on the assumption that the reader has an acquaintan...

High resolution NMR spectroscopy of synthetic polymers in bulk

International Nuclear Information System (INIS)

Komorski, R.A.

1986-01-01

The contents of this book are: Overview of high-resolution NMR of solid polymers; High-resolution NMR of glassy amorphous polymers; Carbon-13 solid-state NMR of semicrystalline polymers; Conformational analysis of polymers of solid-state NMR; High-resolution NMR studies of oriented polymers; High-resolution solid-state NMR of protons in polymers; and Deuterium NMR of solid polymers. This work brings together the various approaches for high-resolution NMR studies of bulk polymers into one volume. Heavy emphasis is, of course, given to 13C NMR studies both above and below Tg. Standard high-power pulse and wide-line techniques are not covered

78 FR 64221 - CDC/HRSA Advisory Committee on HIV, Viral Hepatitis and STD Prevention and Treatment; Notice of...

Science.gov (United States)

2013-10-28

... Advisory Committee on HIV, Viral Hepatitis and STD Prevention and Treatment; Notice of Meeting In... Administrator, HRSA, regarding activities related to prevention and control of HIV/AIDS, Viral Hepatitis and... professionals and the public about HIV/AIDS, Viral Hepatitis, and other STDs. Agenda: Agenda items include: (1...

Methods of NMR structure refinement: molecular dynamics simulations improve the agreement with measured NMR data of a C-terminal peptide of GCN4-p1

Energy Technology Data Exchange (ETDEWEB)

Dolenc, Jozica [Swiss Federal Institute of Technology, Laboratory of Physical Chemistry, ETH (Switzerland); Missimer, John H.; Steinmetz, Michel O. [Paul Scherrer Institut, Biomolecular Research (Switzerland); Gunsteren, Wilfred F. van, E-mail: wfvgn@igc.phys.chem.ethz.c [Swiss Federal Institute of Technology, Laboratory of Physical Chemistry, ETH (Switzerland)

2010-07-15

The C-terminal trigger sequence is essential in the coiled-coil formation of GCN4-p1; its conformational properties are thus of importance for understanding this process at the atomic level. A solution NMR model structure of a peptide, GCN4p16-31, encompassing the GCN4-p1 trigger sequence was proposed a few years ago. Derived using a standard single-structure refinement protocol based on 172 nuclear Overhauser effect (NOE) distance restraints, 14 hydrogen-bond and 11 {phi} torsional-angle restraints, the resulting set of 20 NMR model structures exhibits regular {alpha}-helical structure. However, the set slightly violates some measured NOE bounds and does not reproduce all 15 measured {sup 3}J(H{sub N}-H{sub C{alpha}})-coupling constants, indicating that different conformers of GCN4p16-31 might be present in solution. With the aim to resolve structures compatible with all NOE upper distance bounds and {sup 3}J-coupling constants, we executed several structure refinement protocols employing unrestrained and restrained molecular dynamics (MD) simulations with two force fields. We find that only configurational ensembles obtained by applying simultaneously time-averaged NOE distance and {sup 3}J-coupling constant restraining with either force field reproduce all the experimental data. Additionally, analyses of the simulated ensembles show that the conformational variability of GCN4p16-31 in solution admitted by the available set of 187 measured NMR data is larger than represented by the set of the NMR model structures. The conformations of GCN4p16-31 in solution differ in the orientation not only of the side-chains but also of the backbone. The inconsistencies between the NMR model structures and the measured NMR data are due to the neglect of averaging effects and the inclusion of hydrogen-bond and torsional-angle restraints that have little basis in the primary, i.e. measured NMR data.

The NMR probe of high-Tc materials and correlated electron systems. 2. ed.

International Nuclear Information System (INIS)

Walstedt, Russell E.

2018-01-01

This new edition updates readers in three areas of NMR studies, namely, recent developments in high-T c materials, heavy fermion systems and actinide oxides are presented. The NMR probe has yielded a vast array of data for solid state materials, corresponding to different compounds, ionic sites, and nuclear species, as well as to a wide variety of experimental conditions. The last two parts of the book are completely new in this edition, while the first part has seen major updates. This edition features the latest developments for high-T c materials, especially the advances in the area of pseudogap studies are reviewed. An in depth overview of heavy fermion systems is presented in the second part, notably Kondo lattices, quantum critical points and unconventional superconductivity are areas of intense research recently and are covered extensively. Finally, valuable information from NMR studies with actinide oxides will be provided. Ongoing analysis and discussion of NMR data have resulted in a wealth of important insights into the physics of these exotic systems. The aims of this monograph are manifold. First, it reviews NMR methodology as it has been applied to the different studies. This is addressed to NMR practitioners and to physics laypersons alike. Next, it presents a review of NMR measurements and the wide variety of phenomena which they represent. The third phase is to recount the theoretical model calculations and other proposals which have been put forward to account for these data.

Quantitative produced water analysis using mobile 1H NMR

International Nuclear Information System (INIS)

Wagner, Lisabeth; Fridjonsson, Einar O; May, Eric F; Stanwix, Paul L; Graham, Brendan F; Carroll, Matthew R J; Johns, Michael L; Kalli, Chris

2016-01-01

Measurement of oil contamination of produced water is required in the oil and gas industry to the (ppm) level prior to discharge in order to meet typical environmental legislative requirements. Here we present the use of compact, mobile 1 H nuclear magnetic resonance (NMR) spectroscopy, in combination with solid phase extraction (SPE), to meet this metrology need. The NMR hardware employed featured a sufficiently homogeneous magnetic field, such that chemical shift differences could be used to unambiguously differentiate, and hence quantitatively detect, the required oil and solvent NMR signals. A solvent system consisting of 1% v/v chloroform in tetrachloroethylene was deployed, this provided a comparable 1 H NMR signal intensity for the oil and the solvent (chloroform) and hence an internal reference 1 H signal from the chloroform resulting in the measurement being effectively self-calibrating. The measurement process was applied to water contaminated with hexane or crude oil over the range 1–30 ppm. The results were validated against known solubility limits as well as infrared analysis and gas chromatography. (paper)

Structural Studies of Biological Solids Using NMR

Science.gov (United States)

Ramamoorthy, Ayyalusamy

2011-03-01

High-resolution structure and dynamics of biological molecules are important in understanding their function. While studies have been successful in solving the structures of water-soluble biomolecules, it has been proven difficult to determine the structures of membrane proteins and fibril systems. Recent studies have shown that solid-state NMR is a promising technique and could be highly valuable in studying such non-crystalline and non-soluble biosystems. I will present strategies to study the structures of such challenging systems and also about the applications of solid-state NMR to study the modes of membrane-peptide interactions for a better assessment of the prospects of antimicrobial peptides as substitutes to antibiotics in the control of human disease. Our studies on the mechanism of membrane disruption by LL-37 (a human antimicrobial peptide), analogs of the naturally occurring antimicrobial peptide magainin2 extracted from the skin of the African frog Xenopus Laevis, and pardaxin will be presented. Solid-state NMR experiments were used to determine the secondary structure, dynamics and topology of these peptides in lipid bilayers. Similarities and difference in the cell-lysing mechanism, and their dependence on the membrane composition, of these peptides will be discussed. Atomic-level resolution NMR structures of amyloidogenic proteins revealing the misfolding pathway and early intermediates that play key roles in amyloid toxicity will also be presented.

International symposium on NMR spectroscopy

International Nuclear Information System (INIS)

The publication consists of 32 papers and presentations from the field of NMR spectroscopy applications submitted to the International Symposium on NMR Spectroscopy held at Smolenice between 29 Sep and 3 Oct, 1980. (B.S.)

Public opinion about condoms for HIV and STD prevention: a Midwestern state telephone survey.

Science.gov (United States)

Yarber, William L; Milhausen, Robin R; Crosby, Richard A; Torabi, Mohammad R

2005-09-01

Public opinion is important in determining condom and condom education policies in public high schools. A random telephone survey of 517 Indiana residents was conducted from July through October 2003 to assess public opinion about education on correct condom use for HIV and STD prevention; condom availability in Indiana public high schools; and issues related to condom use, effectiveness and promotion. Data were analyzed using bivariate and linear regression techniques. A majority of respondents strongly or somewhat agreed that instruction on correct condom use for HIV and STD prevention should be provided in public high schools (77%), classroom instruction should include condoms (71%), only medically accurate information about condoms should being given (94%) and the federal government should promote condoms (70%). Fewer than half (48%) strongly or somewhat agreed that condoms should be made available to teenagers in public high schools without parental permission. Nearly all (92%) considered condoms at least somewhat effective in preventing HIV and other STDs. Non-Republican party affiliation, younger age and condom use within the previous five years were each significantly associated with having positive opinions on many of the condom-related statements. Public opinion appears to support the provision of correct condom use information in Indiana public schools. Schools should consider providing only medically accurate information about condoms and including condoms in instruction so students can see and touch them.

Sexual Sensation Seeking, Social Stress, and Coping Styles as Predictors of HIV/STD Risk Behaviors in Adolescents

Science.gov (United States)

Teva, Inmaculada; Bermudez, Maria Paz; Buela-Casal, Gualberto

2010-01-01

The aim of this study was to assess whether coping styles, social stress, and sexual sensation seeking were predictors of HIV/STD risk behaviours in adolescents. A representative sample of 4,456 female and male Spanish high school students aged 13 to 18 years participated. A stratified random sampling procedure was used. Self-report questionnaires…

Oriented solid-state NMR spectrosocpy

DEFF Research Database (Denmark)

Bertelsen, Kresten

This thesis is concerned with driving forward oriented solid-state NMR spectroscopy as a viable technique for studying peptides in membrane bilayers. I will show that structural heterogeneity is an intrinsic part of the peptide/lipid system and that NMR can be used to characterize static...... and dynamic structural features of the peptides and its local surroundings. In fact one need to take into account the dynamical features of the system in order to correctly predict the structure from oriented solid-state NMR spectra.      ...

NMR-Based Metabolic Profiling of Field-Grown Leaves from Sugar Beet Plants Harbouring Different Levels of Resistance to Cercospora Leaf Spot Disease

Directory of Open Access Journals (Sweden)

Yasuyo Sekiyama

2017-01-01

Full Text Available Cercospora leaf spot (CLS is one of the most serious leaf diseases for sugar beet (Beta vulgaris L. worldwide. The breeding of sugar beet cultivars with both high CLS resistance and high yield is a major challenge for breeders. In this study, we report the nuclear magnetic resonance (NMR-based metabolic profiling of field-grown leaves for a subset of sugar beet genotypes harbouring different levels of CLS resistance. Leaves were collected from 12 sugar beet genotypes at four time points: seedling, early growth, root enlargement, and disease development stages. 1H-NMR spectra of foliar metabolites soluble in a deuterium-oxide (D2O-based buffer were acquired and subjected to multivariate analyses. A principal component analysis (PCA of the NMR data from the sugar beet leaves shows clear differences among the growth stages. At the later time points, the sugar and glycine betaine contents were increased, whereas the choline content was decreased. The relationship between the foliar metabolite profiles and resistance level to CLS was examined by combining partial least squares projection to latent structure (PLS or orthogonal PLS (OPLS analysis and univariate analyses. It was difficult to build a robust model for predicting precisely the disease severity indices (DSIs of each genotype; however, GABA and Gln differentiated susceptible genotypes (genotypes with weak resistance from resistant genotypes (genotypes with resistance greater than a moderate level before inoculation tests. The results suggested that breeders might exclude susceptible genotypes from breeding programs based on foliar metabolites profiled without inoculation tests, which require an enormous amount of time and effort.

Continuous Flow 1H and 13C NMR Spectroscopy in Microfluidic Stripline NMR Chips

NARCIS (Netherlands)

Oosthoek-de Vries, Anna Jo; Bart, Jacob; Tiggelaar, Roald M.; Janssen, Johannes W.G.; van Bentum, Jan (P.J.M.); Gardeniers, Han J.G.E.; Kentgens, Arno P.M.

2017-01-01

Microfluidic stripline NMR technology not only allows for NMR experiments to be performed on small sample volumes in the submicroliter range, but also experiments can easily be performed in continuous flow because of the stripline's favorable geometry. In this study we demonstrate the possibility of

Untangle soil-water-mucilage interactions: 1H NMR Relaxometry is lifting the veil

Science.gov (United States)

Brax, Mathilde; Buchmann, Christian; Schaumann, Gabriele Ellen

2017-04-01

Mucilage is mainly produced at the root tips and has a high water holding capacity derived from highly hydrophilic gel-forming substances. The objective of the MUCILAGE project is to understand the mechanistic role of mucilage for the regulation of water supply for plants. Our subproject investigates the chemical and physical properties of mucilage as pure gel and mixed with soil. 1H-NMR Relaxometry and PFG NMR represent non-intrusive powerful methods for soil scientific research by allowing quantification of the water distribution as well as monitoring of the water mobility in soil pores and gel phases.Relaxation of gel water differs from the one of pure water due to additional interactions with the gel matrix. Mucilage in soil leads to a hierarchical pore structure, consisting of the polymeric biohydrogel network surrounded by the surface of soil particles. The two types of relaxation rates 1/T1 and 1/T2 measured with 1H-NMR relaxometry refer to different relaxation mechanisms of water, while PFG-NMR measures the water self-diffusion coefficient. The objective of our study is to distinguish in situ water in gel from pore water in a simplified soil system, and to determine how the "gel effect" affects both relaxation rates and the water self-diffusion coefficient in porous systems. We demonstrate how the mucilage concentration and the soil solution alter the properties of water in the respective gel phases and pore systems in model soils. To distinguish gel-inherent processes from classical processes, we investigated the variations of the water mobility in pure chia mucilage under different conditions by using 1H-NMR relaxometry and PFG NMR. Using model soils, the signals coming from pore water and gel water were differentiated. We combined the equations describing 1H-NMR relaxation in porous systems and our experimental results, to explain how the presence of gel in soil affects 1H-NMR relaxation. Out of this knowledge we propose a method, which determines in

4-Carboxyl-2,6-dinitrophenylazohydroxynaphthalenes tautomerism NMR re-explained and other methods verified

DEFF Research Database (Denmark)

Hristova, Silvia; Angelova, Silvia; Hansen, Poul Erik

2017-01-01

In two consecutive studies the tautomerism in 4-((2-hydroxynaphthalen-1-yl)diazenyl)-3,5-dinitrobenzoic acid and the structurally similar 1-((2-nitrophenyl)diazenyl)naphthalen-2-ol has been considered from viewpoint of theoretical chemistry, UV–Vis spectroscopy and NMR. Although the theoretical...... data (at M062X level) show that both compounds exist only as a keto tautomer, the experiment proves existence of the enol form. The difference in the results obtained by UV–Vis spectroscopy and NMR requires a deeper consideration and verification of the NMR approach, which is based on using model...... compounds to provide the NMR signal pattern of individual tautomers....

NMR and pattern recognition methods in metabolomics: From data acquisition to biomarker discovery: A review

International Nuclear Information System (INIS)

Smolinska, Agnieszka; Blanchet, Lionel; Buydens, Lutgarde M.C.; Wijmenga, Sybren S.

2012-01-01

Highlights: ► Procedures for acquisition of different biofluids by NMR. ► Recent developments in metabolic profiling of different biofluids by NMR are presented. ► The crucial steps involved in data preprocessing and multivariate chemometric analysis are reviewed. ► Emphasis is given on recent findings on Multiple Sclerosis via NMR and pattern recognition methods. - Abstract: Metabolomics is the discipline where endogenous and exogenous metabolites are assessed, identified and quantified in different biological samples. Metabolites are crucial components of biological system and highly informative about its functional state, due to their closeness to functional endpoints and to the organism's phenotypes. Nuclear Magnetic Resonance (NMR) spectroscopy, next to Mass Spectrometry (MS), is one of the main metabolomics analytical platforms. The technological developments in the field of NMR spectroscopy have enabled the identification and quantitative measurement of the many metabolites in a single sample of biofluids in a non-targeted and non-destructive manner. Combination of NMR spectra of biofluids and pattern recognition methods has driven forward the application of metabolomics in the field of biomarker discovery. The importance of metabolomics in diagnostics, e.g. in identifying biomarkers or defining pathological status, has been growing exponentially as evidenced by the number of published papers. In this review, we describe the developments in data acquisition and multivariate analysis of NMR-based metabolomics data, with particular emphasis on the metabolomics of Cerebrospinal Fluid (CSF) and biomarker discovery in Multiple Sclerosis (MScl).

NMR metabolomics of thrips (Frankliniella occidentalis) resistance in Senecio hybrids.

Science.gov (United States)

Leiss, Kirsten A; Choi, Young H; Abdel-Farid, Ibrahim B; Verpoorte, Robert; Klinkhamer, Peter G L

2009-02-01

Western flower thrips (Frankliniella occidentalis) has become a key insect pest of agricultural and horticultural crops worldwide. Little is known about host plant resistance to thrips. In this study, we investigated thrips resistance in F (2) hybrids of Senecio jacobaea and Senecio aquaticus. We identified thrips-resistant hybrids applying three different bioassays. Subsequently, we compared the metabolomic profiles of these hybrids applying nuclear magnetic resonance spectroscopy (NMR). The new developments of NMR facilitate a wide range coverage of the metabolome. This makes NMR especially suitable if there is no a priori knowledge of the compounds related to herbivore resistance and allows a holistic approach analyzing different chemical compounds simultaneously. We show that the metabolomes of thrips-resistant and -susceptible hybrids differed considerably. Thrips-resistant hybrids contained higher amounts of the pyrrolizidine alkaloids (PA), jacobine, and jaconine, especially in younger leaves. Also, a flavanoid, kaempferol glucoside, accumulated in the resistant plants. Both PAs and kaempferol are known for their inhibitory effect on herbivores. In resistant and susceptible F (2) hybrids, young leaves showed less thrips damage than old leaves. Consistent with the optimal plant defense theory, young leaves contained increased levels of primary metabolites such as sucrose, raffinose, and stachyose, but also accumulated jacaranone as a secondary plant defense compound. Our results prove NMR as a promising tool to identify different metabolites involved in herbivore resistance. It constitutes a significant advance in the study of plant-insect relationships, providing key information on the implementation of herbivore resistance breeding strategies in plants.

NMR investigation of boron impurities in refined metallurgical grade silicon

Energy Technology Data Exchange (ETDEWEB)

Grafe, Hans-Joachim; Loeser, Wolfgang; Schmitz, Steffen; Sakaliyska, Miroslava [Leibniz Institute for Solid State and Materials Research (IFW), Dresden (Germany); Wurmehl, Sabine [Leibniz Institute for Solid State and Materials Research (IFW), Dresden (Germany); Institute for Solid State Physics, Technische Universitaet Dresden (Germany); Eisert, Stefan; Reichenbach, Birk; Mueller, Tim [Adensis GmbH, Dresden (Germany); Acker, Joerg; Rietig, Anja; Ducke, Jana [Department of Chemistry, Faculty for Natural Sciences, Brandenburg Technical University Cottbus-Senftenberg, Senftenberg (Germany)

2015-09-15

The nuclear magnetic resonance (NMR) method was applied for tracking boron impurities in the refining process of metallurgical grade (MG) silicon. From the NMR signal of the {sup 11}B isotope at an operating temperature 4.2 K, the boron concentration can be estimated down to the order of 1-10 wppm B. After melting and resolidification of MG-Si alloyed with Ca and Ti, a major fraction of B impurities remains in the Si solid solution as inferred from the characteristic NMR frequency. The alloying element Ti does not form substantial fractions of TiB{sub 2}. Acid leaching of crushed powders of MG-Si alloyed with Ca and Ti can diminish the initial impurity content of B suggesting its accumulation in the grain boundary phases. NMR signals of TiB{sub 2} at 4.2 K and room temperature (RT), and of poly-Si with different B doping at 4.2 K. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Interaction Between Cyanine Dye IR-783 and Polystyrene Nanoparticles in Solution.

Science.gov (United States)

Zhang, Yunzhi; Xu, Hui; Casabianca, Leah B

2018-05-17

The interactions between small molecule drugs or dyes and nanoparticles are important to the use of nanoparticles in medicine. Noncovalent adsorption of dyes on nanoparticle surfaces is also important to the development of nanoparticle dual-use imaging contrast agents. In the present work, solution-state NMR is used to examine the noncovalent interaction between a near-infrared cyanine dye and the surface of polystyrene nanoparticles in solution. Using 1D proton NMR, we can approximate the number of dye molecules that associate with each nanoparticle for different sized nanoparticles. Saturation-Transfer Difference (STD)-NMR was also used to show that protons near the positively-charged nitrogen in the dye are more strongly associated with the negatively-charged nanoparticle surface than protons near the negatively-charged sulfate groups of the dye. The methods described here can be used to study similar drug or dye molecules interacting with the surface of organic nanoparticles. This article is protected by copyright. All rights reserved.

'In vivo' and high resolution spectroscopy in solids by NMR: an instrument for transgenic plants study

International Nuclear Information System (INIS)

Colnago, L.A.; Herrmann, P.S.P.; Bernardes Filho, R.

1995-01-01

This work has developed a study on transgenic plants using two different techniques of nuclear magnetic resonance, in vivo NMR and high resolution NMR. In order to understand the gene mutations and characterize the plants constituents, NMR spectral data were analysed and discussed, then the results were presented

Study on 1H-NMR fingerprinting of Rhodiolae Crenulatae Radix et Rhizoma.

Science.gov (United States)

Wen, Shi-yuan; Zhou, Jiang-tao; Chen, Yan-yan; Ding, Li-qin; Jiang, Miao-miao

2015-07-01

Nuclear magnetic resonance (1H-NMR) fingerprint of Rhodiola rosea medicinal materials was established, and used to distinguish the quality of raw materials from different sources. Pulse sequence for water peak inhibition was employed to acquire 1H-NMR spectra with the temperature at 298 K and spectrometer frequency of 400.13 MHz. Through subsection integral method, the obtained NMR data was subjected to similarity analysis and principal component analysis (PCA). 10 batches raw materials of Rhodiola rosea from different origins were successfully distinguished by PCA. The statistical results indicated that rhodiola glucoside, butyl alcohol, maleic acid and alanine were the main differential ingredients. This method provides an auxiliary method of Chinese quality approach to evaluate the quality of Rhodiola crenulata without using natural reference substances.

A new approach to the silica gel surface : characterization of different surface regions by 29Si magic angle spinning NMR relaxation parameters and consequences for quantification of silica gels by NMR: characterization of different surface regions by silicon-29 magic angle spinning NMR relaxation parameters and consequences for quantification of silica gels by NMR

NARCIS (Netherlands)

Pfleiderer, B.; Albert, K.; Bayer, E.; Ven, van de L.J.M.; Haan, de J.W.; Cramers, C.A.M.G.

1990-01-01

Native and some monofunctionally derivatized silica gels have been investigated by 29Si CP MAS NMR spectroscopy with pulse and with cross-polarization (CP) excitation. Contact time variation experiments for some native materials yield results for the siloxane (Q4)g roups which cannot be described

Annual reports on NMR spectroscopy

CERN Document Server

Webb, Graham A; McCarthy, M J

1995-01-01

Over recent years, no other technique has grown to such importance as that of NMR spectroscopy. It is used in all branches of science where precise structural determination is required and where the nature of interactions and reactions in solution is being studied. Annual Reports on NMR Spectroscopy has established itself as a means for the specialist and non-specialist alike to become familiar with new applications of the technique in all branches of chemistry, including biochemistry, and pharmaceutics. This volume focuses on theoretical aspects of NMR nuclear shielding and on applications of

Detection of Virgin Olive Oil Adulteration Using Low Field Unilateral NMR

Directory of Open Access Journals (Sweden)

Zheng Xu

2014-01-01

Full Text Available The detection of adulteration in edible oils is a concern in the food industry, especially for the higher priced virgin olive oils. This article presents a low field unilateral nuclear magnetic resonance (NMR method for the detection of the adulteration of virgin olive oil that can be performed through sealed bottles providing a non-destructive screening technique. Adulterations of an extra virgin olive oil with different percentages of sunflower oil and red palm oil were measured with a commercial unilateral instrument, the profile NMR-Mouse. The NMR signal was processed using a 2-dimensional Inverse Laplace transformation to analyze the transverse relaxation and self-diffusion behaviors of different oils. The obtained results demonstrated the feasibility of detecting adulterations of olive oil with percentages of at least 10% of sunflower and red palm oils.

NMR shielding calculations across the periodic table: diamagnetic uranium compounds. 2. Ligand and metal NMR.

Science.gov (United States)

Schreckenbach, Georg

2002-12-16

In this and a previous article (J. Phys. Chem. A 2000, 104, 8244), the range of application for relativistic density functional theory (DFT) is extended to the calculation of nuclear magnetic resonance (NMR) shieldings and chemical shifts in diamagnetic actinide compounds. Two relativistic DFT methods are used, ZORA ("zeroth-order regular approximation") and the quasirelativistic (QR) method. In the given second paper, NMR shieldings and chemical shifts are calculated and discussed for a wide range of compounds. The molecules studied comprise uranyl complexes, [UO(2)L(n)](+/-)(q); UF(6); inorganic UF(6) derivatives, UF(6-n)Cl(n), n = 0-6; and organometallic UF(6) derivatives, UF(6-n)(OCH(3))(n), n = 0-5. Uranyl complexes include [UO(2)F(4)](2-), [UO(2)Cl(4)](2-), [UO(2)(OH)(4)](2-), [UO(2)(CO(3))(3)](4-), and [UO(2)(H(2)O)(5)](2+). For the ligand NMR, moderate (e.g., (19)F NMR chemical shifts in UF(6-n)Cl(n)) to excellent agreement [e.g., (19)F chemical shift tensor in UF(6) or (1)H NMR in UF(6-n)(OCH(3))(n)] has been found between theory and experiment. The methods have been used to calculate the experimentally unknown (235)U NMR chemical shifts. A large chemical shift range of at least 21,000 ppm has been predicted for the (235)U nucleus. ZORA spin-orbit appears to be the most accurate method for predicting actinide metal chemical shifts. Trends in the (235)U NMR chemical shifts of UF(6-n)L(n) molecules are analyzed and explained in terms of the calculated electronic structure. It is argued that the energy separation and interaction between occupied and virtual orbitals with f-character are the determining factors.

Quantification of organic acids in beer by nuclear magnetic resonance (NMR)-based methods

International Nuclear Information System (INIS)

Rodrigues, J.E.A.; Erny, G.L.; Barros, A.S.; Esteves, V.I.; Brandao, T.; Ferreira, A.A.; Cabrita, E.; Gil, A.M.

2010-01-01

The organic acids present in beer provide important information on the product's quality and history, determining organoleptic properties and being useful indicators of fermentation performance. NMR spectroscopy may be used for rapid quantification of organic acids in beer and different NMR-based methodologies are hereby compared for the six main acids found in beer (acetic, citric, lactic, malic, pyruvic and succinic). The use of partial least squares (PLS) regression enables faster quantification, compared to traditional integration methods, and the performance of PLS models built using different reference methods (capillary electrophoresis (CE), both with direct and indirect UV detection, and enzymatic essays) was investigated. The best multivariate models were obtained using CE/indirect detection and enzymatic essays as reference and their response was compared with NMR integration, either using an internal reference or an electrical reference signal (Electronic REference To access In vivo Concentrations, ERETIC). NMR integration results generally agree with those obtained by PLS, with some overestimation for malic and pyruvic acids, probably due to peak overlap and subsequent integral errors, and an apparent relative underestimation for citric acid. Overall, these results make the PLS-NMR method an interesting choice for organic acid quantification in beer.

Quantification of organic acids in beer by nuclear magnetic resonance (NMR)-based methods

Energy Technology Data Exchange (ETDEWEB)

Rodrigues, J.E.A. [CICECO-Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Erny, G.L. [CESAM - Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Barros, A.S. [QOPNAA-Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Esteves, V.I. [CESAM - Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Brandao, T.; Ferreira, A.A. [UNICER, Bebidas de Portugal, Leca do Balio, 4466-955 S. Mamede de Infesta (Portugal); Cabrita, E. [Department of Chemistry, New University of Lisbon, 2825-114 Caparica (Portugal); Gil, A.M., E-mail: agil@ua.pt [CICECO-Department of Chemistry, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal)

2010-08-03

The organic acids present in beer provide important information on the product's quality and history, determining organoleptic properties and being useful indicators of fermentation performance. NMR spectroscopy may be used for rapid quantification of organic acids in beer and different NMR-based methodologies are hereby compared for the six main acids found in beer (acetic, citric, lactic, malic, pyruvic and succinic). The use of partial least squares (PLS) regression enables faster quantification, compared to traditional integration methods, and the performance of PLS models built using different reference methods (capillary electrophoresis (CE), both with direct and indirect UV detection, and enzymatic essays) was investigated. The best multivariate models were obtained using CE/indirect detection and enzymatic essays as reference and their response was compared with NMR integration, either using an internal reference or an electrical reference signal (Electronic REference To access In vivo Concentrations, ERETIC). NMR integration results generally agree with those obtained by PLS, with some overestimation for malic and pyruvic acids, probably due to peak overlap and subsequent integral errors, and an apparent relative underestimation for citric acid. Overall, these results make the PLS-NMR method an interesting choice for organic acid quantification in beer.

Dynamics and interactions of ibuprofen in cyclodextrin nanosponges by solid-state NMR spectroscopy

Directory of Open Access Journals (Sweden)

Monica Ferro

2017-01-01

Full Text Available Two different formulations of cyclodextrin nanosponges (CDNS, obtained by polycondensation of β-cyclodextrin with ethylenediaminetetraacetic acid dianhydride (EDTAn, were treated with aqueous solutions of ibuprofen sodium salt (IbuNa affording hydrogels that, after lyophilisation, gave two solid CDNS-drug formulations. 1H fast MAS NMR and 13C CP-MAS NMR spectra showed that IbuNa was converted in situ into its acidic and dimeric form (IbuH after freeze-drying. 13C CP-MAS NMR spectra also indicated that the structure of the nanosponge did not undergo changes upon drug loading compared to the unloaded system. However, the 13C NMR spectra collected under variable contact time cross-polarization (VCT-CP conditions showed that the polymeric scaffold CDNS changed significantly its dynamic regime on passing from the empty CDNS to the drug-loaded CDNS, thus showing that the drug encapsulation can be seen as the formation of a real supramolecular aggregate rather than a conglomerate of two solid components. Finally, the structural features obtained from the different solid-state NMR approaches reported matched the information from powder X-ray diffraction profiles.

Solid-state NMR spectroscopy on complex biomolecules

NARCIS (Netherlands)

Renault, M.A.M.; Cukkemane, A.A.; Baldus, M.

2010-01-01

Biomolecular applications of NMR spectroscopy are often merely associated with soluble molecules or magnetic resonance imaging. However, since the late 1970s, solid-state NMR (ssNMR) spectroscopy has demonstrated its ability to provide atomic-level insight into complex biomolecular systems ranging

Exploring the limits to spatially resolved NMR

Energy Technology Data Exchange (ETDEWEB)

Gaedke, Achim; Nestle, Nikolaus [TU Darmstadt, Institute of Condensed Matter Physics (Germany)

2010-07-01

Recent advances in MRI have demonstrated resolutions down to 1 {mu}m. Magnetic resonance force microscopy has the potential to reach sensitivity for single nuclear spins. Given these numbers, in vivo imaging of single cells or even biomacromolecules may seem possible. However, for in vivo applications, there are fundamental differences in the contrast mechanisms compared to MRI at macroscopic scales as the length scale of of molecular self-diffusion exceeds that of the spatial resolution on the NMR time scale. Those effects - which are fundamentally different from the echo attenuation in field gradient NMR - even may lead to general limitations on the spatial resolution achievable in aqueous systems with high water content. In our contribution, we explore those effects on a model system in a high-resolution stray-field imaging setup. In addition to experimental results, simulations based on the Bloch-Torrey equation are presented.

Complete 1H NMR spectral analysis of ten chemical markers of Ginkgo biloba.

Science.gov (United States)

Napolitano, José G; Lankin, David C; Chen, Shao-Nong; Pauli, Guido F

2012-08-01

The complete and unambiguous (1)H NMR assignments of ten marker constituents of Ginkgo biloba are described. The comprehensive (1)H NMR profiles (fingerprints) of ginkgolide A, ginkgolide B, ginkgolide C, ginkgolide J, bilobalide, quercetin, kaempferol, isorhamnetin, isoquercetin, and rutin in DMSO-d(6) were obtained through the examination of 1D (1)H NMR and 2D (1)H,(1)H-COSY data, in combination with (1)H iterative full spin analysis (HiFSA). The computational analysis of discrete spin systems allowed a detailed characterization of all the (1)H NMR signals in terms of chemical shifts (δ(H)) and spin-spin coupling constants (J(HH)), regardless of signal overlap and higher order coupling effects. The capability of the HiFSA-generated (1)H fingerprints to reproduce experimental (1)H NMR spectra at different field strengths was also evaluated. As a result of this analysis, a revised set of (1)H NMR parameters for all ten phytoconstituents was assembled. Furthermore, precise (1)H NMR assignments of the sugar moieties of isoquercetin and rutin are reported for the first time. Copyright © 2012 John Wiley & Sons, Ltd.

Integrative NMR for biomolecular research

International Nuclear Information System (INIS)

Lee, Woonghee; Cornilescu, Gabriel; Dashti, Hesam; Eghbalnia, Hamid R.; Tonelli, Marco; Westler, William M.; Butcher, Samuel E.; Henzler-Wildman, Katherine A.; Markley, John L.

2016-01-01

NMR spectroscopy is a powerful technique for determining structural and functional features of biomolecules in physiological solution as well as for observing their intermolecular interactions in real-time. However, complex steps associated with its practice have made the approach daunting for non-specialists. We introduce an NMR platform that makes biomolecular NMR spectroscopy much more accessible by integrating tools, databases, web services, and video tutorials that can be launched by simple installation of NMRFAM software packages or using a cross-platform virtual machine that can be run on any standard laptop or desktop computer. The software package can be downloaded freely from the NMRFAM software download page ( http://pine.nmrfam.wisc.edu/download-packages.html http://pine.nmrfam.wisc.edu/download_packages.html ), and detailed instructions are available from the Integrative NMR Video Tutorial page ( http://pine.nmrfam.wisc.edu/integrative.html http://pine.nmrfam.wisc.edu/integrative.html ).

Integrative NMR for biomolecular research

Energy Technology Data Exchange (ETDEWEB)

Lee, Woonghee, E-mail: whlee@nmrfam.wisc.edu; Cornilescu, Gabriel; Dashti, Hesam; Eghbalnia, Hamid R.; Tonelli, Marco; Westler, William M.; Butcher, Samuel E.; Henzler-Wildman, Katherine A.; Markley, John L., E-mail: markley@nmrfam.wisc.edu [University of Wisconsin-Madison, National Magnetic Resonance Facility at Madison and Biochemistry Department (United States)

2016-04-15

NMR spectroscopy is a powerful technique for determining structural and functional features of biomolecules in physiological solution as well as for observing their intermolecular interactions in real-time. However, complex steps associated with its practice have made the approach daunting for non-specialists. We introduce an NMR platform that makes biomolecular NMR spectroscopy much more accessible by integrating tools, databases, web services, and video tutorials that can be launched by simple installation of NMRFAM software packages or using a cross-platform virtual machine that can be run on any standard laptop or desktop computer. The software package can be downloaded freely from the NMRFAM software download page ( http://pine.nmrfam.wisc.edu/download-packages.html http://pine.nmrfam.wisc.edu/download{sub p}ackages.html ), and detailed instructions are available from the Integrative NMR Video Tutorial page ( http://pine.nmrfam.wisc.edu/integrative.html http://pine.nmrfam.wisc.edu/integrative.html ).

Basics of spectroscopic instruments. Hardware of NMR spectrometer

International Nuclear Information System (INIS)

Sato, Hajime

2009-01-01

NMR is a powerful tool for structure analysis of small molecules, natural products, biological macromolecules, synthesized polymers, samples from material science and so on. Magnetic Resonance Imaging (MRI) is applicable to plants and animals Because most of NMR experiments can be done by an automation mode, one can forget hardware of NMR spectrometers. It would be good to understand features and performance of NMR spectrometers. Here I present hardware of a modern NMR spectrometer which is fully equipped with digital technology. (author)

33S NMR cryogenic probe for taurine detection

Science.gov (United States)

Hobo, Fumio; Takahashi, Masato; Maeda, Hideaki

2009-03-01

With the goal of a S33 nuclear magnetic resonance (NMR) probe applicable to in vivo NMR on taurine-biological samples, we have developed the S33 NMR cryogenic probe, which is applicable to taurine solutions. The NMR sensitivity gain relative to a conventional broadband probe is as large as 3.5. This work suggests that improvements in the preamplifier could allow NMR measurements on 100 μM taurine solutions, which is the level of sensitivity necessary for biological samples.

1H HR-MAS NMR and S180 cells: metabolite assignment and evaluation of pulse sequence

International Nuclear Information System (INIS)

Oliveira, Aline L. de; Martinelli, Bruno César B.; Lião, Luciano M.; Pereira, Flávia C.; Silveira-Lacerda, Elisangela P.; Alcantara, Glaucia B.

2014-01-01

High resolution magic angle spinning 1 H nuclear magnetic resonance spectroscopy (HR-MAS NMR) is a useful technique for evaluation of intact cells and tissues. However, optimal NMR parameters are crucial in obtaining reliable results. To identify the key steps for the optimization of HR-MAS NMR parameters, we assessed different pulse sequences and NMR parameters using sarcoma 180 (S180) cells. A complete assignment of the metabolites of S180 is given to assist future studies. (author)

Solution NMR Spectroscopy in Target-Based Drug Discovery.

Science.gov (United States)

Li, Yan; Kang, Congbao

2017-08-23

Solution NMR spectroscopy is a powerful tool to study protein structures and dynamics under physiological conditions. This technique is particularly useful in target-based drug discovery projects as it provides protein-ligand binding information in solution. Accumulated studies have shown that NMR will play more and more important roles in multiple steps of the drug discovery process. In a fragment-based drug discovery process, ligand-observed and protein-observed NMR spectroscopy can be applied to screen fragments with low binding affinities. The screened fragments can be further optimized into drug-like molecules. In combination with other biophysical techniques, NMR will guide structure-based drug discovery. In this review, we describe the possible roles of NMR spectroscopy in drug discovery. We also illustrate the challenges encountered in the drug discovery process. We include several examples demonstrating the roles of NMR in target-based drug discoveries such as hit identification, ranking ligand binding affinities, and mapping the ligand binding site. We also speculate the possible roles of NMR in target engagement based on recent processes in in-cell NMR spectroscopy.

NMR and pattern recognition methods in metabolomics: From data acquisition to biomarker discovery: A review

Energy Technology Data Exchange (ETDEWEB)

Smolinska, Agnieszka, E-mail: A.Smolinska@science.ru.nl [Institute for Molecules and Materials, Radboud University Nijmegen, Nijmegen (Netherlands); Blanchet, Lionel [Institute for Molecules and Materials, Radboud University Nijmegen, Nijmegen (Netherlands); Department of Biochemistry, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen (Netherlands); Buydens, Lutgarde M.C.; Wijmenga, Sybren S. [Institute for Molecules and Materials, Radboud University Nijmegen, Nijmegen (Netherlands)

2012-10-31

Highlights: Black-Right-Pointing-Pointer Procedures for acquisition of different biofluids by NMR. Black-Right-Pointing-Pointer Recent developments in metabolic profiling of different biofluids by NMR are presented. Black-Right-Pointing-Pointer The crucial steps involved in data preprocessing and multivariate chemometric analysis are reviewed. Black-Right-Pointing-Pointer Emphasis is given on recent findings on Multiple Sclerosis via NMR and pattern recognition methods. - Abstract: Metabolomics is the discipline where endogenous and exogenous metabolites are assessed, identified and quantified in different biological samples. Metabolites are crucial components of biological system and highly informative about its functional state, due to their closeness to functional endpoints and to the organism's phenotypes. Nuclear Magnetic Resonance (NMR) spectroscopy, next to Mass Spectrometry (MS), is one of the main metabolomics analytical platforms. The technological developments in the field of NMR spectroscopy have enabled the identification and quantitative measurement of the many metabolites in a single sample of biofluids in a non-targeted and non-destructive manner. Combination of NMR spectra of biofluids and pattern recognition methods has driven forward the application of metabolomics in the field of biomarker discovery. The importance of metabolomics in diagnostics, e.g. in identifying biomarkers or defining pathological status, has been growing exponentially as evidenced by the number of published papers. In this review, we describe the developments in data acquisition and multivariate analysis of NMR-based metabolomics data, with particular emphasis on the metabolomics of Cerebrospinal Fluid (CSF) and biomarker discovery in Multiple Sclerosis (MScl).

Application of NMR Spectroscopy in the Analysis of Petroleum Derivatives and Products

Directory of Open Access Journals (Sweden)

Parlov Vuković, J.

2012-11-01

Full Text Available Complex chemical composition and physical properties of oil and fuel make their complete cha racterization very difficult. Components present in oil and oil products differ in structure, size, po larity and functionality. The presence and structure of specific hydrocarbons in final products depend on the processing procedure and type of the fuel. In order to predict or improve fuel pro perties it is necessary to determine its composition. Thus, new and more sophisticated analytical methods and procedures are constantly being developed. NMR spectroscopy plays a significant role in analysis and identification of complex hydrocarbon mixtures of petroleum and petroleum products. In this review, we describe the application of NMR spectroscopy for analyzing gasoline and diesel fuels. Hence, by using NMR spectroscopy it is possible to determine gasoline composition and presence of benzene and oxygenates, as well as some important physical characteristics of gasoli ne such as the research octane number. An application of different NMR techniques made it pos sible to characterize diesel fuels and middle oil distillates from various refineries. Data so obtained can be used in combination with statistical methods to predict fuel properties and to monitor pro- duction processes in the petroleum industry. NMR spectroscopy has proven useful in analysis of FAME which has recently been used as an ecologically acceptable alternative fuel. Furthermore, techniques such as CP/MAS for characterization of solid state oil-geochemical samples are inclu- ded. Also, possibilities of using NMR spectroscopy in the analysis of polymeric additives are di- scussed.

In situ viscosity of oil sands using low field NMR

International Nuclear Information System (INIS)

Bryan, J.; Moon, D.; Kantzas, A.

2005-01-01

In heavy oil and bitumen reservoirs, oil viscosity is a vital piece of information that will have great bearing on the chosen EOR scheme and the recovery expected. Prediction of in situ viscosity with a logging tool would he very beneficial in reservoir characterization and exploitation design. Low field NMR is a technology that has shown great potential as a tool for characterizing hydrocarbon properties in heavy oil and bitumen reservoirs. An oil viscosity correlation has previously been developed that is capable of providing order of magnitude viscosity estimates for a wide range of oils taken from various fields in Alberta. This paper presents tuning procedures to improve the NMR predictions for different viscosity ranges, and extends the NMR viscosity model to in situ heavy oil in unconsolidated sands. The results of this work show that the NMR oil peak can be de-convoluted from the in situ signals of the oil and water, and the bulk viscosity correlation that was developed for bulk oils can he applied to predict the in situ oil viscosity. These results can be translated to an NMR logging tool algorithm, allowing for in situ measurements of oil viscosity at the proper reservoir conditions. (author)

High-throughput authentication of edible oils with benchtop Ultrafast 2D NMR.

Science.gov (United States)

Gouilleux, B; Marchand, J; Charrier, B; Remaud, G S; Giraudeau, P

2018-04-01

We report the use of an Ultrafast 2D NMR approach applied on a benchtop NMR system (43 MHz) for the authentication of edible oils. Our results demonstrate that a profiling strategy based on fast 2D NMR spectra recorded in 2.4 min is more efficient than the standard 1D experiments to classify oils from different botanical origins, since 1D spectra on the same samples suffer from strong peak overlaps. Six edible oils with different botanical origins (olive, hazelnut, sesame, rapeseed, corn and sunflower) have been clearly discriminated by PCA analysis. Furthermore, we show how this approach combined with a PLS model can detect adulteration processes such as the addition of hazelnut oil into olive oil, a common fraud in food industry. Copyright © 2017 Elsevier Ltd. All rights reserved.

Non-destructive characterization of materials by single-sided NMR

International Nuclear Information System (INIS)

Goga, Nicolae-Octavian

2007-01-01

The experiments conducted in this work demonstrate the efficiency and sensitivity of single-sided NMR for investigating macromolecular materials on large time and length scales. Elastomers can readily be characterized by unilateral NMR of protons in terms of a variety of parameters, which correlate with the overall molecular mobility. In this way information about the cross-link density, state of cure and strain, the effects of aging and product heterogeneity can obtained. For these purposes, the NMR-MOUSE was used to optimize product development and to monitor product and production quality on-line. The sensor is also suitable for nondestructive probing of the mechanical deformation in cross-linked elastomers. A special magnet design that fits a stress-strain device has been used for complementary investigation of a series of different rubber stripes during mechanical testing. The profile NMR-MOUSE was found to be a unique tool for the characterization of changes induced by the UV irradiation in natural rubber. The aging profiles were interpreted for the first time based on a novel model in which the radiation absorption coefficient depends on the depth in the sample. (orig.)

Non-destructive characterization of materials by single-sided NMR

Energy Technology Data Exchange (ETDEWEB)

Goga, Nicolae-Octavian

2007-08-20

The experiments conducted in this work demonstrate the efficiency and sensitivity of single-sided NMR for investigating macromolecular materials on large time and length scales. Elastomers can readily be characterized by unilateral NMR of protons in terms of a variety of parameters, which correlate with the overall molecular mobility. In this way information about the cross-link density, state of cure and strain, the effects of aging and product heterogeneity can obtained. For these purposes, the NMR-MOUSE was used to optimize product development and to monitor product and production quality on-line. The sensor is also suitable for nondestructive probing of the mechanical deformation in cross-linked elastomers. A special magnet design that fits a stress-strain device has been used for complementary investigation of a series of different rubber stripes during mechanical testing. The profile NMR-MOUSE was found to be a unique tool for the characterization of changes induced by the UV irradiation in natural rubber. The aging profiles were interpreted for the first time based on a novel model in which the radiation absorption coefficient depends on the depth in the sample. (orig.)

Nurses' perceptions of the vulnerabilities to STD/AIDS in light of the process of adolescence

OpenAIRE

Silva, Ítalo Rodolfo; Gomes, Antonio Marcos Tosoli; Valadares, Glaucia Valente; Santos, Nereida Lúcia Palko dos; Silva, Thiago Privado da; Leite, Joséte Luzia

2015-01-01

Objective: to understand the perception of nurses on the vulnerabilities to STD/AIDS in light of the process of adolescence.Method: qualitative research conducted with 15 nurses in a centre for the studies of adolescent healthcare of a university hospital in Rio de Janeiro/Brazil. The adopted theoretical and methodological frameworks were the Complexity Theory and the Grounded Theory, respectively. The semi-structured interview was used to collect data from January to August 2012.Results: thi...

NMR imaging of osteoarticular pathology

International Nuclear Information System (INIS)

Frocrain, L.; Duvauferrier, R.; Gagey, N.

1987-01-01

NMR imaging is assuming an increasingly important role in the diagnosis of osteo-articular disorders. Semiological descriptions of the mean pathological disorders of the locomotor system are presented. Some investigation strategies are proposed to compare NMR imaging with other imaging techniques in various pathological states [fr

Development and applications of quantitative NMR spectroscopy

International Nuclear Information System (INIS)

Yamazaki, Taichi

2016-01-01

Recently, quantitative NMR spectroscopy has attracted attention as an analytical method which can easily secure traceability to SI unit system, and discussions about its accuracy and inaccuracy are also started. This paper focuses on the literatures on the advancement of quantitative NMR spectroscopy reported between 2009 and 2016, and introduces both NMR measurement conditions and actual analysis cases in quantitative NMR. The quantitative NMR spectroscopy using an internal reference method enables accurate quantitative analysis with a quick and versatile way in general, and it is possible to obtain the precision sufficiently applicable to the evaluation of pure substances and standard solutions. Since the external reference method can easily prevent contamination to samples and the collection of samples, there are many reported cases related to the quantitative analysis of biologically related samples and highly scarce natural products in which NMR spectra are complicated. In the precision of quantitative NMR spectroscopy, the internal reference method is superior. As the quantitative NMR spectroscopy widely spreads, discussions are also progressing on how to utilize this analytical method as the official methods in various countries around the world. In Japan, this method is listed in the Pharmacopoeia and Japanese Standard of Food Additives, and it is also used as the official method for purity evaluation. In the future, this method will be expected to spread as the general-purpose analysis method that can ensure traceability to SI unit system. (A.O.)

Complex Mixture Analysis of Organic Compounds in Yogurt by NMR Spectroscopy

Science.gov (United States)

Lu, Yi; Hu, Fangyu; Miyakawa, Takuya; Tanokura, Masaru

2016-01-01

NMR measurements do not require separation and chemical modification of samples and therefore rapidly and directly provide non-targeted information on chemical components in complex mixtures. In this study, one-dimensional (1H, 13C, and 31P) and two-dimensional (1H-13C and 1H-31P) NMR spectroscopy were conducted to analyze yogurt without any pretreatment. 1H, 13C, and 31P NMR signals were assigned to 10 types of compounds. The signals of α/β-lactose and α/β-galactose were separately observed in the 1H NMR spectra. In addition, the signals from the acyl chains of milk fats were also successfully identified but overlapped with many other signals. Quantitative difference spectra were obtained by subtracting the diffusion ordered spectroscopy (DOSY) spectra from the quantitative 1H NMR spectra. This method allowed us to eliminate interference on the overlaps; therefore, the correct intensities of signals overlapped with those from the acyl chains of milk fat could be determined directly without separation. Moreover, the 1H-31P HMBC spectra revealed for the first time that N-acetyl-d-glucosamine-1-phosphate is contained in yogurt. PMID:27322339

Whole-core analysis by 13C NMR

International Nuclear Information System (INIS)

Vinegar, H.J.; Tutunjian, P.N.; Edelstein, W.A.; Roemer, P.B.

1991-01-01

This paper reports on a whole-core nuclear magnetic resonance (NMR) system that was used to obtain natural abundance 13 C spectra. The system enables rapid, nondestructive measurements of bulk volume of movable oil, aliphatic/aromatic ratio, oil viscosity, and organic vs. carbonate carbon. 13 C NMR can be used in cores where the 1 H NMR spectrum is too broad to resolve oil and water resonances separately. A 5 1/4-in. 13 C/ 1 H NMR coil was installed on a General Electric (GE) CSI-2T NMR imager/spectrometer. With a 4-in.-OD whole core, good 13 C signal/noise ratio (SNR) is obtained within minutes, while 1 H spectra are obtained in seconds. NMR measurements have been made of the 13 C and 1 H density of crude oils with a wide range of API gravities. For light- and medium-gravity oils, the 13 C and 1 H signal per unit volume is constant within about 3.5%. For heavy crudes, the 13 C and 1 H density measured by NMR is reduced by the shortening of spin-spin relaxation time. 13 C and 1 H NMR spin-lattice relaxation times were measured on a suite of Cannon viscosity standards, crude oils (4 to 60 degrees API), and alkanes (C 5 through C 16 ) with viscosities at 77 degrees F ranging from 0.5 cp to 2.5 x 10 7 cp. The 13 C and 1 H relaxation times show a similar correlation with viscosity from which oil viscosity can be estimated accurately for viscosities up to 100 cp. The 13 C surface relaxation rate for oils on water-wet rocks is very low. Nonproton decoupled 13 C NMR is shown to be insensitive to kerogen; thus, 13 C NMR measures only the movable hydrocarbon content of the cores. In carbonates, the 13 C spectrum also contains a carbonate powder pattern useful in quantifying inorganic carbon and distinguishing organic from carbonate carbon

Automated NMR relaxation dispersion data analysis using NESSY

Directory of Open Access Journals (Sweden)

Gooley Paul R

2011-10-01

Full Text Available Abstract Background Proteins are dynamic molecules with motions ranging from picoseconds to longer than seconds. Many protein functions, however, appear to occur on the micro to millisecond timescale and therefore there has been intense research of the importance of these motions in catalysis and molecular interactions. Nuclear Magnetic Resonance (NMR relaxation dispersion experiments are used to measure motion of discrete nuclei within the micro to millisecond timescale. Information about conformational/chemical exchange, populations of exchanging states and chemical shift differences are extracted from these experiments. To ensure these parameters are correctly extracted, accurate and careful analysis of these experiments is necessary. Results The software introduced in this article is designed for the automatic analysis of relaxation dispersion data and the extraction of the parameters mentioned above. It is written in Python for multi platform use and highest performance. Experimental data can be fitted to different models using the Levenberg-Marquardt minimization algorithm and different statistical tests can be used to select the best model. To demonstrate the functionality of this program, synthetic data as well as NMR data were analyzed. Analysis of these data including the generation of plots and color coded structures can be performed with minimal user intervention and using standard procedures that are included in the program. Conclusions NESSY is easy to use open source software to analyze NMR relaxation data. The robustness and standard procedures are demonstrated in this article.

PDBStat: a universal restraint converter and restraint analysis software package for protein NMR

International Nuclear Information System (INIS)

Tejero, Roberto; Snyder, David; Mao, Binchen; Aramini, James M.; Montelione, Gaetano T.

2013-01-01

The heterogeneous array of software tools used in the process of protein NMR structure determination presents organizational challenges in the structure determination and validation processes, and creates a learning curve that limits the broader use of protein NMR in biology. These challenges, including accurate use of data in different data formats required by software carrying out similar tasks, continue to confound the efforts of novices and experts alike. These important issues need to be addressed robustly in order to standardize protein NMR structure determination and validation. PDBStat is a C/C++ computer program originally developed as a universal coordinate and protein NMR restraint converter. Its primary function is to provide a user-friendly tool for interconverting between protein coordinate and protein NMR restraint data formats. It also provides an integrated set of computational methods for protein NMR restraint analysis and structure quality assessment, relabeling of prochiral atoms with correct IUPAC names, as well as multiple methods for analysis of the consistency of atomic positions indicated by their convergence across a protein NMR ensemble. In this paper we provide a detailed description of the PDBStat software, and highlight some of its valuable computational capabilities. As an example, we demonstrate the use of the PDBStat restraint converter for restrained CS-Rosetta structure generation calculations, and compare the resulting protein NMR structure models with those generated from the same NMR restraint data using more traditional structure determination methods. These results demonstrate the value of a universal restraint converter in allowing the use of multiple structure generation methods with the same restraint data for consensus analysis of protein NMR structures and the underlying restraint data

PDBStat: a universal restraint converter and restraint analysis software package for protein NMR

Energy Technology Data Exchange (ETDEWEB)

Tejero, Roberto [Rutgers, The State University of New Jersey, Center for Advanced Biotechnology and Medicine (United States); Snyder, David [William Paterson University, Department of Chemistry (United States); Mao, Binchen; Aramini, James M.; Montelione, Gaetano T., E-mail: guy@cabm.rutgers.edu [Rutgers, The State University of New Jersey, Center for Advanced Biotechnology and Medicine (United States)

2013-08-15

The heterogeneous array of software tools used in the process of protein NMR structure determination presents organizational challenges in the structure determination and validation processes, and creates a learning curve that limits the broader use of protein NMR in biology. These challenges, including accurate use of data in different data formats required by software carrying out similar tasks, continue to confound the efforts of novices and experts alike. These important issues need to be addressed robustly in order to standardize protein NMR structure determination and validation. PDBStat is a C/C++ computer program originally developed as a universal coordinate and protein NMR restraint converter. Its primary function is to provide a user-friendly tool for interconverting between protein coordinate and protein NMR restraint data formats. It also provides an integrated set of computational methods for protein NMR restraint analysis and structure quality assessment, relabeling of prochiral atoms with correct IUPAC names, as well as multiple methods for analysis of the consistency of atomic positions indicated by their convergence across a protein NMR ensemble. In this paper we provide a detailed description of the PDBStat software, and highlight some of its valuable computational capabilities. As an example, we demonstrate the use of the PDBStat restraint converter for restrained CS-Rosetta structure generation calculations, and compare the resulting protein NMR structure models with those generated from the same NMR restraint data using more traditional structure determination methods. These results demonstrate the value of a universal restraint converter in allowing the use of multiple structure generation methods with the same restraint data for consensus analysis of protein NMR structures and the underlying restraint data.

An Inversion Recovery NMR Kinetics Experiment

OpenAIRE

Williams, Travis J.; Kershaw, Allan D.; Li, Vincent; Wu, Xinping

2011-01-01

A convenient laboratory experiment is described in which NMR magnetization transfer by inversion recovery is used to measure the kinetics and thermochemistry of amide bond rotation. The experiment utilizes Varian spectrometers with the VNMRJ 2.3 software, but can be easily adapted to any NMR platform. The procedures and sample data sets in this article will enable instructors to use inversion recovery as a laboratory activity in applied NMR classes and provide research students with a conveni...

Recommendations of the wwPDB NMR Validation Task Force

Science.gov (United States)

Montelione, Gaetano T.; Nilges, Michael; Bax, Ad; Güntert, Peter; Herrmann, Torsten; Richardson, Jane S.; Schwieters, Charles; Vranken, Wim F.; Vuister, Geerten W.; Wishart, David S.; Berman, Helen M.; Kleywegt, Gerard J.; Markley, John L.

2013-01-01

As methods for analysis of biomolecular structure and dynamics using nuclear magnetic resonance spectroscopy (NMR) continue to advance, the resulting 3D structures, chemical shifts, and other NMR data are broadly impacting biology, chemistry, and medicine. Structure model assessment is a critical area of NMR methods development, and is an essential component of the process of making these structures accessible and useful to the wider scientific community. For these reasons, the Worldwide Protein Data Bank (wwPDB) has convened an NMR Validation Task Force (NMR-VTF) to work with the wwPDB partners in developing metrics and policies for biomolecular NMR data harvesting, structure representation, and structure quality assessment. This paper summarizes the recommendations of the NMR-VTF, and lays the groundwork for future work in developing standards and metrics for biomolecular NMR structure quality assessment. PMID:24010715

Quali- and quantitative analysis of commercial coffee by NMR

International Nuclear Information System (INIS)

Tavares, Leila Aley; Ferreira, Antonio Gilberto

2006-01-01

Coffee is one of the beverages most widely consumed in the world and the 'cafezinho' is normally prepared from a blend of roasted powder of two species, Coffea arabica and Coffea canephora. Each one exhibits differences in their taste and in the chemical composition, especially in the caffeine percentage. There are several procedures proposed in the literature for caffeine determination in different samples like soft drinks, coffee, medicines, etc but most of them need a sample workup which involves at least one step of purification. This work describes the quantitative analysis of caffeine using 1 H NMR and the identification of the major components in commercial coffee samples using 1D and 2D NMR techniques without any sample pre-treatment. (author)

Fourier transform NMR

International Nuclear Information System (INIS)

Hallenga, K.

1991-01-01

This paper discusses the concept of Fourier transformation one of the many precious legacies of the French mathematician Jean Baptiste Joseph Fourier, essential for understanding the link between continuous-wave (CW) and Fourier transform (FT) NMR. Although in modern FT NMR the methods used to obtain a frequency spectrum from the time-domain signal may vary greatly, from the efficient Cooley-Tukey algorithm to very elaborate iterative least-square methods based other maximum entropy method or on linear prediction, the principles for Fourier transformation are unchanged and give invaluable insight into the interconnection of many pairs of physical entities called Fourier pairs

Guiding automated NMR structure determination using a global optimization metric, the NMR DP score

Energy Technology Data Exchange (ETDEWEB)

Huang, Yuanpeng Janet, E-mail: yphuang@cabm.rutgers.edu; Mao, Binchen; Xu, Fei; Montelione, Gaetano T., E-mail: gtm@rutgers.edu [Rutgers, The State University of New Jersey, Department of Molecular Biology and Biochemistry, Center for Advanced Biotechnology and Medicine, and Northeast Structural Genomics Consortium (United States)

2015-08-15

ASDP is an automated NMR NOE assignment program. It uses a distinct bottom-up topology-constrained network anchoring approach for NOE interpretation, with 2D, 3D and/or 4D NOESY peak lists and resonance assignments as input, and generates unambiguous NOE constraints for iterative structure calculations. ASDP is designed to function interactively with various structure determination programs that use distance restraints to generate molecular models. In the CASD–NMR project, ASDP was tested and further developed using blinded NMR data, including resonance assignments, either raw or manually-curated (refined) NOESY peak list data, and in some cases {sup 15}N–{sup 1}H residual dipolar coupling data. In these blinded tests, in which the reference structure was not available until after structures were generated, the fully-automated ASDP program performed very well on all targets using both the raw and refined NOESY peak list data. Improvements of ASDP relative to its predecessor program for automated NOESY peak assignments, AutoStructure, were driven by challenges provided by these CASD–NMR data. These algorithmic improvements include (1) using a global metric of structural accuracy, the discriminating power score, for guiding model selection during the iterative NOE interpretation process, and (2) identifying incorrect NOESY cross peak assignments caused by errors in the NMR resonance assignment list. These improvements provide a more robust automated NOESY analysis program, ASDP, with the unique capability of being utilized with alternative structure generation and refinement programs including CYANA, CNS, and/or Rosetta.

Nuclear magnetic resonance apparatus having semitoroidal RF coil for use in topical NMR and NMR imaging

International Nuclear Information System (INIS)

Fukushima, E.; Assink, R.A.; Roeder, S.B.W.; Gibson, A.A.V.

1984-01-01

An improved nuclear magnetic resonance (NMR) apparatus for use in topical magnetic resonance (TMR) spectroscopy and other remote sensing NMR applications includes a semitoroidal radio frequency (rf) coil. The semitoroidal rf coil produces an effective alternating magnetic field at a distance from the poles of the coil, to enable NMR measurements to be taken from selected regions inside an object, particularly human and other living subjects. The semitoroidal rf coil is relatively insensitive to magnetic interference from metallic objects located behind the coil, thereby rendering the coil particularly suited for use in both conventional and superconducting NMR magnets. The semitoroidal NMR coil can be constructed so that it emits little or no excess rf electric field associated with the rf magnetic field, thus avoiding adverse effects due to dielectric heating of the sample or to any other electric field interactions. The coil may be combined with a like orthogonal coil and suitably driven to provide a circularly polarised field; or it may be used in conjunction with a concentrically nested smaller semitoroidal coil to move the maximum field further from the coil assembly. (author)

Experimental demonstration of quantum contextuality on an NMR qutrit

Energy Technology Data Exchange (ETDEWEB)

Dogra, Shruti; Dorai, Kavita, E-mail: kavita@iisermohali.ac.in; Arvind

2016-05-20

We experimentally test quantum contextuality of a single qutrit using NMR. The contextuality inequalities based on nine observables developed by Kurzynski et al. are first reformulated in terms of traceless observables which can be measured in an NMR experiment. These inequalities reveal the contextuality of almost all single-qutrit states. We demonstrate the violation of the inequality on four different initial states of a spin-1 deuterium nucleus oriented in a liquid crystal matrix, and follow the violation as the states evolve in time. We also describe and experimentally perform a single-shot test of contextuality for a subclass of qutrit states whose density matrix is diagonal in the energy basis. - Highlights: • A contextuality inequality for a single qutrit was designed using traceless observables. • The violation of the inequality was experimentally demonstrated using NMR. • A single-shot test was experimentally performed for a subclass of diagonal qutrit states.

Experimental demonstration of quantum contextuality on an NMR qutrit

International Nuclear Information System (INIS)

Dogra, Shruti; Dorai, Kavita; Arvind

2016-01-01

We experimentally test quantum contextuality of a single qutrit using NMR. The contextuality inequalities based on nine observables developed by Kurzynski et al. are first reformulated in terms of traceless observables which can be measured in an NMR experiment. These inequalities reveal the contextuality of almost all single-qutrit states. We demonstrate the violation of the inequality on four different initial states of a spin-1 deuterium nucleus oriented in a liquid crystal matrix, and follow the violation as the states evolve in time. We also describe and experimentally perform a single-shot test of contextuality for a subclass of qutrit states whose density matrix is diagonal in the energy basis. - Highlights: • A contextuality inequality for a single qutrit was designed using traceless observables. • The violation of the inequality was experimentally demonstrated using NMR. • A single-shot test was experimentally performed for a subclass of diagonal qutrit states.

The NMR probe of high-Tc materials and correlated electron systems

CERN Document Server

Walstedt, Russell E

2018-01-01

This new edition updates readers in three areas of NMR studies, namely, recent developments in high-Tc materials, heavy fermion systems and actinide oxides are presented.  The NMR probe has yielded a vast array of data for solid state materials, corresponding to different compounds, ionic sites, and nuclear species, as well as to a wide variety of experimental conditions. The last two parts of the book are completely new in this edition, while the first part has seen major updates. This edition features the latest developments for high-Tc materials, especially the advances in the area of pseudogap studies are reviewed.  An in depth overview of heavy fermion systems is presented in the second part,  notably Kondo lattices, quantum critical points and unconventional superconductivity are areas of intense research recently and are covered extensively. Finally, valuable information from NMR studies with actinide oxides will be provided. Ongoing analysis and discussion of NMR data have resulted in a wealth o...

Comparative 1H NMR-based metabonomic analysis of HIV-1 sera

International Nuclear Information System (INIS)

Philippeos, C.; Steffens, F. E.; Meyer, D.

2009-01-01

1 H NMR spectroscopy of sera from HIV-1 infected and uninfected individuals was performed on 300 and 600 MHz instruments. The resultant spectra were automatically data reduced to 90 and 180 integral segments of equal length. Analysis of variance identified significant differences between the sample groups, especially for the samples analyzed on 600 MHz and reduced to fewer segments. Linear discriminant analysis correctly classified 100% of the samples analyzed on the 300 MHz NMR (reduced to 180 segments); an increase in instrument sensitivity resulted in lower percentages of correctly classified samples. Multinomial logistic regression (MLR) resulted in 100% correct classification of all samples from both instruments. Thus 1 H-NMR metabonomics on either instrument distinguishes HIV-positive individuals using or not using anti retroviral therapy, but the sensitivity of the instrument impacts on data reduction. Furthermore, MLR is a novel multivariate statistical technique for improved classification of biological data analyzed in NMR

[Monitoring of chemical components with different color traits of Tussilago farfara using NMR-based metabolomics].

Science.gov (United States)

Mi, Xi; Li, Zhen-yu; Qin, Xue-mei; Zhang, Li-zeng

2013-11-01

The quality and grade of traditional Chinese medicinal herbs were assessed by their characteristics traditionally. According to traditional experience, the quality of the purple Flos Farfarae is better than that of yellow buds. NMR-based metabolomic approach combined with significant analysis of microarray (SAM) and Spearman rank correlation analysis were used to investigate the different metabolites of the Flos Farfarae with different color feature. Principal component analysis (PCA) showed clear distinction between the purple and yellow flower buds of Tussilago farfara. The S-plot of orthogonal PLS-DA (OPLS-DA) and t test revealed that the levels of threonine, proline, phosphatidylcholine, creatinine, 4, 5-dicaffeoylquinic acid, rutin, caffeic acid, kaempferol analogues, and tussilagone were higher in the purple flower buds than that in the yellow buds, in agreement with the results of SAM and Spearman rank correlation analysis. The results confirmed the traditional medication experience that "purple flower bud is better than the yellow ones", and provide a scientific basis for assessing the quality of Flos Farfarae by the color features.

Carbon-13 NMR of flavinoids

International Nuclear Information System (INIS)

Agrawal, P.K.

1989-01-01

The present book has been written with the objective of introducing the organic chemists with the conceptual and experimental basis required for interpretation of 13 C NMR spectra of a flavonoid and to a discussion of general usefulness of the technique in solving flavonoid structural problem. After a brief general introduction to the essential aspects of flavonoids and 13 C NMR spectroscopy, considerable emphasis has been placed in chapter 2 on the various experimental methods and the interpretation of spectral details which enable individual resonance lines to be associated with the appropriate carbons in a molecule. The whole bulk of the literature, published on 13 C NMR of flavonoids in the major journals upto 1986 alongwith some recent references of 1987 has been classified in several categories such as: flavonoids, isflavonoids, other flavonoids, flavonoid glycosides, chalconoids and flavanoids. Each category constitutes a chapter. Finally the last chapter is devoted largely to a discussion for the differentiation of various categories and subcategories of flavonoids and for the establishment of aromatic substitution pattern in these compounds. It should be emphasized that the book is a data book and only concerned with the actual analysis of 13 C NMR spectra, thus a reasonable familiarity with basic instrumentation of 13 C NMR and general pattern of nuclear chemical shifts has been assumed. (author). refs.; figs.; tabs

NMR characterization of pituitary tumors

International Nuclear Information System (INIS)

Osbakken, M.; Gonzales, J.; Page, R.

1984-01-01

Twelve patients (5 male, 7 female, mean age 37.9 +- 20) with pituitary tumors were extensively evaluated with NMR imaging using a 1.5K gauss resistive magnet. Saturation recovery (SR), inversion recovery (IR) and spin echo (SE) pulse sequences were used for qualitative characterization of the lesions. T/sub 1/ calculations were also performed for brain and pituitary. Tumor histology and endocrine status were correlated with NMR data. All tumors were large with suprasellar extension (6 with prolactin secretion, 6 without). Pituitary T/sub 1/'s ranged from .2 to .64, the mean T/sub 1/ being longer than that of brain (Brain = .4 +- .04; Pit = .48 +- .14). 3 patients with histological evidence of homogeneous adenomas had long T/sub 1/'s (0.58 +- .05). 3 patients with evidence of recent or old hemorhage into the pituitary had much shorter T/sub 1/'s (0.29 +- .12). There was no relationship between prolactin secretion and T/sub 1/. Qualitative T/sub 1/ and T/sub 2/ information can be obtained by using a combination of SR, IR, and SE images. Using this method in the patients, homogeneous adenomas had similar T/sub 1/'s and longer T/sub 2/'s compared to the brain, while patients with bleeds had shorter T/sub 1/'s and T/sub 2/'s. Image T/sub 1/ characteristics correlated well with the calculated T/sub 1/ values. The range of T/sub 1/ (and potentially T/sub 2/) values which occur in apparently similar lesions are most likely due to anatomical and pathophysiological variations in these lesions. It may be ultimately possible to separate different types of pathological processes based on NMR image T/sub 1/ and T/sub 2/ characteristics after careful comparative studies of NMR and histological data are completed. The combination of calculated T/sub 1/ and T/sub 2/ with image T/sub 1/ and T/sub 2/ information may also be useful in further characterization of lesions

NMR imaging

International Nuclear Information System (INIS)

Ouchi, Toshihiro; Steiner, R.E.

1984-01-01

Three epidermoid and two dermoid tumours, pathologically proven, were examined by NMR and CT scans. Although most brain tumours have a low signal with a long T 1 , a dermoid cyst and one of the two components of the other dermoid tumour had a high signal and therefore a short T 1 . All three epidermoid tumours had a low signal and a long T 1 . Because of the high level contrast between some of the tumours and cerebrospinal fluid, NMR is helpful to detect the lesion. Neither of the liquid fluid levels in the tumour cysts or floating fat in the subarachnoid space was recognized in one patients, but the fine leakage of the content from the epidermoid cyst into the lateral ventricle was detected on a saturation recovery 1000 image in one case. (author)

Structural properties of carbon nanotubes derived from 13C NMR

KAUST Repository

Abou-Hamad, E.

2011-10-10

We present a detailed experimental and theoretical study on how structural properties of carbon nanotubes can be derived from 13C NMR investigations. Magic angle spinning solid state NMR experiments have been performed on single- and multiwalled carbon nanotubes with diameters in the range from 0.7 to 100 nm and with number of walls from 1 to 90. We provide models on how diameter and the number of nanotube walls influence NMR linewidth and line position. Both models are supported by theoretical calculations. Increasing the diameter D, from the smallest investigated nanotube, which in our study corresponds to the inner nanotube of a double-walled tube to the largest studied diameter, corresponding to large multiwalled nanotubes, leads to a 23.5 ppm diamagnetic shift of the isotropic NMR line position δ. We show that the isotropic line follows the relation δ = 18.3/D + 102.5 ppm, where D is the diameter of the tube and NMR line position δ is relative to tetramethylsilane. The relation asymptotically tends to approach the line position expected in graphene. A characteristic broadening of the line shape is observed with the increasing number of walls. This feature can be rationalized by an isotropic shift distribution originating from different diamagnetic shielding of the encapsulated nanotubes together with a heterogeneity of the samples. Based on our results, NMR is shown to be a nondestructive spectroscopic method that can be used as a complementary method to, for example, transmission electron microscopy to obtain structural information for carbon nanotubes, especially bulk samples.

MetAssimulo:Simulation of Realistic NMR Metabolic Profiles

Directory of Open Access Journals (Sweden)

De Iorio Maria

2010-10-01

Full Text Available Abstract Background Probing the complex fusion of genetic and environmental interactions, metabolic profiling (or metabolomics/metabonomics, the study of small molecules involved in metabolic reactions, is a rapidly expanding 'omics' field. A major technique for capturing metabolite data is 1H-NMR spectroscopy and this yields highly complex profiles that require sophisticated statistical analysis methods. However, experimental data is difficult to control and expensive to obtain. Thus data simulation is a productive route to aid algorithm development. Results MetAssimulo is a MATLAB-based package that has been developed to simulate 1H-NMR spectra of complex mixtures such as metabolic profiles. Drawing data from a metabolite standard spectral database in conjunction with concentration information input by the user or constructed automatically from the Human Metabolome Database, MetAssimulo is able to create realistic metabolic profiles containing large numbers of metabolites with a range of user-defined properties. Current features include the simulation of two groups ('case' and 'control' specified by means and standard deviations of concentrations for each metabolite. The software enables addition of spectral noise with a realistic autocorrelation structure at user controllable levels. A crucial feature of the algorithm is its ability to simulate both intra- and inter-metabolite correlations, the analysis of which is fundamental to many techniques in the field. Further, MetAssimulo is able to simulate shifts in NMR peak positions that result from matrix effects such as pH differences which are often observed in metabolic NMR spectra and pose serious challenges for statistical algorithms. Conclusions No other software is currently able to simulate NMR metabolic profiles with such complexity and flexibility. This paper describes the algorithm behind MetAssimulo and demonstrates how it can be used to simulate realistic NMR metabolic profiles with

Use of NMR and NMR Prediction Software to Identify Components in Red Bull Energy Drinks

Science.gov (United States)

Simpson, Andre J.; Shirzadi, Azadeh; Burrow, Timothy E.; Dicks, Andrew P.; Lefebvre, Brent; Corrin, Tricia

2009-01-01

A laboratory experiment designed as part of an upper-level undergraduate analytical chemistry course is described. Students investigate two popular soft drinks (Red Bull Energy Drink and sugar-free Red Bull Energy Drink) by NMR spectroscopy. With assistance of modern NMR prediction software they identify and quantify major components in each…

{sup 1}H HR-MAS NMR and S180 cells: metabolite assignment and evaluation of pulse sequence

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Aline L. de; Martinelli, Bruno César B.; Lião, Luciano M. [Universidade Federal de Goiás (UFG), Goiânia, GO (Brazil). Instituto de Química. Lab. de RMN; Pereira, Flávia C.; Silveira-Lacerda, Elisangela P. [Universidade Federal de Goiás (UFG), Goiânia, GO (Brazil). Instituto de Ciências Biológicas. Laboratório Genética Molecular e Citogenética; Alcantara, Glaucia B., E-mail: glaucia.alcantara@ufms.br [Universidade Federal de Mato Grosso do Sul (UFMS), Campo Grande, MS (Brazil). Inst. de Química

2014-07-01

High resolution magic angle spinning {sup 1}H nuclear magnetic resonance spectroscopy (HR-MAS NMR) is a useful technique for evaluation of intact cells and tissues. However, optimal NMR parameters are crucial in obtaining reliable results. To identify the key steps for the optimization of HR-MAS NMR parameters, we assessed different pulse sequences and NMR parameters using sarcoma 180 (S180) cells. A complete assignment of the metabolites of S180 is given to assist future studies. (author)

NMR study of Albemoschus esculentus characterization

International Nuclear Information System (INIS)

Bathista, A.L.B.S; Silva, E.O.; Nogueira, Jose de S.; Tavares, M.I.B.

2001-01-01

The investigation of the main compounds presented in the Albemoschus esculentus has been carried out employing nuclear magnetic resonance spectroscopy (NMR), using solution and solid state NMR when it one was necessary. The evaluation of NMR data allowed us to characterize the main type of components presented in this kind of sample. It was necessary to use a total information from solid state NMR and also the solution response. From these information we could get that four main components were presented in this sample. One in the shell, that is cellulose, another one between the shell and seeds that is a polysaccharide and in the seed two components were found one is a starch and the second one is an oil, a triacylglycerol. These components are responsible by its physical chemistry properties. (author)

Magic Angle Spinning NMR Structure Determination of Proteins from Pseudocontact Shifts

KAUST Repository

Li, Jianping

2013-06-05

Magic angle spinning solid-state NMR is a unique technique to study atomic-resolution structure of biomacromolecules which resist crystallization or are too large to study by solution NMR techniques. However, difficulties in obtaining sufficient number of long-range distance restraints using dipolar coupling based spectra hamper the process of structure determination of proteins in solid-state NMR. In this study it is shown that high-resolution structure of proteins in solid phase can be determined without the use of traditional dipolar-dipolar coupling based distance restraints by combining the measurements of pseudocontact shifts (PCSs) with Rosetta calculations. The PCSs were generated by chelating exogenous paramagnetic metal ions to a tag 4-mercaptomethyl-dipicolinic acid, which is covalently attached to different residue sites in a 56-residue immunoglobulin-binding domain of protein G (GB1). The long-range structural restraints with metal-nucleus distance of up to ∼20 Å are quantitatively extracted from experimentally observed PCSs, and these are in good agreement with the distances back-calculated using an X-ray structure model. Moreover, we demonstrate that using several paramagnetic ions with varied paramagnetic susceptibilities as well as the introduction of paramagnetic labels at different sites can dramatically increase the number of long-range restraints and cover different regions of the protein. The structure generated from solid-state NMR PCSs restraints combined with Rosetta calculations has 0.7 Å root-mean-square deviation relative to X-ray structure. © 2013 American Chemical Society.

Magic Angle Spinning NMR Structure Determination of Proteins from Pseudocontact Shifts

KAUST Repository

Li, Jianping; Pilla, Kala Bharath; Li, Qingfeng; Zhang, Zhengfeng; Su, Xuncheng; Huber, Thomas; Yang, Jun

2013-01-01

Magic angle spinning solid-state NMR is a unique technique to study atomic-resolution structure of biomacromolecules which resist crystallization or are too large to study by solution NMR techniques. However, difficulties in obtaining sufficient number of long-range distance restraints using dipolar coupling based spectra hamper the process of structure determination of proteins in solid-state NMR. In this study it is shown that high-resolution structure of proteins in solid phase can be determined without the use of traditional dipolar-dipolar coupling based distance restraints by combining the measurements of pseudocontact shifts (PCSs) with Rosetta calculations. The PCSs were generated by chelating exogenous paramagnetic metal ions to a tag 4-mercaptomethyl-dipicolinic acid, which is covalently attached to different residue sites in a 56-residue immunoglobulin-binding domain of protein G (GB1). The long-range structural restraints with metal-nucleus distance of up to ∼20 Å are quantitatively extracted from experimentally observed PCSs, and these are in good agreement with the distances back-calculated using an X-ray structure model. Moreover, we demonstrate that using several paramagnetic ions with varied paramagnetic susceptibilities as well as the introduction of paramagnetic labels at different sites can dramatically increase the number of long-range restraints and cover different regions of the protein. The structure generated from solid-state NMR PCSs restraints combined with Rosetta calculations has 0.7 Å root-mean-square deviation relative to X-ray structure. © 2013 American Chemical Society.

MIL-STD-1553 dynamic bus controller/remote terminal hybrid set

Science.gov (United States)

Friedman, S. N.

This paper describes the performance, physical and electrical requirements of a Dual Redundant BUS Interface Unit (BIU) acting as a BUS Controller Interface Unit (BCIU) or Remote Terminal Unit (RTU) between a Motorola 68000 VME BUS and MIL-STD-1553B Multiplex Data Bus. A discussion of how the BIU Hybrid set is programmed, and operates as a BCIU or RTU, will be included. This paper will review Dynamic Bus Control and other Mode Code capabilities. The BIU Hybrid Set interfaces to a 68000 Microprocessor with a VME Bus using programmed I/O transfers. This special interface will be discussed along with the internal Dual Access Memory (4K x 16) used to support the data exchanges between the CPU and the BIU Hybrid Set. The hybrid set's physical size and power requirements will be covered. This includes the present Double Eurocard the BIU function is presently being offered on.

NMR spectroscopy and drug development

International Nuclear Information System (INIS)

Craik, D.; Munro, S.

1990-01-01

The use of nuclear magnetic resonance (NMR) spectroscopy for structural and conformational studies on drug molecules, the three-dimensional investigation of proteins structure and their interactions with ligands are discussed. In-vivo NMR studies of the effects of drugs on metabolism in perfused organs and whole animals are also briefly presented. 5 refs., ills

NMR in pulsed magnetic field

KAUST Repository

Abou-Hamad, Edy; Bontemps, P.; Rikken, Geert L J A

2011-01-01

Nuclear magnetic resonance (NMR) experiments in pulsed magnetic fields up to 30.4 T focused on 1H and 93Nb nuclei are reported. Here we discuss the advantage and limitation of pulsed field NMR and why this technique is able to become a promising research tool. © 2011 Elsevier Inc. All Rights Reserved.

NMR in pulsed magnetic field

KAUST Repository

Abou-Hamad, Edy

2011-09-01

Nuclear magnetic resonance (NMR) experiments in pulsed magnetic fields up to 30.4 T focused on 1H and 93Nb nuclei are reported. Here we discuss the advantage and limitation of pulsed field NMR and why this technique is able to become a promising research tool. © 2011 Elsevier Inc. All Rights Reserved.

Quantification of taurine in energy drinks using ¹H NMR.

Science.gov (United States)

Hohmann, Monika; Felbinger, Christine; Christoph, Norbert; Wachter, Helmut; Wiest, Johannes; Holzgrabe, Ulrike

2014-05-01

The consumption of so called energy drinks is increasing, especially among adolescents. These beverages commonly contain considerable amounts of the amino sulfonic acid taurine, which is related to a magnitude of various physiological effects. The customary method to control the legal limit of taurine in energy drinks is LC-UV/vis with postcolumn derivatization using ninhydrin. In this paper we describe the quantification of taurine in energy drinks by (1)H NMR as an alternative to existing methods of quantification. Variation of pH values revealed the separation of a distinct taurine signal in (1)H NMR spectra, which was applied for integration and quantification. Quantification was performed using external calibration (R(2)>0.9999; linearity verified by Mandel's fitting test with a 95% confidence level) and PULCON. Taurine concentrations in 20 different energy drinks were analyzed by both using (1)H NMR and LC-UV/vis. The deviation between (1)H NMR and LC-UV/vis results was always below the expanded measurement uncertainty of 12.2% for the LC-UV/vis method (95% confidence level) and at worst 10.4%. Due to the high accordance to LC-UV/vis data and adequate recovery rates (ranging between 97.1% and 108.2%), (1)H NMR measurement presents a suitable method to quantify taurine in energy drinks. Copyright © 2013 Elsevier B.V. All rights reserved.

Two-dimensional NMR spectroscopy. Applications for chemists and biochemists

International Nuclear Information System (INIS)

Croasmun, W.R.; Carlson, R.M.K.

1987-01-01

Two-dimensional nuclear magnetic resonance spectroscopy (2-D NMR) has become a very powerful class of experiments (in the hands of an adept scientist) with broad adaptability to new situations. It is the product of a happy marriage between modern pulse FT-NMR technology, with its large memory and high-speed computers, and the physicists and chemists who love to manipulate spin systems. Basic 2-D experiments are now a standard capability of modern NMR spectrometers, and this timely book intends to make 2-D NMR users of those who are familiar with normal 1-D NMR. The 2-D NMR goal is correlation of the lines of the observed NMR spectrum with other properties of the system. This book deals with applications to high-resolution spectrum analysis, utilizing either coupling between the NMR-active nuclei or chemical exchange to perform the correlation. The coupling can be scalar (through bonds) or direct through space (within 5 A). The coupling may be homonuclear (between like nuclei) or heteronuclear

Push-through Direction Injectin NMR Automation

Science.gov (United States)

Nuclear magnetic resonance (NMR) and mass spectrometry (MS) are the two major spectroscopic techniques successfully used in metabolomics studies. The non-invasive, quantitative and reproducible characteristics make NMR spectroscopy an excellent technique for detection of endogeno...

NMR reaction monitoring in flow synthesis.

Science.gov (United States)

Gomez, M Victoria; de la Hoz, Antonio

2017-01-01

Recent advances in the use of flow chemistry with in-line and on-line analysis by NMR are presented. The use of macro- and microreactors, coupled with standard and custom made NMR probes involving microcoils, incorporated into high resolution and benchtop NMR instruments is reviewed. Some recent selected applications have been collected, including synthetic applications, the determination of the kinetic and thermodynamic parameters and reaction optimization, even in single experiments and on the μL scale. Finally, software that allows automatic reaction monitoring and optimization is discussed.

The NMR probe of high-T{sub c} materials and correlated electron systems. 2. ed.

Energy Technology Data Exchange (ETDEWEB)

Walstedt, Russell E. [Michigan Univ., Ann Arbor, MI (United States). Dept. of Physics

2018-03-01

This new edition updates readers in three areas of NMR studies, namely, recent developments in high-T{sub c} materials, heavy fermion systems and actinide oxides are presented. The NMR probe has yielded a vast array of data for solid state materials, corresponding to different compounds, ionic sites, and nuclear species, as well as to a wide variety of experimental conditions. The last two parts of the book are completely new in this edition, while the first part has seen major updates. This edition features the latest developments for high-T{sub c} materials, especially the advances in the area of pseudogap studies are reviewed. An in depth overview of heavy fermion systems is presented in the second part, notably Kondo lattices, quantum critical points and unconventional superconductivity are areas of intense research recently and are covered extensively. Finally, valuable information from NMR studies with actinide oxides will be provided. Ongoing analysis and discussion of NMR data have resulted in a wealth of important insights into the physics of these exotic systems. The aims of this monograph are manifold. First, it reviews NMR methodology as it has been applied to the different studies. This is addressed to NMR practitioners and to physics laypersons alike. Next, it presents a review of NMR measurements and the wide variety of phenomena which they represent. The third phase is to recount the theoretical model calculations and other proposals which have been put forward to account for these data.

Emission Properties, Solubility, Thermodynamic Analysis and NMR Studies of Rare-Earth Complexes with Two Different Phosphine Oxides

Directory of Open Access Journals (Sweden)

Hiroki Iwanaga

2010-07-01

Full Text Available The paper proposes novel molecular designs for rare-earth complexes involving the introduction of two different phosphine oxide structures into one rare-earth ion. These designs are effective for improving solubility and emission intensity. Additionally, the complexes are indispensable for realizing high performances in LEDs and security media. The thermodynamic properties of Eu(III complexes are correlated with the solubility. Correlations between coordination structures and emission intensity were explained by NMR analysis. The luminous flux of red LED devices with Eu(III complexes is very high (20 mA, 870 m lumen. A new white LED has its largest spectra intensity in the red region and a human look much more vividly under this light.

First NMR Experiments in the Hybrid, 40T and beyond: A challenge to traditional NMR instrumentation

Science.gov (United States)

Reyes, Arneil P.

2001-03-01

The recent commissioning of the continuous 45T hybrid magnet at NHMFL has opened new horizon for science but carried with it new challenges that forced NMR spectroscopists to reevaluate the traditional approach to NMR instrumentation. Very recently, a world record frequency at 1.5GHz has been achieved, signaling the new era of NMR probe designs that may someday blur the distinction between the classic NMR and millimeter-wave spectroscopies. No longer can we ignore stray capacitances and exposed leads in the terrain where every millimeter of cable counts. The challenge brought about by ever increasing fields and consequently, frequency, requirements has stimulated ingenuity among scientists. This is eased by accelerated growth in RF communications and computing technologies that made available advanced devices with more speed, power, bandwidth, noise immunity, flexibility, and complexity in small space at very low costs. Utilization of these devices have been paramount consideration in cutting-edge designs at NHMFL for Condensed Matter NMR and will be described in this talk. I will also discuss a number of first >33T NMR experiments to date utilizing the strength of the field to expose, as well as to induce occurrence of, new physical phenomena in condensed matter and which resulted in better understanding of the physics of materials. This work has been a result of continuing collaboration with P. L Kuhns, W. G. Moulton, W. P. Halperin (NU), and W. G. Clark (UCLA). The NHMFL is supported through the National Science Foundation and the State of Florida.

Solid-state 29Si NMR and FTIR analyses of lignin-silica coprecipitates

DEFF Research Database (Denmark)

Cabrera Orozco, Yohanna; Cabrera, Andrés; Larsen, Flemming Hofmann

2016-01-01

When agricultural residues are processed to ethanol, lignin and silica are some of the main byproducts. Separation of these two products is difficult and the chemical interactions between lignin and silica are not well described. In the present study, the effect of lignin-silica complexing has been...... investigated by characterizing lignin and silica coprecipitates by FTIR and solid state NMR. Silica particles were coprecipitated with three different lignins, three lignin model compounds, and two silanes representing silica-in-lignin model compounds. Comparison of 29Si SP/MAS NMR spectra revealed differences...

NMR/MS Translator for the Enhanced Simultaneous Analysis of Metabolomics Mixtures by NMR Spectroscopy and Mass Spectrometry: Application to Human Urine.

Science.gov (United States)

Bingol, Kerem; Brüschweiler, Rafael

2015-06-05

A novel metabolite identification strategy is presented for the combined NMR/MS analysis of complex metabolite mixtures. The approach first identifies metabolite candidates from 1D or 2D NMR spectra by NMR database query, which is followed by the determination of the masses (m/z) of their possible ions, adducts, fragments, and characteristic isotope distributions. The expected m/z ratios are then compared with the MS(1) spectrum for the direct assignment of those signals of the mass spectrum that contain information about the same metabolites as the NMR spectra. In this way, the mass spectrum can be assigned with very high confidence, and it provides at the same time validation of the NMR-derived metabolites. The method was first demonstrated on a model mixture, and it was then applied to human urine collected from a pool of healthy individuals. A number of metabolites could be detected that had not been reported previously, further extending the list of known urine metabolites. The new analysis approach, which is termed NMR/MS Translator, is fully automated and takes only a few seconds on a computer workstation. NMR/MS Translator synergistically uses the power of NMR and MS, enhancing the accuracy and efficiency of the identification of those metabolites compiled in databases.

A combined NMR and XRD study of AFI and AEL type molecular sieves

NARCIS (Netherlands)

Peeters, M.P.J.; Ven, van de L.J.M.; Haan, de J.W.; Hooff, van J.H.C.

1993-01-01

Calcined dehydrated AlPO4-5 was studied by x-ray powder diffraction, 31P MAS, and 27Al double-resonance (DOR) NMR. Three crystallog. different sites can be distinguished in the structure of dehydrated AlPO4-5 in the ratio 1:1:1. The obsd. splitting of the NMR spectra is correlated to the line width

NMR structure of the HIV-1 reverse transcriptase thumb subdomain

Energy Technology Data Exchange (ETDEWEB)

Sharaf, Naima G. [University of Pittsburgh, School of Medicine, Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions (United States); Brereton, Andrew E. [Oregon State University, Department of Biochemistry and Biophysics, 2011 Ag & Life Sciences Bldg (United States); Byeon, In-Ja L. [University of Pittsburgh, School of Medicine, Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions (United States); Andrew Karplus, P. [Oregon State University, Department of Biochemistry and Biophysics, 2011 Ag & Life Sciences Bldg (United States); Gronenborn, Angela M., E-mail: amg100@pitt.edu [University of Pittsburgh, School of Medicine, Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions (United States)

2016-12-15

The solution NMR structure of the isolated thumb subdomain of HIV-1 reverse transcriptase (RT) has been determined. A detailed comparison of the current structure with dozens of the highest resolution crystal structures of this domain in the context of the full-length enzyme reveals that the overall structures are very similar, with only two regions exhibiting local conformational differences. The C-terminal capping pattern of the αH helix is subtly different, and the loop connecting the αI and αJ helices in the p51 chain of the full-length p51/p66 heterodimeric RT differs from our NMR structure due to unique packing interactions in mature RT. Overall, our data show that the thumb subdomain folds independently and essentially the same in isolation as in its natural structural context.

Toxic actions of dinoseb in medaka (Oryzias latipes) embryos as determined by in vivo 31P NMR, HPLC-UV and 1H NMR metabolomics.

Science.gov (United States)

Viant, Mark R; Pincetich, Christopher A; Hinton, David E; Tjeerdema, Ronald S

2006-03-10

Changes in metabolism of Japanese medaka (Oryzias latipes) embryos exposed to dinoseb (2-sec-butyl-4,6-dinitrophenol), a substituted dinitrophenol herbicide, were determined by in vivo (31)P NMR, high-pressure liquid chromatography (HPLC)-UV, and (1)H NMR metabolomics. ATP and phosphocreatine (PCr) metabolism were characterized within intact embryos by in vivo (31)P NMR; concentrations of ATP, GTP, ADP, GDP, AMP and PCr were determined by HPLC-UV; and changes in numerous polar metabolites were characterized by (1)H NMR-based metabolomics. Rangefinding exposures determined two sublethal doses of dinoseb, 50 and 75 ppb, in which embryos survived from 1-day post fertilization (DPF) through the duration of embryogenesis. In vivo (31)P NMR data were acquired from 900 embryos in 0, 50, and 75 ppb dinoseb at 14, 62, and 110 h (n = 6 groups) after initiation of exposure. After 110 h, embryos were observed for normal development and hatching success, then either preserved in 10% formalin for growth analysis or flash frozen and extracted for HPLC-UV and (1)H NMR analysis. Dinoseb exposure at both concentrations resulted in significant declines in [ATP] and [PCr] at 110 h as measured by in vivo (31)P NMR (p fashion. Metabolic effects measured by in vivo (31)P NMR showed a significant increase in orthophosphate levels (P(i); p < 0.05), and significant decreases in [ATP], [PCr] and the PCr/P(i) ratio (p < 0.05). Metabolomics revealed a dose-response relationship between dinoseb and endogenous metabolite changes, with both dinoseb concentrations producing significantly different metabolic profiles from controls (p < 0.05). Metabolic changes included decreased concentrations of ATP, PCr, alanine and tyrosine, and increased concentrations of lactate with medaka embryotoxicity. This study demonstrated that medaka embryos respond to dinoseb with significant changes in metabolism, reduced growth and heart rates, and increased abnormal development and post-exposure mortality. All

O-17 NMR measurement of water

International Nuclear Information System (INIS)

Fukazawa, Nobuyuki

1990-01-01

Recently, attention has been paid to the various treatment of water and the utilization of water by magnetic treatment, electric field treatment and so on. It has been said that by these treatments, the change in the properties of water arises. The state of this treated water cannot be explained by the properties of water from conventional physical and chemical standpoints. In addition, the method of measurement of whether the change arose or not is not yet determined. It is necessary to establish the method of measurement for the basic state of water. In this study, O-17 NMR which observes the state of water directly at molecular or atomic level was investigated as the method of measuring water. The measurement of O-17 NMR was carried out with a JNR 90Q FT NMR of Fourier transformation type of JEOL Ltd. The experimental method and the results are reported. The result of measurement of the O-17 NMR spectrum for distilled ion exchange water is shown. It is know that it has very wide line width as compared with the NMR spectra of protons and C-13. The relative sensitivity of O-17 observation is about 1/100,000 of that of protons. As to the information on the state of water obtained by O-17 NMR, there are chemical shift and line width. As temperature rose, the line width showed decrease, which seemed to be related to the decrease of hydrogen combination. (K.I.)

Study of β-NMR for Liquid Biological Samples

CERN Document Server

Beattie, Caitlin

2017-01-01

β-NMR is an exotic form of NMR spectroscopy that allows for the characterization of matter based on the anisotropic β-decay of radioactive probe nuclei. This has been shown to be an effective spectroscopic technique for many different compounds, but its use for liquid biological samples is relatively unexplored. The work at the VITO line of ISOLDE seeks to employ this technique to study such samples. Currently, preparations are being made for an experiment to characterize DNA G-quadruplexes and their interactions with stabilizing cations. More specifically, the work in which I engaged as a summer student focused on the experiment’s liquid handling system and the stability of the relevant biological samples under vacuum.

Solution NMR structure determination of proteins revisited

International Nuclear Information System (INIS)

Billeter, Martin; Wagner, Gerhard; Wuethrich, Kurt

2008-01-01

This 'Perspective' bears on the present state of protein structure determination by NMR in solution. The focus is on a comparison of the infrastructure available for NMR structure determination when compared to protein crystal structure determination by X-ray diffraction. The main conclusion emerges that the unique potential of NMR to generate high resolution data also on dynamics, interactions and conformational equilibria has contributed to a lack of standard procedures for structure determination which would be readily amenable to improved efficiency by automation. To spark renewed discussion on the topic of NMR structure determination of proteins, procedural steps with high potential for improvement are identified

NMR reaction monitoring in flow synthesis

Directory of Open Access Journals (Sweden)

M. Victoria Gomez

2017-02-01

Full Text Available Recent advances in the use of flow chemistry with in-line and on-line analysis by NMR are presented. The use of macro- and microreactors, coupled with standard and custom made NMR probes involving microcoils, incorporated into high resolution and benchtop NMR instruments is reviewed. Some recent selected applications have been collected, including synthetic applications, the determination of the kinetic and thermodynamic parameters and reaction optimization, even in single experiments and on the μL scale. Finally, software that allows automatic reaction monitoring and optimization is discussed.

Petrophysical properties of greensand as predicted from NMR measurements

DEFF Research Database (Denmark)

Hossain, Zakir; Grattoni, Carlos A.; Solymar, Mikael

2011-01-01

ABSTRACT: Nuclear magnetic resonance (NMR) is a useful tool in reservoir evaluation. The objective of this study is to predict petrophysical properties from NMR T2 distributions. A series of laboratory experiments including core analysis, capillary pressure measurements, NMR T2 measurements...... with macro-pores. Permeability may be predicted from NMR by using Kozeny's equation when surface relaxivity is known. Capillary pressure drainage curves may be predicted from NMR T2 distribution when pore size distribution within a sample is homogeneous....

Dynamics of solutions and fluid mixtures by NMR

International Nuclear Information System (INIS)

Delpuech, J.J.

1994-01-01

After a short introduction to NMR spectroscopy, with a special emphasis on dynamical aspects, an overview on two fundamental aspects of molecular dynamics, NMR relaxation and its relationship with molecular reorientation, and magnetization transfer phenomena induced by molecular rate processes (dynamic NMR) is presented, followed by specific mechanisms of relaxation encountered in paramagnetic systems or with quadrupolar nuclei. Application fields are then reviewed: solvent exchange on metal ions with a variable pressure NMR approach, applications of field gradients in NMR, aggregation phenomena and micro-heterogeneity in surfactant solutions, polymers and biopolymers in the liquid state, liquid-like molecules in rigid matrices and in soft matter (swollen polymers and gels, fluids in and on inorganic materials, food)

New methods for the correction of 31P NMR spectra in in vivo NMR spectroscopy

International Nuclear Information System (INIS)

Starcuk, Z.; Bartusek, K.; Starcuk, Z. jr.

1994-01-01

The new methods for the correction of 31 P NMR spectra in vivo NMR spectroscopy have been performed. A method for the baseline correction of the spectra which represents a combination of time-domain and frequency-domain has been discussed.The method is very fast and efficient for minimization of base line artifacts of biological tissues impact

NMR techniques in the study of cardiovascular structure and functions

International Nuclear Information System (INIS)

Osbakken, M.; Haselgrove, J.

1987-01-01

The chapter titles of this book are: Introduction to NMR Techniques;Theory of NMR Probe Design;Overview of Magnetic Resonance Imaging to Study the Cardiovascular System;Vascular Anatomy and Physiology Studied with NMR Techniques;Assessment of Myocardial Ischemia and Infarction by Nuclear Magnetic Resonance Imaging;The Use of MRI in Congenital Heart Disease;Cardiomyopathies and Myocarditis Studied with NMR Techniques;Determination of Myocardial Mechanical Function with Magnetic Resonance Imaging Techniques;Determination of Flow Using NMR Techniques;The Use of Contrast Agents in Cardiac MRI;Can Cardiovascular Disease Be Effectively Evaluated with NMR Spectroscopy? NMR Studies of ATP Synthesis Reactions in the Isolated Heart;Studies of Intermediary Metabolism in the Heart by 13C NMR Spectroscopy;23Na and 39K NMR Spectroscopic Studies of the Intact Beating Heart;and Evaluation of Skeletal Muscle Metabolism in Patients with Congestive Heart Failure Using Phosphorus Nuclear Magnetic Resonance

Systematic comparison of crystal and NMR protein structures deposited in the protein data bank.

Science.gov (United States)

Sikic, Kresimir; Tomic, Sanja; Carugo, Oliviero

2010-09-03

Nearly all the macromolecular three-dimensional structures deposited in Protein Data Bank were determined by either crystallographic (X-ray) or Nuclear Magnetic Resonance (NMR) spectroscopic methods. This paper reports a systematic comparison of the crystallographic and NMR results deposited in the files of the Protein Data Bank, in order to find out to which extent these information can be aggregated in bioinformatics. A non-redundant data set containing 109 NMR - X-ray structure pairs of nearly identical proteins was derived from the Protein Data Bank. A series of comparisons were performed by focusing the attention towards both global features and local details. It was observed that: (1) the RMDS values between NMR and crystal structures range from about 1.5 Å to about 2.5 Å; (2) the correlation between conformational deviations and residue type reveals that hydrophobic amino acids are more similar in crystal and NMR structures than hydrophilic amino acids; (3) the correlation between solvent accessibility of the residues and their conformational variability in solid state and in solution is relatively modest (correlation coefficient = 0.462); (4) beta strands on average match better between NMR and crystal structures than helices and loops; (5) conformational differences between loops are independent of crystal packing interactions in the solid state; (6) very seldom, side chains buried in the protein interior are observed to adopt different orientations in the solid state and in solution.

13C-NMR assignment, structure, and dynamics of deoxyoligonucleotides

International Nuclear Information System (INIS)

Zanatta, N.; Borer, P.N.; Levy, G.C.

1986-01-01

The unique spectral properties of 13 C-NMR for studying nucleic acids and some of the important features of 13 C-NMR in oligonucleotide studies are demostrated. The main difficulty in studying oligonucleotides by 13 C-NMR and recent improvements in NMR instrumentation and advances in oligonucleotide synthesis are presented. The high resolution 13 C-NMR spectra, T 1 relaxation times and NOEs were measured for duplex of the self-complementary oligo-DNAs: d(CG) 3 and d(GGTATACC) are studied. The target of this study is to developed a systematic 13 C-NMR spectral assignment and to investigate the structure and dynamics of these two sequences by this techniques. (M.J.C.) [pt

NMR imaging studies of coal

Energy Technology Data Exchange (ETDEWEB)

Ma, Z.R.; Zhang, P.Z.; Ding, G.L.; Li, L.Y.; Ye, C.H. [University of Science and Technology, Beijing (China). Dept. of Chemistry

1996-06-01

The permeation transportation and swelling behavior of solvents into coal are investigated by NMR imaging using pyridine-d{sub 5} and acetone-d{sub 6}. Images of coal swollen with deuterated solvents illuminate proton distributions of mobile phases within the coal macromolecular networks. More information about the chemical and physical structure of coal can be obtained using NMR imaging techniques.

Variations of NMR signals by hyperpolarization and ultrasound; Variation von NMR-Signalen durch Hyperpolarisation und Ultraschall

Energy Technology Data Exchange (ETDEWEB)

Engelbertz, A.

2006-07-01

In this thesis it is described how p-NMR can be applied to metals with verlo low hydrogen concentrations and how a combination of ultrasound and NMR can lead to an improvement of the measureing method. As examples measurements on H{sub 2}O and ethanol are described. (HSI)

NMR investigation of coal extracts

Energy Technology Data Exchange (ETDEWEB)

Lang, I; Sebor, G [Ceskoslovenska Akademie Ved, Prague. Hornicky Ustav; Sebor, G Jr; Hajek, M; Mostecky, J [Vysoka Skola Chemicko-Technologicka, Prague (Czechoslovakia)

1978-07-01

Proton NMR spectroscopy was used for the evaluation of 10% coal extract solutions in deuterated pyridine. Four types of Czechoslovak coal were analyzed. Agreement was found between the aromaticity of coal extracts calculated from /sup 1/H NMR data using Brown's method and Ladner's and Williams' method and the characterization of an average molecule of the coal extract by the number of non-bridge carbon atoms of aromatic rings, by the overall number of aromatic ring carbon atoms and the number of aromatic rings, determined by the Williams and Ferris methods. The methods for calculating carbon distribution from /sup 1/H NMR data, however, contain some constants theoretically estimated or experimentally found using the method which still remain to be verified.

Discrimination of sugarcane according to cultivar by 1H NMR and chemometric analyses

Energy Technology Data Exchange (ETDEWEB)

Alves Filho, Elenilson G.; Silva, Lorena M.A.; Choze, Rafael; Liao, Luciano M. [Laboratorio de Ressonancia Magnetica Nuclear, Instituto de Quimica, Universidade Federal de Goias (UFG), Goiania, GO (Brazil); Honda, Neli K.; Alcantara, Glaucia B. [Departamento de Quimica, Universidade Federal de Mato Grosso do Sul (UFMS), Campo Grande, MS (Brazil)

2012-07-01

Several technologies for the development of new sugarcane cultivars have mainly focused on the increase in productivity and greater disease resistance. Sugarcane cultivars are usually identified by the organography of the leaves and stems, the analysis of peroxidase and esterase isoenzyme activities and the total soluble protein as well as soluble solid content. Nuclear magnetic resonance (NMR) associated with chemometric analysis has proven to be a valuable tool for cultivar assessment. Thus, this article describes the potential of chemometric analysis applied to 1H high resolution magic angle spinning (HRMAS) and NMR in solution for the investigation of sugarcane cultivars. For this purpose, leaves from eight different cultivars of sugarcane were investigated by {sup 1}H NMR spectroscopy in combination with chemometric analysis. The approach shows to be a useful tool for the distinction and classification of different sugarcane cultivars as well as to access the differences on its chemical composition. (author)

NMR characteristics of low-grade glioma. Comparison with CT

Energy Technology Data Exchange (ETDEWEB)

Asato, Reinin; Tokuriki, Yasuhiko; Nakano, Yoshihisa; Itoh, Harumi; Torizuka, Kanji; Ueda, Tohru; Yamashita, Junkoh; Handa, Hajime

1985-08-01

Sixteen low-grade gliomas were evaluated both with nuclear magnetic resonance (NMR) imaging and with computed tomography (CT). In 13 cases (81%), the NMR images were much better in tissue contrast than the contrast-enhanced CT images. The tumors were shown as well-circumscribed oval lesions in the NMR, though they appeared as ill-defined, irregular, low-attenuation areas in the CT. The extent of the lesion, which was supposed to represent the active tumor tissue, was greater in the NMR than in the CT, because NMR tissue parameters (T/sub 1/, T/sub 2/) are more sensitive to pathological changes in brain tissue than is the X-ray attenuation coefficient. Though, in an optic glioma and a brain-stem astrocytoma, the CT with contrast enhancement displayed the contour of the mass as well as did NMR, it was inferior to the NMR in showing the cephalocaudal extension of the tumors. Calcification does not give a proton NMR signal under the present measuring conditions; thus the calcified cystic wall of a hypothalamic astrocytoma was displayed only in the CT images. In conclusion, the NMR imaging was apparently superior to contrast-enhanced CT in demonstrating the lesions due to low-grade glioma.

Carbon-13 NMR spectroscopy of biological systems

CERN Document Server

Beckmann, Nicolau

1995-01-01

This book is intended to provide an in-depth understanding of 13C NMR as a tool in biological research. 13C NMR has provided unique information concerning complex biological systems, from proteins and nucleic acids to animals and humans. The subjects addressed include multidimensional heteronuclear techniques for structural studies of molecules in the liquid and solid states, the investigation of interactions in model membranes, the elucidation of metabolic pathwaysin vitro and in vivo on animals, and noninvasive metabolic studies performed on humans. The book is a unique mix of NMR methods and biological applications which makes it a convenient reference for those interested in research in this interdisciplinary area of physics, chemistry, biology, and medicine.Key Features* An interdisciplinary text with emphasis on both 13C NMR methodology and the relevant biological and biomedical issues* State-of-the-art 13C NMR techniques are described; Whenever possible, their advantages over other approaches are empha...

Comparison of NMR and crystal structures for the proteins TM1112 and TM1367

International Nuclear Information System (INIS)

Mohanty, Biswaranjan; Serrano, Pedro; Pedrini, Bill; Jaudzems, Kristaps; Geralt, Michael; Horst, Reto; Herrmann, Torsten; Elsliger, Marc-André; Wilson, Ian A.; Wüthrich, Kurt

2010-01-01

NMR structures of the proteins TM1112 and TM1367 solved by the JCSG in solution at 298 K could be superimposed with the corresponding crystal structures at 100 K with r.m.s.d. values of <1.0 Å for the backbone heavy atoms. For both proteins the structural differences between multiple molecules in the asymmetric unit of the crystals correlated with structural variations within the bundles of conformers used to represent the NMR solution structures. A recently introduced JCSG NMR structure-determination protocol, which makes use of the software package UNIO for extensive automation, was further evaluated by comparison of the TM1112 structure obtained using these automated methods with another NMR structure that was independently solved in another PSI center, where a largely interactive approach was applied. The NMR structures of the TM1112 and TM1367 proteins from Thermotoga maritima in solution at 298 K were determined following a new protocol which uses the software package UNIO for extensive automation. The results obtained with this novel procedure were evaluated by comparison with the crystal structures solved by the JCSG at 100 K to 1.83 and 1.90 Å resolution, respectively. In addition, the TM1112 solution structure was compared with an NMR structure solved by the NESG using a conventional largely interactive methodology. For both proteins, the newly determined NMR structure could be superimposed with the crystal structure with r.m.s.d. values of <1.0 Å for the backbone heavy atoms, which provided a starting platform to investigate local structure variations, which may arise from either the methods used or from the different chemical environments in solution and in the crystal. Thereby, these comparative studies were further explored with the use of reference NMR and crystal structures, which were computed using the NMR software with input of upper-limit distance constraints derived from the molecular models that represent the results of structure

Changes in molecular structure and properties of irradiated polymers of different compositions - ESR and NMR study

International Nuclear Information System (INIS)

Carswell-Pomerantz, T.; Babanalbandi, A.; Dong, L.; Hill, D.J.T.; Perera, M.C.S.; Pomery, P.J.; Saadat, G.; Whittaker, A.K.

1999-01-01

Investigations of molecular structural changes in polymers during exposure to high energy radiation is the long term interest of the Polymer Materials and Radiation Group at the University of Queensland. Recently, the group had looked at a range of polymers including natural and synthetic rubbers, methacrylates and polyesters. The objective of the work has been to investigate the relationships between polymer structure and sensitivity towards high energy radiation, including gamma radiation. This report will focus on the Electron Spin Resonance (ESR) and Nuclear Magnetic Resonance (NMR) studies of the effects of gamma irradiation on these polymers. Other methods such as Gas Chromatography (GC), Gel Permeation Chromatography (GPC), Fourier Transformed Infra Red (FTIR), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA) and Dynamic Mechanical Analysis (DMA) have also been used as these methods combine with ESR and NMR, to provide a more complete picture of the mechanism of the structural changes. (author)

Another Look at the Draft Mil-Std-1540E Unit Random Vibration Test Requirements

Science.gov (United States)

Perl, E.; Peterson, A. J..; Davis, D.

2012-07-01

The draft Mil-Std-1540E has been updated to reflect lessons learned since its publication as an SMC Standard in 2008, [1], and an earlier Aerospace Corporation Technical Report released in 2006, [2]. This paper discusses the technical rationale supporting some of the unit random vibration test requirements to provide better insight into their derivation and application to programs. It is intended that these requirements be tailored for each program to reflect the customer risk profile. Several tailoring options are provided and a two phase test strategy is discussed to highlight its applicability to utilizing heritage hardware in new applications.

Solid state NMR study of cumbaru flour

International Nuclear Information System (INIS)

Nogueira, Jose S.; Bathista, Andre L.B.S.; Silva, Emerson O.; Priante Filho, Nicolau; Tavares, Maria I.B.

2001-01-01

The polysaccharide obtained by seed of Dipteryx alata Vog, has been characterised by 13 C solid state, using the basic routine techniques, like MAS and CPMAS and by the proton spin-lattice relaxation time in the rotating frame parameter (T 1 H ρ). Knowing that the chemical structure and molecular dynamic are extremely necessary route to obtain information on the polysaccharides, this work contributes to the classification of the seed containing in the cumbaru fruit to get response on its application. To obtain the initial responses for our purposes some solid state NMR techniques were chosen. The CPMAS 13 C NMR spectrum of the polysaccharide was investigated to know if it has some crystallinity. The MAS 13 C NMR spectrum showed the presence of domains with distinct molecular mobility, because these domains will differ basically in the distribution size and chain packing. The variable contact time experiment was used to analyse the distribution form of 13 C decays, which give us more information about sample heterogeneity. The T 1 H ρHr values were obtained from the variable contact time and by delayed contact time experiment, because these parameter indicate the order of polysaccharides. From the values of this parameter, we found that this polysaccharide is completely non-ordered. (author)

NMR in the SPINE Structural Proteomics project.

Science.gov (United States)

Ab, E; Atkinson, A R; Banci, L; Bertini, I; Ciofi-Baffoni, S; Brunner, K; Diercks, T; Dötsch, V; Engelke, F; Folkers, G E; Griesinger, C; Gronwald, W; Günther, U; Habeck, M; de Jong, R N; Kalbitzer, H R; Kieffer, B; Leeflang, B R; Loss, S; Luchinat, C; Marquardsen, T; Moskau, D; Neidig, K P; Nilges, M; Piccioli, M; Pierattelli, R; Rieping, W; Schippmann, T; Schwalbe, H; Travé, G; Trenner, J; Wöhnert, J; Zweckstetter, M; Kaptein, R

2006-10-01

This paper describes the developments, role and contributions of the NMR spectroscopy groups in the Structural Proteomics In Europe (SPINE) consortium. Focusing on the development of high-throughput (HTP) pipelines for NMR structure determinations of proteins, all aspects from sample preparation, data acquisition, data processing, data analysis to structure determination have been improved with respect to sensitivity, automation, speed, robustness and validation. Specific highlights are protonless (13)C-direct detection methods and inferential structure determinations (ISD). In addition to technological improvements, these methods have been applied to deliver over 60 NMR structures of proteins, among which are five that failed to crystallize. The inclusion of NMR spectroscopy in structural proteomics pipelines improves the success rate for protein structure determinations.

ECG gated NMR-CT for cardiovascular diseases

International Nuclear Information System (INIS)

Nishikawa, J.; Machida, K.; Iio, M.; Yoshimoto, N.; Sugimoto, T.; Kawaguchi, H.; Mano, H.

1984-01-01

The authors applied NMR-CT to cardiac study with ECG gated technique to evaluate the left ventricular (LV) function and compared it with cardiovascular nuclear medicine study (NM). The NMR-CT machine has resistive air-core magnet with 0.15 Tesla. The saturation recovery image or inversion recovery image were obtained as 256 x 256 matrix and 15 mm in thickness. The study population was ten patients who were evaluated both by NMR image and by NM performed within one week interval. The heart muscle was able to be visualized without any contrast material nor radioisotopes in inversion recovery images, whereas saturation recovery images failed to separate heart muscle from blood pool. The wall motions of LV in both methods were well correlated except for inferior wall. The values of ejection fraction in NMR image were moderately low, but two modalities showed satisfactory correlation (r=0.85). The region of myocardial infarction was revealed as wall thinning and/or wall motion abnormality. It is still preliminary to draw a conclusion, however, it can be said that in the evaluation of LV function, method by NMR might be of equal value to those of NM. It can be certain that eventually gated NMR-CT will become more effective method for various aspects of cardiovascular evaluation

Determination of the three-dimensional structure for weakly aligned biomolecules by NMR spectroscopy

International Nuclear Information System (INIS)

Shahkhatuni, Astghik A; Shahkhatuni, Aleksan G

2002-01-01

The key achievements and the potential of NMR spectroscopy for weakly aligned biomolecules are considered. Due to weak alignment, it becomes possible to determine a number of NMR parameters dependent on the orientation of biomolecules, which are averaged to zero in usual isotropic media. The addition of new orientational constraints to standard procedures of 3D structure determination markedly increases the achievable accuracy. The possibility of structure determination for biomolecules using only orientation-dependent parameters without invoking other NMR data is discussed. The methods of orientation, experimental techniques, and calculation methods are systematised. The main results obtained and the prospects of using NMR spectroscopy of weakly aligned systems to study different classes of biomolecules and to solve various problems of molecular biology are analysed. Examples of biomolecules whose structures have been determined using orientation-dependent parameters are given. The bibliography includes 508 references.

Structural investigations of substituted indolizine derivatives by NMR studies

International Nuclear Information System (INIS)

Furdui, Bianca; Dinica, Rodica; Demeunynck, Martine; Druta, Ioan

2008-01-01

Owing to the increasing importance of indolizine heterocycles in the field of biology and pharmacology we have synthesized and investigated the obtained heterocycles by NMR techniques. In order to investigate the substituent effects on the spectroscopic properties, a series of indolizine derivatives were studied by 1 H-NMR, 13 C-NMR and 2D NMR (GCOSY, GHMBC and GHMQC spectra). (authors)

New NMR method for measuring the difference between corresponding proton and deuterium chemical shifts: isotope effects on exchange equilibria

International Nuclear Information System (INIS)

Saunders, M.; Saunders, S.; Johnson, C.A.

1984-01-01

A convenient and accurate method is described for measuring the difference between a proton frequency and the corresponding deuterium frequency in its deuterated analogue relative to a reference system by using the deuterium lock in a Fourier-transform NMR spectrometer. This measurement is a sensitive way of measuring equilibrium isotope effects for hydrogen-deuterium exchange. A value of 1.60 per H-D pair is obtained for the equilibrium 2H 3 O + + 3D 2 O in equilibrium 2D 3 O + + 3H 2 O at 30 0 C in aqueous perchloric acid (HClO 4 ). 7 references, 2 tables

Comparative {sup 1}H NMR-based metabonomic analysis of HIV-1 sera

Energy Technology Data Exchange (ETDEWEB)

Philippeos, C. [University of Johannesburg, Department of Biochemistry (South Africa); Steffens, F. E. [University of Pretoria, Department of Statistics (South Africa); Meyer, D. [University of Pretoria, Department of Biochemistry (South Africa)], E-mail: debra.meyer@up.ac.za

2009-07-15

{sup 1}H NMR spectroscopy of sera from HIV-1 infected and uninfected individuals was performed on 300 and 600 MHz instruments. The resultant spectra were automatically data reduced to 90 and 180 integral segments of equal length. Analysis of variance identified significant differences between the sample groups, especially for the samples analyzed on 600 MHz and reduced to fewer segments. Linear discriminant analysis correctly classified 100% of the samples analyzed on the 300 MHz NMR (reduced to 180 segments); an increase in instrument sensitivity resulted in lower percentages of correctly classified samples. Multinomial logistic regression (MLR) resulted in 100% correct classification of all samples from both instruments. Thus {sup 1}H-NMR metabonomics on either instrument distinguishes HIV-positive individuals using or not using anti retroviral therapy, but the sensitivity of the instrument impacts on data reduction. Furthermore, MLR is a novel multivariate statistical technique for improved classification of biological data analyzed in NMR.

NMR study of LaPb2

International Nuclear Information System (INIS)

Ueda, K.; Kohara, T.; Yamada, Y.

1995-01-01

La and Pb NMR signals were observed in LaPb 2 with a superconducting transition temperature of about 7 K. The width of the Pb NMR spectrum with an asymmetric line shape was rather narrower than those of Er-, Gd- and Ho-Pb 2 . The spin-lattice relaxation time of Pb nuclei was twice longer than that of Pb metal. La NMR spectrum had satellites due to the electric quadrupole interaction. These results show that each local environment at La or Pb site in LaPb 2 compound is uniquely determined, compared with those in randomly substituted alloys. ((orig.))

NMR determinations of molecular geometries in liquid crystal media

International Nuclear Information System (INIS)

Long, R.C.; Goldstein, J.H.

1983-01-01

The application of NMR spectroscopy in oriented media to the determination of molecular geometries is illustrated by results for three distinctly different molecules: naphthalene, ethylene oxide and spiropentane. The need for systematic application of vibrational corrections is emphasized and some of the effects associated with the different choices of solvent media are considered

Hyperpolarized 129Xe as an NMR probe for functional studies

International Nuclear Information System (INIS)

Wolber, J.

2000-01-01

The nuclear spin polarization of 129 Xe can be enhanced by several orders of magnitude using optical pumping techniques, resulting in a dramatic enhancement of the 129 Xe Nuclear Magnetic Resonance (NMR) signal. The 'hyperpolarized' gas can be used for Magnetic Resonance Imaging (MRI) of the void spaces of the lungs after introduction of the gas into the respiratory system. Furthermore, the high solubility of xenon in blood and lipids suggests the use of 129 Xe NMR for studying blood flow, permeability, perfusion and blood volume. Hyperpolarized 129 Xe MRI has the potential of combining the high sensitivity and functional information of radioactive tracer studies with the high spatial and temporal resolution of MRI. The spin-lattice relaxation time T 1 of 129 Xe in blood determines the loss of polarization during transit from the lungs to the tissue of interest. A difference in the relaxation times of xenon in oxygenated and deoxygenated blood could be used as a contrast mechanism in functional Magnetic Resonance Imaging (fMRI). In this thesis, the hyperpolarized 129 Xe T 1 in human blood is measured in vitro as a function of blood oxygenation, and the relevant relaxation mechanisms are discussed. A new and unexpected finding is that the hyperpolarized 129 Xe NMR spectrum in blood is highly sensitive to blood oxygenation. Therefore, hyperpolarized 129 Xe NMR provides a powerful means of measuring blood oxygenation quantitatively and non-invasively. The interaction of xenon with hemoglobin is responsible for an oxygen-dependent shift of the 129 Xe NMR resonance of xenon in red blood cells. Injection delivery of hyperpolarized 129 Xe in solution could be a more efficient method of administrating the gas for functional NMR studies. For this purpose, suitable biocompatible carrier media have been studied. In particular, the use of perfluorocarbon emulsions, which are already in use as blood substitutes, as delivery media for hyperpolarized 129 Xe has been investigates

Nuclear magnetic resonance (NMR) tomography

International Nuclear Information System (INIS)

Skalpe, I.O.

1984-01-01

A brief survey of the working principle of the NMR technique in diagnostical medicine is given. Its clinical usefulness for locating tumors, diagnosing various other diseases, such as some mental illnesses and multiple sclerosis, and its possibilities for studying biochemical processes in vivo are mentioned. The price of NMR image scanners and the problems of the strong magnetic field around the machines are mentioned

Using the Auditory Hazard Assessment Algorithm for Humans (AHAAH) With Hearing Protection Software, Release MIL-STD-1474E

Science.gov (United States)

2013-12-01

unfolding.” Invited article in NHCA’s Spectrum. 1997 MIL-STD-1474D. (1997). “Department of defense design criteria. Noise limits,” http...Passenger Safety, Washington, DC. Price, G. R. (1997). “Understanding hazard from intense sounds.” Invited seminar to Audiology Department, University of...Putting theory into practice.” In H. M. Borchgrevink (Ed.), Hearing and hearing prophylaxis, Scandinavian Audiology Supplement 16 (pp. 111-121

NMR studies of differences in the conformations and dynamics of ligand complexes formed with mutant dihydrofolate reductases

International Nuclear Information System (INIS)

Birdsall, B.; Andrews, J.; Ostler, G.; Tendler, S.J.B.; Feeney, J.; Roberts, G.C.K.; Davies, R.W.; Cheung, H.T.A.

1989-01-01

Two mutants of Lactobacillus casei dihydrofolate reductase, Trp 21 → Leu and Asp 26 → Glu, have been prepared by using site-directed mutagenesis methods, and their ligand binding and structural properties have been compared with those of the wild-type enzyme. 1 H, 13 C, and 31 P NMR studies have been carried out to characterize the structural changes in the complexes of the mutant and wild-type enzymes. Replacement of the conserved Trp 21 by a Leu residue causes a decrease in activity of the enzyme and reduces the NADPH binding constant by a factor of 400. The binding of substrates and substrate analogues is only slightly affected. 1 H NMR studies of the Trp 21 → Leu enzyme complexes have confirmed the original resonance assignments for Trp 21. In complexes formed with methotrexate and the mutant enzyme, the results indicate some small changes in conformation occurring as much as 14 angstrom away from the site of substitution. For the enzyme-NADPH complexes, the chemical shifts of nuclei in the bound coenzyme indicate that the nicotinamide ring binds differently in complexes with the mutant and the wild-type enzyme. There are complexes where the wild-type enzyme has been shown to exist in solution as a mixture of conformations, and studies on the corresponding complexes with the Trp 21 → Leu mutant indicate that the delicately poised equilibria can be perturbed. Some conformational adjustments are required to allow the carboxylate of Glu 26 to bind effectively to the N1 proton of inhibitors such as methotrexate and trimethoprim

Bayesian Peak Picking for NMR Spectra

KAUST Repository

Cheng, Yichen

2014-02-01

Protein structure determination is a very important topic in structural genomics, which helps people to understand varieties of biological functions such as protein-protein interactions, protein–DNA interactions and so on. Nowadays, nuclear magnetic resonance (NMR) has often been used to determine the three-dimensional structures of protein in vivo. This study aims to automate the peak picking step, the most important and tricky step in NMR structure determination. We propose to model the NMR spectrum by a mixture of bivariate Gaussian densities and use the stochastic approximation Monte Carlo algorithm as the computational tool to solve the problem. Under the Bayesian framework, the peak picking problem is casted as a variable selection problem. The proposed method can automatically distinguish true peaks from false ones without preprocessing the data. To the best of our knowledge, this is the first effort in the literature that tackles the peak picking problem for NMR spectrum data using Bayesian method.

NMR imaging of the cardiovascular system

International Nuclear Information System (INIS)

Canby, R.C.; Evanochko, W.T.; Pohost, G.M.

1986-01-01

Proton nuclear magnetic resonance (NMR) imaging permits high-resolution tomographic and three-dimensional images of the human body to be obtained without exposure to ionizing radiation. Such imaging not only yields anatomic resolution comparable to X-ray examinations but also provides a potential means to discriminate between healthy tissue and diseased tissue. This potential is based on certain NMR properties known as relaxation times, which determine, in part, the signal intensity in an image. These properties are related to such factors as the sizes and concentrations of proteins and mobile lipids and the compartmentalization of the protons of water. Although NMR imaging (also called magnetic resonance imaging, MRI) is becoming widely available for clinical use, application to the cardiovascular system, though promising, remains primarily a research tool. Gated proton NMR imaging can generate cardiac images with excellent morphologic detail and contrast; however, its ultimate importance as a cardiovascular diagnostic modality will depend on the development of several unique applications. These applications are discussed in this paper

Performance of new 400-MHz HTS power-driven magnet NMR technology on typical pharmaceutical API, cinacalcet HCl.

Science.gov (United States)

Silva Elipe, Maria Victoria; Donovan, Neil; Krull, Robert; Pooke, Donald; Colson, Kimberly L

2018-04-17

After years towards higher field strength magnets, nuclear magnetic resonance (NMR) technology in commercial instruments in the past decade has expanded at low and high magnetic fields to take advantage of new opportunities. At lower field strengths, permanent magnets are well established, whereas for midrange and high field, developments utilize superconducting magnets cooled with cryogenic liquids. Recently, the desire to locate NMR spectrometers in nontypical NMR laboratories has created interest in the development of cryogen-free magnets. These magnets require no cryogenic maintenance, eliminating routine filling and large cryogen dewars in the facility. Risks of spontaneous quenches and safety concerns when working with cryogenic liquids are eliminated. The highest field commercially available cryogen-free NMR magnet previously reported was at 4.7 T in 2013. Here we tested a prototype cryogen-free 9.4-T power-driven high-temperature-superconducting (HTS) magnet mated to commercial NMR spectrometer electronics. We chose cinacalcet HCl, a typical active pharmaceutical ingredient, to evaluate its performance towards structure elucidation. Satisfactory standard 1D and 2D homonuclear and heteronuclear NMR results were obtained and compared with those from a standard 9.4-T cryogenically cooled superconducting NMR instrument. The results were similar between both systems with minor differences. Further comparison with different shims and probes in the HTS magnet system confirmed that the magnet homogeneity profile could be matched with commercially available NMR equipment for optimal results. We conclude that HTS magnet technology works well providing results comparable with those of standard instruments, leading us to investigate additional applications for this magnet technology outside a traditional NMR facility. Copyright © 2018 John Wiley & Sons, Ltd.

Simultaneous acquisition of three NMR spectra in a single ...

Indian Academy of Sciences (India)

Simultaneous acquisition of three NMR spectra in a single experiment ... set, which is based on a combination of different fast data acquisition techniques such as G-matrix ..... The sign and intensity of the CHn resonance depends on the delay.

31-P NMR spectroscopy in radiotherapy

International Nuclear Information System (INIS)

Kiricuta, I.C.; Schmitt, W.G.H.; Beyer, H.K.

1987-01-01

Results suggest 31-P NMR spectroscopy to allow a discrimination between good and bad blood supply to the tumour owing to different metabolic behaviour and to furnish important information on tumour response to radiotherapy just a few hours after the application of a relatively low dose. Spectroscopy showed the radiation-sensitive tumour cells to behave relatively uniformly after radiotherapy suggesting this behaviour to be interpreted as therapeutical effectiveness. (orig./SHA) [de

Characterization of natural bentonite by NMR; Caracterizacao de bentonitas naturais por ressonancia magnetica nuclear

Energy Technology Data Exchange (ETDEWEB)

Leite, Sidnei Q.M.; Dieguez, Lidia C [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia; Menezes, Sonia M.C. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas; San Gil, Rosane A.S. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Quimica

1994-12-31

Solid state NMR as well as several other instrumental chemical analysis techniques were used in order to characterize two natural occurring bentonite. The methodology is described. The NMR spectra, together with the other used techniques suggest that the observed differences are due to iron inclusions in tetrahedral and octahedral sites 5 refs., 3 figs., 5 tabs.

Natural abundance 15N NMR assignments delineate structural differences between intact and reactive-site hydrolyzed Cucurbita maxima trypsin inhibitor III.

Science.gov (United States)

Krishnamoorthi, R; Nemmers, S; Tobias, B

1992-06-15

15N NMR assignments were made to the backbone amide nitrogen atoms at natural isotopic abundance of intact and reactive-site (Arg5-Ile6) hydrolyzed Cucurbita maxima trypsin inhibitor III (CMTI-III and CMTI-III*, respectively) by means of 2D proton-detected heteronuclear single bond chemical shift correlation (HSBC) spectroscopy, utilizing the previously made sequence-specific 1H NMR assignments (Krishnamoorthi et al. (1992) Biochemistry 31, 898-904). Comparison of the 15N chemical shifts of the two forms of the inhibitor molecule revealed significant changes not only for residues located near the reactive-site region, but also for those distantly located. Residues Cys3, Arg5, Leu7, Met8, Cys10, Cys16, Glu19, His25, Tyr27, Cys28 and Gly29 showed significant chemical shift changes ranging from 0.3 to 6.1 ppm, thus indicating structural perturbations that were transmitted throughout the molecule. These findings confirm the earlier conclusions based on 1H NMR investigations.

Contact replacement for NMR resonance assignment.

Science.gov (United States)

Xiong, Fei; Pandurangan, Gopal; Bailey-Kellogg, Chris

2008-07-01

Complementing its traditional role in structural studies of proteins, nuclear magnetic resonance (NMR) spectroscopy is playing an increasingly important role in functional studies. NMR dynamics experiments characterize motions involved in target recognition, ligand binding, etc., while NMR chemical shift perturbation experiments identify and localize protein-protein and protein-ligand interactions. The key bottleneck in these studies is to determine the backbone resonance assignment, which allows spectral peaks to be mapped to specific atoms. This article develops a novel approach to address that bottleneck, exploiting an available X-ray structure or homology model to assign the entire backbone from a set of relatively fast and cheap NMR experiments. We formulate contact replacement for resonance assignment as the problem of computing correspondences between a contact graph representing the structure and an NMR graph representing the data; the NMR graph is a significantly corrupted, ambiguous version of the contact graph. We first show that by combining connectivity and amino acid type information, and exploiting the random structure of the noise, one can provably determine unique correspondences in polynomial time with high probability, even in the presence of significant noise (a constant number of noisy edges per vertex). We then detail an efficient randomized algorithm and show that, over a variety of experimental and synthetic datasets, it is robust to typical levels of structural variation (1-2 AA), noise (250-600%) and missings (10-40%). Our algorithm achieves very good overall assignment accuracy, above 80% in alpha-helices, 70% in beta-sheets and 60% in loop regions. Our contact replacement algorithm is implemented in platform-independent Python code. The software can be freely obtained for academic use by request from the authors.

NMR characterization of thin films

Science.gov (United States)

Gerald II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

2010-06-15

A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

NMR characterization of thin films

Science.gov (United States)

Gerald, II, Rex E.; Klingler, Robert J.; Rathke, Jerome W.; Diaz, Rocio; Vukovic, Lela

2008-11-25

A method, apparatus, and system for characterizing thin film materials. The method, apparatus, and system includes a container for receiving a starting material, applying a gravitational force, a magnetic force, and an electric force or combinations thereof to at least the starting material, forming a thin film material, sensing an NMR signal from the thin film material and analyzing the NMR signal to characterize the thin film of material.

Applications of solid-state Nuclear Magnetic Resonance (NMR) in studies of Portland cements-based materials

DEFF Research Database (Denmark)

Skibsted, Jørgen; Andersen, Morten Daugaard; Jakobsen, Hans Jørgen

2007-01-01

Solid-state NMR spectroscopy represents an important research tool in the characterization of a range of structural properties for cement-based materials. Different approaches of the technique can be used to obtain information on hydration kinetics, mobile and bound water, porosity, and local...... atomic structures. After a short introduction to these NMR techniques, it is exemplified how magic-angle spinning (MAS) NMR can provide quantitative and structural information about specific phases in anhydrous and hydrated Portland cements with main emphasis on the incorporation of Al3+ ions...

Software Library for Bruker TopSpin NMR Data Files

Energy Technology Data Exchange (ETDEWEB)

2016-10-14

A software library for parsing and manipulating frequency-domain data files that have been processed using the Bruker TopSpin NMR software package. In the context of NMR, the term "processed" indicates that the end-user of the Bruker TopSpin NMR software package has (a) Fourier transformed the raw, time-domain data (the Free Induction Decay) into the frequency-domain and (b) has extracted the list of NMR peaks.

Polymeric proanthocyanidins 13C NMR studies of procyanidins

Science.gov (United States)

Lawrence J. Porter; Roger H. Newman; Lai Yeap Foo; Herbert Wong; Richard W. Hemingway

1982-01-01

Proanthocyanidin polymers have been shown to consist entirely of flavan-3-ol units by a combination of techniques including 13C n.m.r. spectroscopy. The 13C n.m.r. spectra of the polymers and related molecules are now considered in more detail. Prior to this study UC n.m.r. data has been published of procyanidins and...

Flow units from integrated WFT and NMR data

Energy Technology Data Exchange (ETDEWEB)

Kasap, E.; Altunbay, M.; Georgi, D.

1997-08-01

Reliable and continuous permeability profiles are vital as both hard and soft data required for delineating reservoir architecture. They can improve the vertical resolution of seismic data, well-to-well stratigraphic correlations, and kriging between the well locations. In conditional simulations, permeability profiles are imposed as the conditioning data. Variograms, covariance functions and other geostatistical indicators are more reliable when based on good quality permeability data. Nuclear Magnetic Resonance (NMR) logging and Wireline Formation Tests (WFT) separately generate a wealth of information, and their synthesis extends the value of this information further by providing continuous and accurate permeability profiles without increasing the cost. NMR and WFT data present a unique combination because WFTs provide discrete, in situ permeability based on fluid-flow, whilst NMR responds to the fluids in the pore space and yields effective porosity, pore-size distribution, bound and moveable fluid saturations, and permeability. The NMR permeability is derived from the T{sub 2}-distribution data. Several equations have been proposed to transform T{sub 2} data to permeability. Regardless of the transform model used, the NMR-derived permeabilities depend on interpretation parameters that may be rock specific. The objective of this study is to integrate WFT permeabilities with NMR-derived, T{sub 2} distribution-based permeabilities and thereby arrive at core quality, continuously measured permeability profiles. We outlined the procedures to integrate NMR and WFT data and applied the procedure to a field case. Finally, this study advocates the use of hydraulic unit concepts to extend the WFT-NMR derived, core quality permeabilities to uncored intervals or uncored wells.

Comparison of soil organic carbon speciation using C NEXAFS and CPMAS 13C NMR spectroscopy.

Science.gov (United States)

Prietzel, Jörg; Müller, Svenja; Kögel-Knabner, Ingrid; Thieme, Jürgen; Jaye, Cherno; Fischer, Daniel

2018-07-01

We compared synchrotron-based C near-edge X-ray absorption fine structure (NEXAFS) and CPMAS 13 C nuclear magnetic resonance (NMR) spectroscopy with respect to their precision and accuracy to quantify different organic carbon (OC) species in defined mixtures of soil organic matter source compounds. We also used both methods to quantify different OC species in organic surface horizons of a Histic Leptosol as well as in mineral topsoil and subsoil horizons of two soils with different parent material, stage of pedogenesis, and OC content (Cambisol: 15-30 OC mgg -1 , Podzol: 0.9-7 OC mgg -1 ). CPMAS 13 C NMR spectroscopy was more accurate and precise (mean recovery of different C functional groups 96-103%) than C NEXAFS spectroscopy (mean recovery 92-113%). For organic surface and topsoil samples, NMR spectroscopy consistently yielded larger O-alkyl C percentages and smaller alkyl C percentages than C NEXAFS spectroscopy. For the Cambisol subsoil samples both methods performed well and showed similar C speciation results. NEXAFS spectroscopy yielded excellent spectra with a high signal-to-noise ratio also for OC-poor Podzol subsoil samples, whereas this was not the case for CPMAS 13 C NMR spectroscopy even after sample treatment with HF. Our results confirm the analytical power of CPMAS 13 C NMR spectroscopy for a reliable quantitative OC speciation in soils with >10mgOCg -1 . Moreover, they highlight the potential of synchrotron-based C NEXAFS spectroscopy as fast, non-invasive method to semi-quantify different C functional groups in soils with low C content (0.9-10mgg -1 ). Copyright © 2018 Elsevier B.V. All rights reserved.

A microscale protein NMR sample screening pipeline

Energy Technology Data Exchange (ETDEWEB)

Rossi, Paolo; Swapna, G. V. T.; Huang, Yuanpeng J.; Aramini, James M. [State University of New Jersey, Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Rutgers (United States); Anklin, Clemens [Bruker Biospin Corporation (United States); Conover, Kenith; Hamilton, Keith; Xiao, Rong; Acton, Thomas B.; Ertekin, Asli; Everett, John K.; Montelione, Gaetano T., E-mail: guy@cabm.rutgers.ed [State University of New Jersey, Center for Advanced Biotechnology and Medicine, Department of Molecular Biology and Biochemistry, Rutgers (United States)

2010-01-15

As part of efforts to develop improved methods for NMR protein sample preparation and structure determination, the Northeast Structural Genomics Consortium (NESG) has implemented an NMR screening pipeline for protein target selection, construct optimization, and buffer optimization, incorporating efficient microscale NMR screening of proteins using a micro-cryoprobe. The process is feasible because the newest generation probe requires only small amounts of protein, typically 30-200 {mu}g in 8-35 {mu}l volume. Extensive automation has been made possible by the combination of database tools, mechanization of key process steps, and the use of a micro-cryoprobe that gives excellent data while requiring little optimization and manual setup. In this perspective, we describe the overall process used by the NESG for screening NMR samples as part of a sample optimization process, assessing optimal construct design and solution conditions, as well as for determining protein rotational correlation times in order to assess protein oligomerization states. Database infrastructure has been developed to allow for flexible implementation of new screening protocols and harvesting of the resulting output. The NESG micro NMR screening pipeline has also been used for detergent screening of membrane proteins. Descriptions of the individual steps in the NESG NMR sample design, production, and screening pipeline are presented in the format of a standard operating procedure.

Solid-state 27Al and 29Si NMR investigations on Si-substituted hydrogarnets

International Nuclear Information System (INIS)

Rivas Mercury, J.M.; Pena, P.; Aza, A.H. de; Turrillas, X.; Sobrados, I.; Sanz, J.

2007-01-01

Partially deuterated Ca 3 Al 2 (SiO 4 ) 3-x (OH) 4x hydrates prepared by a reaction in the presence of D 2 O of synthetic tricalcium aluminate with different amounts of amorphous silica were characterized by 29 Si and 27 Al magic-angle spinning nuclear magnetic resonance (NMR) spectroscopy. The 29 Si NMR spectroscopy was used for quantifying the non-reacted silica and the resulting hydrated products. The incorporation of Si into Ca 3 Al 2 (SiO 4 ) 3-x (OH) 4x was followed by 27 Al NMR spectroscopy: Si:OH ratios were determined quantitatively from octahedral Al signals ascribed to Al(OH) 6 and Al(OSi)(OH) 5 environments. The NMR data obtained were consistent with the concentrations of the Al and Si species deduced from transmission electron microscopy energy-dispersive spectrometry and Rietveld analysis of both X-ray and neutron diffraction data

Selective sensitivity enhancement in FT-NMR

International Nuclear Information System (INIS)

Farrar, T.C.

1987-01-01

In this article the basic two-spin nuclear magnetic resonance (NMR) experiment and the new sensitivity enhancement experiments are reviewed. In part two of this two-part series an overview of two-dimensional NMR experiments will be presented. Part two will appear in the June 1 issue of Analytical Chemistry

NMR-Fragment Based Virtual Screening: A Brief Overview.

Science.gov (United States)

Singh, Meenakshi; Tam, Benjamin; Akabayov, Barak

2018-01-25

Fragment-based drug discovery (FBDD) using NMR has become a central approach over the last twenty years for development of small molecule inhibitors against biological macromolecules, to control a variety of cellular processes. Yet, several considerations should be taken into account for obtaining a therapeutically relevant agent. In this review, we aim to list the considerations that make NMR fragment screening a successful process for yielding potent inhibitors. Factors that may govern the competence of NMR in fragment based drug discovery are discussed, as well as later steps that involve optimization of hits obtained by NMR-FBDD.

NMR-Fragment Based Virtual Screening: A Brief Overview

Directory of Open Access Journals (Sweden)

Meenakshi Singh

2018-01-01

Full Text Available Fragment-based drug discovery (FBDD using NMR has become a central approach over the last twenty years for development of small molecule inhibitors against biological macromolecules, to control a variety of cellular processes. Yet, several considerations should be taken into account for obtaining a therapeutically relevant agent. In this review, we aim to list the considerations that make NMR fragment screening a successful process for yielding potent inhibitors. Factors that may govern the competence of NMR in fragment based drug discovery are discussed, as well as later steps that involve optimization of hits obtained by NMR-FBDD.

High resolution NMR study of cellulose in solid state and in solution

International Nuclear Information System (INIS)

Saint-Germain, Jean

1983-01-01

This research thesis reports the study of native cellulose (cotton) and wood by nuclear magnetic resonance (NMR). As far as the cotton spectrum is concerned, the author assigned resonances which more specifically corresponded to amorphous or crystalline areas. Wood was studied in its bulk condition, and resonances have been determined for the different wood components. The behaviour of cellulose in solution in a solvent has been studied by liquid high resolution NMR. The solvation mechanism has been determined and a study of model components of the macromolecule allowed a conformational study of cellulose in this solvent to be performed. Bi-dimensional NMR and longitudinal relaxation time measurements highlighted the existence of an intramolecular hydrogen bond in the cellulose in solution [fr

Fluid-Rock Characterization and Interactions in NMR Well Logging

Energy Technology Data Exchange (ETDEWEB)

George J. Hirasaki; Kishore K. Mohanty

2005-09-05

The objective of this report is to characterize the fluid properties and fluid-rock interactions that are needed for formation evaluation by NMR well logging. The advances made in the understanding of NMR fluid properties are summarized in a chapter written for an AAPG book on NMR well logging. This includes live oils, viscous oils, natural gas mixtures, and the relation between relaxation time and diffusivity. Oil based drilling fluids can have an adverse effect on NMR well logging if it alters the wettability of the formation. The effect of various surfactants on wettability and surface relaxivity are evaluated for silica sand. The relation between the relaxation time and diffusivity distinguishes the response of brine, oil, and gas in a NMR well log. A new NMR pulse sequence in the presence of a field gradient and a new inversion technique enables the T{sub 2} and diffusivity distributions to be displayed as a two-dimensional map. The objectives of pore morphology and rock characterization are to identify vug connectivity by using X-ray CT scan, and to improve NMR permeability correlation. Improved estimation of permeability from NMR response is possible by using estimated tortuosity as a parameter to interpolate between two existing permeability models.

UNDP supports HIV / AIDS / STD project for war-torn south Sudan -- a special report.

Science.gov (United States)

Del Viso, N

1997-01-01

This article describes a UN HIV/AIDS and sexually transmitted disease (STD) project in war-torn south Sudan. The 3-year project relies on collaboration between adversaries and implementation in government-held and rebel-controlled areas. The project aims to reduce the risk and vulnerability to HIV/AIDS/STDs and to foster dialogue among adversaries as a means of conflict resolution. The World Health Organization will contribute technical assistance. Local partners including the government, the Southern Sudan Independence Movement, and the Sudanese People's Liberation Movement will contribute resources valued at about $100,000. The total UN contribution is about $300,000. HIV transmission has increased due to a high concentration of military personnel and population displacement. Available information suggests that the south has the highest HIV prevalence and 46% of known AIDS cases. STDs increased from 2.3% in 1989 to 14.1% in 1994. The project focuses on women, youth, and other vulnerable groups. The project is in its 9-month preparatory phase. The preparatory phase includes analysis of the HIV/AIDS/STD situation, design of a sustainable program, assessment of causative factors, and establishment of a mechanism for effectively coordinating the project. The civil war will affect priorities, strategies, and activities. In government-controlled areas, the Sudan National AIDS program will conduct activities. In non-government areas, the Sudan Rehabilitation and Relief Association, the Relief Association for South Sudan, and health and humanitarian authorities of the liberation groups will conduct programs. The UN Office of Special Projects will provide oversight during the preparatory phase. Sudan's UN Country Theme Group on HIV/AIDS will be the coordinating group.

NMR investigations of molecular dynamics

Science.gov (United States)

Palmer, Arthur

2011-03-01

NMR spectroscopy is a powerful experimental approach for characterizing protein conformational dynamics on multiple time scales. The insights obtained from NMR studies are complemented and by molecular dynamics (MD) simulations, which provide full atomistic details of protein dynamics. Homologous mesophilic (E. coli) and thermophilic (T. thermophilus) ribonuclease H (RNase H) enzymes serve to illustrate how changes in protein sequence and structure that affect conformational dynamic processes can be monitored and characterized by joint analysis of NMR spectroscopy and MD simulations. A Gly residue inserted within a putative hinge between helices B and C is conserved among thermophilic RNases H, but absent in mesophilic RNases H. Experimental spin relaxation measurements show that the dynamic properties of T. thermophilus RNase H are recapitulated in E. coli RNase H by insertion of a Gly residue between helices B and C. Additional specific intramolecular interactions that modulate backbone and sidechain dynamical properties of the Gly-rich loop and of the conserved Trp residue flanking the Gly insertion site have been identified using MD simulations and subsequently confirmed by NMR spin relaxation measurements. These results emphasize the importance of hydrogen bonds and local steric interactions in restricting conformational fluctuations, and the absence of such interactions in allowing conformational adaptation to substrate binding.

Straightforward and complete deposition of NMR data to the PDBe

International Nuclear Information System (INIS)

Penkett, Christopher J.; Ginkel, Glen van; Velankar, Sameer; Swaminathan, Jawahar; Ulrich, Eldon L.; Mading, Steve; Stevens, Tim J.; Fogh, Rasmus H.; Gutmanas, Aleksandras; Kleywegt, Gerard J.; Henrick, Kim; Vranken, Wim F.

2010-01-01

We present a suite of software for the complete and easy deposition of NMR data to the PDB and BMRB. This suite uses the CCPN framework and introduces a freely downloadable, graphical desktop application called CcpNmr Entry Completion Interface (ECI) for the secure editing of experimental information and associated datasets through the lifetime of an NMR project. CCPN projects can be created within the CcpNmr Analysis software or by importing existing NMR data files using the CcpNmr FormatConverter. After further data entry and checking with the ECI, the project can then be rapidly deposited to the PDBe using AutoDep, or exported as a complete deposition NMR-STAR file. In full CCPN projects created with ECI, it is straightforward to select chemical shift lists, restraint data sets, structural ensembles and all relevant associated experimental collection details, which all are or will become mandatory when depositing to the PDB. Instructions and download information for the ECI are available from the PDBe web site at http://www.ebi.ac.uk/pdbe/nmr/deposition/eci.htmlhttp://www.ebi.ac.uk/pdbe/nmr/deposition/eci.html.

Enhanced NMR signal detection of imino protons in RNA molecules containing 3' dangling nucleotides

International Nuclear Information System (INIS)

Amborski, Andrew N.; Johnson, Philip E.

2008-01-01

We present a method for improving the quality of nuclear magnetic resonance (NMR) spectra involving exchangeable protons near the base of the stem of RNA hairpin molecules. NMR spectra of five different RNA hairpins were compared. These hairpins consisted of a native RNA structure and four molecules each having different unpaired, or dangling, nucleotides at the 3' end. NMR experiments were acquired in water for each construct and the quality of the imino proton spectral regions were examined. The imino resonances near the base of the stem of the wild type RNA structure were not observed due to breathing motions. However, a significant increase in spectral quality for molecules with dangling 3' adenosine or guanosine nucleotides was observed, with imino protons detected in these constructs that were not observed in the wild type construct. A modest improvement in spectral quality was seen for the construct with a 3' unpaired uridine, whereas no significant improvement was observed for a 3' unpaired cytidine. This improvement in NMR spectral quality mirrors the increased thermodynamic stability observed for 3' unpaired nucleotides which is dependant on the stacking interactions of these nucleotides against the base of the stem. The use of a dangling 3' adenosine nucleotide represents an easy method to significantly improve the quality of NMR spectra of RNA molecules

(S)Pinning down protein interactions by NMR

DEFF Research Database (Denmark)

Teilum, Kaare; Kunze, Micha Ben Achim; Erlendsson, Simon

2017-01-01

Protein molecules are highly diverse communication platforms and their interaction repertoire stretches from atoms over small molecules such as sugars and lipids to macromolecules. An important route to understanding molecular communication is to quantitatively describe their interactions...... all types of protein reactions, which can span orders of magnitudes in affinities, reaction rates and lifetimes of states. As the more versatile technique, solution NMR spectroscopy offers a remarkable catalogue of methods that can be successfully applied to the quantitative as well as qualitative...... descriptions of protein interactions. In this review we provide an easy-access approach to NMR for the non-NMR specialist and describe how and when solution state NMR spectroscopy is the method of choice for addressing protein ligand interaction. We describe very briefly the theoretical background...

Autonomous driving in NMR.

Science.gov (United States)

Perez, Manuel

2017-01-01

The automatic analysis of NMR data has been a much-desired endeavour for the last six decades, as it is the case with any other analytical technique. This need for automation has only grown as advances in hardware; pulse sequences and automation have opened new research areas to NMR and increased the throughput of data. Full automatic analysis is a worthy, albeit hard, challenge, but in a world of artificial intelligence, instant communication and big data, it seems that this particular fight is happening with only one technique at a time (let this be NMR, MS, IR, UV or any other), when the reality of most laboratories is that there are several types of analytical instrumentation present. Data aggregation, verification and elucidation by using complementary techniques (e.g. MS and NMR) is a desirable outcome to pursue, although a time-consuming one if performed manually; hence, the use of automation to perform the heavy lifting for users is required to make the approach attractive for scientists. Many of the decisions and workflows that could be implemented under automation will depend on the two-way communication with databases that understand analytical data, because it is desirable not only to query these databases but also to grow them in as much of an automatic manner as possible. How these databases are designed, set up and the data inside classified will determine what workflows can be implemented. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

sup 1 sup 1 B nutation NMR study of powdered borosilicates

CERN Document Server

Woo, A J; Han, D Y

1998-01-01

In this work, we applied the 1D sup 1 sup 1 B nutation NMR method for the analysis of the local structural environments in powdered borosilicates (SiO sub 2 -B sub 2 O sub 3). Spin dynamics during a rf irradiation for spin I=3/2 was analytically calculated with a density matrix formalism. Spectral simulation programs were written in MATLAB on a PC. Two borosilicates prepared by the sol-gel process at different stabilization temperature were used for the 1D sup 1 sup 1 B nutation NMR experiment. The sup 1 sup 1 B NMR parameters, quadrupole coupling constants (e sup 2 qQ/h) and asymmetry parameters (eta), for each borosilicate were extracted from the nonlinear least-squares fitting. The effects of heat treatments on the local structures of boron sites in borosilicates were discussed.

Coherent evolution of parahydrogen induced polarisation using laser pump, NMR probe spectroscopy: Theoretical framework and experimental observation.

Science.gov (United States)

Halse, Meghan E; Procacci, Barbara; Henshaw, Sarah-Louise; Perutz, Robin N; Duckett, Simon B

2017-05-01

We recently reported a pump-probe method that uses a single laser pulse to introduce parahydrogen (p-H 2 ) into a metal dihydride complex and then follows the time-evolution of the p-H 2 -derived nuclear spin states by NMR. We present here a theoretical framework to describe the oscillatory behaviour of the resultant hyperpolarised NMR signals using a product operator formalism. We consider the cases where the p-H 2 -derived protons form part of an AX, AXY, AXYZ or AA'XX' spin system in the product molecule. We use this framework to predict the patterns for 2D pump-probe NMR spectra, where the indirect dimension represents the evolution during the pump-probe delay and the positions of the cross-peaks depend on the difference in chemical shift of the p-H 2 -derived protons and the difference in their couplings to other nuclei. The evolution of the NMR signals of the p-H 2 -derived protons, as well as the transfer of hyperpolarisation to other NMR-active nuclei in the product, is described. The theoretical framework is tested experimentally for a set of ruthenium dihydride complexes representing the different spin systems. Theoretical predictions and experimental results agree to within experimental error for all features of the hyperpolarised 1 H and 31 P pump-probe NMR spectra. Thus we establish the laser pump, NMR probe approach as a robust way to directly observe and quantitatively analyse the coherent evolution of p-H 2 -derived spin order over micro-to-millisecond timescales. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Dynamic NMR Study of Model CMP Slurry Containing Silica Particles as Abrasives

Science.gov (United States)

Odeh, F.; Al-Bawab, A.; Li, Y.

2018-02-01

Chemical mechanical planarization (CMP) should provide a good surface planarity with minimal surface defectivity. Since CMP slurries are multi-component systems, it is very important to understand the various processes and interactions taking place in such slurries. Several techniques have been employed for such task, however, most of them lack the molecular recognition to investigate molecular interactions without adding probes which in turn increase complexity and might alter the microenvironment of the slurry. Nuclear magnetic resonance (NMR) is a powerful technique that can be employed in such study. The longitudinal relaxation times (T1) of the different components of CMP slurries were measured using Spin Echo-NMR (SE-NMR) at a constant temperature. The fact that NMR is non-invasive and gives information on the molecular level gives more advantage to the technique. The model CMP slurry was prepared in D2O to enable monitoring of T1 for the various components' protons. SE-NMR provide a very powerful tool to study the various interactions and adsorption processes that take place in a model CMP silica based slurry which contains BTA and/or glycine and/or Cu+2 ions. It was found that BTA is very competitive towards complexation with Cu+2 ions and BTA-Cu complex adsorbs on silica surface.

TD-NMR studies on CuSO{sub 4} salt hydrates

Energy Technology Data Exchange (ETDEWEB)

Nestle, Nikolaus; Magin, Peter; Wengeler, Robert [BASF Aktiengesellschaft, Ludwigshafen (Germany); Kleinschmidt, Sebastian [Universitaet Magdeburg, FB Chemie (Germany)

2008-07-01

Despite the high concentration of paramagnetic copper ions, solid CuSO{sub 4} hydrates exhibit surprizingly narrow NMR signals. This is known since the late 1940s. Using TD-NMR methods established for polymer studies, the relaxation behaviour of CuSO{sub 4} preparations with different water content was studied at room temperature. For the water content of the pentahydrate and below, the NMR signal exhibits a pure solid-state-type magnetization decay behaviour. For slightly overstoichiometric moisture contents, a liquid-like signal is observed in addition to the solid signal. However, the relative amplitudes of the solid and the liquid signal do not mirror the stoichiometric composition of the pentahydrate and the excess water. Instead, the solid signal amplitude only accounts for four hydrate water molecules while the fifth water exhibits rapid exchange with the liquid phase and thus contributes to the liquid-type signal. This finding is in good agreement to results from investigations into the crystal structure of solid CuSO4 pentahydrate.

Combined chemometric analysis of (1)H NMR, (13)C NMR and stable isotope data to differentiate organic and conventional milk.

Science.gov (United States)

Erich, Sarah; Schill, Sandra; Annweiler, Eva; Waiblinger, Hans-Ulrich; Kuballa, Thomas; Lachenmeier, Dirk W; Monakhova, Yulia B

2015-12-01

The increased sales of organically produced food create a strong need for analytical methods, which could authenticate organic and conventional products. Combined chemometric analysis of (1)H NMR-, (13)C NMR-spectroscopy data, stable-isotope data (IRMS) and α-linolenic acid content (gas chromatography) was used to differentiate organic and conventional milk. In total 85 raw, pasteurized and ultra-heat treated (UHT) milk samples (52 organic and 33 conventional) were collected between August 2013 and May 2014. The carbon isotope ratios of milk protein and milk fat as well as the α-linolenic acid content of these samples were determined. Additionally, the milk fat was analyzed by (1)H and (13)C NMR spectroscopy. The chemometric analysis of combined data (IRMS, GC, NMR) resulted in more precise authentication of German raw and retail milk with a considerably increased classification rate of 95% compared to 81% for NMR and 90% for IRMS using linear discriminate analysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

2D NMR studies of biomolecules

International Nuclear Information System (INIS)

Lamerichs, R.M.J.N.

1989-01-01

The work described in this thesis comprises two related subjects. The first part describes methods to derive high-resolution structures of proteins in solution using two-dimensional (2-D) NMR. The second part describes 2-D NMR studies on the interaction between proteins and DNA. (author). 261 refs.; 52 figs.; 23 tabs

Investigation of sea microorganisms of the genus Alteromonas by 31P-NMR of high resolution

International Nuclear Information System (INIS)

Ivanova, E.P.; Isakov, V.V.; Mikhajlov, V.V.; Sokolova, S.V.; Gorshkova, N.M.; Fedosov, Yu.V.; Kiprianova, E.A.

1993-01-01

Comparative analysis of the 31 P-NMR spectra of intact cells of bacteria belonging to the genus Alteromonas, the producers of alkaline phosphatase was carried out. Differences in the content of phosphate-containing compounds were detected in individual species of the genus Alteromonas. By comparing the data on 31 P-NMR spectra, the electron micrographs and phosphatase activities, the possibility of revealing the presence of capsules was shown. Peculiar features of the 31 P-NMR spectra of alteromonades, as compared with other taxonomic groups of microorganisms, have been discussed

Experimental solid state NMR of gas hydrates : problems and solutions

Energy Technology Data Exchange (ETDEWEB)

Moudrakovski, I.; Lu, H.; Ripmeester, J. [National Research Council of Canada, Ottawa, ON (Canada). Steacie Inst. for Molecular Sciences; Kumar, R.; Susilo, R. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Chemical and Biological Engineering; Luzi, M. [GeoForschungsZentrum Potsdam, Potsdam (Germany)

2008-07-01

Solid State NMR is a suitable spectroscopic technique for hydrate research for several reasons, including its capability to distinguish between different structural types of hydrates, its quantitative nature and potential for both in-situ and time resolved experiments. This study illustrated the applications of solid state NMR for compositional and structural studies of clathrate hydrates, with particular emphasis on experimental techniques and potential ways to overcome technical difficulties. In order to use the method to its full capacity, some instrumental developments are needed to adapt it to the specific experimental requirements of hydrate studies, such as very low temperatures and high pressures. This presentation discussed the quantification of the Carbon-13 spectra with examples from natural and synthetic hydrates prepared from multi-component mixtures of hydrocarbons. The main approach used for the first two examples was Carbon-13 NMR with Magic Angle Spinning (MAS) at -100 degrees C. The detailed characterization of mixed hydrogen hydrates required low temperature hydrogen MAS. The quantification problems encountered during these experiments were also discussed. The purpose of these recent experimental developments was to prompt wider application of Solid State NMR in hydrate research. NMR proved to be a viable method for analyzing the composition and structure of multi-component mixed gas hydrates; characterizing natural gas hydrates; and, evaluating the formation conditions and properties of mixed hydrogen hydrates. The limitations of the method were highlighted and sensible choices of experimental conditions and techniques that ensure accurate results were discussed. 34 refs., 10 figs.

NMR studies of macroscopic and microscopic properties of liquid crystals

International Nuclear Information System (INIS)

Hughes, J.R.

1998-03-01

The work presented is concerned with studies of orientational order in liquid crystals and the behaviour of certain mesophases. The experimental technique used in common with all the work is deuterium NMR spectroscopy. Much of the work involves studies of the orientational order of deuteriated solute molecules dissolved in liquid crystal solvents. Chapter 1 gives an introduction to liquid crystals followed by a quantitative description of orientational order. Deuterium NMR in liquid crystals is described and an outline of the molecular field theory behind the orientational order of a rigid, biaxial solute in a uniaxial mesophase is given. In Chapter 2 a novel type of mesophase induction is studied using NMR, where a solute induces up to two extra phases in a discotic mesogen depending on its concentration. The purpose of this work is to try to gain an understanding into the mechanism of the phase induction involved. Chapter 3 is concerned primarily with the macroscopic behaviour of the nematic phase formed by a semi-rigid main-chain polymer in solution. Of particular interest is the study of the reorientation of the monodomain, once the director has been rotated with respect to the magnetic field of the NMR spectrometer. A mesogen which has been claimed to exhibit a biaxial nematic phase is studied in Chapter 4, in order to determine the symmetry of the phase using NMR. Finally, Chapter 5 deals with the differing behaviour of a liquid crystal monomer and its dimer dissolved in common nematic solvents in order to determine whether this agrees with molecular field theory. (author)

nmr spectroscopic study and dft calculations of giao nmr shieldings

African Journals Online (AJOL)

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3Department of Physics, Arts and Science Faculty, Dumlupinar University, Kütahya, ... 1H, 13C NMR chemical shifts and 1JCH coupling constants of .... then estimated using the corresponding TMS shieldings calculated in advance at the same.

Two-dimensional NMR spectrometry

International Nuclear Information System (INIS)

Farrar, T.C.

1987-01-01

This article is the second in a two-part series. In part one (ANALYTICAL CHEMISTRY, May 15) the authors discussed one-dimensional nuclear magnetic resonance (NMR) spectra and some relatively advanced nuclear spin gymnastics experiments that provide a capability for selective sensitivity enhancements. In this article and overview and some applications of two-dimensional NMR experiments are presented. These powerful experiments are important complements to the one-dimensional experiments. As in the more sophisticated one-dimensional experiments, the two-dimensional experiments involve three distinct time periods: a preparation period, t 0 ; an evolution period, t 1 ; and a detection period, t 2

1H-NMR/13C-NMR studies of branched structures in PVC obtained at atmospheric pressure

International Nuclear Information System (INIS)

Braun, D.; Holzer, G.; Hjertberg, T.

1981-01-01

The 1 H-NMR-spectra of raw poly (vinyl cloride) obtained at atmospheric pressure (U-PVC) have revealed the presence of high concentrations of branches. The content of labile chlorine was determined by reaction with phenole in order to estimate the branch points with tertiary chlorine. The branch length of reductively dehalogenated U-PVC by 13 C-NMR analysis have provided evidence for both short chain branches including chloromethyl groups and 2.4-dichloro-n-butyl groups and long chain branching. For a number of U-polymers the total amount of branching ranges from 7.5 to 13.5/1000 C. The 13 C-NMR measurements point to a ratio of methyl/butyl branches of 1:1 and short chains/long chains of 6:1. (orig.)

Introduction to some basic aspects of NMR

International Nuclear Information System (INIS)

Goldman, M.

1992-01-01

The principal interactions are reviewed that are experienced by nuclear spins making magnetic resonance feasible and which disturb it in a way that gives access to the properties of bulk matter. The interactions leading to NMR include Zeeman interaction, dipole-dipole interactions, and exchange interactions. Spin-lattice relaxation relevant to NMR is revisited next. It is followed by an overview of spin temperature. Finally, the care of periodic Hamiltonian is discussed in detail as another contribution to NMR. (R.P.) 48 refs., 12 figs

Determination of binder distributions in green-state ceramics by NMR imaging

International Nuclear Information System (INIS)

Garrido, L.; Ackerman, J.L.; Ellingson, W.A.; Weyand, J.D.

1988-03-01

The manufacture of reliable high performance structural ceramics requires a good understanding of the different steps involved in the process. The presence of nonuniformities in the distribution of the polymeric binder could give rise to local fluctuations of density that could produce failure of the ceramic piece. Specimens prepared from Al 2 O 3 with 15 and 2.5% ww binder were imaged using NMR in order to measure binder distribution maps. Results show that NMR imaging could be a useful technique to nondestructively evaluate the quality of green-state specimens. 5 refs., 5 figs

Structural Studies of Bcl-xL/ligand Complexes using {sup 19}F NMR

Energy Technology Data Exchange (ETDEWEB)

Yu Liping; Hajduk, Philip J.; Mack, Jamey; Olejniczak, Edward T. [GPRD, Abbott Laboratories, Pharmaceutical Discovery Division (United States)], E-mail: Edward.olejniczak@abbott.com

2006-04-15

Fluorine atoms are often incorporated into drug molecules as part of the lead optimization process in order to improve affinity or modify undesirable metabolic and pharmacokinetic profiles. From an NMR perspective, the abundance of fluorinated drug leads provides an exploitable niche for structural studies using {sup 19}F NMR in the drug discovery process. As {sup 19}F has no interfering background signal from biological sources, {sup 19}F NMR studies of fluorinated drugs bound to their protein receptors can yield easily interpretable and unambiguous structural constraints. {sup 19}F can also be selectively incorporated into proteins to obtain additional constraints for structural studies. Despite these advantages, {sup 19}F NMR has rarely been exploited for structural studies due to its broad lines in macromolecules and their ligand complexes, leading to weak signals in {sup 1}H/{sup 19}F heteronuclear NOE experiments. Here we demonstrate several different experimental strategies that use {sup 19}F NMR to obtain ligand-protein structural constraints for ligands bound to the anti-apoptotic protein Bcl-xL, a drug target for anti-cancer therapy. These examples indicate the applicability of these methods to typical structural problems encountered in the drug development process.

An Inversion Recovery NMR Kinetics Experiment

Science.gov (United States)

Williams, Travis J.; Kershaw, Allan D.; Li, Vincent; Wu, Xinping

2011-01-01

A convenient laboratory experiment is described in which NMR magnetization transfer by inversion recovery is used to measure the kinetics and thermochemistry of amide bond rotation. The experiment utilizes Varian spectrometers with the VNMRJ 2.3 software, but can be easily adapted to any NMR platform. The procedures and sample data sets in this…

Discriminative Analysis of Different Grades of Gaharu (Aquilaria malaccensis Lamk. via 1H-NMR-Based Metabolomics Using PLS-DA and Random Forests Classification Models

Directory of Open Access Journals (Sweden)

Siti Nazirah Ismail

2017-09-01

Full Text Available Gaharu (agarwood, Aquilaria malaccensis Lamk. is a valuable tropical rainforest product traded internationally for its distinctive fragrance. It is not only popular as incense and in perfumery, but also favored in traditional medicine due to its sedative, carminative, cardioprotective and analgesic effects. The current study addresses the chemical differences and similarities between gaharu samples of different grades, obtained commercially, using 1H-NMR-based metabolomics. Two classification models: partial least squares-discriminant analysis (PLS-DA and Random Forests were developed to classify the gaharu samples on the basis of their chemical constituents. The gaharu samples could be reclassified into a ‘high grade’ group (samples A, B and D, characterized by high contents of kusunol, jinkohol, and 10-epi-γ-eudesmol; an ‘intermediate grade’ group (samples C, F and G, dominated by fatty acid and vanillic acid; and a ‘low grade’ group (sample E and H, which had higher contents of aquilarone derivatives and phenylethyl chromones. The results showed that 1H- NMR-based metabolomics can be a potential method to grade the quality of gaharu samples on the basis of their chemical constituents.

$\\beta$-NMR of copper isotopes in ionic liquids

CERN Multimedia

We propose to test the feasibility of spin-polarization and $\\beta$-NMR studies on several short-lived copper isotopes, $^{58}$ Cu, $^{74}$Cu and $^{75}$Cu in crystals and liquids. The motivation is given by biological studies of Cu with $\\beta$-NMR in liquid samples, since Cu is present in a large number of enzymes involved in electron transfer and activation of oxygen. The technique is based on spin-polarization via optical pumping in the new VITO beamline. We will use the existing lasers, NMR magnet and NMR chambers and we will prepare a new optical pumping system. The studies will be devoted to tests of achieved $\\beta$-asymmetry in solid hosts, the behaviour of asymmetry when increasing vacuum, and finally NMR scans in ionic liquids. The achieved spin polarization will be also relevant for the plans to measure with high precision the magnetic moments of neutron-rich Cu isotopes.

Peakr: simulating solid-state NMR spectra of proteins

International Nuclear Information System (INIS)

Schneider, Robert; Odronitz, Florian; Hammesfahr, Bjorn; Hellkamp, Marcel; Kollmar, Martin

2013-01-01

When analyzing solid-state nuclear magnetic resonance (NMR) spectra of proteins, assignment of resonances to nuclei and derivation of restraints for 3D structure calculations are challenging and time-consuming processes. Simulated spectra that have been calculated based on, for example, chemical shift predictions and structural models can be of considerable help. Existing solutions are typically limited in the type of experiment they can consider and difficult to adapt to different settings. Here, we present Peakr, a software to simulate solid-state NMR spectra of proteins. It can generate simulated spectra based on numerous common types of internuclear correlations relevant for assignment and structure elucidation, can compare simulated and experimental spectra and produces lists and visualizations useful for analyzing measured spectra. Compared with other solutions, it is fast, versatile and user friendly. (authors)

Automatic NMR-based identification of chemical reaction types in mixtures of co-occurring reactions.

Science.gov (United States)

Latino, Diogo A R S; Aires-de-Sousa, João

2014-01-01

The combination of chemoinformatics approaches with NMR techniques and the increasing availability of data allow the resolution of problems far beyond the original application of NMR in structure elucidation/verification. The diversity of applications can range from process monitoring, metabolic profiling, authentication of products, to quality control. An application related to the automatic analysis of complex mixtures concerns mixtures of chemical reactions. We encoded mixtures of chemical reactions with the difference between the (1)H NMR spectra of the products and the reactants. All the signals arising from all the reactants of the co-occurring reactions were taken together (a simulated spectrum of the mixture of reactants) and the same was done for products. The difference spectrum is taken as the representation of the mixture of chemical reactions. A data set of 181 chemical reactions was used, each reaction manually assigned to one of 6 types. From this dataset, we simulated mixtures where two reactions of different types would occur simultaneously. Automatic learning methods were trained to classify the reactions occurring in a mixture from the (1)H NMR-based descriptor of the mixture. Unsupervised learning methods (self-organizing maps) produced a reasonable clustering of the mixtures by reaction type, and allowed the correct classification of 80% and 63% of the mixtures in two independent test sets of different similarity to the training set. With random forests (RF), the percentage of correct classifications was increased to 99% and 80% for the same test sets. The RF probability associated to the predictions yielded a robust indication of their reliability. This study demonstrates the possibility of applying machine learning methods to automatically identify types of co-occurring chemical reactions from NMR data. Using no explicit structural information about the reactions participants, reaction elucidation is performed without structure elucidation of

Automatic NMR-based identification of chemical reaction types in mixtures of co-occurring reactions.

Directory of Open Access Journals (Sweden)

Diogo A R S Latino

Full Text Available The combination of chemoinformatics approaches with NMR techniques and the increasing availability of data allow the resolution of problems far beyond the original application of NMR in structure elucidation/verification. The diversity of applications can range from process monitoring, metabolic profiling, authentication of products, to quality control. An application related to the automatic analysis of complex mixtures concerns mixtures of chemical reactions. We encoded mixtures of chemical reactions with the difference between the (1H NMR spectra of the products and the reactants. All the signals arising from all the reactants of the co-occurring reactions were taken together (a simulated spectrum of the mixture of reactants and the same was done for products. The difference spectrum is taken as the representation of the mixture of chemical reactions. A data set of 181 chemical reactions was used, each reaction manually assigned to one of 6 types. From this dataset, we simulated mixtures where two reactions of different types would occur simultaneously. Automatic learning methods were trained to classify the reactions occurring in a mixture from the (1H NMR-based descriptor of the mixture. Unsupervised learning methods (self-organizing maps produced a reasonable clustering of the mixtures by reaction type, and allowed the correct classification of 80% and 63% of the mixtures in two independent test sets of different similarity to the training set. With random forests (RF, the percentage of correct classifications was increased to 99% and 80% for the same test sets. The RF probability associated to the predictions yielded a robust indication of their reliability. This study demonstrates the possibility of applying machine learning methods to automatically identify types of co-occurring chemical reactions from NMR data. Using no explicit structural information about the reactions participants, reaction elucidation is performed without structure

Quantification of aluminium-27 NMR spectra of high-surface-area oxides

International Nuclear Information System (INIS)

Pearson, R.M.; Schramm, C.M.

1990-01-01

This paper discusses the quantitation of 27 Al NMR spectra. It is showns that the so called 'invisible' aluminium atoms seen by recent workers are completely consistent with known continuous wave NMR studies of the 27 Al NMR spectra of high surface area aluminium oxides. The use of pulsed NMR techniques further complicate the quantitative measurement of 27 Al NMR spectra, especially when high resolution NMR spectrometers are used for this purpose. Methods are described which allow both the estimation of aluminium not seen by continuous wave techniques and the amounts of the NMR spectra lost in pulsed work. (author). 24 refs.; 6 figs.; 1 tab

A Toolbox of Solid-State NMR Experiments for the Characterization of Soft Organic Nanomaterials

KAUST Repository

Straasø, Lasse Arnt

2016-02-02

Determining how organic molecules self-assemble into a solid material is a challenging and demanding task if a single crystal of the material cannot be produced. Solid-state NMR spectroscopy offers access to such molecular details via an appropriate selection of techniques. This report gives a selected overview of 1D and 2D solid-state NMR techniques for elucidating the structure of soft organic solids. We focus on how the solid-state NMR techniques are designed from the perspective of the different nuclear interactions, using average Hamiltonian theory and product operators. We also introduce recent methods for quantification and reduction of experimental artifacts. Finally, we highlight how the solid-state NMR techniques can be applied to soft organic materials by reviewing recent applications to semicrystalline polymers, π-conjugated polymers, natural silk, and graphene-related materials.

A Toolbox of Solid-State NMR Experiments for the Characterization of Soft Organic Nanomaterials

KAUST Repository

Straasø , Lasse Arnt; Saleem, Qasim; Hansen, Michael Ryan

2016-01-01

Determining how organic molecules self-assemble into a solid material is a challenging and demanding task if a single crystal of the material cannot be produced. Solid-state NMR spectroscopy offers access to such molecular details via an appropriate selection of techniques. This report gives a selected overview of 1D and 2D solid-state NMR techniques for elucidating the structure of soft organic solids. We focus on how the solid-state NMR techniques are designed from the perspective of the different nuclear interactions, using average Hamiltonian theory and product operators. We also introduce recent methods for quantification and reduction of experimental artifacts. Finally, we highlight how the solid-state NMR techniques can be applied to soft organic materials by reviewing recent applications to semicrystalline polymers, π-conjugated polymers, natural silk, and graphene-related materials.

NMRbox: A Resource for Biomolecular NMR Computation.

Science.gov (United States)

Maciejewski, Mark W; Schuyler, Adam D; Gryk, Michael R; Moraru, Ion I; Romero, Pedro R; Ulrich, Eldon L; Eghbalnia, Hamid R; Livny, Miron; Delaglio, Frank; Hoch, Jeffrey C

2017-04-25

Advances in computation have been enabling many recent advances in biomolecular applications of NMR. Due to the wide diversity of applications of NMR, the number and variety of software packages for processing and analyzing NMR data is quite large, with labs relying on dozens, if not hundreds of software packages. Discovery, acquisition, installation, and maintenance of all these packages is a burdensome task. Because the majority of software packages originate in academic labs, persistence of the software is compromised when developers graduate, funding ceases, or investigators turn to other projects. To simplify access to and use of biomolecular NMR software, foster persistence, and enhance reproducibility of computational workflows, we have developed NMRbox, a shared resource for NMR software and computation. NMRbox employs virtualization to provide a comprehensive software environment preconfigured with hundreds of software packages, available as a downloadable virtual machine or as a Platform-as-a-Service supported by a dedicated compute cloud. Ongoing development includes a metadata harvester to regularize, annotate, and preserve workflows and facilitate and enhance data depositions to BioMagResBank, and tools for Bayesian inference to enhance the robustness and extensibility of computational analyses. In addition to facilitating use and preservation of the rich and dynamic software environment for biomolecular NMR, NMRbox fosters the development and deployment of a new class of metasoftware packages. NMRbox is freely available to not-for-profit users. Copyright © 2017 Biophysical Society. All rights reserved.

Estimation of the Thickness and the Material Combination of the Thermal Stress Control Layer (TSCL) for the Stellite21 Hardfaced STD61 Hot Working Tool Steel Using Three-Dimensional Finite Element Analysis

International Nuclear Information System (INIS)

Park, Na-Ra; Ahn, Dong-Gyu; Oh, Jin-Woo

2014-01-01

The research on a thermal stress control layer (TSCL) begins to undertake to reduce residual stress and strain in the vicinity of the joined region between the hardfacing layer and the base part. The goal of this paper is to estimate the material combination and the thickness of TSCL for the Stellite21 hardfaced STD61 hot working tool steel via three-dimensional finite element analysis (FEA). TSCL is created by the combination of Stellite21 and STD61. The thickness of TSCL ranges from 0.5 mm to 1.5 mm. The influence of the material combination and the thickness of TSCL on temperature, thermal stress and thermal strain distributions of the hardfaced part have been investigated. The results of the investigation have been revealed that a proper material combination of TSCL is Stellite21 of 50 % and STD61 of 50 %, and its appropriate thickness is 1.0 mm

Evaluation of a Statewide HIV-HCV-STD Online Clinical Education Program by Healthcare Providers - A Comparison of Nursing and Other Disciplines.

Science.gov (United States)

Wang, Dongwen; Luque, Amneris E

2016-01-01

The New York State HIV-HCV-STD Clinical Education Initiative (CEI) has developed a large repository of online resources and disseminated them to a wide range of healthcare providers. To evaluate the CEI online education program and in particular to compare the self-reported measures by clinicians from different disciplines, we analyzed the data from 1,558 course completions in a study period of three months. The results have shown that the overall evaluations by the clinicians were very positive. Meanwhile, there were significant differences across the clinical disciplines. In particular, physicians and nurse practitioners were the most satisfied. In contrast, pharmacists and case/care managers recorded lower than average responses. Nurses and counselors had mixed results. Nurse practitioners' responses were very similar to physicians on most measures, but significantly different from nurses in many aspects. For more effective knowledge dissemination, online education programs should consider the unique needs by clinicians from specific disciplines.

Metabolomic Characterization of Ovarian Epithelial Carcinomas by HRMAS-NMR Spectroscopy

Directory of Open Access Journals (Sweden)

D. Ben Sellem

2011-01-01

Full Text Available Objectives. The objectives of the present study are to determine if a metabolomic study by HRMAS-NMR can (i discriminate between different histological types of epithelial ovarian carcinomas and healthy ovarian tissue, (ii generate statistical models capable of classifying borderline tumors and (iii establish a potential relationship with patient's survival or response to chemotherapy. Methods. 36 human epithelial ovarian tumor biopsies and 3 healthy ovarian tissues were studied using 1H HRMAS NMR spectroscopy and multivariate statistical analysis. Results. The results presented in this study demonstrate that the three histological types of epithelial ovarian carcinomas present an effective metabolic pattern difference. Furthermore, a metabolic signature specific of serous (N-acetyl-aspartate and mucinous (N-acetyl-lysine carcinomas was found. The statistical models generated in this study are able to predict borderline tumors characterized by an intermediate metabolic pattern similar to the normal ovarian tissue. Finally and importantly, the statistical model of serous carcinomas provided good predictions of both patient's survival rates and the patient's response to chemotherapy. Conclusions. Despite the small number of samples used in this study, the results indicate that metabolomic analysis of intact tissues by HRMAS-NMR is a promising technique which might be applicable to the therapeutic management of patients.

Use of NMR as an online sensor in industrial processes

International Nuclear Information System (INIS)

Andrade, Fabiana Diuk de

2012-01-01

Nuclear magnetic resonance (NMR) is one of the most versatile analytical techniques for chemical, biochemical and medical applications. Despite this great success, NMR is seldom used as a tool in industrial applications. The first application of NMR in flowing samples was published in 1951. However, only in the last ten years Flow NMR has gained momentum and new and potential applications have been proposed. In this review we present the historical evolution of flow or online NMR spectroscopy and imaging, and current developments for use in the automation of industrial processes. (author)

Anatomical brain difference of subthreshold depression in young and middle-aged individuals.

Science.gov (United States)

Li, Jing; Wang, Zengjian; Hwang, JiWon; Zhao, Bingcong; Yang, Xinjing; Xin, Suicheng; Wang, Yu; Jiang, Huili; Shi, Peng; Zhang, Ye; Wang, Xu; Lang, Courtney; Park, Joel; Bao, Tuya; Kong, Jian

2017-01-01

Subthreshold depression (StD) is associated with substantial functional impairments due to depressive symptoms that do not fully meet the diagnosis of major depressive disorder (MDD). Its high incidence in the general population and debilitating symptoms has recently put it at the forefront of mood disorder research. In this study we investigated common volumetric brain changes in both young and middle-aged StD patients. Two cohorts of StD patients, young and middle-aged, ( n  = 57) and matched controls ( n  = 76) underwent voxel-based morphometry (VBM). VBM analysis found that: 1) compared with healthy controls, StD patients showed decreased gray matter volume (GMV) in the bilateral globus pallidus and precentral gyrus, as well as increased GMV in the left thalamus and right rostral anterior cingulate cortex/medial prefrontal cortex; 2) there is a significant association between Center for Epidemiological Studies Depression Scale scores and the bilateral globus pallidus (negative) and left thalamus (positive); 3) there is no interaction between age (young vs. middle-age) and group (StD vs. controls). Our findings indicate significant VBM brain changes in both young and middle-aged individuals with StD. Individuals with StD, regardless of age, may share common neural characteristics.

Chlamydia trachomatis serovar distribution and other sexually transmitted coinfections in subjects attending an STD outpatients clinic in Italy.

Science.gov (United States)

Marangoni, Antonella; Foschi, Claudio; Nardini, Paola; D'Antuono, Antonietta; Banzola, Nicoletta; Di Francesco, Antonietta; Ostanello, Fabio; Russo, Incoronata; Donati, Manuela; Cevenini, Roberto

2012-04-01

We studied the prevalence of Chlamydia trachomatis (CT) urogenital infection and the distribution of different genotypes in a non-selected STD population of 1625 patients, evaluating presence of coinfections with other sexually transmitted diseases. Each patient was bled to perform serological tests for syphilis and HIV, then urethral or endocervical swabs were obtained for the detection of CT and Neisseria gonorrhoeae by culture. DNA extracted from remnant positive swabs was amplified by omp1 Nested PCR and products were sequenced. Total prevalence of CT infection was 6.3% (103/1625), with strong differences between men and women (11.4% vs 3.9%, Pmen than in women (Pmen and women (P=0.042) and among patients with or without coinfection (P=0.035); patients infected by serovar D/Da showed the highest coinfection rate. This study can be considered a contribution in increasing knowledge on CT serovar distribution in Italy. Further studies are needed to better define molecular epidemiology of CT infection and to investigate its correlation with other STDs.

Fluorine dynamics in BaF2 superionic conductors investigated by NMR

International Nuclear Information System (INIS)

Gumann, Patryk

2008-01-01

In this work the dynamics of fluorine in solid-state electrolytes having BaF 2 -structure was investigated using three different NMR-methods: field cycling relaxometry, lineshape analysis, and static field gradient NMR. For this purpose a pure BaF 2 crystal, as well as crystals doped with trivalent impurities (LaF 3 ), were studied as a function of temperature. Using MAS NMR it was possible to identify two lines in Ba 0.9 La 0.1 F 2.1 having different chemical shift, and to refer them to the modified crystal structure. On this basis a model for the fluorine lineshape has been developed, taking into account three motional processes characterized by their correlation times. It includes jump diffusion of the fluorine ions among equivalent sites within two crystallographically distinct sublattices, and inter-lattice exchange processes. By measuring frequency and temperature-dependent spin lattice relaxation times, it was possible to gain information about fluorine dynamics on microscopic length scales. An attempt was also made to analyze the data for pure BaF 2 and low admixture concentration samples with a non-exponential correlation function. (orig.)

Selected topics in solution-phase biomolecular NMR spectroscopy

Science.gov (United States)

Kay, Lewis E.; Frydman, Lucio

2017-05-01

Solution bio-NMR spectroscopy continues to enjoy a preeminent role as an important tool in elucidating the structure and dynamics of a range of important biomolecules and in relating these to function. Equally impressive is how NMR continues to 'reinvent' itself through the efforts of many brilliant practitioners who ask increasingly demanding and increasingly biologically relevant questions. The ability to manipulate spin Hamiltonians - almost at will - to dissect the information of interest contributes to the success of the endeavor and ensures that the NMR technology will be well poised to contribute to as yet unknown frontiers in the future. As a tribute to the versatility of solution NMR in biomolecular studies and to the continued rapid advances in the field we present a Virtual Special Issue (VSI) that includes over 40 articles on various aspects of solution-state biomolecular NMR that have been published in the Journal of Magnetic Resonance in the past 7 years. These, in total, help celebrate the achievements of this vibrant field.

NMR detects molecular interactions of graphene with aromatic and aliphatic hydrocarbons in water

Science.gov (United States)

Bichenkova, Elena V.; Raju, Arun P. A.; Burusco, Kepa K.; Kinloch, Ian A.; Novoselov, Kostya S.; Clarke, David J.

2018-03-01

Polyaromatic carbon is widely held to be strongly diamagnetic and hydrophobic, with textbook van der Waals and ‘π-stacked’ binding of hydrocarbons, which disrupt their self-assembled supramolecular structures. The NMR of organic molecules sequestered by polyaromatic carbon is expected to be dominated by shielding from the orbital diamagnetism of π electrons. We report the first evidence of very different polar and magnetic behavior in water, wherein graphene remained well-dispersed after extensive dialysis and behaved as a 1H-NMR-silent ghost. Magnetic effects dominated the NMR of organic structures which interacted with graphene, with changes in spin-spin coupling, vast increase in relaxation, line broadening and decrease in NMR peak heights when bound to graphene. However, the interactions were weak, reversible and did not disrupt organic self-assemblies reliant on hydrophobic ‘π-stacking’, even when substantially sequestered on the surface of graphene by the high surface area available. Interacting assemblies of aromatic molecules retained their strongly-shielded NMR signals and remained within self-assembled structures, with slower rates of diffusion from association with graphene, but with no further shielding from graphene. Binding to graphene was selective for positively-charged organic assemblies, weaker for non-aromatic and negligible for strongly-negatively-charged molecules, presumably repelled by a negative zeta potential of graphene in water. Stronger binders, or considerable excess of weaker binders readily reversed physisorption, with no evidence of structural changes from chemisorption. The fundamental nature of these different electronic interactions between organic and polyaromatic carbon is considered with relevance to electronics, charge storage, sensor, medical, pharmaceutical and environmental research.

Theoretical domains: a heuristic for teaching behavioral theory in HIV/STD prevention courses.

Science.gov (United States)

Dolcini, M Margaret; Canin, Lisa; Gandelman, Alice; Skolnik, Heidi

2004-10-01

The HIV/STD epidemics have broadened the need for better behavioral intervention programs and highlighted the importance of providing training in behavioral theory to frontline program practitioners. However, there is a lack of effective methods for teaching theoretical concepts to people who may not have a background in behavioral science. This article presents a solution to this challenge by introducing a new heuristic for teaching theory and for placing individual theories/models in a broader context. Using a broad framework, we identify five domains that influence behavior: risk appraisal, self-perceptions, emotions and arousal, relationships and social influence, and environmental and structural factors. Each domain is described, and a brief overview of supporting literature is provided. Following the presentation of domains, we discuss course structure and activities.

Comparative NMR study of nPrBTP and iPrBTP

Energy Technology Data Exchange (ETDEWEB)

Adam, C.; Muellich, U.; Geist, A.; Geckeis, H. [Karlsruhe Institute of Technology - KIT, Institute for Nuclear Waste Disposal - INE, Herrmann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Rohde, V. [Fraunhofer Institute for Chemical Technology - ICT, Environmental Engineering, Joseph-von-Fraunhofer-Str. 7, 76327 Pfinztal (Germany); Kaden, P. [Helmholtz-Zentrum Dresden - Rossendorf e. V., Institute of Resource Ecology, Bautzner Landstrasse 400, 01328 Dresden (Germany); Panak, P.J. [Karlsruhe Institute of Technology - KIT, Institute for Nuclear Waste Disposal - INE, Herrmann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); University of Heidelberg, Department of Physical Chemistry, Im Neuenheimer Feld 253, 69120 Heidelberg (Germany)

2016-07-01

Bis-triazinyl-pyridine type ligands are important extracting agents for separating trivalent actinide ions from trivalent lanthanides. The alkyl substituents on the lateral triazine rings have a significant effect on the stability of the ligand against hydrolysis and radiolysis. Furthermore they influence solubility, extraction behaviour and selectivity. TRLFS and extraction studies suggest differences in complexation and extraction behaviour of BTP ligands bearing iso-propyl or n-propyl substituents, respectively. As NMR studies allow insight into the metal-ligand bonding, we conducted NMR studies on a range of {sup 15}N-labelled nPrBTP and iPrBTP Ln(III) and Am(III) complexes. Our results show that no strong change in the metal-ligand bonding occurs, thus excluding electronic reasons for differences in complexation behaviour, extraction kinetics and selectivity. This supports mechanistic reasons for the observed differences. (authors)

NMR examinations of the facial skeleton. Pt. 1

International Nuclear Information System (INIS)

Grodd, W.; Lenz, M.; Baumann, R.; Schroth, G.

1984-01-01

The resolution of NMR and CT was compared using axial sections of the normal anatomic structures of the facial skeleton. Is was shown that NMR was superior in differentiating muscles, tonsils, mucosa, lymph nodes and blood vessels. The demonstration of bone and its differentiation from air-containing spaces is often difficult. Metallic, non-ferromagnetic dental fillings, which cause serious artefacts on CT, do not after NMR. (orig.) [de

The 40th anniversary of the discovery of NMR-chemical shift and nuclear spin-spin coupling

International Nuclear Information System (INIS)

Zhu Zhenghe; Gou Qingquan

1989-01-01

After the discovery of NMR Phenomenon in the physics laboratories of E.M.Purcell at Harvard and F.Bloch at Stanford in 1946, W.G.Proctor and F.C.Yu made the successful discovery of NMR-chemical shift and nuclear spin-spin coupling at Stanford in 1950, Which brought NMR spectroscopy from the physics laboratory to the laboratories of many different fields. This is worth memorizing. Retrospecting the past 40 years, it is sure that chemical shift theory will be much more prosperous prospects

Application of NMR Screening Methods with 19F Detection to Fluorinated Compounds Bound to Proteins

Directory of Open Access Journals (Sweden)

Kazuo Furihata

2017-12-01

Full Text Available The combinational use of one-dimensional (1D NMR-based screening techniques with 1H and 19F detections were applied to a human serum albumin–diflunisal complex. Since most NMR screening methods observe 1H spectra, the overlapped 1H signals were unavailable in the binding epitope mapping. However, the NMR experiments with 19F detection can be used as an effective complementary method. For the purpose of identifying the 1H and 19F binding epitopes of diflunisal, this paper carries out a combinatorial analysis using 1H{1H} and 19F{1H} saturation transfer difference experiments. The differences of the 1H-inversion recovery rates with and without target irradiation are also analyzed for a comprehensive interpretation of binding epitope mapping.

NMR imaging of soft tissue tumors

International Nuclear Information System (INIS)

Laval-Jeantet, M.; Tobolsk, F.; Delepine, N.; Delepine, G.; Roger, B.; Cabanis, E.A.

1986-01-01

Preliminary findings on NMR imaging of 30 soft tissue tumors demonstrated the indispensable value of this examination (particularly when a surface antenna is used) for preoperative investigation and diagnosis of tumoral recurrence when compared with other radiologic techniques. The possible potential of NMR imaging for characterization of tissues, apart from lipoma or liposarcoma, cannot be evaluated at the present time [fr

NMR Phase Noise in Bitter Magnets

Science.gov (United States)

Sigmund, E. E.; Calder, E. S.; Thomas, G. W.; Mitrović, V. F.; Bachman, H. N.; Halperin, W. P.; Kuhns, P. L.; Reyes, A. P.

2001-02-01

We have studied the temporal instability of a high field resistive Bitter magnet through nuclear magnetic resonance (NMR). This instability leads to transverse spin decoherence in repeated and accumulated NMR experiments as is normally performed during signal averaging. We demonstrate this effect via Hahn echo and Carr-Purcell-Meiboom-Gill (CPMG) transverse relaxation experiments in a 23-T resistive magnet. Quantitative analysis was found to be consistent with separate measurements of the magnetic field frequency fluctuation spectrum, as well as with independent NMR experiments performed in a magnetic field with a controlled instability. Finally, the CPMG sequence with short pulse delays is shown to be successful in recovering the intrinsic spin-spin relaxation even in the presence of magnetic field temporal instability.

An NMR Protonation Study of Metal Diethylenetriaminepentaacetic Acid Complexes.

Science.gov (United States)

Letkeman, Peter

1979-01-01

This experiment is suitable for an integrated laboratory course for senior chemistry majors. It introduces the student to a study of the relative basicity of different proton accepting sites. It serves as an opportunity to learn about nmr techniques and could extend to infrared, as well. (BB)

STD Clinic Patients' Awareness of Non-AIDS Complications of HIV Infection.

Science.gov (United States)

Castro, José Guillermo; Granovsky, Inna; Jones, Deborah; Weiss, Stephen M

2015-01-01

Participants were recruited from a sexually transmitted disease (STD) clinic in Florida and were assessed regarding the knowledge and awareness of non-AIDS conditions associated with HIV infection. Questionnaires were administered before and after a brief information session on non-AIDS conditions associated with HIV infection. Participants included men (n = 46) and women (n = 51). Prior to the information session, at baseline, only 34% of the participants were worried about HIV infection. Most participants (82%) agreed that HIV could be treated with antiretroviral therapy (ART), while only 38% were aware that HIV-associated conditions cannot be easily treated with ART. After the information session, almost all participants reported they were concerned regarding the risk of HIV infection. High-risk patients may have limited knowledge about the consequences of HIV infection beyond the traditional AIDS-associated conditions. Increased awareness of these less known consequences of HIV infection may decrease the potential for complacency regarding acquiring HIV infection. © The Author(s) 2014.

Facilitated assignment of large protein NMR signals with covariance sequential spectra using spectral derivatives.

Science.gov (United States)

Harden, Bradley J; Nichols, Scott R; Frueh, Dominique P

2014-09-24

Nuclear magnetic resonance (NMR) studies of larger proteins are hampered by difficulties in assigning NMR resonances. Human intervention is typically required to identify NMR signals in 3D spectra, and subsequent procedures depend on the accuracy of this so-called peak picking. We present a method that provides sequential connectivities through correlation maps constructed with covariance NMR, bypassing the need for preliminary peak picking. We introduce two novel techniques to minimize false correlations and merge the information from all original 3D spectra. First, we take spectral derivatives prior to performing covariance to emphasize coincident peak maxima. Second, we multiply covariance maps calculated with different 3D spectra to destroy erroneous sequential correlations. The maps are easy to use and can readily be generated from conventional triple-resonance experiments. Advantages of the method are demonstrated on a 37 kDa nonribosomal peptide synthetase domain subject to spectral overlap.

Can NMR solve some significant challenges in metabolomics?

Science.gov (United States)

Gowda, G.A. Nagana; Raftery, Daniel

2015-01-01

The field of metabolomics continues to witness rapid growth driven by fundamental studies, methods development, and applications in a number of disciplines that include biomedical science, plant and nutrition sciences, drug development, energy and environmental sciences, toxicology, etc. NMR spectroscopy is one of the two most widely used analytical platforms in the metabolomics field, along with mass spectrometry (MS). NMR's excellent reproducibility and quantitative accuracy, its ability to identify structures of unknown metabolites, its capacity to generate metabolite profiles using intact biospecimens with no need for separation, and its capabilities for tracing metabolic pathways using isotope labeled substrates offer unique strengths for metabolomics applications. However, NMR's limited sensitivity and resolution continue to pose a major challenge and have restricted both the number and the quantitative accuracy of metabolites analyzed by NMR. Further, the analysis of highly complex biological samples has increased the demand for new methods with improved detection, better unknown identification, and more accurate quantitation of larger numbers of metabolites. Recent efforts have contributed significant improvements in these areas, and have thereby enhanced the pool of routinely quantifiable metabolites. Additionally, efforts focused on combining NMR and MS promise opportunities to exploit the combined strength of the two analytical platforms for direct comparison of the metabolite data, unknown identification and reliable biomarker discovery that continue to challenge the metabolomics field. This article presents our perspectives on the emerging trends in NMR-based metabolomics and NMR's continuing role in the field with an emphasis on recent and ongoing research from our laboratory. PMID:26476597

Can NMR solve some significant challenges in metabolomics?

Science.gov (United States)

Nagana Gowda, G A; Raftery, Daniel

2015-11-01

The field of metabolomics continues to witness rapid growth driven by fundamental studies, methods development, and applications in a number of disciplines that include biomedical science, plant and nutrition sciences, drug development, energy and environmental sciences, toxicology, etc. NMR spectroscopy is one of the two most widely used analytical platforms in the metabolomics field, along with mass spectrometry (MS). NMR's excellent reproducibility and quantitative accuracy, its ability to identify structures of unknown metabolites, its capacity to generate metabolite profiles using intact bio-specimens with no need for separation, and its capabilities for tracing metabolic pathways using isotope labeled substrates offer unique strengths for metabolomics applications. However, NMR's limited sensitivity and resolution continue to pose a major challenge and have restricted both the number and the quantitative accuracy of metabolites analyzed by NMR. Further, the analysis of highly complex biological samples has increased the demand for new methods with improved detection, better unknown identification, and more accurate quantitation of larger numbers of metabolites. Recent efforts have contributed significant improvements in these areas, and have thereby enhanced the pool of routinely quantifiable metabolites. Additionally, efforts focused on combining NMR and MS promise opportunities to exploit the combined strength of the two analytical platforms for direct comparison of the metabolite data, unknown identification and reliable biomarker discovery that continue to challenge the metabolomics field. This article presents our perspectives on the emerging trends in NMR-based metabolomics and NMR's continuing role in the field with an emphasis on recent and ongoing research from our laboratory. Copyright © 2015 Elsevier Inc. All rights reserved.

Can NMR solve some significant challenges in metabolomics?

Science.gov (United States)

Nagana Gowda, G. A.; Raftery, Daniel

2015-11-01

The field of metabolomics continues to witness rapid growth driven by fundamental studies, methods development, and applications in a number of disciplines that include biomedical science, plant and nutrition sciences, drug development, energy and environmental sciences, toxicology, etc. NMR spectroscopy is one of the two most widely used analytical platforms in the metabolomics field, along with mass spectrometry (MS). NMR's excellent reproducibility and quantitative accuracy, its ability to identify structures of unknown metabolites, its capacity to generate metabolite profiles using intact bio-specimens with no need for separation, and its capabilities for tracing metabolic pathways using isotope labeled substrates offer unique strengths for metabolomics applications. However, NMR's limited sensitivity and resolution continue to pose a major challenge and have restricted both the number and the quantitative accuracy of metabolites analyzed by NMR. Further, the analysis of highly complex biological samples has increased the demand for new methods with improved detection, better unknown identification, and more accurate quantitation of larger numbers of metabolites. Recent efforts have contributed significant improvements in these areas, and have thereby enhanced the pool of routinely quantifiable metabolites. Additionally, efforts focused on combining NMR and MS promise opportunities to exploit the combined strength of the two analytical platforms for direct comparison of the metabolite data, unknown identification and reliable biomarker discovery that continue to challenge the metabolomics field. This article presents our perspectives on the emerging trends in NMR-based metabolomics and NMR's continuing role in the field with an emphasis on recent and ongoing research from our laboratory.

SPE-NMR metabolite sub-profiling of urine

NARCIS (Netherlands)

Jacobs, D.M.; Spiesser, L.; Garnier, M.; Roo, de N.; Dorsten, van F.; Hollebrands, B.; Velzen, van E.; Draijer, R.; Duynhoven, van J.P.M.

2012-01-01

NMR-based metabolite profiling of urine is a fast and reproducible method for detection of numerous metabolites with diverse chemical properties. However, signal overlap in the (1)H NMR profiles of human urine may hamper quantification and identification of metabolites. Therefore, a new method has

A primer to nutritional metabolomics by NMR spectroscopy and chemometrics

DEFF Research Database (Denmark)

Savorani, Francesco; Rasmussen, Morten Arendt; Mikkelsen, Mette Skau

2013-01-01

This paper outlines the advantages and disadvantages of using high throughput NMR metabolomics for nutritional studies with emphasis on the workflow and data analytical methods for generation of new knowledge. The paper describes one-by-one the major research activities in the interdisciplinary...... metabolomics platform and highlights the opportunities that NMR spectra can provide in future nutrition studies. Three areas are emphasized: (1) NMR as an unbiased and non-destructive platform for providing an overview of the metabolome under investigation, (2) NMR for providing versatile information and data...... structures for multivariate pattern recognition methods and (3) NMR for providing a unique fingerprint of the lipoprotein status of the subject. For the first time in history, by combining NMR spectroscopy and chemometrics we are able to perform inductive nutritional research as a complement to the deductive...

Structure and Dynamic Properties of Membrane Proteins using NMR

DEFF Research Database (Denmark)

Rösner, Heike; Kragelund, Birthe

2012-01-01

conformational changes. Their structural and functional decoding is challenging and has imposed demanding experimental development. Solution nuclear magnetic resonance (NMR) spectroscopy is one of the techniques providing the capacity to make a significant difference in the deciphering of the membrane protein...... structure-function paradigm. The method has evolved dramatically during the last decade resulting in a plethora of new experiments leading to a significant increase in the scientific repertoire for studying membrane proteins. Besides solving the three-dimensional structures using state-of-the-art approaches......-populated states, this review seeks to introduce the vast possibilities solution NMR can offer to the study of membrane protein structure-function analyses with special focus on applicability. © 2012 American Physiological Society. Compr Physiol 2:1491-1539, 2012....

Recombinant Kinase Production and Fragment Screening by NMR Spectroscopy.

Science.gov (United States)

Han, Byeonggu; Ahn, Hee-Chul

2016-01-01

During the past decade fragment-based drug discovery (FBDD) has rapidly evolved and several drugs or drug candidates developed by FBDD approach are clinically in use or in clinical trials. For example, vemurafenib, a V600E mutated BRAF inhibitor, was developed by utilizing FBDD approach and approved by FDA in 2011. In FBDD, screening of fragments is the starting step for identification of hits and lead generation. Fragment screening usually relies on biophysical techniques by which the protein-bound small molecules can be detected. NMR spectroscopy has been extensively used to study the molecular interaction between the protein and the ligand, and has many advantages in fragment screening over other biophysical techniques. This chapter describes the practical aspects of fragment screening by saturation transfer difference NMR.

MAS NMR of HIV-1 protein assemblies

Science.gov (United States)

Suiter, Christopher L.; Quinn, Caitlin M.; Lu, Manman; Hou, Guangjin; Zhang, Huilan; Polenova, Tatyana

2015-04-01

The negative global impact of the AIDS pandemic is well known. In this perspective article, the utility of magic angle spinning (MAS) NMR spectroscopy to answer pressing questions related to the structure and dynamics of HIV-1 protein assemblies is examined. In recent years, MAS NMR has undergone major technological developments enabling studies of large viral assemblies. We discuss some of these evolving methods and technologies and provide a perspective on the current state of MAS NMR as applied to the investigations into structure and dynamics of HIV-1 assemblies of CA capsid protein and of Gag maturation intermediates.

NMR of geophysical drill cores with a mobile Halbach scanner

International Nuclear Information System (INIS)

Talnishnikh, E.

2007-01-01

This thesis is devoted to a mobile NMR with an improved Halbach scanner. This is a lightweight tube-shaped magnet with sensitive volume larger and a homogeneity of the magnetic field higher than the previous prototype version. The improved Halbach scanner is used for analysis of water-saturated drill cores and plugs with diameters up to 60 mm. To provide the analysis, the standard 1D technique with the CPMG sequence as well as 2D correlation experiments were successfully applied and adapted to study properties of fluid-saturated sediments. Afterwards the Halbach scanner was calibrated to fast non-destructive measurements of porosity, relaxation time distributions, and estimation of permeability. These properties can be calculated directly from the NMR data using the developed methodology. Any independent measurements of these properties with other methods are not needed. One of the main results of this work is the development of a new NMR on-line core scanner for measurements of porosity in long cylindrical and semi cylindrical drill cores. Also dedicated software was written to operate the NMR on-line core scanner. The physical background of this work is the study of the diffusion influence on transverse relaxation. The diffusion effect in the presence of internal gradients in porous media was probed by 1D and 2D experiments. The transverse relaxation time distributions obtained from 1D and from 2D experiments are comparable but different in fine details. Two new methodologies were developed based on the results of this study. First is the methodology quantifying the influence of diffusion in the internal gradients of water-saturated sediments on transverse relaxation from 2D correlation experiments. The second one is the correction of the permeability estimation from the NMR data taking in account the influence of the diffusion. Furthermore, PFG NMR technique was used to study restricted diffusion in the same kind of samples. Preliminary results are reported

NMR of geophysical drill cores with a mobile Halbach scanner

Energy Technology Data Exchange (ETDEWEB)

Talnishnikh, E.

2007-08-21

This thesis is devoted to a mobile NMR with an improved Halbach scanner. This is a lightweight tube-shaped magnet with sensitive volume larger and a homogeneity of the magnetic field higher than the previous prototype version. The improved Halbach scanner is used for analysis of water-saturated drill cores and plugs with diameters up to 60 mm. To provide the analysis, the standard 1D technique with the CPMG sequence as well as 2D correlation experiments were successfully applied and adapted to study properties of fluid-saturated sediments. Afterwards the Halbach scanner was calibrated to fast non-destructive measurements of porosity, relaxation time distributions, and estimation of permeability. These properties can be calculated directly from the NMR data using the developed methodology. Any independent measurements of these properties with other methods are not needed. One of the main results of this work is the development of a new NMR on-line core scanner for measurements of porosity in long cylindrical and semi cylindrical drill cores. Also dedicated software was written to operate the NMR on-line core scanner. The physical background of this work is the study of the diffusion influence on transverse relaxation. The diffusion effect in the presence of internal gradients in porous media was probed by 1D and 2D experiments. The transverse relaxation time distributions obtained from 1D and from 2D experiments are comparable but different in fine details. Two new methodologies were developed based on the results of this study. First is the methodology quantifying the influence of diffusion in the internal gradients of water-saturated sediments on transverse relaxation from 2D correlation experiments. The second one is the correction of the permeability estimation from the NMR data taking in account the influence of the diffusion. Furthermore, PFG NMR technique was used to study restricted diffusion in the same kind of samples. Preliminary results are reported

Nuclear magnetic resonance (NMR): principles and applications

International Nuclear Information System (INIS)

Quibilan, E.I.

The basis for the phenomenon of nuclear magnetic resonance (NMR) is the ability of certain nuclei possessing both intrinsic angular momentum or ''spin'' I and magnetic moment to absorb electromagnetic energy in the radio frequency range. In principle, there are approximately 200 nuclei which may be investigated using the NMR technique. The NMR spectrum consists of intensity peaks along an axis calibrated in terms of the steady magnetic field or the frequency of the radiofrequency electromagnetic radiation. Analysis of the number, spacing, position and intensity of the lines in an NMR spectrum consists of intensity peaks along an axis calibrated in terms of the steady magnetic field or the frequency of the radiofrequency electromagnetic radiation. Analysis of the number, spacing, position and intensity of the lines in an NMR spectrum provides a variety of qualitative and quantitative analytical applications. The most obvious applications consist of the measurements of nuclear properties, such as spin number and nuclear magnetic moment. In liquids, the fine structure of resonance spectra provides a tool for chemical identification and molecular structure analysis. Other applications include the measurements of self-diffusion coefficients, magnetic fields and field homogeneity, inter-nuclear distances, and, in some cases, the water content of biological materials. (author)

Chirp echo Fourier transform EPR-detected NMR.

Science.gov (United States)

Wili, Nino; Jeschke, Gunnar

2018-04-01

A new ultra-wide band (UWB) pulse EPR method is introduced for observing all nuclear frequencies of a paramagnetic center in a single shot. It is based on burning spectral holes with a high turning angle (HTA) pulse that excites forbidden transitions and subsequent detection of the hole pattern by a chirp echo. We term this method Chirp Echo Epr SpectroscopY (CHEESY)-detected NMR. The approach is a revival of FT EPR-detected NMR. It yields similar spectra and the same type of information as electron-electron double resonance (ELDOR)-detected NMR, but with a multiplex advantage. We apply CHEESY-detected NMR in Q band to nitroxides and correlate the hyperfine spectrum to the EPR spectrum by varying the frequency of the HTA pulse. Furthermore, a selective π pulse before the HTA pulse allows for detecting hyperfine sublevel correlations between transitions of one nucleus and for elucidating the coupling regime, the same information as revealed by the HYSCORE experiment. This is demonstrated on hexaaquamanganese(II). We expect that CHEESY-detected NMR is generally applicable to disordered systems and that our results further motivate the development of EPR spectrometers capable of coherent UWB excitation and detection, especially at higher fields and frequencies. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Chirp echo Fourier transform EPR-detected NMR

Science.gov (United States)

Wili, Nino; Jeschke, Gunnar

2018-04-01

A new ultra-wide band (UWB) pulse EPR method is introduced for observing all nuclear frequencies of a paramagnetic center in a single shot. It is based on burning spectral holes with a high turning angle (HTA) pulse that excites forbidden transitions and subsequent detection of the hole pattern by a chirp echo. We term this method Chirp Echo Epr SpectroscopY (CHEESY)-detected NMR. The approach is a revival of FT EPR-detected NMR. It yields similar spectra and the same type of information as electron-electron double resonance (ELDOR)-detected NMR, but with a multiplex advantage. We apply CHEESY-detected NMR in Q band to nitroxides and correlate the hyperfine spectrum to the EPR spectrum by varying the frequency of the HTA pulse. Furthermore, a selective π pulse before the HTA pulse allows for detecting hyperfine sublevel correlations between transitions of one nucleus and for elucidating the coupling regime, the same information as revealed by the HYSCORE experiment. This is demonstrated on hexaaquamanganese(II). We expect that CHEESY-detected NMR is generally applicable to disordered systems and that our results further motivate the development of EPR spectrometers capable of coherent UWB excitation and detection, especially at higher fields and frequencies.

Hyperpolarized NMR Probes for Biological Assays

Directory of Open Access Journals (Sweden)

Sebastian Meier

2014-01-01

Full Text Available During the last decade, the development of nuclear spin polarization enhanced (hyperpolarized molecular probes has opened up new opportunities for studying the inner workings of living cells in real time. The hyperpolarized probes are produced ex situ, introduced into biological systems and detected with high sensitivity and contrast against background signals using high resolution NMR spectroscopy. A variety of natural, derivatized and designed hyperpolarized probes has emerged for diverse biological studies including assays of intracellular reaction progression, pathway kinetics, probe uptake and export, pH, redox state, reactive oxygen species, ion concentrations, drug efficacy or oncogenic signaling. These probes are readily used directly under natural conditions in biofluids and are often directly developed and optimized for cellular assays, thus leaving little doubt about their specificity and utility under biologically relevant conditions. Hyperpolarized molecular probes for biological NMR spectroscopy enable the unbiased detection of complex processes by virtue of the high spectral resolution, structural specificity and quantifiability of NMR signals. Here, we provide a survey of strategies used for the selection, design and use of hyperpolarized NMR probes in biological assays, and describe current limitations and developments.

Some exercises in quantitative NMR imaging

International Nuclear Information System (INIS)

Bakker, C.J.G.

1985-01-01

The articles represented in this thesis result from a series of investigations that evaluate the potential of NMR imaging as a quantitative research tool. In the first article the possible use of proton spin-lattice relaxation time T 1 in tissue characterization, tumor recognition and monitoring tissue response to radiotherapy is explored. The next article addresses the question whether water proton spin-lattice relaxation curves of biological tissues are adequately described by a single time constant T 1 , and analyzes the implications of multi-exponentiality for quantitative NMR imaging. In the third article the use of NMR imaging as a quantitative research tool is discussed on the basis of phantom experiments. The fourth article describes a method which enables unambiguous retrieval of sign information in a set of magnetic resonance images of the inversion recovery type. The next article shows how this method can be adapted to allow accurate calculation of T 1 pictures on a pixel-by-pixel basis. The sixth article, finally, describes a simulation procedure which enables a straightforward determination of NMR imaging pulse sequence parameters for optimal tissue contrast. (orig.)

Multicomponent analysis of fat- and water-soluble vitamins and auxiliary substances in multivitamin preparations by qNMR.

Science.gov (United States)

Eiff, Julia; Monakhova, Yulia B; Diehl, Bernd W K

2015-04-01

A nuclear magnetic resonance (NMR) spectroscopic method was tested to control 12 vitamins and accompanying substances in multivitamin preparations. The limits of detection (LODs) and limits of quantification (LOQs) varied in the 9.0-77.0 mg/kg and in the 34.5-93.5 mg/kg range, respectively. The coefficients of variation (CVs) ranged between 0.9% and 12%. The (1)H NMR spectra showed linearity for the 140-260 mg sample weight (R(2) > 0.918). The NMR spectra of multivitamin preparations showed the presence of different degradation products of ascorbic acid. The NMR method was applied to 13 different multivitamin preparations including tablets, capsules, and effervescent tablets with average recovery rates between 85% and 132%. A number of accompanying substances (citric acid, mannitol, saccharin, cyclamate, sum of steviol glycosides, and butylhydroxytoluene) were additionally identified and quantified. NMR was found to be suitable for the simultaneous qualitative measurement of water- and fat-soluble vitamins and accompanying substances and shows some promise for quantitative determination of at least 5 vitamins (B1, B3, B5, B6, and E) in multivitamin preparations.

Distinguishing Vaccinium species by chemical fingerprinting based on NMR spectra, validated with spectra collected in different laboratories.

Science.gov (United States)

Markus, Michelle A; Ferrier, Jonathan; Luchsinger, Sarah M; Yuk, Jimmy; Cuerrier, Alain; Balick, Michael J; Hicks, Joshua M; Killday, K Brian; Kirby, Christopher W; Berrue, Fabrice; Kerr, Russell G; Knagge, Kevin; Gödecke, Tanja; Ramirez, Benjamin E; Lankin, David C; Pauli, Guido F; Burton, Ian; Karakach, Tobias K; Arnason, John T; Colson, Kimberly L

2014-06-01

A method was developed to distinguish Vaccinium species based on leaf extracts using nuclear magnetic resonance spectroscopy. Reference spectra were measured on leaf extracts from several species, including lowbush blueberry (Vaccinium angustifolium), oval leaf huckleberry (Vaccinium ovalifolium), and cranberry (Vaccinium macrocarpon). Using principal component analysis, these leaf extracts were resolved in the scores plot. Analysis of variance statistical tests demonstrated that the three groups differ significantly on PC2, establishing that the three species can be distinguished by nuclear magnetic resonance. Soft independent modeling of class analogies models for each species also showed discrimination between species. To demonstrate the robustness of nuclear magnetic resonance spectroscopy for botanical identification, spectra of a sample of lowbush blueberry leaf extract were measured at five different sites, with different field strengths (600 versus 700 MHz), different probe types (cryogenic versus room temperature probes), different sample diameters (1.7 mm versus 5 mm), and different consoles (Avance I versus Avance III). Each laboratory independently demonstrated the linearity of their NMR measurements by acquiring a standard curve for chlorogenic acid (R(2) = 0.9782 to 0.9998). Spectra acquired on different spectrometers at different sites classifed into the expected group for the Vaccinium spp., confirming the utility of the method to distinguish Vaccinium species and demonstrating nuclear magnetic resonance fingerprinting for material validation of a natural health product. Georg Thieme Verlag KG Stuttgart · New York.

Single-sided NMR

CERN Document Server

Casanova, Federico; Blümich, Bernhard

2011-01-01

Single-Sided NMR describes the design of the first functioning single-sided tomograph, the related measurement methods, and a number of applications. One of the key advantages to this method is the speed at which the images are obtained.

Non-polymeric asymmetric binary glass-formers. II. Secondary relaxation studied by dielectric, 2H NMR, and 31P NMR spectroscopy

Science.gov (United States)

Pötzschner, B.; Mohamed, F.; Bächer, C.; Wagner, E.; Lichtinger, A.; Bock, D.; Kreger, K.; Schmidt, H.-W.; Rössler, E. A.

2017-04-01

We investigate the secondary (β-) relaxations of an asymmetric binary glass former consisting of a spirobichroman derivative (SBC; Tg = 356 K) as the high-Tg component and the low-Tg component tripropyl phosphate (TPP; Tg = 134 K). The main relaxations are studied in Paper I [B. Pötzschner et al., J. Chem. Phys. 146, 164503 (2017)]. A high Tg contrast of ΔTg = 222 K is put into effect in a non-polymeric system. Component-selective studies are carried out by combining results from dielectric spectroscopy (DS) for mass concentrations cTPP ≥ 60% and those from different methods of 2H and 31P NMR spectroscopy. In the case of NMR, the full concentration range (10% ≤ cTPP ≤ 100%) is covered. The neat components exhibit a β-relaxation (β1 (SBC) and β2 (TPP)). The latter is rediscovered by DS in the mixtures for all concentrations with unchanged time constants. NMR spectroscopy identifies the β-relaxations as being alike to those in neat glasses. A spatially highly restricted motion with angular displacement below ±10° encompassing all molecules is involved. In the low temperature range, where TPP shows the typical 31P NMR echo spectra of the β2-process, very similar spectral features are observed for the (deuterated) SBC component by 2H NMR, in addition to its "own" β1-process observed at high temperatures. Apparently, the small TPP molecules enslave the large SBC molecules to perform a common hindered reorientation. The temperature dependence of the spin-lattice relaxation time of both components is the same and reveals an angular displacement of the SBC molecules somewhat smaller than that of TPP, though the time constants τβ2 are the same. Furthermore, T1(T) of TPP in the temperature region of the β2-process is absolutely the same as in the mixture TPP/polystyrene investigated previously. It appears that the manifestations of the β-process introduced by one component are essentially independent of the second component. Finally, at cTPP ≤ 20% one