Chemistryhttp://nur.nu.edu.kz:80/handle/123456789/5082024-03-29T05:06:37Z2024-03-29T05:06:37ZCONTROLLING THE STEREOCHEMISTRY IN 2-OXO-ALDEHYDE-DERIVED UGI ADDUCTS THROUGH THE CINCHONA ALKALOID-PROMOTED ELECTROPHILIC FLUORINATIONWang, YuqingWang, GaigaiPeshkov, Anatoly A.Yao, RuweiHasan, MuhammadZaman, ManzoorLiu, ChaoKashtanov, StepanPereshivko, Olga P.Peshkov, Vsevolod A.http://nur.nu.edu.kz:80/handle/123456789/55942021-07-15T21:00:38Z2020-08-01T00:00:00ZCONTROLLING THE STEREOCHEMISTRY IN 2-OXO-ALDEHYDE-DERIVED UGI ADDUCTS THROUGH THE CINCHONA ALKALOID-PROMOTED ELECTROPHILIC FLUORINATION
Wang, Yuqing; Wang, Gaigai; Peshkov, Anatoly A.; Yao, Ruwei; Hasan, Muhammad; Zaman, Manzoor; Liu, Chao; Kashtanov, Stepan; Pereshivko, Olga P.; Peshkov, Vsevolod A.
In this report, we introduce a new strategy for controlling the stereochemistry in Ugi adducts. Instead of controlling stereochemistry directly during the Ugi reaction we have attempted to stereodefine the chiral center at the peptidyl position through the post-Ugi functionalization. In order to achieve this, we chose to study 2-oxo-aldehyde-derived Ugi adducts many of which partially or fully exist in the enol form that lacks the aforementioned chiral center. This in turn led to their increased nucleophilicity as compared to the standard Ugi adducts. As such, the stereocenter at the peptidyl position could be installed and stereodefined through the reaction with a suitable electrophile. Towards this end, we were able to deploy an asymmetric cinchona alkaloid-promoted electrophilic fluorination producing enantioenriched post-Ugi adducts fluorinated at the peptidyl position.
2020-08-01T00:00:00ZNano-Mole Scale Side-Chain Signal Assignment by 1H-Detected Protein Solid-State NMR by Ultra-Fast Magic-Angle Spinning and Stereo-Array Isotope LabelingWang, SonglinParthasarathy, SudhakarNishiyama, YusukeEndo, YukiNemoto, TakahiroYamauchi, KazuoAsakura, TetsuoTakeda, MitsuhiroTerauchi, TsutomuKainosho, MasatsuneIshii, Yoshitakahttp://nur.nu.edu.kz:80/handle/123456789/45952020-05-04T21:00:33Z2015-04-01T00:00:00ZNano-Mole Scale Side-Chain Signal Assignment by 1H-Detected Protein Solid-State NMR by Ultra-Fast Magic-Angle Spinning and Stereo-Array Isotope Labeling
Wang, Songlin; Parthasarathy, Sudhakar; Nishiyama, Yusuke; Endo, Yuki; Nemoto, Takahiro; Yamauchi, Kazuo; Asakura, Tetsuo; Takeda, Mitsuhiro; Terauchi, Tsutomu; Kainosho, Masatsune; Ishii, Yoshitaka
We present a general approach in 1H-detected 13C solid-state NMR (SSNMR) for side-chain signal assignments of 10-50 nmol quantities of proteins using a combination of a high magnetic field, ultra-fast magic-angle spinning (MAS) at ~80 kHz, and stereo-array-isotope-labeled (SAIL) proteins [Kainosho M. et al., Nature 440, 52–57, 2006]. First, we demonstrate that 1H indirect detection improves the sensitivity and resolution of 13C SSNMR of SAIL proteins for side-chain assignments in the ultra-fast MAS condition. 1H-detected SSNMR was performed for micro-crystalline ubiquitin (~55 nmol or ~0.5mg) that was SAIL-labeled at seven isoleucine (Ile) residues. Sensitivity was dramatically improved by 1H-detected 2D 1H/13C SSNMR by factors of 5.4-9.7 and 2.1-5.0, respectively, over 13C-detected 2D 1H/13C SSNMR and 1D 13C CPMAS, demonstrating that 2D 1H-detected SSNMR offers not only additional resolution but also sensitivity advantage over 1D 13C detection for the first time. High 1H resolution for the SAIL-labeled side-chain residues offered reasonable resolution even in the 2D data. A 1H-detected 3D 13C/13C/1H experiment on SAIL-ubiquitin provided nearly complete 1H and 13C assignments for seven Ile residues only within ~2.5 h. The results demonstrate the feasibility of side-chain signal assignment in this approach for as little as 10 nmol of a protein sample within ~3 days. The approach is likely applicable to a variety of proteins of biological interest without any requirements of highly efficient protein expression systems.
2015-04-01T00:00:00ZDetection of Paracetamol in Water and Urea in Artificial Urine with Gold Nanoparticle@Al Foil Cost-efficient SERS SubstrateMukanova, ZhansayaGudun, KristinaElemessova, ZarinaKhamkhash, LauraRalchenko, EkaterinaBukasov, Rostislavhttp://nur.nu.edu.kz:80/handle/123456789/45522020-03-27T21:00:35Z2018-01-01T00:00:00ZDetection of Paracetamol in Water and Urea in Artificial Urine with Gold Nanoparticle@Al Foil Cost-efficient SERS Substrate
Mukanova, Zhansaya; Gudun, Kristina; Elemessova, Zarina; Khamkhash, Laura; Ralchenko, Ekaterina; Bukasov, Rostislav
We demonstrated that a cost-efficient, easy to prepare, hybrid SERS substrate-gold nanoparticles (AuNPs) on untreated Al foil (AlF) can effectively detect pharmaceuticals, such as paracetamol and clinical biomarkers, like urea in artificial urine. The limit of detection (LOD) for paracetamol on AuNPs on AlF is superior (0.1 vs. 1 mM ) to the LOD reported for SERS detection of paracetamol in the literature. For SERS detection of urea in urine, AuNPs on both Al foil and Au film performed much better than AuNPs on glass, in terms of the concentration range, linearity and LOD. However, assay on AuNPs on AlF showed a better semi-logarithmic trendline with R2 = 0.98 than an assay on AuNPs on Au film with R2 = 0.94. They have comparable sensitivity with LOD 0.024 and 0.017 M, respectively. The limit of quantification (LOQ) of the former is 0.026 M, which makes it sufficient for the quantification of urea in urine at both normal and pathophysiological (0.03 – 0.15 M) concentration.
https://www.jstage.jst.go.jp/article/analsci/34/2/34_183/_article
2018-01-01T00:00:00ZMonitoring of vegetation drying by Brillouin and Raman spectroscopiesRakymzhan, AdiyaYakupov, Talgat A.Yelemessova, ZarinaBukasov, RostislavYakovlev, Vladislav V.Utegulov, Zhandos N.http://nur.nu.edu.kz:80/handle/123456789/42302020-07-14T04:32:46Z2017-05-01T00:00:00ZMonitoring of vegetation drying by Brillouin and Raman spectroscopies
Rakymzhan, Adiya; Yakupov, Talgat A.; Yelemessova, Zarina; Bukasov, Rostislav; Yakovlev, Vladislav V.; Utegulov, Zhandos N.
Raman and Brillouin spectroscopic provide with a powerful way to non-invasively assess both chemical and physical (viscoelastic) properties. In this report, Brillouin microspectroscopy was used for real time analysis of elastic properties
of Populus and Geranium leaves, while Raman spectroscopy and imaging were employed for assessment of their chemical variation during drying. When used together, those techniques can improve our understanding of mechanochemical changes of plants in response to environmental stress and pathogens at microscopic (cellular) level. Our results have demonstrated for the first time the ability of multimodal assessment of elasticity modulus, hydraulic conductance and interatomic vibrational modes in plants as emerging new markers for real time quantitative assessment of agricultural crops.
2017-05-01T00:00:00ZTurbulence Generation by Shock-Acoustic-Wave Interaction in Core-Collapse SupernovaeAbdikamalov, ErnazarHuete, CésarNussupbekov, AyanBerdibek, Shapagathttp://nur.nu.edu.kz:80/handle/123456789/38672019-04-27T21:00:34Z2018-05-07T00:00:00ZTurbulence Generation by Shock-Acoustic-Wave Interaction in Core-Collapse Supernovae
Abdikamalov, Ernazar; Huete, César; Nussupbekov, Ayan; Berdibek, Shapagat
Convective instabilities in the advanced stages of nuclear shell burning can play
an important role in neutrino-driven supernova explosions. In our previous work, we studied
the interaction of vorticity and entropy waves with the supernova shock using a linear perturbations
theory. In this paper, we extend our work by studying the effect of acoustic waves. As the acoustic
waves cross the shock, the perturbed shock induces a field of entropy and vorticity waves in the
post-shock flow. We find that, even when the upstream flow is assumed to be dominated by sonic
perturbations, the shock-generated vorticity waves contain most of the turbulent kinetic energy in the
post-shock region, while the entropy waves produced behind the shock are responsible for most of
the density perturbations. The entropy perturbations are expected to become buoyant as a response
to the gravity force and then generate additional turbulence in the post-shock region. This leads to
a modest reduction of the critical neutrino luminosity necessary for producing an explosion, which
we estimate to be less than 5%.
2018-05-07T00:00:00ZCarbon Dots Doped with Dysprosium: A Bimodal Nanoprobe for MRI and Fluorescence ImagingAtabaev, TimurPiao, ZhonglieMolkenova, Anarahttp://nur.nu.edu.kz:80/handle/123456789/38632019-04-27T21:00:35Z2018-05-18T00:00:00ZCarbon Dots Doped with Dysprosium: A Bimodal Nanoprobe for MRI and Fluorescence Imaging
Atabaev, Timur; Piao, Zhonglie; Molkenova, Anara
In recent years, functional nanoprobes with multiple imaging modalities have become an
emerging field of biomedical research. In this preliminary study, we utilized a facile hydrothermal
method for the preparation of magneto-fluorescent bimodal carbon dots doped with dysprosium
(Dy-CDs). The prepared Dy-CDs have shown a good colloidal stability in a water solution and strong
blue–green fluorescence, with a maximum at 452 nm. In addition, the excellent transverse relaxivity of
the prepared Dy-CDs (r2 = 7.42 ± 0.07 mM−1
s
−1
) makes them also suitable for T2-weighted magnetic
resonance imaging (MRI). Thus, synthesized Dy-CDs could be potentially utilized for both MRI and
fluorescence imaging of living cells.
2018-05-18T00:00:00Z