scholarly journals Chitosan-Capped Au Nanoparticles for Laser Photothermal Ablation Therapy: UV-Vis Characterization and Optothermal Performances

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Giancarlo Margheri ◽  
Silvana Trigari ◽  
Mariabeatrice Berti ◽  
Maurizio Muniz Miranda ◽  
Rita Traversi
Keyword(s):  
Near Infrared ◽  
Au Nanoparticles ◽  
Ablation Therapy ◽  
Synthesis Conditions ◽  
Photothermal Ablation ◽  
Nir Absorption ◽  
One Step ◽  
The One ◽  
Refined Version

We have reported on the synthesis and characterization of near-infrared- (NIR-) absorbing colloidal nanoparticles prepared by exploiting the one-step reaction of HAuCl4 and Na2S2O3, followed by their stabilization with chitosan. This reaction also produces a big amount of unwanted nanoparticles detuned with respect to the NIR spectral region. For this reason, it is usually assumed that the product has to be filtered and enriched to enhance its NIR absorption, and the possible exploitation of the simpler raw product has never been worthy to be considered. Aiming to investigate this missing aspect, we chose to avoid the purification steps and rather focused on the preparation of the unrefined colloid, identifying the synthesis conditions that maximize its NIR absorbance and, subsequently, testing it as an optothermal transducer by measuring its molar heating rate (MHR). As expected, we found that the performances of the raw colloid are indeed lower than those of its refined version, but only to a limited extent. Moreover, MHR is unexpectedly higher than that deducible for other classical NIR-absorbing nanoparticles, like Au nanorods or Au nanostars. Thus, the product of the simpler preparation protocol appears as a competitive trade-off solution between easy manufacturing and optothermal performances.

scholarly journals Characterization of highly active 2-keto-3-deoxy-L-arabinonate and 2-keto-3-deoxy-D-xylonate dehydratases in terms of the biotransformation of hemicellulose sugars to chemicals

2020 ◽  
Vol 104 (16) ◽  
pp. 7023-7035
Author(s):  
Samuel Sutiono ◽  
Bettina Siebers ◽  
Volker Sieber
Keyword(s):  
Racemic Mixture ◽  
Highly Active ◽  
Key Points ◽  
Deoxy Sugar ◽  
Weimberg Pathway ◽  
One Step ◽  
The One ◽  
Increased Activity ◽  
Enzyme Class

Abstract2-keto-3-L-arabinonate dehydratase (L-KdpD) and 2-keto-3-D-xylonate dehydratase (D-KdpD) are the third enzymes in the Weimberg pathway catalyzing the dehydration of respective 2-keto-3-deoxy sugar acids (KDP) to α-ketoglutaric semialdehyde (KGSA). The Weimberg pathway has been explored recently with respect to the synthesis of chemicals from L-arabinose and D-xylose. However, only limited work has been done toward characterizing these two enzymes. In this work, several new L-KdpDs and D-KdpDs were cloned and heterologously expressed in Escherichia coli. Following kinetic characterizations and kinetic stability studies, the L-KdpD from Cupriavidus necator (CnL-KdpD) and D-KdpD from Pseudomonas putida (PpD-KdpD) appeared to be the most promising variants from each enzyme class. Magnesium had no effect on CnL-KdpD, whereas increased activity and stability were observed for PpD-KdpD in the presence of Mg2+. Furthermore, CnL-KdpD was not inhibited in the presence of L-arabinose and L-arabinonate, whereas PpD-KdpD was inhibited with D-xylonate (I50 of 75 mM), but not with D-xylose. Both enzymes were shown to be highly active in the one-step conversions of L-KDP and D-KDP. CnL-KdpD converted > 95% of 500 mM L-KDP to KGSA in the first 2 h while PpD-KdpD converted > 90% of 500 mM D-KDP after 4 h. Both enzymes in combination were able to convert 83% of a racemic mixture of D,L-KDP (500 mM) after 4 h, with both enzymes being specific toward the respective stereoisomer. Key points• L-KdpDs and D-KdpDs are specific toward L- and D-KDP, respectively.• Mg2+affected activity and stabilities of D-KdpDs, but not of L-KdpDs.• CnL-KdpD and PpD-KdpD converted 0.5 M of each KDP isomer reaching 95 and 90% yield.• Both enzymes in combination converted 0.5 M racemic D,L-KDP reaching 83% yield.

scholarly journals Influence of the calibration on experimental UV index at a midlatitude site, Granada (Spain)

2010 ◽  
Vol 3 (6) ◽  
pp. 5645-5670
Author(s):  
M. Antón ◽  
J. E. Gil ◽  
A. Cazorla ◽  
J. M. Vilaplana ◽  
F. J. Olmo ◽  
...  
Keyword(s):  
Calibration Method ◽  
Conversion Factors ◽  
Uv Index ◽  
Calibration Methods ◽  
One Step ◽  
The Difference ◽  
Mean Differences ◽  
Experimental Values ◽  
The One

Abstract. The ultraviolet (UV) index is the variable most commonly used to inform the general public about the levels and potential harmful effects of UV radiation incident at Earth's surface. This variable is derived from the output signal of the UV radiometers applying conversion factors obtained by calibration methods. This paper focused on the influence of the use of two of these methods (called one-step and two-steps methods) on the resulting experimental UV Index (UVI) as measured by a YES UVB-1 radiometer located in a midlatitude station, Granada (Spain) for the period 2006–2009. In addition, it is also analyzed the difference with the UVI values obtained when the calibration factors provided by the manufacturer are used. For this goal, the detailed characterization of the UVB-1 radiometer obtained in the first Spanish calibration campaign of broadband UV radiometers at the "El Arenosillo" INTA station in 2007 is used. In addition, modeled UVI data derived from the LibRadtran/UVSPEC radiative transfer code are compared with the experimental values recorded at Granada for cloud-free conditions. The absolute mean differences between the measured and modeled UVI data at Granada are around 5% using the one-step and two-steps calibration methods. This result indicates the excellent performance of these two techniques for obtaining UVI data from the UVB-1 radiometer. In contrast, the application of the calibration factor supplied by the manufacturer produces a high overestimation (~14%) of the UVI values. This fact generates unreliable alarming high UVI data in summer when the manufacturer's factor is used. Thus, days with an extreme erythemal risk (UVI higher than 10) increase up to 46% of all cases measured between May and September at Granada when the manufacturer's factor is applied. This percentage is reduced to a more reliable value of 3% when the conversion factors obtained with the two-steps calibration method are used. All these results report about the need of a sound calibration of the broadband UV instruments in order to obtain reliable measurements.

Gold nanorod-seeded synthesis of Au@Ag/Au nanospheres with broad and intense near-infrared absorption for photothermal cancer therapy

2014 ◽  
Vol 2 (23) ◽  
pp. 3667-3673 ◽  
Author(s):  
Xiaosheng Ye ◽  
Hui Shi ◽  
Xiaoxiao He ◽  
Kemin Wang ◽  
Duo Li ◽  
...  
Keyword(s):  
Cancer Therapy ◽  
Infrared Absorption ◽  
Near Infrared ◽  
Au Nanoparticles ◽  
Gold Nanorod ◽  
Synthesis Strategy ◽  
Nir Absorption

A shape-controllable and spectrum-adjustable synthesis strategy is proposed to develop Au@Ag/Au nanoparticles with intense NIR-absorption, efficacious thermotherapy and low dark-cytotoxicity.

scholarly journals A Straightforward Substitution Strategy to Tune BODIPY Dyes Spanning the Near-Infrared Region via Suzuki–Miyaura Cross-Coupling

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1297 ◽  
Author(s):  
Guanglei Li ◽  
Yu Otsuka ◽  
Takuya Matsumiya ◽  
Toshiyuki Suzuki ◽  
Jianye Li ◽  
...  
Keyword(s):  
Near Infrared ◽  
Cross Coupling ◽  
Cumulus Cells ◽  
Infrared Region ◽  
Quantum Yields ◽  
Nir Dyes ◽  
Wide Range ◽  
One Step ◽  
The One ◽  
First Time

In this study, a series of new red and near-infrared (NIR) dyes derived from 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) were developed by introducing thiophene and its derivatives to the 3- and 5- positions of the dichloroBODIPY core. For the first time, cyclictriol boronates and N-methyliminodiacetic acid (MIDA) boronate were used as organoboron species to couple with 3,5-dichloroBODIPY via the one-step Suzuki–Miyaura cross-coupling. Six kinds of thieno-expended BODIPY dyes were synthesized in acceptable yields ranging from 31% to 79%. All six dyes showed different absorption and emission wavelengths spanning a wide range (c.a. 600–850 nm) in the red and NIR regions with relatively high quantum yields (19–85%). Cellular imaging of 8-(2,6-dimethylphenyl)-re3,5-di(2-thienyl)-BODIPY (dye 1) was conducted using bovine cumulus cells, and the fluorescence microscopy images indicated that the chromophore efficiently accumulated and was exclusively localized in the cytoplasm, suggesting it could be utilized as a subcellular probe. All six dyes were characterized using 1H-NMR and mass spectrometry.

Porous Pd nanoparticles with high photothermal conversion efficiency for efficient ablation of cancer cells

Nanoscale ◽  
2014 ◽  
Vol 6 (8) ◽  
pp. 4345-4351 ◽  
Author(s):  
Jia-Wen Xiao ◽  
Shi-Xuan Fan ◽  
Feng Wang ◽  
Ling-Dong Sun ◽  
Xiao-Yu Zheng ◽  
...  
Keyword(s):  
Porous Structure ◽  
Cancer Cells ◽  
Hela Cells ◽  
Near Infrared ◽  
Pd Nanoparticles ◽  
Photothermal Effect ◽  
High Efficacy ◽  
Photothermal Ablation ◽  
Nir Absorption ◽  
Very High

Pd NPs with a porous structure exhibit enhanced near infrared (NIR) absorption and enhanced photothermal effect compared to Pd nanocubes with a similar size, and show very high efficacy in photothermal ablation of HeLa cells.

scholarly journals CHARACTERIZATION OF T4 MUTANTS THAT PARTIALLY SUPPRESS THE INABILITY OF T4rII TO GROW IN LAMBDA LYSOGENS

Genetics ◽  
1976 ◽  
Vol 83 (3) ◽  
pp. 477-487
Author(s):  
Theodore Homyk ◽  
Angel Rodriguez ◽  
Jon Weil
Keyword(s):  
Burst Size ◽  
Personal Communication ◽  
Growth Cycle ◽  
Plaque Morphology ◽  
One Step ◽  
Step Growth ◽  
The One ◽  
Phage Growth ◽  
L1 And L2

ABSTRACT In the course of isolating viable T4 deletions that affect plaque morphology (Homyk and Weil 1974), two closely linked point mutants, sip1 and sip2, were obtained. They map between genes t and 52, cause a reduction in plaque size and burst size, and partially suppress the lethality of rII mutants for growth in lambda lysogens. These characteristics demonstrate that sip1 and sip2 are similar to mutants previously reported by Freedman and Brenner (1972). In addition, D. Hall (personal communication) has shown that sip1 and sip2 are similar to the mutant farP85, which affects the regulation of a number of early genes (Chace and Hall 1975).—Sip suppression of rII mutants can be demonstrated in one-step growth experiments, even when both rII genes are completely deleted. This indicates that sip mutants do not simply reduce the level of rII gene products required for growth in a lambda lysogen. Instead, they alter the growth cycle so as to partially circumvent the need for any rII products.—Mutations at two other sites, designated L1 and L2, reverse the poor phage growth caused by sip and, in the one case tested, reverse the rII-suppressing ability of sip.

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