Room temperature rectification in tapered-channel thermal diodes through nanoscale confinement-induced liquid–solid phase change

Abstract Background The AAZTA chelator and in particular its bifunctional derivative AAZTA5 was recently investigated to demonstrate unique capabilities to complex diagnostic and therapeutic trivalent radiometals under mild conditions. This study presents a comparison of 68Ga, 44Sc and 177Lu-labeled AAZTA5-PSMA-617 with DOTA-PSMA-617 analogues. We evaluated the radiolabeling characteristics, in vitro stability of the radiolabeled compounds and evaluated their binding affinity and internalization behavior on LNCaP tumor cells in direct comparison to the radiolabeled DOTA-conjugated PSMA-617 analogs. Results AAZTA5 was synthesized in a five-step synthesis and coupled to the PSMA-617 backbone on solid phase. Radiochemical evaluation of AAZTA5-PSMA-617 with 68Ga, 44Sc and 177Lu achieved quantitative radiolabeling of > 99% after less than 5 min at room temperature. Stabilities against human serum, PBS buffer and EDTA and DTPA solutions were analyzed. While there was a small degradation of the 68Ga complex over 2 h in human serum, PBS and EDTA/DTPA, the 44Sc and 177Lu complexes were stable at 2 h and remained stable over 8 h and 1 day. For all three compounds, i.e. [natGa]Ga-AAZTA5-PSMA-617, [natSc]Sc-AAZTA5-PSMA-617 and [natLu]Lu-AAZTA5-PSMA-617, in vitro studies on PSMA-positive LNCaP cells were performed in direct comparison to radiolabeled DOTA-PSMA-617 yielding the corresponding inhibition constants (Ki). Ki values were in the range of 8–31 nM values which correspond with those of [natGa]Ga-DOTA-PSMA-617, [natSc]Sc-DOTA-PSMA-617 and [natLu]Lu-DOTA-PSMA-617, i.e. 5–7 nM, respectively. Internalization studies demonstrated cellular membrane to internalization ratios for the radiolabeled 68Ga, 44Sc and 177Lu-AAZTA5-PSMA-617 tracers (13–20%IA/106 cells) in the same range as the ones of the three radiolabeled DOTA-PSMA-617 tracers (17–20%IA/106 cells) in the same assay. Conclusions The AAZTA5-PSMA-617 structure proved fast and quantitative radiolabeling with all three radiometal complexes at room temperature, excellent stability with 44Sc, very high stability with 177Lu and medium stability with 68Ga in human serum, PBS and EDTA/DTPA solutions. All three AAZTA5-PSMA-617 tracers showed binding affinities and internalization ratios in LNCaP cells comparable with that of radiolabeled DOTA-PSMA-617 analogues. Therefore, the exchange of the chelator DOTA with AAZTA5 within the PSMA-617 binding motif has no negative influence on in vitro LNCaP cell binding characteristics. In combination with the faster and milder radiolabeling features, AAZTA5-PSMA-617 thus demonstrates promising potential for in vivo application for theranostics of prostate cancer.

Download Full-text

Non-Destructive Detection of Pentachlorophenol Residues in Historical Wooden Objects

Polymers ◽

10.3390/polym13071052 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1052

Author(s):

Ida Kraševec ◽

Nataša Nemeček ◽

Maja Lozar Štamcar ◽

Irena Kralj Cigić ◽

Helena Prosen

Keyword(s):

Indoor Air ◽

Room Temperature ◽

Quantitative Methods ◽

Solid Phase ◽

Contact Mode ◽

Solvent Extraction Method ◽

Museum Objects ◽

Wooden Furniture ◽

Non Destructive ◽

Heritage Collections

Wood is a natural polymeric material that is an important constituent of many heritage collections. Because of its susceptibility to biodegradation, it is often chemically treated with substances that can be harmful to human health. One of the most widely used wood preservatives was pentachlorophenol (PCP), which is still present in museum objects today, although its use has been restricted for about forty years. The development of non-destructive methods for its determination, suitable for the analysis of valuable objects, is therefore of great importance. In this work, two non-destructive solid-phase microextraction (SPME) methods were developed and optimized, using either headspace or contact mode. They were compared with a destructive solvent extraction method and found to be suitable for quantification in the range of 7.5 to 75 mg PCP/kg wood at room temperature. The developed semi-quantitative methods were applied in the wooden furniture depot of National Museum of Slovenia. PCP was detected inside two furniture objects using headspace mode. The pesticide lindane was also detected in one object. The indoor air of the depot with furniture was also sampled with HS SPME, and traces of PCP were found. According to the results, SPME methods are suitable for the detection of PCP residues in museum objects and in the environment.

Download Full-text

The effect of short-term storage temperature on the key headspace volatile compounds observed in Canadian faba bean flour

Food Science and Technology International ◽

10.1177/1082013221998843 ◽

2021 ◽

pp. 108201322199884

Author(s):

Rami Akkad ◽

Ereddad Kharraz ◽

Jay Han ◽

James D House ◽

Jonathan M Curtis

Keyword(s):

Fatty Acids ◽

Volatile Compounds ◽

Room Temperature ◽

Unsaturated Fatty Acids ◽

Solid Phase ◽

Short Term ◽

Bean Flour ◽

Odour Activity Value ◽

Short Term Storage ◽

Term Storage

The odour emitted from the high-tannin fab bean flour ( Vicia faba var. minor), was characterized by headspace solid-phase microextraction/gas chromatography-mass spectrometry (HS-SPME/GC–MS). The relative odour activity value (ROAV) was used to monitor the changes in key volatile compounds in the flour during short-term storage at different temperature conditions. The key flavour compounds of freshly milled flour included hexanal, octanal, nonanal, decanal, 3-methylbutanal, phenyl acetaldehyde, (E)-2-nonenal, 1-hexanol, phenyl ethyl alcohol, 1-octen-3-ol, β-linalool, acetic acid, octanoic acid, and 3-methylbutyric acid; these are oxidative degradation products of unsaturated fatty acids and amino acids. Despite the low lipid content of faba beans, the abundances of aldehydes arising during room temperature storage greatly contributed to the flavour of the flour due to their very low odour thresholds. Two of the key volatiles responsible for beany flavour in flour (hexanal, nonanal) increased greatly after 2 weeks of storage at room temperature or under refrigerated conditions. These volatile oxidation products may arise as a result of enzymatic activity on unsaturated fatty acids, and was seen to be arrested by freezing the flour.

Download Full-text

Electrospun Polyethylene Glycol/Polyvinyl Alcohol Composite Nanofibrous Membranes as Shape-Stabilized Solid–Solid Phase Change Materials

Advanced Fiber Materials ◽

10.1007/s42765-020-00038-8 ◽

2020 ◽

Vol 2 (3) ◽

pp. 167-177 ◽

Cited By ~ 1

Author(s):

Junwen Huang ◽

Houyong Yu ◽

Somia Yassin Hussain Abdalkarim ◽

Jaromir Marek ◽

Jiri Militky ◽

...

Keyword(s):

Polyethylene Glycol ◽

Polyvinyl Alcohol ◽

Phase Change ◽

Phase Change Materials ◽

Solid Phase ◽

Nanofibrous Membranes

Download Full-text

Optimization of thermal conductivity in composites loaded with the solid-solid phase-change materials

Science and Engineering of Composite Materials ◽

10.1515/secm-2016-0301 ◽

2018 ◽

Vol 25 (6) ◽

pp. 1157-1165

Author(s):

Taoufik Mnasri ◽

Adel Abbessi ◽

Rached Ben Younes ◽

Atef Mazioud

Keyword(s):

Thermal Conductivity ◽

Phase Change ◽

Phase Change Materials ◽

Solid Phase ◽

Spherical Inclusions ◽

First Case ◽

The Matrix ◽

Composite Conductivity ◽

First Time

AbstractThis work focuses on identifying the thermal conductivity of composites loaded with phase-change materials (PCMs). Three configurations are studied: (1) the PCMs are divided into identical spherical inclusions arranged in one plane, (2) the PCMs are inserted into the matrix as a plate on the level of the same plane of arrangement, and (3) the PCMs are divided into identical spherical inclusions arranged periodically in the whole matrix. The percentage PCM/matrix is fixed for all cases. A comparison among the various situations is made for the first time, thus providing a new idea on how to insert PCMs into composite matrices. The results show that the composite conductivity is the most important consideration in the first case, precisely when the arrangement plane is parallel with the flux and diagonal to the entry face. In the present work, we are interested in exploring the solid-solid PCMs. The PCM polyurethane and a wood matrix are particularly studied.

Download Full-text

Ferroelectric Tunability Studies in Doped BaTiO3 and Ba1−xSrxTiO3

MRS Proceedings ◽

10.1557/proc-658-gg3.4 ◽

2000 ◽

Vol 658 ◽

Author(s):

Dong Li ◽

M. A. Subramanian

Keyword(s):

Curie Temperature ◽

Phase Change ◽

Tetragonal Phase ◽

Cryogenic Temperature ◽

Room Temperature ◽

Co Doping ◽

Structure Changes

ABSTRACTAcceptor and Donor codoped BaTiO3 and Ba1−xSrxTiO3 are prepared. For Ba1−xLaxTi1−xFexO3,BaTiO3 remains as tetragonal phase up to about 5mol% LaFeO3. For x ≥0.06, the structure changes to cubic at room temperature. The phase change shifts the Curie temperature to lower value and increases the tunability at room temperature. Doping of other acceptor (Al, Cr) and donor (Sm, Gd, Dy) ions has the same effect although with varying levels of tuning. BaTiO3: 4%LaFeO3 has the highest tunability among the studied systems, which is even higher than Ba0.6Sr0.4TiO3. Co-doping of (La, Fe) and (La, Al) in Ba1−xSrxTiO3 also lowers the Curie temperature and increases the tunability of high Ba content samples at cryogenic temperature.

Download Full-text