Interaction between Temozolomide and Water: Preferred Binding Sites

Computational methods are used to predict the most favorable site of temozolomide towards attack by a water molecule. The energetics of the various complexes are presented as well as their geometries, including perturbations of each subunit caused by the presence of the other. Molecular electrostatic potential and Natural Bond Orbital (NBO) data are used to understand the interactions which conclude the terminal amide group is the preferred attack site where water can act as simultaneous proton donor and acceptor. Other potential proton acceptor N atoms within the aromatic ring structure represent weaker binding sites. Some of the less strongly bound structures include a CH⋯O H-bond

La creatinina

La "Oficina de los suelos" del Departamento de Agricultura de Washington, dirigido por M. Whitney y secundado por un gran número de especialistas, se ha entregado desde hace algunos años a importantes investigaciones científicas, concernientes a la agrología y la química de los suelos. De esas investigaciones, las más interesantes son sin duda, las relativas al estudio y rol de lar materias orgánicas constituyentes, y sus relajones con la fertilidad y esterilidad de los suelos. (Párrafo extraído del texto a modo de resumen)Facultad de Ciencias Agrarias y Forestale

The Magnitude and Mechanism of Charge Enhancement of CH∙∙O H-bonds

Quantum calculations find that neutral methylamines and thioethers form complexes, with N-methylacetamide (NMA) as proton acceptor, with binding energies of 2–5 kcal/mol. This interaction is magnified by a factor of 4–9, bringing the binding energy up to as much as 20 kcal/mol, when a CH3+ group is added to the proton donor. Complexes prefer trifurcated arrangements, wherein three separate methyl groups donate a proton to the O acceptor. Binding energies lessen when the systems are immersed in solvents of increasing polarity, but the ionic complexes retain their favored status even in water. The binding energy is reduced when the methyl groups are replaced by longer alkyl chains. The proton acceptor prefers to associate with those CH groups that are as close as possible to the S/N center of the formal positive charge. A single linear CH··O hydrogen bond (H-bond) is less favorable than is trifurcation with three separate methyl groups. A trifurcated arrangement with three H atoms of the same methyl group is even less favorable. Various means of analysis, including NBO, SAPT, NMR, and electron density shifts, all identify the +CH··O interaction as a true H-bond

Ovarian Control of Nectar Collection in the Honey Bee (Apis mellifera)

Honey bees are a model system for the study of division of labor. Worker bees demonstrate a foraging division of labor (DOL) by biasing collection towards carbohydrates (nectar) or protein (pollen). The Reproductive ground-plan hypothesis of Amdam et al. proposes that foraging DOL is regulated by the networks that controlled foraging behavior during the reproductive life cycle of honey bee ancestors. Here we test a proposed mechanism through which the ovary of the facultatively sterile worker impacts foraging bias. The proposed mechanism suggests that the ovary has a regulatory effect on sucrose sensitivity, and sucrose sensitivity impacts nectar loading. We tested this mechanism by measuring worker ovary size (ovariole number), sucrose sensitivity, and sucrose solution load size collected from a rate-controlled artificial feeder. We found a significant interaction between ovariole number and sucrose sensitivity on sucrose solution load size when using low concentration nectar. This supports our proposed mechanism. As nectar and pollen loading are not independent, a mechanism impacting nectar load size would also impact pollen load size

Transcriptional Silencing of Multiple Genes in Trophozoites of Entamoeba histolytica

In a previous work we described the transcriptional silencing of the amoebapore A (AP-A) gene (Ehap-a) of Entamoeba histolytica strain HM-1:IMSS. The silencing occurred following transfection with a plasmid containing a 5′ upstream region (473 bp) of Ehap-a that included a truncated segment (140 bp) of a short interspersed nuclear element (SINE1). Silencing remained in effect even after removal of the plasmid (clone G3). Neither short interfering RNA nor methylated DNA were detected, but the chromatin domain of Ehap-a in the gene-silenced trophozoites was modified. Two other similar genes (Ehap-b and one encoding a Saposin-like protein, SAPLIP 1) also became silenced. In the present work we demonstrate the silencing of a second gene of choice, one that encodes the light subunit of the Gal/GalNAc inhibitable lectin (Ehlgl1) and the other, the cysteine proteinase 5 (EhCP-5). This silencing occurred in G3 trophozoites transfected with a plasmid in which the 473 bp 5′ upstream Ehap-a fragment was directly ligated to the second gene. Transcriptional silencing occurred in both the transgene and the chromosomal gene. SINE1 sequences were essential, as was a direct connection between the Ehap-a upstream region and the beginning of the open reading frame of the second gene. Gene silencing did not occur in strain HM-1:IMSS with any of these plasmid constructs. The trophozoites with two silenced genes were virulence-attenuated as were those of clone G3. In addition, trophozoites not expressing Lgl1 and AP-A proteins had a significantly reduced ability to cap the Gal/GalNAc-lectin to the uroid region when incubated with antibodies against the heavy (170 kDa) subunit of the lectin. Lysates of trophozoites lacking cysteine proteinase 5 and AP-A proteins had 30% less cysteine proteinase activity than those of HM-1:IMSS strain or the G3 clone. Silencing of other genes in G3 amoebae could provide a model to study their various functions. In addition, double gene-silenced, virulence-attenuated trophozoites may be an important tool in vaccine development

Visual Associative Learning in Restrained Honey Bees with Intact Antennae

A restrained honey bee can be trained to extend its proboscis in response to the pairing of an odor with a sucrose reward, a form of olfactory associative learning referred to as the proboscis extension response (PER). Although the ability of flying honey bees to respond to visual cues is well-established, associative visual learning in restrained honey bees has been challenging to demonstrate. Those few groups that have documented vision-based PER have reported that removing the antennae prior to training is a prerequisite for learning. Here we report, for a simple visual learning task, the first successful performance by restrained honey bees with intact antennae. Honey bee foragers were trained on a differential visual association task by pairing the presentation of a blue light with a sucrose reward and leaving the presentation of a green light unrewarded. A negative correlation was found between age of foragers and their performance in the visual PER task. Using the adaptations to the traditional PER task outlined here, future studies can exploit pharmacological and physiological techniques to explore the neural circuit basis of visual learning in the honey bee

NEW PARADIGM FOR REAL-TIME MEASUREMENT AND MAPPING IN a-Si:H/uc-Si:H TANDEM DEVICES

Thin-film Si solar module production requires a fast wide area tool for layer characteristic measurement and control. Non-uniformity in layer deposition is expected to induce loss in module power. Simulations of amorphous Si modules using a two-dimensional model have been used to examine the efficiency loss associated with non uniformity of large scale monolithically integrated thin film modules. The results indicate that non uniform deposition significantly lowers the module efficiency, in a magnitude that varies depending on the shape and orientation of the deposition signature relative to the scribe lines. In order to control the deposition process of individual layers in layer stacks in thin-film PV modules a wide area metrology tools has been developed and tested. Example of layers maps obtained during production of Si layers module are shown. Comparisons of layer characteristics obtained using this tool and values obtained by conventional methods are given to validate the tool performances

Ionometric sensor for ammonium ions control in sewage waters

Цель работы заключалась в создании измерительного датчика для автоматизированного потенциометрического контроля содержания ионов аммония в проточных условиях. В результате исследования разработана конструкция электрода сравнения измерительного датчика, представляющая собой ионоселективный электрод, опущенный в буферную систему с катионитом. В работе представлен потенциометрический анализ модельных растворов ионов аммония, изучено мешающее влияние температуры, а также определена стабильность предложенной системы. The purpose of the work was to create a sensor for automated potentiometric monitoring of the ammonium ions content in flowing conditions. As a result of the study, the reference electrode design was developed. This is an ion-selective electrode lowered into a buffer system with cation exchanger. The work presents a potentiometric analysis of ammonium ions model solutions, the study of temperature interfering effect, and system's stability determination

Efficacy and safety of palliative treatment in patients with autoimmune liver disease-associated hepatocellular carcinoma

Introduction and Objectives: Autoimmune liver diseases (AILD) are rare causes hepatocellular carcinoma (HCC), and data on the efficacy and tolerability of anti-tumor therapies are scarce. This pan-European study aimed to assess outcomes in AILD-HCC patients treated with tyrosine kinase inhibitors (TKIs) or transarterial chemoembolization (TACE) compared with patients with more common HCC etiologies, including viral, alcoholic or non-alcoholic fatty liver disease. / Materials and Methods: 107 patients with HCC-AILD (AIH:55; PBC:52) treated at 13 European centres between 1996 and 2020 were included. 65 received TACE and 28 received TKI therapy. 43 (66 %) were female (median age 73 years) with HCC tumor stage BCLC A (34 %), B (46 %), C (9 %) or D (11 %). For each treatment type, propensity score matching was used to match AILD to non-AILD-HCC on a 1:1 basis, yielding in a final cohort of 130 TACE and 56 TKI patients for comparative analyses of median overall survival (mOS) and treatment tolerability. / Results: HCC-AILD patients showed comparable mOS to controls for both TACE (19.5 vs. 22.1 months, p = 0.9) and TKI (15.4 vs. 15.1 months, p = 0.5). Adverse events were less frequent in AILD-HCC patients than controls (33 % % vs. 62 %, p = 0.003). For TKIs, there were no significant differences in adverse events (73% vs. 86%, p = 0.2) or interruption rates (44% vs. 36 %, p = 0.7). / Conclusions: In summary, this study demonstrates comparable mOS for AILD-HCC patients undergoing local and systemic treatments, with better tolerability than HCC of other causes. TKIs remain important therapeutic options for AILD-HCC patients, particularly given their exclusion from recent immunotherapy trials