Human Physiological Temperature Research Articles

Fibrinolytic enzyme from Arthrospira platensis: Kinetic and thermodynamic investigation

Fibrinolytic enzymes from microorganisms have been investigated by their potential application as thrombolytic agents. Previous studies show that the fibrinolytic enzyme from Arthrospira platensis (FEAP) is stable at human physiological temperature (<50 °C) and pH (6.0–10.0). Understanding of the kinetic/thermodynamic characteristics is important to make the advances for industrial applications feasible. Therefore, a kinetic/thermodynamic analysis of FEAP was performed on the fibrin hydrolysis and enzyme thermoinactivation. Results showed two Michaelis-Menten-type profiles with two plateaus, revealing high affinity for the substrate with low Michaelis constant values (0.02 and 6.37 µg∙mL−1). The activation energy of the hydrolysis catalyzed by FEAP and the standard enthalpy variations of reversible enzyme unfolding were 49.65 and 107.01 kJ∙mol−1, respectively. When the temperature increased from 40 to 70 °C, the deactivation rate constant increased from 0.0050 to 0.0134 min−1, while the half-life decreased from 138.62 to 51.72 min. These results allowed to estimate the activation energy (E*d = 27.50 kJ∙mol−1), enthalpy (24.64 ≤ ΔH*d ≤ 24.89 kJ∙mol−1), entropy (−209.86 ≤ ΔS*d ≤ −210.10 J∙mol−1∙K−1), and Gibbs free energy (90.61 ≤ ΔG*d ≤ 96.74 kJ∙mol−1) of thermal denaturation. The data suggest that FEAP is a promising and thermostable biocatalyst that could be exploited for industrial applications.

Bipolar radiofrequency ablation lesion areas and confluence: An exvivo study and technical report.

Radiofrequency ablation (RFA) has been used for nearly 100 years, treating an array of medical conditions including chronic pain. Radiofrequency (RF) energy depolarizes and repolarizes tissues adjacent to a probe producing heat and causing direct thermal injury. When positioned adjacent to neural structures, it leads to neural tissue injury and cell death interrupting pain signaling with the ultimate goal of providing lasting pain relief. Today, RFA is commonly used to treat cervical, thoracic, and lumbar zygapophyseal joints, sacroiliac joint, and more recently large peripheral joint-mediated pain. There are several applications of RFA systems, including bipolar, conventional thermal, cooled, protruding, and pulsed. As yet, no study has determined the best technical practice for bipolar RFA. This exvivo study examines RFA lesion midpoint (LMP) area and lesion confluence comparing three different commonly used gauge (g) probes (18-g, 20-g, and 22-g) with 10-mm active tips at various interprobe distances (IPD) to guide best technical practices for its clinical application. Bipolar RFA lesions were generated in preservative-free chicken breast specimens using three different gauge probes (18-g, 20-g, and 22-g) with 10-mm active tips at various IPD (6, 8, 10, 12, 14, 16, and 18 mm). RF was applied for 105 s (15-s ramp time) at 80°C for each lesion at both room and human physiological temperature. The specimen tissues were dissected through the lesion to obtain a length, width, and depth, which were used to calculate the LMP area (mm2 ). The LMP areas of each thermal ablation were investigated using visualization and descriptive analysis. The Kruskal-Wallis test was performed to compare LMP areas between the two temperature groups and the three different gauge probe subgroups at the various IPDs. Of the 36 RF lesions (14: 18-g, 12: 20-g, and 10: 22-g) performed, 24 demonstrated lesion confluence. The average time to reach 80°C was 16-17 s; therefore, the average time of RF-energy delivery (at goal temperature) was 88-89 s despite varying needle size or IPD. Comparing the 25 and 37°C groups, 18-g probes produced mean LMP areas of 73.7 and 79.2 mm2 , respectively; 20-g probes produced mean LMP areas of 66 and 66.8 mm2 , respectively; 22-g probes produced mean LMP areas of 56.6 and 59.7 mm2 , respectively. There was no statistical evidence to state a difference regarding LMP area between temperature groups; however, the 18-g probes produced consistently larger LMP areas in the 37°C compared to 25°C specimen groups at each IPD. Lesion confluence was lost for 18-g, 20-g, and 22-g probes at IPD of 14, 12, and 10 mm, respectively, in both 25 and 37°C groups. LMP area was similar between 6 and 8 mm IPD in all of the three-gauge groups; however, there was a significant drop in LMP area from 8 mm IPD to 10 mm and greater. The 18-g, 20-g, and 22-g probes all demonstrated a sharp decline in LMP area when increasing the IPD from 8 to 10 mm. This exvivo technical study evaluated bipolar RFA LMP areas and lesion confluence, and determined the recommended IPD of 18-g, 20-g, and 22-g probes to be less than 12, 10, and 8 mm, respectively, for best clinical practice. Placing bipolar probes at an IPD greater than 14, 12, and 10 mm, respectively, risks the loss of lesion confluence and failure to produce a clinically significant treatment response due to lack of nerve capture. In clinical practice, the use of injectate may produce larger lesions than demonstrated in this study. Additionally, invivo factors may impact ablation zone size and ablation patterns. As there are a paucity of studies comparing various RFA applications and conventional RFA needles are least expensive, it is possible that bipolar conventional RFA is more cost-effective than other techniques.

Thermo-sensitive composite microspheres incorporating cellulose nanocrystals for regulated drug release kinetics

Thermo-sensitive composite microspheres (TPCP) were developed to achieve the on-demand release of drugs. The TPCP microspheres were synthesized using Oil-in-Water (O/W) emulsion evaporation technique and then impregnated with thermo-sensitive polyethylene glycol (PEG). The addition of cellulose nanocrystals (CNCs) significantly enhance thermal stability, crystallization ability, and surface hydrophilicity of TPCP microspheres due to heterogeneous nucleation effect and hydrogen bonding interaction, resulting in stable microsphere structure. The thermal degradation temperature (Tmax) increased by 13.8 °C, and the crystallinity improved by 20.9 % for 10 % TPCP. The thermo-sensitive composite microspheres showed the regulated cumulative release according to in vitro human physiological temperature changes. Besides, four release kinetics and possible release mechanism of TPCP microspheres were provided. Such thermo-responsive composite microspheres with control microsphere sizes and high encapsulation rate may have the potential to the development of on-demand and advanced controlled-release delivery systems.

A Bombyx mori Infection Model for Screening Antibiotics against Staphylococcus epidermidis.

Simple SummaryThe use and misuse of antibiotics in the past decades have contributed to the wide spread of antibiotic resistance, which currently represents a major issue and threat to human health. Consequently, the discovery of new anti-infective molecules is of primary importance. In vivo studies are crucial for testing the efficacy of novel antibiotics. Invertebrate models look promising to reduce the large-scale use of mammalians, which is mainly limited by high costs and ethical concerns. In this scenario, the silkworm proved to be an interesting alternative among insects. Here, we developed a silkworm infection model by challenging the larvae with Staphylococcus epidermidis, one common cause of infections in hospitals, and assessing the curative effects of three life-saving glycopeptide antibiotics that are used to treat infections caused by multidrug-resistant Gram-positive pathogens.The increasing number of microorganisms that are resistant to antibiotics is prompting the development of new antimicrobial compounds and strategies to fight bacterial infections. The use of insects to screen and test new drugs is increasingly considered a promising tool to accelerate the discovery phase and limit the use of mammalians. In this study, we used for the first time the silkworm, Bombyx mori, as an in vivo infection model to test the efficacy of three glycopeptide antibiotics (GPAs), against the nosocomial pathogen Staphylococcus epidermidis. To reproduce the human physiological temperature, the bacterial infection was performed at 37 °C and it was monitored over time by evaluating the survival rate of the larvae, as well the response of immunological markers (i.e., activity of hemocytes, activation of the prophenoloxidase system, and lysozyme activity). All the three GPAs tested (vancomycin, teicoplanin, and dalbavancin) were effective in curing infected larvae, significantly reducing their mortality and blocking the activation of the immune system. These results corroborate the use of this silkworm infection model for the in vivo studies of antimicrobial molecules active against staphylococci.

Highly Sensitive Temperature-Pressure Bimodal Aerogel with Stimulus Discriminability for Human Physiological Monitoring.

Multimodal sensor with high sensitivity, accurate sensing resolution, and stimuli discriminability is very desirable for human physiological state monitoring. A dual-sensing aerogel is fabricated with independent pyro-piezoresistive behavior by leveraging MXene and semicrystalline polymer to assemble shrinkable nanochannel structures inside multilevel cellular walls of aerogel for discriminable temperature and pressure sensing. The shrinkable nanochannels, controlled by the melt flow-triggered volume change of semicrystalline polymer, act as thermoresponsive conductive channels to endow the pyroresistive aerogel with negative temperature coefficient of resistance of -10.0% °C-1 and high accuracy within 0.2 °C in human physiological temperature range of 30-40 °C. The flexible cellular walls, working as pressure-responsive conductive channels, enable the piezoresistive aerogel to exhibit a pressure sensitivity up to 777 kPa-1 with a detectable pressure limit of 0.05 Pa. The pyro-piezoresistive aerogel can detect the temperature-dependent characteristics of pulse pressure waveforms from artery vessels under different human body temperature states.

A controlled recognizing and releasing glycoprotein based on temperature-responsive phenylboronic microgels for colorimetric analysis of complex samples.

It is challenging to capture glycoprotein from complicated samples with both high specificity and high recovery. Herein, we synthesized temperature-responsive poly (N-isopropylacrylamide-4-vinylbenzeneboronic acid) (PNIPAM-VPBA) microgels having enhanced affinity capability towards glycoprotein, resulting signal amplification in colorimetric analysis subsequently. Through temperature control, the target glycoprotein can be captured and released by the reported microgels unbiasedly. The microgels fabricated were characterized in terms of particle size, phase transition temperature, and toxicity. It was revealed that obvious changes in the particle diameter ranged from 600 to 323nm between 25°C and 55°C, the volume transition temperature was close to human physiological temperature, and low toxicity towards HeLa cells after 24h incubation. Using glucose oxidase as a model target, the microgels were applied as adsorbent materials for preconcentration of glucose oxidase, resulting 22-fold signal enhancement and a limit of detection (LOD) as low as 16.7 U/L. In beer sample analysis, satisfied recoveries of 78.7%-101.6% with the relative standard deviations (RSDs) less than 7.2% was observed. Subsequently, the microgels were combined with enzyme-linked immunosorbent assay (ELISA) for alpha fetoprotein (AFP) determination, by immobilizing horseradish peroxidase (HRP) and anti-AFP antibodies on the surface of microgels. A meaningful low concentration range of 2.5×10-2 to 1.0μg/L was obtained for AFP detection using the microgels based colorimetric method with a LOD of 8.4ng/L. In human serum sample analysis, good accuracy was achieved from method comparing with commercial ELISA kit, satisfied recoveries of 86.1%-96.4% with the RSDs less than 6.0% was observed. The proposed PNIPAM-VPBA microgels have great potential applications in the fields of food and clinical analysis.

Biophysical study on the phase transition behaviour of biocompatible thermoresponsive polymer influenced by tryptophan-based amino acid ionic liquids

Biocompatible thermoresponsive polymers are known to have numerous biomedical applications as they are capable of exhibiting a change in conformational states on changing the solution temperature. Poly(N-vinyl caprolactam) (PVCL) is one such polymer assessed frequently on conformational changes with biomolecules due to its amphiphilic nature. The goal of this work is to explore the impact of two tryptophan-based amino acid ionic liquids (AAILs), such as cholinium tryptophan ionic liquid ([CHO][Trp]IL) and tetraethylammonium tryptophan ionic liquid ([TEA][Trp]IL) on phase transition behaviour of aqueous PVCL solution. Biophysical techniques like steady-state fluorescence spectroscopy, thermal fluorescence spectroscopy, Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS) and differential scanning calorimetry (DSC) are used to investigate the phase transition behaviour of aqueous PVCL-AAILs solution. The lower critical solution temperature (LCST) of PVCL was elevated by 4 and 2 °C on increase in the concentration from 1 to 5 mM of [CHO][Trp]IL and [TEA][Trp]IL, respectively. On comparing both AAILs, [CHO][Trp]IL has shown higher LCST (near to human physiological temperature) with aqueous PVCL solution than [TEA][Trp]IL due to its additional hydrogen bonding ability and its higher hydrophilicity compared to [TEA][Trp]IL. The structural functionalities of the cholinium cation like hydroxyl group and methyl substituents make it more advantageous than tetraethylammonium cation. This is the first time study on the phase transition behaviour of biocompatible thermoresponsive polymer PVCL influenced by tryptophan-based AAILs. These findings could be exploited for the development of biocompatible polymer to use in drug delivery and other biomedical applications.

Humidified and Heated Cascade Impactor for Aerosol Sizing.

Aerosol sizing is generally measured at ambient air but human airways have different temperature (37°C) and relative humidity (100%) which can affect particle size in airways and consequently deposition prediction. This work aimed to develop and evaluate a new method using cascade impactor to measure particle size at human physiological temperature and humidity (HPTH) taking into account ambient air conditions. A heated and humidified trachea was built and a cascade impactor was heated to 37°C and humidified inside. Four medical aerosols [jet nebulizer, mesh nebulizer, Presurized Metered Dose Inhaler (pMDI), and Dry Powder Inhaler (DPI)] under ambient conditions and at HPTH were tested. MMAD was lower at HPTH for the two nebulizers; it was similar at ambient conditions and HPTH for pMDI, and the mass of particles smaller than 5 μm decreased for DPI at HPTH (51.9 vs. 82.8 μg/puff). In conclusion, we developed a new method to measure particle size at HPTH affecting deposition prediction with relevance. In vivo studies are required to evaluate the interest of this new model to improve the precision of deposition prediction.

Self-contracting oxidized starch/gelatin hydrogel for noninvasive wound closure and wound healing

Major challenges in traditional wound closure methods (e.g. using sutures and skin staplers) remain inadequately unaddressed; these invasive treatments induce extra puncture wounds, anesthetic side effects, and severe scarring. Herein, an oxidized starch/gelatin-based shape memory hydrogel (OSG) was fabricated as a self-contracting wound dressing to facilitate noninvasive wound closure. The self-contracting properties were attributed by introducing crosslink net-points in the hydrogel polymer structure through Schiff base reaction between oxidized starch (OS) and gelatin. We systematically investigated the self-contracting properties to determine the feasibility of the hydrogel to treat wounds and promote wound closure noninvasively. Following elongation, OSGs could be entirely fixed in a temporary shape at 4 °C, and then contracted under infrared irradiation (IR) for shape memory activation near human physiological temperature (38 °C), providing sufficient recovery force (4 kPa) for successful noninvasive wound closure. Additionally, H&E staining revealed that thicker epidermis and dermis layers were achieved upon OSG treatment, confirming that the OSG facilitated tissue reconstruction in an in vivo rabbit model. Moreover, the OSG-treated wounds displayed smoother skin and no visible scarring compared to sutured wounds. Such excellent performance suggests that OSG hydrogel exhibits high potential as an alternative to medical sutures to facilitate noninvasive would closure.

Poly(N-Isopropylacrylamide) Microgel Synthesised by Emulsion Polymerization

Smart polymers have been one of the most popularly studied materials owing to their capability to alter physio-chemical behaviour upon exposure to specific external stimuli. The biocompatible thermally responsive poly (N-isopropylacrylamide), PNIPAm shows reversible transition between hydrophilic-hydrophobic characteristics at the vicinity of human physiological temperature has great potential to propel the development of smart tissue engineering scaffold and drug delivery. However, the limited availability and its high cost have dampened the extent of research on this polymer. To address these challenges, the current work demonstrates an economical lab-scale polymerization of crosslinked PNIPAm and the optimised parameters to produce mono-dispersed polymer hydrogel particles were investigated. Characterisation of the synthesized PNIPAm polymer revealed particle size polydispersity index of 0.215, indicative of distribution within the mono-dispersed range, with average hydrodynamic diameter of 346.3 nm. Zeta-potential of the synthesized PNIPAm was found to be -20.6 mV, suggesting an incipient instability in terms of colloidal coagulation. Viscosity of the synthesized PNIPAm (4 wt% concentration in methanol) was 28.6 cP. Thermal gravimetric analysis (TGA) indicated the thermal degradation of main chain PNIPAm fell in the range of 340 to 480°C.

Lipid-lipid interactions of Escherichia coli mimetic inner membrane at human physiological temperature.

The current strategies to eradicate bacteria require that the antimicrobial agent either penetrate or disrupt the bacterial membrane. In Escherichia coli (E.coli) as a model of Gram-negative strains, the antimicrobials have to cross two barriers - the outer and the inner membrane being the latter composed by ~ 77% phosphatidylethanolamine (PE), ~ 13% phosphatidylglycerol (PG) and ~ 10% cardiolipin (CL) lipids. Each one of these lipid families shares the same headgroup, but contains acyl chains with varying length and degree of unsaturation. Bacteria adapt their membrane lipid composition and metabolism in response to environmental signals, such as the temperature, resulting in different interactions with exogenous molecules, e.g. antibacterial agents. Herein, bacterial model membranes are prepared to evaluate the lipid-lipid interactions in Langmuir monolayers of binary mixtures at several molar ratios of PE and PG or CL at human physiological temperature (37°C). Both PE:PG and PE:CL monolayers were stable at 37°C and presented higher molecular areas (> 20 Å2/molecule) than at 23°C. However, these lipid mixtures presented liquid-expanded state and rigidity (inverse of the compressibility modulus ~ 90 mN/m) slightly lower than at 23°C. Such athermalicity at biologically relevant temperatures may favour the preservation of the biological functions of E.coli.

Biological and genomic analyses of a clinical isolate of Yarrowia galli from China.

Infections caused by emerging fungal pathogens represent a new threat to human health. The yeast Yarrowia (Candida) galli was first described from chicken breast and liver in 2004 and has occasionally been isolated in clinical settings. In this study, we present the first report of a Y. galli isolate from a face granuloma of a woman. Y. galli is unable to grow at human physiological temperature (37°C). Phenotypic analysis demonstrates that Y. galli can exist as several morphological types, namely fluffy, sticky, tight, and yeast forms, based on their cellular and colony appearances. Interestingly, Y. galli is able to undergo switching among different morphologies. These morphological changes are similar to the switching systems in pathogenic Candida species such as Candida albicans and Candida tropicalis. We further sequenced the genome of the Y. galli isolate. A comparative analysis with pathogenic yeast species indicated that a set of lipid metabolism genes were enriched in Y. galli. Domain enrichment analysis demonstrated that, similar to Candida clade species, the genome of Y. galli maintained several gene families required for virulence. Our biological and genomic analyses provide new insights into the understanding of the biology of Y. galli as either an environmental isolate or a potential human pathogen.

Human macrophages survive and adopt activated genotypes in living zebrafish

The inflammatory response, modulated both by tissue resident macrophages and recruited monocytes from peripheral blood, plays a critical role in human diseases such as cancer and neurodegenerative disorders. Here, we sought a model to interrogate human immune behavior in vivo. We determined that primary human monocytes and macrophages survive in zebrafish for up to two weeks. Flow cytometry revealed that human monocytes cultured at the physiological temperature of the zebrafish survive and differentiate comparable to cohorts cultured at human physiological temperature. Moreover, key genes that encode for proteins that play a role in tissue remodeling were also expressed. Human cells migrated within multiple tissues at speeds comparable to zebrafish macrophages. Analysis of gene expression of in vivo educated human macrophages confirmed expression of activated macrophage phenotypes. Here, human cells adopted phenotypes relevant to cancer progression, suggesting that we can define the real time immune modulation of human tumor cells during the establishment of a metastatic lesion in zebrafish.

Discovery of New Genes Involved in Curli Production by a Uropathogenic Escherichia coli Strain from the Highly Virulent O45:K1:H7 Lineage.

ABSTRACTCurli are bacterial surface-associated amyloid fibers that bind to the dye Congo red (CR) and facilitate uropathogenic Escherichia coli (UPEC) biofilm formation and protection against host innate defenses. Here we sequenced the genome of the curli-producing UPEC pyelonephritis strain MS7163 and showed it belongs to the highly virulent O45:K1:H7 neonatal meningitis-associated clone. MS7163 produced curli at human physiological temperature, and this correlated with biofilm growth, resistance of sessile cells to the human cationic peptide cathelicidin, and enhanced colonization of the mouse bladder. We devised a forward genetic screen using CR staining as a proxy for curli production and identified 41 genes that were required for optimal CR binding, of which 19 genes were essential for curli synthesis. Ten of these genes were novel or poorly characterized with respect to curli synthesis and included genes involved in purine de novo biosynthesis, a regulator that controls the Rcs phosphorelay system, and a novel repressor of curli production (referred to as rcpA). The involvement of these genes in curli production was confirmed by the construction of defined mutants and their complementation. The mutants did not express the curli major subunit CsgA and failed to produce curli based on CR binding. Mutation of purF (the first gene in the purine biosynthesis pathway) and rcpA also led to attenuated colonization of the mouse bladder. Overall, this work has provided new insight into the regulation of curli and the role of these amyloid fibers in UPEC biofilm formation and pathogenesis.

Unusual Isothermal Hysteresis in DNA i-Motif pH Transitions: A Study of the RAD17 Promoter Sequence

We have interrogated the isothermal folding behavior of the DNA i-motif of the human telomere, dC19, and a high-stability i-motif-forming sequence in the promoter of the human DNA repair gene RAD17 using human physiological solution and temperature conditions. We developed a circular-dichroism-spectroscopy-based pH titration method that is followed by analysis of titration curves in the derivative domain and found that the observed pH-dependent folding behavior can be significantly different and, in some cases, multiphasic, with a dependence on how rapidly i-motif folding is induced. Interestingly, the human telomere sequence exhibits unusual isothermal hysteresis in which the unfolding process always occurs at a higher pH than the folding process. For the RAD17 i-motif, rapid folding by injection into a low-pH solution results in triphasic unfolding behavior that is completely diminished when samples are slowly folded in a stepwise manner via pH titration. Chemical footprinting of the RAD17 sequence and pH titrations of dT-substituted mutants of the RAD17 sequence were used to develop a model of RAD17 folding and unfolding. These results may provide valuable information pertinent to i-motif use in sensors and materials, as well as insight into the potential biological activity of i-motif-forming sequences under stepwise or instantaneous changes in pH.

Spontaneous Charge Generation in Flowing Albumin Solutions at 35 °C and 38 °C.

The time dependence of a charge accumulation in a 10−15 M albumin solution, flowing through a measuring cell of an analytical flow system injector, had a nonlinear character under certain conditions, within a human physiological temperature range. Sharp charge increases depended on albumin concentration. This effect must be taken into consideration when generating models that describe electrokinetic phenomena in flowing protein solutions and when developing analytical flow systems for the registration of biomolecules in low concentration ranges.

A dual-function chymotrypsin-like serine protease with plasminogen activation and fibrinolytic activities from the GRAS fungus, Neurospora sitophila

In this study, we have isolated and characterized a fibrinolytic enzyme from the GRAS (Generally Recognized as Safe) fungus, Neurospora sitophila. The enzyme was purified by fractional ammonium sulfate precipitation, hydrophobic interaction, ion exchange and gel filtration chromatography to 45.2 fold with a specific activity of 415.6U/mg protein. The native molecular mass of the enzyme was 49kDa, while the denatured molecular mass was 30kDa and 17.5kDa, indicating that the enzyme was a hetero-dimer. It was optimally active at 50°C and pH 7.4 and stable at human physiological temperature and pH. It was found to be a chymotrypsin-like serine protease which cleaved the synthetic chromogenic substrate, N-Succinyl-Ala-Ala-Pro-Phe-pNA for which the apparent Km and Vmax values were 0.24mM and 4.17×10−5mM/s, respectively. The enzyme hydrolyzed all the chains of fibrinogen by cleaving α chain first, followed by β chain and then γ chain. Moreover, the enzyme possessed dual function of direct fibrinolysis as well as plasminogen activation. Due to its attractive biochemical and fibrinolytic properties and being from a GRAS fungus, the fibrinolytic enzyme has application as a safe and efficient thrombolytic drug.

Assessing the efficiency of imidazolium-based ionic liquids on the phase behavior of a synthetic biomedical thermoresponsive polymer

HypothesisTemperature-responsive polymers (TRPs) with a phase transition temperature close to human physiological body temperature have attracted much attention in biomedical and pharmaceutical fields. Addition of small amount of cosolvent to TRPs is expected to influence the molecular interactions, thereby affecting the phase transition temperature of TRPs. Hence, it is possible to tune the phase behavior of TRPs and also drive transitions in TRPs by variation of chemical structure of cosolvent. ExperimentsTo elucidate the conformational changes of the phase transition of TRP aqueous solution in ionic liquids (ILs), poly(N-vinylcaprolactam) (PVCL), a well known TRP was synthesized by solution polymerization. The lower critical solution temperature (LCST) behavior of polymer aqueous solution, with the addition of imidazolium-based ILs possessing same Cl− anion and a set of cations [Cnmim]+ such as 1-ethyl-3-methylimidazolium ([Emim]+), 1-butyl-3-methylimidazolium ([Bmim]+), 1-hexyl-3-methylimidazolium ([Hmim]+), 1-decyl-3-methylimidazolium ([Dmim]+), 1-allyl-3-methylimidazolium ([Amim]+) and 1-benzyl-3-methylimidazolium ([Bzmim]+), was monitored by using various sophisticated experimental techniques. FindingsThe modulations on the LCST of PVCL aqueous solutions follow the order of [Emim][Cl]<[Amim][Cl]<[Bmim][Cl]<[Hmim][Cl]<[Bzmim][Cl]<[Dmim][Cl]. This order shows that the LCST value increase with increasing the alkyl chain length of cation from [Emim]+ to [Dmim]+ of IL. To the best of our knowledge, this is the first report on comprehensive unequivocal evidence of the phase transition behavior of PVCL in presence of imidazolium-based ILs.

Human Thermal Conditions and North Europeans’ Web Searching Behavior (Google Trends) on Mediterranean Touristic Destinations

Global economy, trade and other human activities are affected by the behaviour and the psychology of the individuals [1–3]. Knowing the influential factors, which contribute to the perception, behaviour and psychology, a positive reinforcement to the economic cycle could be possible [2,4,5]. Human behaviour is affected by a wide set of factors, some of them being the social and environmental conditions. The expression of behaviour is frequently reflected as wishes, desires and preferences which drive to everyday choices and actions. Scientists have already described the influence of the environmental conditions, especially weather, on the psychology and behaviour via conscious and subconscious functions [6–9]. The essential datasets for the analysis of weather influence on human life are the meteorological data, along with archives of medical registries, psychiatric hospital databases, and police stations’ records [9–17] or structured questionnaires completed by individuals in open public spaces [18–20]. The major drawback of those datasets is that are fragmented and more or less biased by several known and unknown factors [9,21,22] such as the unknown physical, mental and psychological conditions of interviewees along with their acclimatization level when we referred to structured questionnaires [7,23]. An essential part of individuals’ lifestyle (as a part of their behaviour) is the choice of summer vacation destinations. It is known that tourism, especially summer tourism, can be described by the Triple S (Sun, Sea and Sand), which is an abundant feature of the Mediterranean region [24,25]. Many of the major tourism factors for the triple S depend on weather and local climate. Tourist decision making with respect to the destination choice could be supported by specific indices such as, among others, the Tourism Climate Index (TCI) developed by Mieczkowski [26], the Climate Index for Tourism [27] and the ClimateTourism/Transfer-Information-Scheme [25,28,29]. Further, the application of new tools and applications such as Decision Support Systems (DSS) takes into account distinct criteria in a decision making process about preliminary ratting destinations [30]. DSS are usually refers to demand-oriented systems such as destination management or consumer-oriented travel-counselling systems [31]. A DSS is usually built to support the solution of a certain problem or to evaluate an opportunity, through the design of computer models and the simulation of real-life experiences [32]. DSSs continue to improve the quality of decisions by standardizing the process and logic information managers’ choices and making the criteria for determining appropriate outcomes systematic [33]. To investigate the relation between the outdoor thermal conditions and the individuals’ desires related to the summer holidays, we examined the searching frequency of specific keywords as retrieved by the Google Trends service and the values of human thermal index Physiological Equivalent Temperature (PET) during the simultaneous time period. The summer holidays terms, thereafter keywords, were a set of famous summer holiday destinations over Mediterranean Sea and northern coastal European regions, accompanied by some very common words linked with the summer. The results indicate a clearly positive relation between the searched keywords and the PET values.

Synthesis and characterization of thermosensitive poly(N-vinylcaprolactam)-g-collagen

In this study, we synthesized poly(N-vinylcaprolactam)-g-collagen (PNVCL-g-Col) by grafting collagen with carboxyl group-terminated thermosensitive PNVCL-COOH. The resulting biopolymer was evaluated for its structural, thermal, and rheological properties. Aqueous solutions of PNVCL-g-Col exhibited a temperature-dependent phase transition around human physiological temperature (at ∼38.5 °C), and temperature-dependent tunability. PNVCL-g-Col exhibited temperature-dependent release of the model drugs, lidocaine hydrochloride and bovine serum albumin. Thus, PNVCL-g-Col biopolymer may have wide potential use in various biomedical applications, including controlled release and tissue engineering.