This study aimed to develop a chitosan‐based hydrogel containing a mixture of flavonoids isolated from the leaves of Passiflora edulis Sims and to evaluate its stability, antioxidant properties, and ...wound healing effects on cutaneous lesions in diabetic rats. in vitro studies were carried out to evaluate the biocompatibility and flavonoid release from the chitosan hydrogel. in vivo wound healing studies were conducted on male Wistar rats, where the injured tissue was removed for histological analysis and determination of lipid peroxidation, superoxide dismutase activity, and glutathione peroxidase activity. From the histological analysis and macroscopic evaluation of the contraction of the wounds, it was observed that the formulation presented wound healing properties. In addition, treatment of the wound with the formulation stimulated the antioxidant defense system, suggesting a beneficial effect during the treatment of skin lesions in diabetic rats, especially in the first few days after wounding. According to these results, we can conclude that the chitosan hydrogel containing the flavonoid analyzed in this study has potential use as dressings in the treatment of wounds.
Recent studies have recognised the importance of pulmonary hypertension (PH) in sickle cell disease (SCD). The aim of this study was to determine the prevalence and prognostic impact of PH and its ...features in patients with SCD. 80 patients with SCD underwent baseline clinical evaluation, laboratory testing, 6-min walk tests (6MWTs) and echocardiography. Patients with a peak tricuspid regurgitant jet velocity (TRV) of ≥ 2.5 m·s(-1) were further evaluated through right heart catheterisation (RHC) to assure the diagnosis of PH. Our study evidenced a 40% prevalence of patients with elevated TRV at echocardiography. RHC (performed in 25 out of 32 patients) confirmed PH in 10% (95% CI 3.4-16.5%) of all patients, with a prevalence of post-capillary PH of 6.25% (95% CI 0.95-11.55%) and pre-capillary PH of 3.75% (95% CI -0.4-7.9%). Patients with PH were older, had worse performance in 6MWTs, and more pronounced anaemia, haemolysis and renal dysfunction. Survival was shorter in patients with PH. Our study reinforced the use of echocardiography as a screening tool for PH in SCD and the mandatory role of RHC for proper diagnosis. Our findings confirmed the prognostic significance of PH in SCD as its association to pronounced haemolytic profile.
We report the timing results for PSR J2234+0611, a 3.6 ms pulsar in a 32 day, eccentric (e = 0.13) orbit with a helium white dwarf. The precise timing and eccentric nature of the orbit allow ...measurements of an unusual number of parameters: (a) a precise proper motion of 27.10(3) mas yr−1 and a parallax of 1.05(4) mas resulting in a pulsar distance of 0.95(4) kpc; enabling an estimate of the transverse velocity, 123(5) km s−1. Together with previously published spectroscopic measurements of the systemic radial velocity, this allows a 3D determination of the system's velocity; (b) precise measurements of the rate of advance of periastron yields a total system mass of M ; (c) a Shapiro delay measurement, h3 = 82 14 ns, despite the orbital inclination not being near 90°; combined with the measurement of the total mass yields a pulsar mass of and a companion mass of (d) we measure precisely the secular variation of the projected semimajor axis and detect a significant annual orbital parallax; together these allow a determination of the 3D orbital geometry of the system, including an unambiguous orbital inclination ( ) and a position angle for the line of nodes ( ). We discuss the component masses to investigate the hypotheses previously advanced to explain the origin of eccentric MSPs. The unprecedented determination of the 3D position, motion, and orbital orientation of the system, plus the precise pulsar and WD masses and the latter's optical detection make this system a unique test of our understanding of white dwarfs and their atmospheres.
Community-acquired pneumonia (CAP) is amongst the leading causes of death worldwide. As inflammatory markers, cytokines can predict outcomes, if interpreted together with clinical data and scoring ...systems such as CURB-65, CRB, and Acute Physiology and Chronic Health Evaluation II (APACHE II). The aim of this study was to determine the impact of inflammatory biomarkers on the early mortality of hospitalized CAP patients. Twenty-seven CAP patients needing hospitalization were enrolled for the study and samples of interleukin-1 (IL-1) and interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), C-reactive protein (CRP), and homocystein were collected at the time of admission (day 1) as well as on the seventh day of the treatment. There was a significant reduction in the levels of IL-6 between the first and the second collections. Median IL-6 values decreased from 24 pg/mL (day 1) to 8 pg/mL (day 7) (P=0.016). The median levels of TNF-α were higher in patients: i) with acute kidney injury (AKI) (P=0.045), ii) requiring mechanical ventilation (P=0.040), iii) with short hospital stays (P=0.009), iv) admitted to the intensive care unit (ICU) (P=0.040), v) who died early (P=0.003), and vi) with worse CRB scores (P=0.013). In summary, IL-6 and TNF-α levels were associated with early mortality of CAP patients. Longer admission levels demonstrated greater likelihood of early death and overall mortality, necessity of mechanical ventilation, and AKI.
The surface chemistry of a commercial activated carbon with a slightly basic nature was modified by appropriate treatments in order to obtain two additional samples, respectively with acidic and ...basic properties, without changing its textural parameters significantly. Different techniques (N
2 adsorption at 77 K, temperature programmed desorption, and determination of acidity, basicity, and pH at the point of zero charge) were used to characterize the adsorbents. Kinetic and equilibrium adsorption data of a selected textile reactive dye (Rifafix Red 3BN, C.I. reactive red 241) on the mentioned materials were obtained at the pH values of 2, 7, and 12. The kinetic curves are fitted using the second-order model. The respective rate constants seem to diminish progressively with the initial concentration for the more diluted solutions tested, reaching a constant value at higher concentrations, which depends on the experimental system under consideration (adsorbent and pH). In general, the Langmuir model provides the best fit for the equilibrium data. The different uptakes obtained are discussed in relation to the surface chemical properties of the adsorbents. It is shown that the adsorption of the reactive (anionic) dye on the basic sample (prepared by thermal treatment under H
2 flow at 700 °C) is favored. This conclusion is explained on the basis of the dispersive and electrostatic interactions involved. Moreover, it is also shown that the optimal adsorption condition for all the activated carbons tested corresponds to solution pH values not higher than the pH
pzc of the adsorbents, which may be interpreted by taking into account the electrostatic forces present.
The adsorption of reactive dyes on activated carbon involves electrostatic and dispersive interactions. High adsorbent basicity and pH values not higher than pH
pzc favor the dye uptake.
The application of the Shuttle Walking Test (SWT) to assess cardiorespiratory fitness and the intensity of this test in healthy participants has rarely been studied. This study aimed to assess and ...correlate the cardiorespiratory responses of the SWT with the cardiopulmonary exercise testing (CEPT) and to develop a regression equation for the prediction of peak oxygen uptake (VO2 peak) in healthy sedentary adult men.
In the first stage of this study, 12 participants underwent the SWT and the CEPT on a treadmill. In the second stage, 53 participants underwent the SWT twice. In both phases, the VO2 peak, respiratory exchange ratio (R), and heart rate (HR) were evaluated.
Similar results in VO2 peak (P>0.05), R peak (P>0.05) and predicted maximum HR (P>0.05) were obtained between the SWT and CEPT. Both tests showed strong and significant correlations of VO2 peak (r = 0.704, P = 0.01) and R peak (r = 0.737, P<0.01), as well as the agreement of these measurements by Bland-Altman analysis. Body mass index and gait speed were the variables that explained 40.6% (R2 = 0.406, P = 0.001) of the variance in VO2 peak. The results obtained by the equation were compared with the values obtained by the gas analyzer and no significant difference between them (P>0.05) was found.
The SWT produced maximal cardiorespiratory responses comparable to the CEPT, and the developed equation showed viability for the prediction of VO2 peak in healthy sedentary men.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The chemical composition of red seaweed
Gracilaria cervicornis and brown seaweed
Sargassum vulgare from Brazil was investigated. In this study, the relationship between the nutritive components of ...each species and the environment was established. Protein content varied from 23.05
±
3.04% to 15.97
±
3.04%. The highest value was found in
G. cervicornis. The protein levels were positively correlated with nitrogen content and negatively with water temperature and salinity. Carbohydrate contents of both species varied significantly (
p
<
0.01) and the values observed were superior to others chemical constituents. Contrary to carbohydrates, the lipid concentrations were the lowest recorded chemical component and varied slightly between the two species. Ash content was greater in
S. vulgare (14.20
±
3.86) than in
G. cervicornis (7.74
±
1.15). In general the variation in chemical composition was related to environment.
Posterior tibial tendon (PTT) dysfunction is three times more common in females, and some patients may have a predisposition without a clinically evident cause, suggesting that individual ...characteristics play an important role in tendinopathy. The present study investigated the association of rs4986938 (+ 1730G > A; AluI RFLP) and rs1256049 (− 1082G > A; RsaI RFLP) single nucleotide polymorphisms (SNPs) of estrogen receptor-beta (
ER-β
) gene with PTT dysfunction. A total of 400 participants were recruited. The PTT dysfunction group: these patients underwent surgery, with PTT tendinopathy confirmed by histopathology and magnetic resonance image (MRI). The control group was composed of participants with no clinical or MRI evidence of PTT dysfunction. Each group was composed of 100 postmenopausal women, 50 premenopausal women, and 50 men. Genomic DNA was extracted from saliva samples, and genotypes were obtained by polymerase chain reaction restriction fragment length polymorphism (PCR–RFLP). Concerning the
ER-β
SNP rs4986938, there were significant differences in the frequencies of alleles between test and control groups of all the cases, only postmenopausal women and only men (
p
< 0.0001,
p
= 0.0016 and
p
= 0.0001). Considering the PTT dysfunction group and comparing postmenopausal women versus premenopausal women adding men, the analysis showed significant differences in the allelic distribution (
p
= 0.0450): the allele A in postmenopausal women is a risk factor. The
ER-β
SNP rs1256049 did not show differences in the frequencies of alleles and genotypes between groups. The
ER-β
SNP rs4986938, but not ER -β SNPs rs1256049, may contribute to PTT insufficiency in the Brazilian population, with additional risk in postmenopausal women. Addition, in men the genetic factor could be more determinant.
Nickel-based superalloys are known for their high-temperature performance regarding oxidation, creep and fatigue resistance. For this reason, they are widely used as structural components in the ...aerospace industry. However, because of these properties, they are difficult to machine, and normally a rigorous control of the surface integrity and residual stresses are required to avoid structural premature failures. Residual stresses are present in all mechanical components regardless of the manufacturing process applied, and they are either of thermal or mechanical origins. In machining several variables affect the residual stresses, but the tool quality is one that is most influential. The present work studies the influence of the wear of coated cemented carbide tools on the surface integrity of Inconel 718 alloy in the face milling process. Tools with different stages of wear were tested under finishing, roughing, and moderate machining conditions. During milling tests, the machining forces and cutting temperatures were monitored, the latter by two different techniques, using a thermal camera and with J-type thermocouples welded on the workpiece surface close to the cutting region. The surface roughness, microhardness, and residual stresses were measured after each machining test. The results showed that there is a close relationship between the tool wear and the residual stresses that varied from compressive to tensile stresses – the latter being of thermal origin. A direct relationship between tool wear and machining forces and cutting temperature were also observed.
•The artificially produced tool wear types had a significant influence on the machinability.•The cutting temperatures were correlated with the residual stresses in the workpiece.•The cutting conditions significantly influenced the hardness of the machined surface.
Oral squamous cell carcinoma (OSCC) is a worldwide public health problem, accounting for approximately 90% of all oral cancers, and is the eighth most common cancer in men. Cisplatin and carboplatin ...are the main chemotherapy drugs used in the clinic. However, in addition to their serious side effects, such as damage to the nervous system and kidneys, there is also drug resistance. Thus, the development of new drugs becomes of great importance. Naphthoquinones have been described with antitumor activity. Some of them are found in nature, but semi synthesis has been used as strategy to find new chemical entities for the treatment of cancer. In the present study, we promote a multiple component reaction (MCR) among lawsone, arylaldehydes, and benzylamine to produce sixteen chemoselectively derivated Mannich adducts of 1,4-naphthoquinones in good yield (up to 97%). The antitumor activities and molecular mechanisms of action of these compounds were investigated in OSCC models and the compound 6a induced cytotoxicity in three different tumor cell lines (OSCC4, OSCC9, and OSCC25) and was more selective (IS > 2) for tumor cells than the chemotropic drug carboplatin and the controls lapachol and shikonin, which are chemically similar compounds with cytotoxic effects. The 6a selectively and significantly reduced the amount of cell colony growth, was not hemolytic, and tolerable in mice with no serious side effects at a concentration of 100 mg/kg with a LD50 of 150 mg/kg. The new compound is biologically stable with a profile similar to carboplatin. Morphologically, 6a does not induce cell retraction or membrane blebs, but it does induce intense vesicle formation and late emergence of membrane bubbles. Exploring the mechanism of cell death induction, compound 6a does not induce ROS formation, and cell viability was not affected by inhibitors of apoptosis (ZVAD) and necroptosis (necrostatin 1). Autophagy followed by a late apoptosis process appears to be the death-inducing pathway of 6a, as observed by increased viability by the autophagy inhibitor (3-MA) and by the appearance of autophagosomes, later triggering a process of late apoptosis with the presence of caspase 3/7 and DNA fragmentation. Molecular modeling suggests the ability of the compound to bind to topoisomerase I and II and with greater affinity to hPKM2 enzyme than controls, which could explain the mechanism of cell death by autophagy. Finally, the in-silico prediction of drug-relevant properties showed that compound 6a has a good pharmacokinetic profile when compared to carboplatin and doxorubicin. Among the sixteen naphthoquinones tested, compound 6a was the most effective and is highly selective and well tolerated in animals. The induction of cell death in OSCC through autophagy followed by late apoptosis possibly via inhibition of the PKM2 enzyme points to a promising potential of 6a as a new preclinical anticancer candidate.
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