Influence of Ligand Shell Composition upon Interparticle Interactions in Multifunctional Nanoparticles.

The interactions of nanoparticles with biomolecules, surfaces, or other nanostructures are dictated by the nanoparticle's surface chemistry. Thus, far, shortcomings of syntheses of nanoparticles with defined ligand shell architectures have limited our ability to understand how changes in their surface composition influence reactivity and assembly. We report new synthetic approaches to systematically control the number (polyvalency), length, and steric interactions of omega-functionalized (targeting) ligands within an otherwise passivating (diluent) ligand shell. A mesofluidic reactor was used to prepare nanoparticles with the same core diameter for each of the designed ligand architectures. When the targeting ligands are malonamide groups, the nanoparticles assemble via cross-linking in the presence of trivalent lanthanides. We examined the influence of ligand composition on assembly by monitoring the differences in optical properties of the cross-linked and free nanoparticles. Infrared spectroscopy, electron microscopy, and solution small-angle X-ray scattering provided additional insight into the assembly behavior. Lower (less than 33%) malonamide ligand densities (where the binding group extends beyond the periphery of diluent ethylene glycol ligands) produce the strongest optical responses and largest assemblies. Surprisingly, nanoparticles containing a higher surface number of targeting ligand did not produce an optical response or assemble, underscoring the importance of an informed mixed ligand strategy for highest nanoparticle performance.

[Psychological burden of patients diagnosed with obstructive sleep apnea].

Obstructive sleep apnea syndrome (OSAS) is characterized by repeated episodes of upper airway obstruction during sleep, which leads to the presence of excessive daytime drowsiness. Regarding the psychological comorbidity in patients diagnosed with OSAS, previous studies focused mainly on depressive and secondarily on anxiety symptoms. Due to the lack of research data regarding the prevalence of anxiety and depressive symptoms as well as of alexithymic characteristics in patients with OSAS in Greece, the aim of the study was to record the above symptomatology in a sample of Greek OSAS patients and to investigate its relation to the respiratory parameter (Apnea-Hypopnea Index, AHI) of polysomnography. The study was conducted in a certified sleep laboratory. Thirty five randomly selected patients who attended the laboratory with symptoms of daytime drowsiness, fatigue, disrupted sleep and snoring, were examined for anxiety, depression and alexithymia using the Spielberger Trait Anxiety Inventory (STAI), the Beck Depression Inventory (BDI) and the Toronto Alexithymia Scale (TAS-20), respectively, 24 hours prior to being submitted to polysomnography. All 35 patients met the inclusion criteria of the study (age≤75 years, no other chronic diseases and no history of major psychiatric disorders). Six patients did not meet the diagnostic criteria for OSAS and were thus used as the control group of the study. A high prevalence of anxiety (41.4%) and depressive (55.2%) symptoms and of alexithymic characteristics (41.4%) was observed in OSAS patients. Although the control group showed a higher prevalence of anxiety (66.7%) and depressive (83.3%) symptoms, there were no differences between the two groups (STAI: t=-0.927, p=0.360, BDI: t=-1.537, p=0.134, TAS-20: t=0.196, p=0.846). With regard to severity, no differences were observed between control, mild, moderate and severe OSAS subgroups (STAI: F=0.583, p=0.660, BDI: F=0.829, p=0.488, TAS-20: F=0.987, p=0.412). Females scored higher on the BDI and on the STAI compared to males (STAI: t=-2.38, p=0.039, BDI: t=-3.59, p=0.01). Finally, no correlation was observed between psychometric scores and AHI (Pearson correlation p>0.05). The study confirms the high prevalence of anxiety and depressive symptoms which has been found in previous studies. Furthermore, we found a high prevalence of alexithymic characteristics, a factor that has not been investigated previously and which is positively correlated with anxiety symptoms. The coexistence of alexithymic characteristics may further complicate the clinical manifestations of OSAS due to the fact that patients with alexithymia typically have difficulty in indentifying and describing their underlying psychological symptomatology and, moreover, tend to exhibit more, and often atypical, physical symptoms. In conclusion, the study supports the presence of a high degree of psychological burden in patients diagnosed with OSAS, regardless of the severity of their symptoms, as determined by the AHI. This comorbidity should be taken into consideration during the clinical assessment of OSAS and for the treatment planning.

Higher-order correlations for fluctuations in the presence of fields.

The higher-order moments of the fluctuations for thermodynamic systems in the presence of fields are investigated in the framework of a theoretical method. The method uses a generalized statistical ensemble consistent with an adequate expression for the internal energy. The applications refer to the case of a system in a magnetoquasistatic field. In the case of linear magnetic media, one finds that, for the description of the magnetic induction fluctuations, the Gaussian approximation is satisfactory. For nonlinear media, the corresponding fluctuations are non-Gaussian, having a non-null asymmetry. Furthermore, the respective fluctuations have characteristics of leptokurtic, mesokurtic and platykurtic type, depending on the value of the magnetic field strength as compared with a scaling factor of the magnetization curve.

Fluctuations in the presence of fields: phenomenological Gaussian approximation and a class of thermodynamic inequalities.

The fluctuations of thermodynamic systems in the presence of the fields are considered. The approach is of phenomenological nature and developed in a Gaussian approximation. The cases of a magnetizable continuum in a magnetoquasistatic field, as well as the so called discrete systems are used to exemplify the study. In the latter case one finds that the fluctuation estimators depend both on the intrinsic properties of the system and on the characteristics of the environment. Following earlier ideas of one of the authors we present a class of thermodynamic inequalities for the systems investigated in this paper. In the case of two variables these inequalities are nonquantum analogs of the well known quantum Heisenberg "uncertainty" relations. In this context, the fluctuation estimators support the idea that Boltzmann's constant k has the signification of a generic indicator of stochasticity for thermodynamic systems.

[The efficacy of Macronil in treating acute respiratory infections in children 0 to 5 years old]. / Eficienta produsului Macronil în tratarea infectiilor respiratorii acute, la copii de 0-5 ani.

The authors followed the efficiency of product Macronil in association with the usual (antibiotic and symptomatic) treatments in acute, viral respiratory infections in 62 children, 0-5 years old, admitted into hospital. Besides the usual treatment (25 cases--control group) Macronil was administered in 37 cases (experimental group). A significant improvement was found in clinical evolution (duration of disease evolution, improvement of general state, good appetite, fever duration, increase in weight) of the experimental group versus the control group. An important reduction (twice) of the pharyngeal viral population appeared in the experimental group treated with Macronil. In the control group, the viral flora, remained, practically, the same after treatment.

[Effects of treatment with Macronil on the viral population of the pharynx in 0- to 5-year-old children with acute respiratory infections]. / Etude des effets du traitement au Macronil sur la population virale pharyngienne chez des enfants âgés de 0 à 5 ans, souffrant d'infections respiratoires aiguës.

Macronil (a concentrated proteic extract from mackerel) associated to usual therapeutics (antibiotics, antipyretics, vitamins) in children aged 0-5 years, with acute respiratory infections led to a reduction of the viral pharyngeal population as detected by immunofluorescence (IF) technics. The IF positivity rate in children receiving Macronil was half as high as in controls receiving only the usual therapeutics. At the same time, the number of virus species detected in the pharynx of Macronil treated children was lower than in controls in which the viral pharyngeal population was not influenced in any way by the administered therapeutics without Macronil.

[Renal complications after rifampicin]. / Accidente renale dupa rifampicina

Six observations are presented of patients receiving intermitent rifampicin treatment (900 mg twice weekly) that developed acute renal failure during treatment (4 cases) or when treatment was taken up again, after an interruption of 6 months (2 cases). Following anuria of 4--14 days and nitrogen retention between 248 and 521 mg, the evolution was favourable. Clinical, biological and immunological data (anti-rifampicin antibodies were detected in 1/8 and 1/16 in 3 cases) suggest the immune origin of this type of renal accidents.