Low-temperature pseudo-phase-transition in an extended Hubbard diamond chain.

We consider the extended Hubbard diamond chain with an arbitrary number of particles driven by chemical potential. The interaction between dimer diamond chain and nodal couplings is considered in the atomic limit (no hopping), whereas the dimer interaction includes the hopping term. We demonstrate that this model exhibits a pseudo-transition effect in the low-temperature regime. Here, we explore the pseudo-transition rigorously by analyzing several physical quantities. The internal energy and entropy depict sudden, although continuous, jumps which closely resembles discontinuous or first-order phase-transition. At the same time, the correlation length and specific heat exhibit astonishing strong sharp peaks quite similar to a second-order phase-transition. We associate the ascending and descending parts of the peak with power-law "pseudo-critical" exponents. We determine the pseudo-critical exponents in the temperature range where these peaks are developed, namely, ν=1 for the correlation length and α=3 for the specific heat. We also study the behavior of the electron density and isothermal compressibility around the pseudo-critical temperature.

A molecular dynamics study of ferroelectric nanoparticles immersed in a nematic liquid crystal.

A large number of interesting phenomena related to the insertion of colloidal particles in liquid crystals (LC) have recently been reported. Here, we investigate effects caused by the addition of spherically shaped ferroelectric nanoparticles to a nematic liquid crystal. Using molecular dynamics (MD) simulations, the density of LC molecules, the orientational order parameter, and the polar and azimuthal angle profiles are calculated as functions of the distance to the center of the immersed nanoparticle for different temperatures of the system. We observe that the assembly of ferroelectric nanoparticles enhances the nematic order in the LC medium changing many properties of its host above the nematic-isotropic transition temperature T (*) (NI) .

Nematic reorientation effects on resonant modes, wavelength mismatch, and slow-light phenomena in one-dimensional magnetophotonic crystals with a dual anisotropic defect.

The present study is devoted to the investigation of spectral properties of an alternated sequence of magnetic and dielectric layers containing a dual defect based on magnetic and nematic layers. Combining the Hydrodynamic Continuum Theory for nematic liquid crystals and Berreman's formalism, we determine how the nematic ordering affects the light localization, polarization rotation, and slow-light phenomena observed in the magnetophotonic system. In particular, we analyze the effects associated with a field-induced reorientation of the director in a nematic defect with strong planar boundary conditions. Our results reveal that field-induced reorientation of the nematic ordering can be used as an efficient mechanism to tune and control the spectral properties of magnetophotonic structure, anomalies in group velocity, and the wavelength mismatch between resonant mode and maximum polarization. The effects of nematic layer thickness are also analyzed.

Phase diagram and re-entrant fermionic entanglement in a hybrid Ising-Hubbard ladder.

The degree of fermionic entanglement is examined in an exactly solvable Ising-Hubbard ladder, which involves interacting electrons on the ladder's rungs described by Hubbard dimers at half-filling on each rung, accounting for intrarung hopping and Coulomb terms. The coupling between neighboring Hubbard dimers is assumed to have an Ising-like nature. The ground-state phase diagram consists of four distinct regions corresponding to the saturated paramagnetic, the classical antiferromagnetic, the quantum antiferromagnetic, and the mixed classical-quantum phase. We have exactly computed the fermionic concurrence, which measures the degree of quantum entanglement between the pair of electrons on the ladder rungs. The effects of the hopping amplitude, the Coulomb term, temperature, and magnetic fields on the fermionic entanglement are explored in detail. It is shown that the fermionic concurrence displays a re-entrant behavior when quantum entanglement is being generated at moderate temperatures above the classical saturated paramagnetic ground state.

Chemical and pharmacological aspects of neutralization of heparins from different animal sources by protamine.

Essentials Bovine (HBI) and porcine (HPI) heparins differ in structure and anticoagulant activity. Protamine-neutralization was evaluated on a variety of physical-chemical methods. HBI requires more protamine than HPI to fully neutralize its anticoagulant activity. Protamine preferentially removes higher-sulfated chains of HBI while HPI is evenly precipitated. SUMMARY: Background Protamine neutralization is an essential step for the safe use and inactivation of the unfractionated heparin (UFH) that is widely employed in surgical and non-surgical procedures involving extracorporeal circulation. Objective To compare protamine neutralization of different pharmaceutical-grade UFHs prepared from porcine or bovine intestine (HPI and HBI, respectively). HBI has approximately half the anticoagulant potency of HPI, mostly as consequence of its fraction enriched with N-sulfated α-glucosamine disaccharides. Methods Protamine neutralization of HPI and HBI was evaluated with in vitro, ex vivo and in vivo assays. We also performed in-depth assessments of the complexation of protamine with these distinct UFHs by using nuclear magnetic resonance and mass spectroscopy. Results HPI and HBI interact similarly with protamine on a mass/mass basis; however, HBI requires more protamine than HPI to have its anticoagulant activity fully neutralized, because of its lower potency, which entails the use of higher doses. Nuclear magnetic resonance spectra revealed that HPI precipitates homogeneously with protamine. On the other hand, the low-sulfated fraction of HBI, enriched with N-sulfated α-glucosamine, precipitates at higher concentrations of protamine than the fraction more like HPI, with a preponderance of N,6-disulfated α-glucosamine disaccharides. Finally, mass spectroscopy spectra showed that some of the different peptide components of protamine interact preferentially with the heparins, irrespective of their animal origin. Conclusion Our results have important medical implications, indicating that protamine neutralization of HBI, determined exclusively by point-of-care coagulation assessments, must fail because of its lower-sulfated fraction with reduced anticoagulant activity that could remain in the circulation after the neutralization procedure.

Ground-state phase diagram, fermionic entanglement and kinetically-induced frustration in a hybrid ladder with localized spins and mobile electrons.

We introduce an exactly solvable hybrid spin-ladder model containing localized nodal Ising spins and interstitial mobile electrons, which are allowed to perform a quantum-mechanical hopping between the ladder's legs. The quantum-mechanical hopping process induces an antiferromagnetic coupling between the ladder's legs that competes with a direct exchange coupling of the nodal spins. The model is exactly mapped onto the Ising spin ladder with temperature-dependent two- and four-spin interactions, which is subsequently solved using the transfer-matrix technique. We report the ground-state phase diagram and compute the fermionic concurrence to characterize the quantum entanglement between the pair of interstitial mobile electrons. We further provide a detailed analysis of the local spin ordering including the pair and four-spin correlation functions around an elementary plaquette, as well as, the local ordering diagrams. It is shown that a complex sequence of distinct local orderings and frustrated correlations takes place when the model parameters drive the investigated system close to a zero-temperature triple coexistence point.

Leishmania infantum-induced primary and challenge infections in rhesus monkeys (Macaca mulatta): a primate model for visceral leishmaniasis.

Visceral leishmaniasis (VL) was experimentally induced in rhesus macaques (Macaca mulatta) by intravenously inoculating 2 x 10(7)amastigotes/kg of body weight of Leishmania infantum. The macaques developed a systemic disease showing characteristic features of human VL such as fever, diarrhoea, body weight loss, anaemia, hypergammaglobulinaemia and transient lymphocytosis, as well as lymph node, liver and/or spleen enlargement. Nine weeks after infection, one primate showed pronounced weight loss, became moribund and was euthanized. The necropsy findings included granulomas composed of parasite-containing macrophages, lymphocytes and plasma cells in the liver, spleen and lymph nodes. The remaining macaques had a sustained course of infection but developed a mild-to-moderate illness that subsequently showed evidence of self-cure. Of note, pathological findings included a typical cell-mediated immunity-induced granulomatous reaction that had an effect on the control of parasite replication. All infected monkeys responded with increased production of anti-Leishmania-specific IgG antibodies. Despite the fact that clinical resistance to L. infantum was not consistently associated with a parasite-specific cell-mediated immune response, drug-cured macaques from the primary infection acquired immunity to homologous re-infection. These findings point to the feasibility of using the L. infantum macaque model for pre-clinical evaluation of novel chemotherapeutics or vaccine candidates for human VL.

Searching for alternatives to heparin: sulfated fucans from marine invertebrates.

We describe a variety of sulfated polysaccharides with regular and well-defined structures which are useful tools for elucidating structure/biological function relationship. Several of these compounds have anticoagulant and antithrombotic activities. The most studied and promising polysaccharide is a fucosylated chondroitin sulfate, composed of a chondroitin sulfate-like backbone, substituted at position 3 of the beta-D-glucuronic acid with heavily sulfated fucose side chains. The anticoagulant activity of this polysaccharide is mediated by both antithrombin and heparin cofactor II; it has antithrombotic activity when targeted at the intrinsic coagulation pathway.

Dot enzyme immunoassay. A simple, cheap and stable test for antibody to human immunodeficiency virus (HIV).

A dot enzyme immunoassay for antibody to HIV has been developed and tested with a panel of positive and negative sera. It has proved to be of equal or greater sensitivity compared with a commercial ELISA kit, is simple and quick to perform, requires neither sophisticated equipment nor highly trained technical staff. The reagents are stable enough for postal distribution in tropical countries and, other than for the antigen, the costs are low, making it an appropriate test for use in the developing world when funds for expensive commercial kits are not available.

Measurement of heterophil antibody and antibodies to EB viral capsid antigen IgG and IgM in suspected cases of infectious mononucleosis.

The EBV IgG titres in acute and convalescent specimens from 97 cases of infectious mononucleosis were compared with titres from acute and convalescent sera from 96 students with illnesses resembling infectious mononucleosis but without heterophil antibody, EB IgM or EB IgG seroconversion; and also with titres from 91 healthy students known to have had EB IgG antibody for at least six months. These titres were related to the titre of the Research Standard A.66/235 for infectious mononucleosis serum prepared by the National Institute for Biological Standards and Control. Serial sera were tested for heterophil antibody and EBVCA specific IgG and IgM from 61 university students with infectious mononucleosis. The period of persistence of heterophil antibody and EBV IgM after illness was outlined from the results of the tests. Single sera from 406 patients in hospital or general practice sent to the diagnostic laboratory for heterophil antibody tests were also tested for EBV antibodies without prior knowledge of the heterophil antibody result. The close agreement between heterophil antibody and EBV IgM results is shown. False positive EB IgM results were correlated with the presence of rheumatoid factor.

EB virus antibody and infectious mononucleosis in a boarding school for boys.

A study of EB virus antibody was undertaken in a boarding school for boys between 11 and 18 years of age; 35% of boys had EBV antibody when first sampled and a small number acquired antibody each year. Some of these boys had had no recorded illness during the period before the first positive sample and some developed classic infectious mononucleosis which was accompainied by a positive heterophil antibody test and detection of EB virus specific IgM. In a school of 800 boys there were 13 cases of infectious mononucleosis in four years.

Translocation of CD3D gene in an acute myeloid leukemia (M5) with t(11;17)(q23;21).

Cytogenetic studies in patients with acute leukemia showed structural abnormalities on chromosome 11 at band q23 in five cases. Four of these had acute lymphoblastic leukemia (ALL) associated with t(4;11)(q21;q23) and one case had acute nonlymphoblastic leukemia (ANLL) (M5) associated with t(11;17)(q23;q21). We examined the CD3D and c-ets-1 genes in the t(11;17)(q23;q21) patient to ascertain any association between them and the chromosome change. In situ hybridization results showed that unlike in other studied cases with rearrangements of 11q23, the CD3D gene in the t(11;17)(q23;21) is transposed to the der(17) chromosome, providing evidence for a different breakpoint in the 11q23 region.

A sulphated fucan from the Laminaria abyssalis inhibits the human T cell lymphotropic virus type 1-induced syncytium formation in HeLa cells.

This work evaluated the effect of a sulphated fucan extracted from the Laminaria abyssalis marine algae on the human T cell lymphotropic virus type 1 (HTLV-1)-induced syncytium formation. The experiments were carried out in HeLa cells cocultured with a HTLV-1-infected T cell line (C91/PL cells) in the presence of the sulphated polysaccharide at concentration below that corresponding to the ED50. The sulphated fucan inhibited almost 100% of the syncytium formation at concentration of 100 microg/mI and was still active (>95%) at a concentration of 25 microg/ml. It was also observed that the best inhibition occurred when the compound was added in the first 2 h of the cell-to-cell contact. This is the first report showing that a purified sulphated polysaccharide, extracted from marine algae, is able to inhibit the cell-to-cell contact essential for the spreading of the HTLV-1.

Sodium and chloride requirements of growing broiler chickens (twenty-one to forty-two days of age) fed corn-soybean diets.

Two trials were conducted to determine Na+ and Cl- nutritional requirements and dietary electrolyte balance (DEB) and its effects on acid-base balance, litter moisture, and incidence of tibial dyschondroplasia (TD) in broiler chickens during the growing period. Cobb broilers were distributed in a completely randomized design (30 pens) with six treatments, five replicates, and 50 birds per experimental unit at 21 d of age. Treatments used in both trials were a basal diet with 0.10% Na+ (Trial 1) or Cl- (Trial 2) supplemented to result in diets with Na+ or Cl- levels of 0.10, 0.15, 0.20, 0.25, 0.30, and 0.35%. In the first trial, the results indicated an optimum Na+ requirement of 0.15%. The Na+ levels, obtained with supplemental NaHCO3, did not affect blood gas parameters and TD incidence. Litter moisture increased linearly with Na+ levels. In the second trial, the Cl- requirement was estimated at 0.23%. Increasing Cl- levels, provided by NaCl with NaHCO3 to balance Na+, caused a linear effect (P < or = 0.01) on blood gas parameters, with an estimated equilibrium at 0.19% dietary Cl-. No effect (P > or = 0.05) of Cl- levels on litter moisture was observed. The hypertrophic area of growth plate in the proximal tibiotarsus increased with Cl- levels (P < or = 0.001). A nonlinear model describes this response. The best dietary electrolyte balance (DEB) was between 250 to 261 mEq/kg in Trial 1 and 249 to 257 mEq/kg in Trial 2. We concluded that the Na+ requirement was 0.15%, and the Cl- requirement was 0.23% for maximum performance of growing chickens between 21 and 42 d of age, and the best DEB was between 249 and 261 mEq/kg.

[Control of hemotherapy and transfusional Chagas disease: 1988 and 1990]. / Controle da hemoterapia e da doença de Chagas transfusional: 1988 e 1990.

An inquiry with the objective of bringing the study of the hemotherapy situation in the state of S. Paulo, up-to-date was undertaken in 1990 and compared with that carried out in 1988. In 1990 research was undertaken in 62 counties, 48 of which performed blood transfusions through 104 services, with hemocenter participation in 13.5% of these latter. In 1988 the respective figures were 57, 40, 71 and 8.5%. The number of donors and transfusions and prevalence of serological positivity for Chagas' disease were, respectively: 105,170; 79,544 and 1.24%, while in 1988 the corresponding numbers were: 51,614; 49,211 and 1.52%. Evaluating the serological selection it was found that the following percentages of the services performed serological tests: for Chagas' disease (94.2%), syphilis (94.2%), hepatitis (94.2%), HIV (92.3%) and malaria (20.2%) while in 1988 only 69.0%; 70.4%; 67.6%, 63.4% and 16.9%, respectively, of the services utilized these same tests. In respect of the serological trial specific for Chagas' disease the results were: complement fixation-4.9%; latex-4.0%; indirect immunofluoresce-80%; direct hemaglutination-24.0%, indirect hemaglutination-69.0% and ELISA-59.0% of all services. In the preceding inquiry only 14.3% of the services performed the ELISA test, and complement fixation was utilized in 28.6%. The results show that the services are utilizing ever more sensitive techniques in the serological routine. Further it was observed that in 1988, 77.6% of all the services studied used only one technique for the diagnosis of Chagas' disease while in 1990 92.9% utilized two or more different techniques. It is concluded that the quality of the hemotherapy undertaken in the state of S. Paulo has improved significantly.

[Recurrent pericardial effusion --a case of cardiac angiosarcoma]. / Derrame pericárdico recidivante--um caso de angiosarcoma cardíaco.

A case of angiosarcoma of the right atrium in a 59-year-old woman is reported, presenting as a recurrent hematic pericardial effusion. The usefulness of echocardiography in making the diagnosis is emphasized. The tumor was already disseminated at the time of the diagnosis. The patient was on palliative therapy, dying a few months later. The histological examination was done at autopsy. This case highlights the difficulty in diagnosis and the various modalities available for an accurate diagnosis of a rare clinical entity. It has a rapid and aggressive course with a very poor prognosis.

[Hospital infections in teaching hospitals: analysis of their control]. / Infecção hospitalar nos hospitais escola: uma análise sobre seu controle.

The purpose of this study is to identify methodologies of vigilance and hospital infection control, to analyse nurse's actuation in the context of hospital infection control and to associate nurse's actuation on the control of hospital infection and the execution of nursing process. It is an analytic-descriptive study developed at 81 Commissions of Hospital Infection Control (CCIH) at School Hospitals from 21 Brazilian states through a questionnaire. The variables studied were: characteristics and functioning of CCIH; criteria to diagnose hospital infection; methods of data collection; types of epidemiological vigilance, prevention and control measures and nurse's participation. The analysis of data was qualitative and quantitative. The results showed that in the collection of data prevailed general vigilance (66.6%) and the association of passive and active methods (48.4%); 67 CCIH mentioned measures of prevention and control, related to urinary tract (54 CCIH) and to respiratory tract (21 CCIH). The antimicrobian control distinguishing the lack of resonance between the CCIH and the units personnel brings to the conclusion that the problems of hospital infection control are, in their essence, of philosophical, educational or administrative character. Authors evidenced the importance of the implementation of methodologies to facilitate the control of hospital infection, indicating that the adoption of nursing process, as an instrument, can result in benefits to CCIH and to patients.

[Disinfection of medical and surgical equipment: efficacy of chemical disinfectants and water and soap]. / Descontaminação prévia de materiais médico-cirúrgicos: estudo da eficácia de desinfetantes químicos e água e sabão.

In this experimental study we compared the previous descontamination efficacy of the medical surgical materials by the use of chemical disinfectants and the mechanical cleaning with water and soap, as well as verified the organic material interference in these procedures. To carry out this study, we used surgical pincers under contamination with: Staphylococcus aureus ATCC-6538, Salmonella cholerae suis ATCC-10708, and Pseudomonas aeruginosa ATCC-15442 in presence and absence of organic matter (fetal bovine serum). The following treatments: glutaraldehyde 2%, sodium hypochlorite 1%, hydrogen peroxide 6%, alcohol 70% and the mechanical cleaning with water and soap were compared with eight repetitions in a total of 480 observations. In the described conditions, the disinfectants had a good efficacy in the previous descontamination of the medical surgical materials and a less inactivation by the organic material. The mechanical cleaning with water and soap showed a reduction of the microrganism to safe levels, considered adequate for previous descontamination.

[Iatrogenic vascular injuries]. / Traumatismos vasculares iatrogénicos.

Iatrogenic vascular injuries include an extremely broad group of lesions with multiple etiology and polymorphic manifestations. We present a series of 44 patients with iatrogenic vascular lesions that result from arterial and venous catheterizations and surgical interventions. The arterial catheterization for coronariography and arteriography and orthopaedic surgery were the agents that most frequently caused vascular injury. Arterial and venous reconstructive surgery were the predominant treatment procedures. In our series, morbidity and mortality were 4.6% and 2.3%, respectively.

[Research, conferences and articles on hospital infection: the aspects addressed by nurses]. / Pesquisas, conferências e artigos em infecção hospitalar: aspectos abordados pelos enfermeiros.

The purpose of this paper is to study investigations that were developed by nurses and deal with Hospital Infection, in order to understand which features of this subject have been more emphasized. A retrospective survey was made, of the papers published in Brazilian Nursing Congresses and in Brazilian Periodicals of Nursing, from 1980 th 1987.