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J L Serrano

Publications and source records attributed to J L Serrano.

15 recordsLinked to original sources
PubMed2006

Characterization by fourier transform infrared spectroscopy (FT-IR) and 2D IR correlation spectroscopy of PAMAM dendrimer.

FT-IR and 2D correlation spectroscopy were employed to study the microstructural changes occurring during phase transitions of a liquid crystal poly(amidoamine) codendrimer (PAMAM (L1)16(L2)16) generation 3, functionalized on the terminal groups by one-chain promesogenic calamitic units (4-(4'-decyloxybenzoyloxy)salicylaldehyde (L1)) and two-chain promesogenic calamitic units (4-(3',4'-didecyloxybenzoyloxy)salicylaldehyde (L2)). Spectral modifications associated with molecular conformation rearrangements allowing for molecular shape change on going from a liquid-crystalline organization to another were found. The transition temperatures were calculated, and they are in good agreement with the DSC data. Spectral analysis gives evidence of the LC phase transitions and to an additional transition associated with the existence of conformers. Various types of hydrogen bonding have been established.

Journal Article↗
PubMed2005

NMR relaxation study of molecular dynamics in columnar and smectic phases of a PAMAM liquid-crystalline co-dendrimer.

We present the first results obtained by proton ((1)H) nuclear magnetic relaxation studies of molecular dynamics in a supermolecular liquid-crystal dendrimer exhibiting columnar rectangular and smectic-A phases. The (1)H spin-lattice relaxation time (T(1)) dispersions are interpreted using two relaxation mechanisms associated with collective motions and local molecular reorientations of the dendritic segments in the low- and high-frequency ranges, respectively. The T(1) values show a drop around 2.3 MHz that is attributed to a contribution coming from cross-relaxation between (1)H and nitrogen nuclear spins. In the high-frequency range the motions appear to be of similar nature in both mesophases and are ascribed to reorientations of dendritic segments (belonging to the core and/or to the mesogenic units) characterized by two correlation times. Notable differences in the dynamics between the columnar and layered phases are observed in the low-frequency range. Depending on the mesophase they are discussed in terms of elastic deformations of the columns and layer undulations. In this study we find that the dendritic core influences the dynamics of the mesogenic units both for local and collective motions. These results can be understood in terms of spatial constraints imposed by the dendritic architecture and by the supermolecular arrangement in the mesophases.

Journal Article↗
PubMed2005

Bayesian methods for the conformational classification of eight-membered rings.

Two methods for the classification of eight-membered rings based on a Bayesian analysis are presented. The two methods share the same probabilistic model for the measurement of torsion angles, but while the first method uses the canonical forms of cyclooctane and, given an empirical sequence of eight torsion angles, yields the probability that the associated structure corresponds to each of the ten canonical conformations, the second method does not assume previous knowledge of existing conformations and yields a clustering classification of a data set, allowing new conformations to be detected. Both methods have been tested using the conformational classification of Csp3 eight-membered rings described in the literature. The methods have also been employed to classify the solid-state conformation in Csp3 eight-membered rings using data retrieved from an updated version of the Cambridge Structural Database (CSD).

Algorithms↗
PubMed2004

Detection of antibodies to tick salivary antigens among patients from a region of Spain.

With a view to determine which tick species bite humans most frequently in the province of Soria (Spain) and to know whether these species act as vectors of Rickettsia conorii and/or Borrelia burgdorferi, we analysed the presence of antibodies against salivary proteins of several tick species and of antibodies against R. conorii and B. burgdorferi sensu lato in 102 samples of serum. The sera were collected from 63 patients who were treated for tick bites at the health services of the Soria Health Area. Thirty-nine percent of the patients displayed antibodies against Dermacentor marginatus; 21% against Ixodes ricinus, and 6% against Rhipicephalus sanguineus. IgM antibodies against R. conorii were found in 15 patients, but none of the patients included in the study displayed IgG/IgM Abs against B. burgdorferi sensu lato. In 30% of the patients bitten by I. ricinus and in 24% bitten by D. marginatus, antibodies against R. conorii were found. None of the patients who had been bitten by R. sanguineus expressed antibodies against this pathogen. The results obtained here suggest that D. marginatus and I. ricinus are the main vectors of the spotted fever group rickettsiae in our environment and that the role of R. sanguineus in the transmission of these rickettsiae is debatable.

Animals↗
PubMed2003

A sero-epidemiological study of Rickettsia typhi infection in dogs from Soria province, central Spain.

Data relating to Rickettsia typhi infection in Spain are scarce. The seroprevalence of canine infection with this species has now been investigated, in dogs from the central province of Soria. The results of indirect immunofluorescence assays indicated that nine (12.3%) of the 73 dogs checked were carrying antibodies against R. typhi. The gender, age and breed of the dog, and whether it was used for hunting, shepherding, guarding or simply as a pet, apparently had no significant affect on the probability of it being seropositive. Being infested with fleas or having a history of such infestation was, however, significantly associated with seropositivity. The present results confirm that dogs may be infected with R. typhi and indicate their potential usefulness as sentinels in epidemiological studies of the pathogen. The results of wide-scale, serological studies of dogs may allow the geographical distribution of R. typhi to be mapped relatively simply.

Animals↗
PubMed2001

Dendromesogens: liquid crystal organizations of poly(amidoamine) dendrimers versus starburst structures.

A new series of liquid crystalline poly(amidoamine) (PAMAM) dendrimers is described. These dendrimers are made by attaching to the 0-, 1-, 2-, 3-, and 4-generation of PAMAM-terminal promesogenic units that carry two decyloxy chains in the 3- and 4-positions of their peripheral aromatic ring. X-ray diffraction studies show that all the compounds display a hexagonal columnar mesophase. A high density of aliphatic chains imposes a curved interface with the promesogenic units that forces the molecules to adopt a radial conformation, and therefore, the columnar structure. A model for the supramolecular organization of the different generations within the columnar mesophase is proposed based on the variation of some of the structural parameters.

Journal Article↗
PubMed2000

Epidemiological characteristics of dogs with Lyme borreliosis in the province of Soria (Spain).

From the point of view of the human disease, dogs are the most important animal reservoir of Lyme borreliosis; therefore, they are used as 'sentinel animals'. In order to know the epidemiological characteristics of dogs with antibodies against Borrelia burgdorferi, 146 canine sera samples collected during 1993-94 have been studied. The antibody detection was made by an indirect immunofluorescence method and confirmed by a haemagglutination test. Seventeen dogs (11.6%) were seropositive, of which seven were hunting dogs, three were shepherd dogs, five were domestic pets, one was a watchdog and one was a stray dog. Seven dogs had longhair phenotype, 2 medium length type, 4 hard-hair and the other 4 were short-haired. Twelve seropositive dogs were males and five were females. All seropositive dogs were more than 1 year old. The dogs with greater seroprevalence were those that harboured ticks more often than the rest. Spring and summer were the seasons when more ticks were observed. The seroprevalence found in dogs was similar to that previously obtained in humans in this area. This finding gave evidence to an intimate association between human and canine seroprevalence.

Animals↗
PubMed2000

Central conduction time of magnetic brain stimulation in attention-deficit hyperactivity disorder.

Twenty-seven children and adolescents aged 4 to 18 years, fulfilling the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria for attention-deficit hyperactivity disorder, were included in this study. The diagnosis was determined by a pediatric neurologist and a psychologist examined all 27 subjects with tests that included the Wechsler Intelligence Scale for Children-Revised (WISC-R) and reading, writing, handedness, personality, and anxiety scores. Subjects with histories of epilepsy, head injury, drug abuse, or psychotic disorders were excluded. Culturally based causes or emotional disorders were also excluded. Transcranial magnetic stimulation was performed on all subjects, with recording of the motor evoked potential at the biceps brachii. Central motor conduction time was calculated by cervical root stimulation. Due to shape variability, the amplitude of the motor responses was not measured in the study. The mean value of central conduction time in the subjects was very significantly increased (P < .001) compared to that in a group of normal controls, case-matched for IQ, age, and sex. A central motor conduction time greater than 12 ms indicates abnormality. A second finding in the subjects was the significant difference of central conduction time on the side-to-side stimulation (P = .03). These findings are correlated with delay in the maturation of the corticomotoneuronal system and might provide neurophysiologic data for diagnosis.

Adolescent↗
PubMed1992

Effect of centrifugation on amniotic fluid phospholipid composition.

The first step in the determination of phospholipid in amniotic fluid is generally the removal of cells and debris from the fluid by centrifugation. Low-speed centrifugation of the supernatant is reported to have the same phospholipidic profile and L/S, PG/S and PI/S ratios similar to those of the uncentrifuged amniotic fluid sample. With high-speed centrifugation almost all the pulmonary surfactant seems to be recovered in pellet with the same characteristics as the uncentrifuged amniotic fluid.

Amniotic Fluid↗
PubMed1991

Full trisomy 22 in a malformed newborn female.

The authors describe a new case of full trisomy 22 in a malformed newborn female, who died shortly after birth. Pathologic findings include cardiac, vascular, renal, gastrointestinal, genital and cerebral malformations. The study of C-heteromorphisms shows a paternal origin of the aneuploidy (non-disjunction at meiosis II).

Abnormalities, Multiple↗
PubMed1986

A practical method to analyze the phospholipids in the amniotic fluid using HPTLC.

An operative method using HPTLC which makes possible the determination of nine phospholipids in the amniotic fluid individually is described: lysophosphatidylcholine, sphingomyelin, phosphatidylcholine, phosphatidylinositol, phosphatidylserine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidic acid and cardiolipine. Since a simple and reliable method for clinical practice was sought, the working techniques, materials, chromatographic solvents and staining reagents were chosen accordingly. The standardization method was made by using standard phospholipids. This method was tested with 34 samples of amniotic fluid. A discussion of the practical application in the determination of some ratios of fetal pulmonary maturity is made.

Amniotic Fluid↗