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Biomedical subjects

M Kasprzak

Publications and source records attributed to M Kasprzak.

16 recordsLinked to original sources
PubMed2005

Measured total cross sections of slow neutrons scattered by solid deuterium and implications for ultracold neutron sources.

The total scattering cross sections for slow neutrons with energies in the range 100 neV to 3 meV for solid ortho-2H2 at 18 and 5 K, frozen from the liquid, have been measured. The 18 K cross sections are found to be in excellent agreement with theoretical expectations and for ultracold neutrons dominated by thermal up scattering. At 5 K the total scattering cross sections are found to be dominated by the crystal defects originating in temperature induced stress but not deteriorated by temperature cycles between 5 and 10 K.

Journal Article↗
PubMed2005

Measured total cross sections of slow neutrons scattered by gaseous and liquid 2H(2).

The total scattering cross sections for slow neutrons with energies E in the range 300 neV to 3 meV for gaseous and liquid ortho-2H2 have been measured. The cross sections for 2H2 gas are found to be in excellent agreement with both the Hamermesh and Schwinger and the Young and Koppel models. For liquid 2H(2), we confirm the existing experimental data in the cold neutron range and the discrepancy with the gas models. We find a clear 1 / square root[E'] dependence at low energies for both states. A simple explanation for the liquid 2H2 cross section is offered.

Journal Article↗
PubMed2005

Summer hypoxia in the northern Gulf of Mexico and its prediction from 1978 to 1995.

An 18-year monitoring record (1978-1995) of dissolved oxygen within a region having hypoxia (dissolved oxygen less than 2 mgl(-1)) in the bottom layer was examined to describe seasonal and annual trends. The monitoring location was near or within a well-described summer hypoxic zone whose size has been up to 20,000 km(2). The monitoring data were used to hindcast the size of the hypoxic zone for before consistent shelfwide surveys started, and to predict it for 1989, when a complete shelfwide survey was not made. The concentration of total Kjeldahl nitrogen (TKN) in surface waters and concentration of bottom water oxygen were directly related, as anticipated if organic loading from surface to bottom was from in situ processes. The TKN data were used to develop a predictive relationship that suggested there was no substantial hypoxia before the 1970s, which was before nitrate flux from the Mississippi River to the Gulf of Mexico began to rise. The peak frequency in monthly hypoxic events is two to three months after both the spring maximum in discharge and nitrate loading of the Mississippi River. These results support the conclusion that persistent, large-sized summer hypoxia is a recently-developed phenomenon that began in the 1970s or early 1980s.

Environmental Monitoring↗
PubMed2004

An algorithm for an automatic NOE pathways analysis of 2D NMR spectra of RNA duplexes.

An algorithm is proposed to provide the tool for an automatic resonance assignment of 2D-NOESY spectra of RNA duplexes. The algorithm, based on a certain subproblem of the Hamiltonian path, reduces a number of possible connections between resonances within aromatic and anomeric region of 2D-NOESY spectra. Appropriate pathways between H6/H8 and H1' resonances were obtained by subsequent implementation of experimental data as limiting factors. Predictive power of the algorithm was tested on both experimental and simulated data for RNA and DNA duplexes.

Algorithms↗
PubMed2001

Construction of DNA restriction maps based on a simplified experiment.

MOTIVATION: A formulation of a new problem of the restriction map construction based on a simplified digestion experiment and a development of an algorithm for solving both ideal and noisy data cases of the introduced problem. RESULTS: A simplified partial digest problem and a branch and cut algorithm for finding the solution of the problem.

Algorithms↗
PubMed1999

DNA sequencing with positive and negative errors.

The problem addressed in this paper is concerned with DNA sequencing by hybridization. An algorithm is proposed that solves a computational phase of this approach in the presence of both positive and negative errors resulting from the hybridization experiment. No a priori knowledge of the nature and source of these errors is required. An extensive set of computational experiments showed that the algorithm behaves surprisingly well if only positive errors appear. The general case, where positive and negative errors occur, can be also solved satisfactorily for an error rate up to 10%.

Algorithms↗
PubMed1997

Sequential and parallel algorithms for DNA sequencing.

MOTIVATION: Reconstruction of the original DNA sequence in the sequencing by the hybridization approach (SBH) requires computational support due to a large number of possible combinations. One can notice a lack of algorithms admitting false-negative data and giving in addition all possible solutions. RESULTS: In this paper, a new method of sequencing has been proposed. An algorithm based on its idea (for the general case, when some data are missing, like in the real experiment) has been implemented and tested. Authentic DNA sequences have been used for testing. A parallel version of the algorithm has also been implemented and tested. The quality of the reconstruction is satisfactory for the library of oligonucleotides of length between 8 and 12, and 100, 200 and 300 bp long sequences. A way to a further decrease in the computation time is also suggested.

Algorithms↗
PubMed1997

Sequencing by Hybridization with Positive Faults.

The paper is concerned with a computational phase of the sequencing DNA chains by hybridization. It is assumed that positive faults can occur in the hybridization experiment. An approach based on a reduction of the problem to a variant of a Selective Traveling Salesman Problem and an algorithm for solving the latter, have been proposed. The algorithm behaves extremely well, even for a fault rate exceeding 50%.

Journal Article↗
PubMed1997

Immunological characteristics of cervical mucus in infertile women.

The presence of local or circulating antisperm antibodies (ASA) in some women may cause infertility. We have examined 43 cervical mucus (CM) samples. In order to determine the total amount of immunoglobulins of individual subclasses we used the rocket immunoelectrophoresis of Laurell. To determine the specificity of the immunoglobulins to sperm surface antigens we employed the immunobead-binding test (IBT). Seventeen CM samples (39.5%) revealed high levels (> 0.22 microgram/microliter) of immunoglobulins. They were mainly of the IgA class, however IgG's were also present. We have found IgM in only two test samples (4.6%). Only two CM samples (4.6%) yielded positive results in indirect IBT. The obtained results show a complex immunological status of the human uterine cervix. Immunological response developed in this compartment may be directed against sperms as well as other antigens.

Adult↗
PubMed1996

The easy formation of antisperm antibodies in prepubertal boys and the difficult humoral response in severe-combined immunodeficiency mice.

OBJECTIVE: To investigate and compare mechanisms controlling the development of antisperm antibodies in situations with different status of active immunosuppression. DESIGN: Antibody activity against human sperm was analyzed by immunosorbent assays (ELISA) in sera samples of prepubertal boys and in circulation of sensitized immunocompromised mice. SETTING: Procedures were performed in a university laboratory. PATIENT(S): Prepubertal healthy boys and patients with testicular failures. INTERVENTION(S): Blood was collected from healthy individuals and from patients with diagnosed testicular pathology; antisperm antibodies were rechecked after surgical intervention (orchidopexia or removal of the pathological gonad). MAIN OUTCOME MEASURE(S): Antisperm antibodies in quantitative ELISA. RESULT(S): Significant antibody activity to finally differentiated human sperm was detected in sera samples from prepubertal boys with testicular failures (cryptorchid or mobile testis), especially in individuals with both pathological gonads. "Naive" human lymphocytes deposited to peritoneal cavity of immunocompromised mice did not respond to in situ challenge with sperm antigens. CONCLUSION(S): High antisperm antibody levels in prepubertal boys may suggest low immunosuppressive activity at this age. This situation may influence future fertility status of these individuals. Immunocompromised mice effectively prevented humoral response to sperm antigens suggesting different mechanism than T suppressor cell activity.

Adolescent↗
PubMed1996

[Immunologic response against spermatozoa in the human genital tract].

Spermatozoa are immunogenic and may induce an immune response in reproductive compartments. There have been controversies concerning the effect of naturally existing antisperm antibodies on fertility of males and females. It is known, that men or women suffering from unexplained infertility have often antisperm antibodies in their urogenital secretions and/or serum. Systemic and local immune responses to sperm antigens differ between each other and they may differently affect the fertilisation process. Physiologically, females are protected from an immune response against "foreign", spermatozoal antigens. Nevertheless under local pathological conditions antisperm antibodies can be induced and may interfere with fertilisation.

Adult↗
PubMed1995

[Immunologic reactions in the male and female reproductive system].

This review describes presence and significance of antisperm antibodies (ASA) in male and female reproductive compartments. We described their relevance to infertility in humans. A structure and function of cervical mucus as the environment of females defensive reactions against all the invasive factors is outlined. There are also briefly characterized techniques of ASA detection.

Agglutination Tests↗
PubMed1989

Identification of self through olfaction.

To study olfactory communication in humans, 100 undergraduates ranging from age 18 to 45 yr. wore freshly washed, identical T-shirts continuously for 24 hr. During this time, the participants did not bathe or shower or apply any scent producing substance to their bodies, i.e., deodorants, perfumes. Upon retrieval, each shirt was placed in an identical brown bag. In groups of 10, each participant attempted to identify the T-shirt he had worn the previous 24 hr. The task was administered separately for each individual so that no participants knew the choice by a previous colleague. Analysis shows that the participants were able to identify correctly their own shirts on the first try three-quarters of the time. Furthermore, sex, age, smoking habit of the participant, and menstrual cycle phase in the women were factors in successful outcomes.

Adolescent↗
PubMedDate not supplied

Pulsepolarographic determination of 6-benzyl-2-thio-uracil.

Polarographic (DPP) activity of 6-benzyl-2-thiouracil (6-benzyl-2-mercapto-4-pyrimidinol, BTU) has been examined in a wide range of pH values and it has been discovered that the number and the height of observed peaks depends on composition of supporting electrolyte and concentration of the thiol. Two different types of signals can be obtained. One of them is controlled by diffusion while the other by adsorption. The procedure for the determination of BTU in pure samples in 0.1 mol.dm-3 sodium hydroxide solution has been worked out. The measurements can be performed in a range 3.10(-4)-3.10(-3) mol.dm-3 of BTU. The detection limit is however lower and reaches 5.10(-6) mol.dm-3. The method has been used in the determination of BTU in an antithyroid drug Basdène.

Antithyroid Agents↗