CYP154C5 Regioselectivity in Steroid Hydroxylation Explored by Substrate Modifications and Protein Engineering**

CYP154C5 from Nocardia farcinica is a P450 monooxygenase able to hydroxylate a range of steroids with high regio- and stereoselectivity at the 16α-position. Using protein engineering and substrate modifications based on the crystal structure of CYP154C5, an altered regioselectivity of the enzyme in steroid hydroxylation had been achieved. Thus, conversion of progesterone by mutant CYP154C5 F92A resulted in formation of the corresponding 21-hydroxylated product 11-deoxycorticosterone in addition to 16α-hydroxylation. Using MD simulation, this altered regioselectivity appeared to result from an alternative binding mode of the steroid in the active site of mutant F92A. MD simulation further suggested that the entrance of water to the active site caused higher uncoupling in this mutant. Moreover, exclusive 15α-hydroxylation was observed for wild-type CYP154C5 in the conversion of 5α-androstan-3-one, lacking an oxy-functional group at C17. Overall, our data give valuable insight into the structure–function relationship of this cytochrome P450 monooxygenase for steroid hydroxylation.     

Lung lamellar bodies lack certain key enzymes of phospholipid metabolism

Palmitoyl CoA-glycerol-3-phosphate acyltransferase, phosphatidate phosphohydrolase, and phospholipase A were assayed in subcellular fractions of rat lung, including lamellar bodies, the putative site of storage and secretion of lung surfactant. The specific activity of each of these enzymes in lamellar bodies was relatively low and could be entirely accounted for by a small contamination of the lamellar bodies fraction by microsomes, as quantitated by the presence of the microsomal marker reduced triphosphopyridine nucleotide cytochromec reductase. These data indicate that lamellar bodies are not the site of synthesis of the lipid component of pulmonary surfactant by pathways involving these enzymes.     

Ontology-driven geographic information integration: A survey of current approaches

Integrating different information sources is a growing research area within different application domains. This is particularly true for the geographic information domain which is facing new challenges because newer and better technologies are capturing large amounts of information about the Earth. This trend can be combined with increases in the distribution of GIS (Geographic Information Systems) on the Web, which is leading to the proliferation of different geospatial information repositories and the subsequent need to integrate information across repositories to get consistent information. To overcome this situation, many proposals use ontologies in the integration process. In this paper we analyze and compare the most widely referred proposals of geographic information integration, focusing on those using ontologies as semantic tools to represent the sources, and to facilitate the integration process.     

A framework to capture dynamic data structures in pointer-based codes

To successfully exploit all the possibilities of current computer/multicomputer architectures, optimization compiling techniques are a must. However, for codes based on pointers and dynamic data structures, these optimization techniques have to be necessarily carried out after identifying the characteristics and properties of the data structure used in the code. We describe the framework and the analyzer we have implemented to capture complex data structures generated, traversed, and modified in codes based on pointers. Our method assigns a reduced set of reference shape graph (RSRSG) to each statement to approximate the shape of the data structure after the execution of such a statement. With the properties and operations that define the behavior of our RSRSG, the method can accurately detect complex recursive data structures such as a doubly linked list of pointers to trees where the leaves point to additional lists. Several experiments are carried out with real codes to validate the capabilities of our analyzer.     

Those Who are no Longer: Photographic image and representation of women’s absence(s) in Mayra Martell’s Ensayo de la Identidad at Ciudad Juarez

The article analyses the work of Mexican photographer Mayra Martell — particularly her series Ensayo de la identidad. Desaparición de mujeres en Ciudad Juárez, México 2005–2010 (Identity Essay. Disappearance of women in Ciudad Juarez, Mexico 2005–2010) — focusing on the visual strategies chosen to represent the absence of those women. this work is particularly interesting, considering both its points of contact and its distance from the strategies used for the representation of desaparecidos (victims of forced disappearance) in contemporary Argentine photography. Special attention is paid to the visual device proposed by Martell to represent these absent bodies and the strategies chosen to denounce these increasingly occurring individual stories with two biographical elements in common: being female and being young. Further, the relationships with previous productions from the Argentine photographic context are discussed in order to reflect on the specific procedures that can induce a tension on the naturalized link between photography and memory, between absence and representation, and between image and denunciation.     

The Advanced Encryption Standard — Implementation and Transition to a New Cryptographic Benchmark

Cryptography is the science of coding information to create unintelligible ciphers that conceal or hide messages. The process that achieves this goal is commonly referred to as encryption. Although encryption processes of various forms have been employed for centuries to protect the exchange of messages, the advent of the information age has underscored the importance of strong cryptography as a process to secure data exchanged through electronic means, and has accentuated the demand for products offering these services. This article describes the process that has led to the development of the latest cryptographic benchmark; the Advanced Encryption Standard (AES). The article briefly examines the requirements set forth for its development, defines how the new standard is implemented, and describes how government, business, and industry can transition to AES with minimum impact to operations.     

Magnetic Force Microscopy in Liquids

In this work, the use of magnetic force microscopy (MFM) to acquire images of magnetic nanostructures in liquid environments is presented. Optimization of the MFM signal acquisition in liquid media is performed and it is applied to characterize the magnetic signal of magnetite nanoparticles. The ability for detecting magnetic nanostructures along with the well‐known capabilities of atomic force microscopy in liquids suggests potential applications in fields such as nanomedicine, nanobiotechnology, or nanocatalysis.     

Relationship between nosocomial infection and hospital mortality. Multicenter study

The more commonly known statistical procedures, such as the t-test, analysis of variance, or chi-squared test, can handle only one dependent variable (DV) at a time. Two types of problems can arise when there is more than one DV: 1. a greater probability of erroneously concluding that there is a significant difference between the groups when in fact there is none (a Type I error); and 2. failure to detect differences between the groups in terms of the patterns of DVs (a Type II error). Multivariate statistics are designed to overcome both of these problems. However, there are costs associated with these benefits, such as increased complexity, decreased power, multiple ways of answering the same question, and ambiguity in the allocation of shared variance. This is the first of a series of articles on multivariate statistical tests which will address these issues and explain their possible uses.     

Risk of nosocomial infection in elderly patients admitted to a university hospital

BACKGROUND: A high percentage of current hospital visits are made by the elderly. The aim of this work is to quantify the risk of contracting a nosocomial infection among elderly patients admitted to a university hospital. METHODS: From the patients admitted from the emergency unit, outpatients and the waiting list, 6 patients of different age groups were chosen each day by a simple random sampling. The criteria of nosocomial infection were those of the CDC. The analysis of the information was made with the programme EPIINFO version 5. The chi 2 tests and Fisher's exact test were used to compare proportions. RESULTS: The rate of nosocomial infection in the group aged over 64 was 14.8%, showing statistically significant differences with respect to other age groups (p = 0.001). In this group the predominant infection was urinary, with an odds-ratio of 3.69, in comparison with the 25 to 44 age group. A prolonged hospital stay (> 15 days) has proved to be closely related to the risk of nosocomial infection in all age groups (p < 0.0001) in patients over 64. CONCLUSIONS: The greater risk of contracting nosocomial infections in the elderly makes it advisable to develop specific prevention programmes for this group, and the fitness of accommodations the length of stay to the care needs suitable to the hospital level.     

Assessment of patients' expectations before admission to a tertiary-care center

BACKGROUND: The customer's final satisfaction with health services depends to some extent, on the relationship between expectancy and perceived quality. Focus groups technique helps in the knowledge of those attributes that patients identified as perceived quality. MATERIAL AND METHODS: The study was performed in the Hospital Clínic i Provincial of Barcelona (HCPB), Spain, by selecting a sample of patient's included in the admission's waiting list (1994) of three common procedures: lens extraction, abdominal hernia repair and routine pregnancy control. The patients were distributed in 12 different semi-structured interview groups (focus groups) and video-taped. From the analysis of those tapes, the main concerns and aspects highlighted by consumers were identified, following a common set of rules: wording, context, internal consistency, precision/vagueness of answers and basic ideas. RESULTS: A total of 106 patients attend the interview. Patients with loss of visual acuity underscore the contribution of quality of life improvement expected from the procedure (technical quality of the surgical procedure, physical improvement and final outcomes). Patient's with abdominal hernia repair highlight the appearance and comfort of hospital setting as the most important item. Pregnant women emphasize the importance of a good follow-up process after delivery, as well as the need for individual services (dignity and intimate). CONCLUSION: The semi-structured interview method (focus group) could be applied in the context of our hospitals, and contribute to improve quality management at our institutions, making effective the patient participation.