Comparative evaluation of HD 2D/3D laparoscopic monitors and benchmarking to a theoretically ideal 3D pseudodisplay: even well-experienced laparoscopists perform better with 3D.

BACKGROUND: Though theoretically superior to standard 2D visualization, 3D video systems have not yet achieved a breakthrough in laparoscopy. The latest 3D monitors, including autostereoscopic displays and high-definition (HD) resolution, are designed to overcome the existing limitations. METHODS: We performed a randomized study on 48 individuals with different experience levels in laparoscopy. Three different 3D displays (glasses-based 3D monitor, autostereoscopic display, and a mirror-based theoretically ideal 3D display) were compared to a 2D HD display by assessing multiple performance and mental workload parameters and rating the subjects during a laparoscopic suturing task. Electromagnetic tracking provided information on the instruments' pathlength, movement velocity, and economy. The usability, the perception of visual discomfort, and the quality of image transmission of each monitor were subjectively rated. RESULTS: Almost all performance parameters were superior with the conventional glasses-based 3D display compared to the 2D display and the autostereoscopic display, but were often significantly exceeded by the mirror-based 3D display. Subjects performed a task faster and with greater precision when visualization was achieved with the 3D and the mirror-based display. Instrument pathlength was shortened by improved depth perception. Workload parameters (NASA TLX) did not show significant differences. Test persons complained of impaired vision while using the autostereoscopic monitor. The 3D and 2D displays were rated user-friendly and applicable in daily work. Experienced and inexperienced laparoscopists profited equally from using a 3D display, with an improvement in task performance about 20%. CONCLUSION: Novel 3D displays improve laparoscopic interventions as a result of faster performance and higher precision without causing a higher mental workload. Therefore, they have the potential to significantly impact the further development of minimally invasive surgery. However, as shown by the custom-built 3D mirror display, this effect can be improved, thus stimulating further research.

[Further technical and digital development in minimally invasive and conventional surgery]. / Technische und digitale Weiterentwicklung in der laparoskopischen/offenen Chirurgie.

Technological innovations have initiated a fundamental change in invasive therapeutic approaches which has led to a welcome reduction of surgical trauma but was also associated with a declining role of conventional surgery. Active utilization of future technological developments is decisive to promote new therapeutic strategies and to avoid a further loss of importance of surgery. This includes individualized preoperative therapy planning as well as intraoperative diagnostic work-up and navigation and the use of new functional intelligent implants. The working environment "surgical operating room" has to be refurbished into an integrated cooperating functional system. The impact of new technological developments is particularly obvious in minimally invasive surgery. There is a clear tendency towards further reduction in trauma in the surgical access. The incision will become smaller and the number of ports will be further reduced, with the aim of ultimately having just one port (monoport surgery) or even via natural access routes (scarless surgery). Among others, improved visualization including, e.g. autostereoscopy, digital image processing and intelligent support systems, which are able to assist in a cooperative way, will enable these goals to be achieved.

Molecular dispersion energy parameters for alkali and halide ions in aqueous solution.

Thermodynamic properties of aqueous solutions containing alkali and halide ions are determined by molecular simulation. The following ions are studied: Li(+), Na(+), K(+), Rb(+), Cs(+), F(-), Cl(-), Br(-), and I(-). The employed ion force fields consist of one Lennard-Jones (LJ) site and one concentric point charge with a magnitude of ±1 e. The SPC/E model is used for water. The LJ size parameter of the ion models is taken from Deublein et al. [J. Chem. Phys. 136, 084501 (2012)], while the LJ energy parameter is determined in the present study based on experimental self-diffusion coefficient data of the alkali cations and the halide anions in aqueous solutions as well as the position of the first maximum of the radial distribution function of water around the ions. On the basis of these force field parameters, the electric conductivity, the hydration dynamics of water molecules around the ions, and the enthalpy of hydration is predicted. Considering a wide range of salinity, this study is conducted at temperatures of 293.15 and 298.15 K and a pressure of 1 bar.

Breathing pattern and thoracoabdominal asynchrony in horses with chronic obstructive and inflammatory lung disease.

The aim of the study was to show that changes in thoracoabdominal asynchrony (TAA) between quiet breathing and CO2-induced hyperpnoea can be used to differentiate between horses with healthy airways and those suffering from inflammatory airway disease (IAD) or recurrent airway obstruction (RAO). The level of TAA was displayed by the Pearson's correlation coefficient (PCC) of thoracic and abdominal signals, generated by respiratory ultrasonic plethysmography (RUP) during quiet breathing and hyperpnoea. Changes in TAA were expressed as the quotient of the PCCs (PCCQ) during normal breathing and hyperpnoea. Horses with RAO and IAD showed significant higher median PCCQ than healthy horses. Median PCCQ of horses with RAO and IAD was not significantly different. Horses affected by a pulmonary disorder showed lower TAA compared to the control group. This study suggests that TAA provides a useful parameter to differentiate horses with RAO and IAD from healthy horses.

Risks of seawater ozonation in recirculation aquaculture--effects of oxidative stress on animal welfare of juvenile turbot (Psetta maxima, L.).

Ozone is frequently used for water treatment and disinfection in recirculating aquaculture systems. However, due to the fragmentary data on chronic toxicity of ozone produced oxidants (OPO) and its safe concentrations, the daily application of ozone in aquaculture is challenging. To evaluate the chronic effects of sublethal OPO concentrations, juvenile turbot (Psetta maxima, L.) were exposed to OPO concentrations of 0.06, 0.10 and 0.15 mg/l for 21 days. Gills were analysed for histopathological alterations and mRNA expression of heat shock protein 70 (hsp70), hsp90 as well as glutathione-S-transferase (gst) were determined in the gills and the liver after 1d, 7d and 21 d. Histopathologic findings confirmed adverse effects at 0.10-0.15 mg/l, but these (necrosis, lamellar clubbing, hypertrophy, hyperplasia) could only be observed after an extended exposure (mostly 21 d), and were considered as irreversible tissue damage. Hsp70 expression in the gills was only significantly increased at the highest OPO concentration (0.15 mg/l) on 1d and 7d, and returned to basic levels until day 21. Hsp90 mRNA was already increased at 0.10mg/l after 1 and 7 days of exposure, and again was comparable to the control group on day 21. In contrast, elevated gst mRNA expression was only observed on day 7 at 0.10mg and 0.15 mg/l. Although similar trends were observed in the liver for all markers, differences were only significant in exceptional cases due to the high individual variation observed. Thus, mRNA expression in the gills rather than in the liver is recommended as a marker to characterize OPO-induced oxidative stress in turbot. It has to be noted that mRNA expression returned to basic levels on day 21 regardless the actual OPO concentration, suggesting a collapse of adaptive mechanisms as a possible explanation for the observed tissue damage.

Characterization and cloning of an (R)-specific trans-2,3-enoylacyl-CoA hydratase from Rhodospirillum rubrum and use of this enzyme for PHA production in Escherichia coli.

An (R)-trans-2,3-enoylacyl-CoA hydratase was purified to near-homogeneity from Rhodospirillum rubrum. Protein sequencing of enriched protein fractions allowed the construction of a degenerate oligonucleotide. The gene encoding the (R)-specific hydratase activity was cloned following three rounds of colony hybridization using the oligonucleotide, and overexpression of the gene in E. coli led to the purification of the enzyme to homogeneity. The purified enzyme used crotonyl-CoA, trans-2,3-pentenoyl-CoA, and trans-2,3-hexenoyl-CoA with approximately equal specificity as substrates in the hydration reaction. However, no activity was observed using trans-2,3-octenoyl-CoA as a substrate, but this compound did partially inhibit crotonyl-CoA hydration. Based on the nucleotide sequence, the protein has a monomeric molecular weight of 15.4 kDa and is a homotetramer in its native form as determined by gel filtration chromatography and native PAGE. The hydratase was expressed together with the PHA synthase from Thiocapsa pfennigii in E. coli strain DH5alpha. Growth of these strains on oleic acid resulted in the production of the terpolyester poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) .

Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) formation from gamma-aminobutyrate and glutamate.

To provide 4-hydroxybutyryl-CoA for poly(3-hydroxybutyrate-co-4-hydroxybutyrate) formation from glutamate in Escherichia coli, an acetyl-CoA:4-hydroxybutyrate CoA transferase from Clostridium kluyveri, a 4-hydroxybutyrate dehydrogenase from Ralstonia eutropha, a gamma-aminobutyrate:2-ketoglutarate transaminase from Escherichia coli, and glutamate decarboxylases from Arabidopsis thaliana or E. coli were cloned and functionality tested by expression of single genes in E. coli to verify enzymatic activity, and uniquely assembled as operons under the control of the lac promoter. These operons were independently transformed into E. coli CT101 harboring the runaway replication vector pJM9238 for polyhydroxyalkanoate (PHA) production. Plasmid pJM9238 contains the PHA biosynthetic operon of R. eutropha under tac promoter control. Polyhydroxyalkanoate formation was monitored by nuclear magnetic resonance (NMR) spectroscopic analysis of the chloroform extracted and ethanol precipitated polyesters. Functionality of the biosynthetic pathway for copolymer production was demonstrated through feeding experiments using various carbon sources that supplied different precursors within the 4HB-CoA biosynthetic pathway.

The technologies of time measurement: implications at the bedside and the bench.

This essay explores how chronologically linked indices of health and illness, such as variation in body temperature, achieved clinical and scientific significance. It shows why time has been a potent concept through which key associations among the data of medicine are ordered and revealed, and it examines the graphical and case reporting methods of organizing evidence that made such associations possible.

Metabolic engineering of Arabidopsis and Brassica for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer production.

Poly(hydroxyalkanoates) are natural polymers with thermoplastic properties. One polymer of this class with commercial applicability, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) can be produced by bacterial fermentation, but the process is not economically competitive with polymer production from petrochemicals. Poly(hydroxyalkanoate) production in green plants promises much lower costs, but producing copolymer with the appropriate monomer composition is problematic. In this study, we have engineered Arabidopsis and Brassica to produce PHBV in leaves and seeds, respectively, by redirecting the metabolic flow of intermediates from fatty acid and amino acid biosynthesis. We present a pathway for the biosynthesis of PHBV in plant plastids, and also report copolymer production, metabolic intermediate analyses, and pathway dynamics.

PHA production, from bacteria to plants.

The genes encoding the polyhydroxyalkanoate (PHA) biosynthetic pathway in Ralstonia eutropha (3-ketothiolase, phaA or bktB; acetoacetyl-CoA reductase, phaB; and PHA synthase, phaC) were engineered for plant plastid targeting and expressed using leaf (e35S) or seed-specific (7s or lesquerella hydroxylase) promoters in Arabidopsis and Brassica. PHA yields in homozygous transformants were 12-13% of the dry mass in homozygous Arabidopsis plants and approximately 7% of the seed weight in seeds from heterozygous canola plants. When a threonine deaminase was expressed in addition to bktB, phaB and phaC, a copolyester of 3-hydroxybutyrate and 3-hydroxyvalerate was produced in both Arabidopsis and Brassica.

Isolation of mutants of Acinetobacter calcoaceticus deficient in wax ester synthesis and complementation of one mutation with a gene encoding a fatty acyl coenzyme A reductase.

Acinetobacter calcoaceticus BD413 accumulates wax esters and triacylglycerol under conditions of mineral nutrient limitation. Nitrosoguanidine-induced mutants of strain BD413 were isolated that failed to accumulate wax esters under nitrogen-limited growth conditions. One of the mutants, Wow15 (without wax), accumulated wax when grown in the presence of cis-11-hexadecenal and hexadecanol but not hexadecane or hexadecanoic acid. This suggested that the mutation may have inactivated a gene encoding either an acyl-acyl carrier protein or acyl-coenzyme A (CoA) reductase. The Wow15 mutant was complemented with a cosmid genomic library prepared from wild-type A. calcoaceticus BD413. The complementary region was localized to a single gene (acr1) encoding a protein of 32,468 Da that is 44% identical over a region of 264 amino acids to a product of unknown function encoded by an open reading frame associated with mycolic acid synthesis in Mycobacterium tuberculosis H37Ra. Extracts of Escherichia coli cells expressing the acr1 gene catalyzed the reduction of acyl-CoA to the corresponding fatty aldehyde, indicating that the gene encodes a novel fatty acyl-CoA reductase.

Linking excellence in teaching to departments' budgets.

It is time for the research and clinical practice communities, which dominate medical schools, to realize that the enhanced support of teaching is essential not only for students and society but also because these communities' successes hinge on how well their investigators and clinicians were taught. The need to learn more about the evaluation of teaching should not be a barrier to the productive use of current knowledge about it, which is sufficient for schools to improve the standing and effectiveness of teaching. A greater focus on teaching is even more urgent now because the disbursement of medical school funding is changing, and fewer funds are being allowed for the use of education. Also, other pressures, such as greater demands on faculty time for research and patient care activities and the tendency for research and clinical care to evolve into autonomously governed activities, are distracting faculty from teaching. To establish a superior ethos for education, the author proposes a new approach to faculty compensation and advancement, in which half of the available resources would be distributed according to departmental merit, which would link compensation to the performance of the faculty group composing a department. Performance in both research and teaching in all venues of medical work would be weighed equally. The dean's office would be responsible for making departmental merit awards, using advice and information from faculty, students, and administrative staff, and all decisions would be reviewed with each department chair.(ABSTRACT TRUNCATED AT 250 WORDS)

The ethics of learning and teaching medicine.

During the second half of the twentieth century, medicine turned its attention to the ethics of practice. A large and important literature has developed that clarifies the problems generated in the treatment of illness. The same focused attention now should be given to ethical issues and relationships connected with teaching and learning in medicine and to elaborating an ethics of education. Pedagogic relationships anticipate professional relationships. The associations that medical students form with teachers, patients, school, and each other, and the values that shape them have a great influence in determining the sort of physicians students will be. This article examines ethical principles and their application to the relationships and pedagogic problems encountered in studying and teaching medicine. It shows how the introduction of ethics into these areas can not only help students and teachers but also enhance the standing of teaching itself.