A randomised controlled trial of 7.5-mm and 7.0-mm tracheal tubes vs. 6.5-mm and 6.0-mm tracheal tubes for men and women during laparoscopic surgery.

Sore throat after tracheal intubation impairs postoperative recovery. We randomly allocated 172 ASA physical status 1-2 participants, scheduled for laparoscopic lower abdominal surgery, to tracheal intubation with larger tubes (n = 88) or smaller tubes (n = 84), with internal diameters 7.5-mm vs. 6.5-mm for men and 7.0-mm vs. 6.0-mm for women. Primary outcome was the rates of no, mild, moderate or severe sore throat 1 h after surgery, which were 60, 10, 17 and 1 with larger tracheal tubes and 79, 5, 0 and 0 with smaller tubes, p < 0.001. The equivalent rates 24 h after surgery were 64, 16, 8 and 0 vs. 74, 6, 3 and 1, p = 0.037. Intra-operative ventilatory variables were unaffected by tube diameter, including peak inspiratory pressure, plateau pressure and end-tidal carbon dioxide partial pressure. In summary, smaller tracheal tubes benefitted patients having laparoscopic operations.

Metal diffusion barriers for GaAs solar cells.

In this study accelerated ageing testing (AAT), J-V characterization and TEM imaging in combination with phase diagram data from literature are used to assess the potential of Ti, Ni, Pd and Pt as diffusion barriers for Au/Cu-based metallization of III-V solar cells. Ni barriers show the largest potential as at an AAT temperature of 250 °C both cells with 10 and 100 nm thick Ni barriers show significantly better performance compared to Au/Cu cells, with the cells with 10 nm Ni barriers even showing virtually no degradation after 7.5 days at 250 °C (equivalent to 10 years at 100 °C at an Ea of 0.70 eV). Detailed investigation shows that Ni does not act as a barrier in the classical sense, i.e. preventing diffusion of Cu and Au across the barrier. Instead Ni modifies or slows down the interactions taking place during device degradation and thus effectively acts as an 'interaction' barrier. Different interactions occur at temperatures below and above 250 °C and for thin (10 nm) and thick (100 nm) barriers. The results of this study indicate that 10-100 nm thick Ni intermediate layers in the Cu/Au based metallization of III-V solar cells may be beneficial to improve the device stability upon exposure to elevated temperatures.

Degradation mechanism(s) of GaAs solar cells with Cu contacts.

Substrate-based GaAs solar cells having a dense Au/Cu front contact grid with 45% surface coverage were exposed to accelerated life testing at temperatures between 200 and 300 °C. TEM analysis of the front contacts was used to gain a better understanding of the degradation process. During accelerated life testing at 200 °C only intermixing of the Au and Cu in the front contact occurs, without any significant influence on the J-V curve of the cells, even after 1320 h (55 days) of accelerated life testing. At temperatures ≥250 °C a recrystallization process occurs in which the metals of the contact and the GaAs front contact layer interact. Once the grainy recrystallized layer starts to approach the window, diffusion via grain boundaries to the window and into the active region of the solar cells occurs, causing a decrease in Voc due to enhanced non-radiative recombination via Cu trap levels introduced in the active region of the solar cell. To be a valid simulation of space conditions the accelerated life testing temperature should be <250 °C in future experiments, in order to avoid recrystallization of the metals with the GaAs contact layer.

Preliminary study of osmotic membrane bioreactor: effects of draw solution on water flux and air scouring on fouling.

Preliminary study on a novel osmotic membrane bioreactor (OMBR) was explored. Objective of this study was to investigate the effects of draw solution on membrane flux and air scouring at the feed side on fouling tendency in a pilot OMBR system composing the anoxic/aerobic and forward osmosis (FO) processes. Domestic sewage was the raw feed, FO membrane from HTI and NaCl/MgSO4 draw solutions were used in the experiments. Fluxes of 3 l/m2/h (LMH) and 7.2 LMH were achieved at osmotic pressure of 5 and 22.4 atm, respectively. No significant flux decline was observed at 3 LMH over 190 h and at 7.2 LMH over 150 h when air scouring was provided at the feed side of the membrane. However, without air scouring, the flux at 22.4 atm osmotic pressure declined by 30% after 195 h and then levelled off. The potential advantages of the fouling reversibility with air scouring under the operating conditions of the pilot OMBR and better water quality in OMBR over the conventional MBR were preliminarily demonstrated.

Cryptopain-1, a cysteine protease of Cryptosporidium parvum, does not require the pro-domain for folding.

SUMMARY: Cryptosporidium parvum is an intracellular protozoan parasite that causes cryptosporidiosis in mammals including humans. In the current study, the gene encoding the cysteine protease of C. parvum (cryptopain-1) was identified and the biochemical properties of the recombinant enzyme were characterized. Cryptopain-1 shared common structural properties with cathepsin L-like papain family enzymes, but lacked a typical signal peptide sequence and contained a possible transmembrane domain near the amino terminus and a unique insert in the front of the mature domain. The recombinant cryptopain-1 expressed in Escherichia coli and refolded to the active form showed typical biochemical properties of cathepsin L-like enzymes. The folding determinant of cryptopain-1 was characterized through multiple constructs with or without different lengths of the pro-domain of the enzyme expressed in E. coli and assessment of their refolding abilities. All constructs, except one that did not contain the full-length mature domain, successfully refolded into the active enzymes, suggesting that cryptopain-1 did not require the pro-domain for folding. Western blot analysis showed that cryptopain-1 was expressed in the sporozoites and the enzyme preferentially degraded proteins, including collagen and fibronectin, but not globular proteins. This suggested a probable role for cryptopain-1 in host cell invasion and/or egression by the parasite.

Protective immunity of SpaA-antigen producing Lactococcus lactis against Erysipelothrix rhusiopathiae infection.

AIMS: To develop an economical, safe and simple vaccination system against swine erysipelas using SpaA-antigen producing Lactococcus lactis. METHODS AND RESULTS: The spaA gene of Erysipelothrix rhusiopathiae was inserted into a shuttle plasmid pSECE1 to construct pSECE1.3. The SpaA produced in L. lactis maintained a stable antigenicity without degrading in growth. After mice were inoculated intranasally and orally with pSECE1.3-carrying L. lactis cells, IgG and IgA specific to SpaA were detected, and all the mice survived a challenge with 100 LD(50) of E. rhusiopathiae Tama-96 in the inner thigh. CONCLUSIONS: SpaA-producing L. lactis appears useful as an effective subunit vaccine against swine erysipelas. SIGNIFICANCE AND IMPACT OF THE STUDY: In this vaccination system, purification of the antigen and injection are unnecessary, leading to a reduced production cost, reduced labour and less stress to the animals. This vaccination system of the lactic acid bacteria should be a safe and suitable vehicle for a polyvalent vaccine.

Rapid and effective detection of anthrax spores in soil by PCR.

AIMS: To detect Bacillus anthracis DNA from soil using rapid and simple procedures. METHODS AND RESULTS: Various amounts of B. anthracis Pasteur II spores were added artificially to 1 g of soil, which was then washed with ethanol and sterile water. Enrichment of the samples in trypticase soy broth was performed twice. A DNA template was prepared from the second enrichment culture using a FastPrep instrument. The template was then used for nested and real-time polymerase chain reaction (PCR) with B. anthracis-specific primers, to confirm the presence of B. anthracis chromosomal DNA and the pXO1/pXO2 plasmids. CONCLUSIONS: One cell of B. anthracis in 1 g of soil could be detected by nested and real-time PCR. The usefulness of the PCR method using field samples was also confirmed. SIGNIFICANCE AND IMPACT OF THE STUDY: The results indicate that this could be a useful method for detecting anthrax-spore contaminated soil with high sensitivity. Its application could have great impact on the progress of epidemiological surveillance.

Detection of anthrax spores from the air by real-time PCR.

AIMS: To detect and isolate Bacillus anthracis from the air by a simple and rapid procedure. METHODS AND RESULTS: One hundred litres of air were filtered through an air monitor device. After the membrane was suspended in PBS, spores of B. anthracis were added. The suspension was plated on Bacillus cereus selective agar (BCA) plates to detect B. anthracis colonies. The suspension was also heated at 95 degrees C for 15 min and used for real-time PCR using a Light Cycler system and anthrax-specific primers. CONCLUSION: A single cell of B. anthracis was detected by real-time PCR within 1 h and was also isolated on a BCA plate within two d. SIGNIFICANCE AND IMPACT OF THE STUDY: Our results provide evidence that anthrax spores from the atmosphere can be detected rapidly, suggesting that real-time PCR and a Light Cycler provides a flexible and powerful tool to prevent epidemics.

A simple and sensitive detection system for Bacillus anthracis in meat and tissue.

AIMS: To detect and isolate Bacillus anthracis from meat and tissue by rapid and simple procedures. METHODS AND RESULTS: Bacillus anthracis Pasteur II cells were added to 1 g lymph node and pig meat, which were then cut into small pieces and suspended in PBS. Aliquots were spread on Bacillus cereus selective agar (BCA) plates to isolate B. anthracis cells, and incubated in trypticase soy broth. The enrichment culture was used for nested PCR with B. anthracis specific primers, which were to confirm the presence of B. anthracis chromosomal DNA and the pXO1/pXO2 plasmids. CONCLUSION: One cell of B. anthracis was detected by nested PCR from 1 g of the samples, and was also isolated on BCA plates according to colony morphology within two days. SIGNIFICANCE AND IMPACT OF THE STUDY: These results could be useful for detecting animals with latent anthrax, and meat contaminated with B. anthracis, rapidly and simply.

Antibacterial activity of chaff vinegar and its practical application.

Since enterohemorrhagic Escherichia coli O157, Salmonella, etc., sometimes contaminate animal feces and may cause infectious diseases to humans, it is important to remove pathogenic bacteria from domestic animal waste. For the purpose, we examined the antibacterial activity of chaff vinegar. We found that the chaff vinegar inhibited the growth of pathogenic bacteria immediately in vitro but not efficiently spores and lactic acid bacteria. Further, it removes bacteria, especially Enterobacteriaceae, from animal feces and the surface of the concrete-floor in the cattle barn. Chaff vinegar is advertised as a natural chemical substance for a soil conditioner, to promote the composting and to deodorize their smell. Chaff vinegar may be useful for organic agriculture without enteric pathogenic bacteria.

Establishment of the PCR system specific to Salmonella spp. and its application for the inspection of food and fecal samples.

We established the PCR detection system specific to Salmonella species using Salmonella enterotoxin gene (stn). The detection limit was one bacterial cell per one gram of fecal and minced-meat samples using enrichment procedure by Tripticase soy broth or Salmonella enrichment broth, respectively. We concluded that this PCR system is useful for the practical application in the field of the public hygiene.