A new culture-independent system for microbial monitoring, called the Lab-On-a-Chip Application Development Portable Test System (LOCAD-PTS), was operated aboard the International Space Station (ISS). LOCAD-PTS was launched to the ISS aboard Space Shuttle STS-116 on December 9, 2006, and has since been used by ISS crews to monitor endotoxin on cabin surfaces. Quantitative analysis was performed within 15 minutes, and sample return to Earth was not required. Endotoxin (a marker of Gram-negative bacteria) was distributed throughout the ISS, despite previous indications that mostbacteria on ISS surfaces were Gram-positive [corrected].Endotoxin was detected at 24 out of 42 surface areas tested and at every surface site where colony-forming units (cfu) were observed, even at levels of 4-120 bacterial cfu per 100 cm(2), which is below NASA in-flight requirements (<10,000 bacterial cfu per 100 cm(2)). Absent to low levels of endotoxin (<0.24 to 1.0 EU per 100 cm(2); defined in endotoxin units, or EU) were found on 31 surface areas, including on most panels in Node 1 and the US Lab. High to moderate levels (1.01 to 14.7 EU per 100 cm(2)) were found on 11 surface areas, including at exercise, hygiene, sleeping, and dining facilities. Endotoxin was absent from airlock surfaces, except the Extravehicular Hatch Handle (>3.78 EU per 100 cm(2)). Based upon data collected from the ISS so far, new culture-independent requirements (defined in EU) are suggested, which are verifiable in flight with LOCAD-PTS yet high enough to avoid false alarms. The suggested requirements are intended to supplement current ISS requirements (defined in cfu) and would serve a dual purpose of safeguarding crew health (internal spacecraft surfaces <20 EU per 100 cm(2)) and monitoring forward contamination during Constellation missions (surfaces periodically exposed to the external environment, including the airlock and space suits, <0.24 EU per 100 cm(2)).
The theory of planned behaviour (TPB) was used to guide an analysis of intentions to recycle household waste in a geographical area (Glasgow, Scotland) with relatively poor recycling facilities. A sample of 252 members of the public completed a questionnaire (response rate of 66%). In addition to TPB variables, the contributions of past recycling behaviour, perceived habit of recycling, and perceived lack of recycling facilities were considered. The TPB components contributed 29% to the variance of intentions to recycle; attitudes and perceived behavioural control (PBC) (but not the subjective norm) were significant on entry. Past recycling and perceived habit made significant independent contributions. Contrary to expectations, there was some evidence to suggest that (a) the past behaviour–intention relationship was stronger for those with no perceived habit of recycling, and (b) the attitude–intention relationship was stronger for those who had recycled more in the past. There was also evidence to suggest that the PBC–intention relationship was weaker when facilities were perceived to be lacking. The findings highlighted methodological, theoretical, and social issues, and it was concluded that full account should be taken of the social context in such research.
The design, development, and evaluation of an experimental translation system that aims to aid transactions between a deaf person and a clerk in a post office (PO) is described. The system uses a speech recognizer to recognize speech from a PO clerk and then synthesizes recognized phrases in British Sign language (BSL) using a specially developed avatar. The main objective in developing this prototype system was to determine how useful it would be to a customer whose first language was BSL, and to discover what areas of the system required more research and development to make it more effective. The system was evaluated by 6 prelingually profoundly deaf people and 3 PO clerks. Deaf users and PO clerks were supportive of the system, but the former group required a higher quality of signing from the avatar and the latter a system that was less constrained in the phrases it could recognize; both these areas are being addressed in the next phase of development.
Rust, Orion Albert MD; Atlas, Robert Oliver MD; Wells, Mark BS; Kimmel, Sharon PhD, MHA Author Information
OBJECTIVE: The study was undetaken to measure cerclage location within the cervix and to determine whether placement closer to the internal os is related to perinatal outcome.STUDY DESIGN: We analyzed data collected during a randomized trial of cervical cerclage versus no cerclage that was conducted at Lehigh Valley Hospital between May 1998 and June 2001 in women with ultrasound findings of short cervix less than 25 mm or funneling between 16 and 24 weeks' gestation. Women who were randomly assigned to the cerclage arm had cervical measurements performed before cerclage, including dilation of the internal os, depth of membrane prolapse into the endocervical canal, cervical length below any funnel (distal length), and total cervical length (including any funnel). Measurements obtained after cerclage placement included the distance from external os to cerclage (A), and a repeat of the same four measurements. The distance from the external os to the cerclage (A) was divided by the total cervical length (B) and a cerclage to cervical length ratio (A/B) was calculated. The relationship between these measurements and gestational age at birth was assessed by linear regression analysis.RESULTS: Of 150 patients enrolled, 74 received a McDonald cerclage suture. Mean distal cervical length was 1.9 +/- 0.9 cm before and 2.9 +/- 1.0 cm after cerclage (P =.001). The mean distance between the cerclage and external os (A) was 1.8 +/- 0.6 cm; the total cervical length after cerclage (B) was 3.6 +/- 0.9 cm. The mean cerclage to cervical length ratio (A/B) was 0.5 +/- 0.1. Linear regression analysis did not demonstrate a correlation between either the cerclage to external os measurement (A) or the cervical length ratio (A/B) and gestational age at birth (R-2 = 0.0006 and 0.008, P =.8 and .6, respectively).CONCLUSION: The length of the cervix below the level of cerclage is not related to duration of pregnancy in women treated with cerclage because of ultrasound evidence of cervical effacement. (Am J Obstet Gynecol 2003;189:1688-91.)
Macromolecular crystals during their growth, incorporate an extensive array of impurities which vary from individual molecules to large particles, and even microcrystals in the micron size range. AFM (atomic force microscopy) along with X-ray topology has shown that the density of defects and faults in most macromolecular crystals is several orders of magnitude higher than in conventional crystals. High defect and impurity density contributes, in turn, to a deterioration of both the mechanical and diffraction properties of crystals, thereby lessening their value for structural biology. In microgravity, access by impurities and aggregates to growing crystal surfaces is restricted due to the elimination of convention and to altered fluid transport properties. We designed, and have now completed construction of an instrument, the OPCGA (Observable Protein Crystal Growth Apparatus) that employs a fused optics, phase shift, Mach-Zehnder interferometer, along with polarized light, time lapse video microscopy to analyze the fluid environment around growing crystals. Using this device, which will ultimately be deployed on the International Space Station, we have, in thin cells on Earth, succeeded in directly visualizing macromolecule concentration gradients around growing protein crystals. This provides the first direct evidence that quasi-stable depletion zones formed around growing crystals in space may explain the improved quality of macromolecular crystals grown in microgravity. Further application of the interferometric technique will allow us to quantitatively describe the shapes, extent, and magnitudes of the concentration gradients and to evaluate their degree of stability. The OPCGA ultimately will be used by the broad crystal growth community to study, and quantitatively describe the development of a vast range of macromolecular crystals. This will have a significant impact on our understanding of crystal growth phenomena and our ability to improve and control the process on earth.
A small rugged interferometer was required for measuring the depletion zones generated in a protein crystal growth experiment. The exploration for an optimum solution yielded an instrument that uses solid optical design techniques, where air is removed from the optical path and replaced with 'solid air' or glass. The interferometer is a Mach-Zehnder configuration with the reference and test arms separated as orthogonal polarization states with a polarization beam splitting cube (PBSC), then recombined by another PBSC, maintaining the orthogonality of the reference and test beam polarizations. An off-the-shelf liquid crystal variable phase plate was sufficient to produce the necessary 2(pi) phase shift. The device was built and tested and shoed excellent performance. The spatial resolution of the interferometer is limited only by the 0.011mm pixels at the 5 by 5 mm detector and the imager is operating at telecentric 1:1 conjugates. Phase resolution, using the Hariharan 5-step algorithm, is measured to be better than (lambda) /50. In this paper, calibration test results are presented and future upgrades are outlined.
Atomic force microscopy (AFM) investigations have revealed that macromolecular crystals, during their growth, incorporate an extensive array of impurities. These vary from individual molecules to large particles, and microcrystals in the micron size range. AFM, along with X-ray topology, has further shown that the density of defects and faults in most macromolecular crystals is very high in comparison with conventional crystals. The high defect density is a consequence of the incorporation of impurities, misoriented nutrient molecules, and aggregates of molecules. High defect and impurity density, contributes to a deterioration of both the mechanical and the diffraction properties of crystals. In microgravity, access by impurities and aggregates to growing crystal surfaces is restricted due to altered fluid transport properties. We designed, and have now constructed an instrument, the observable protein crystal growth apparatus (OPCGA) that employs a fused optics, phase shift, Mach–Zehnder interferometer to analyze the fluid environment around growing crystals. Using this device, which will ultimately be employed on the international space station, we have, in thin cells on earth, succeeded in directly visualizing concentration gradients around growing protein crystals. This provides the first direct evidence that quasi-stable depletion zones formed around growing crystals in space may explain the improved quality of macromolecular crystals grown in microgravity. Further application of the interferometric technique will allow us to quantitatively describe the shapes, extent, and magnitudes of the concentration gradients and to evaluate their degree of stability.
Understanding the phenomena of protein crystal growth has become a critical factor in the advancement of fundamental life sciences. To characterize this process, sensitive non-intrusive monitoring systems must be utilized in a micro-gravity environment. We believe detailed optical monitoring to be the superior technique for use in micro-gravity. The proposed approach includes monitoring the nucleation event, rate and form of crystal growth, and protein density variations throughout the cell volume with four different optical metrology methods running concurrently. The system will incorporate photon correlation spectroscopy, interferometry, Zernike phase contrast imagery, and high-resolution polarization microscopy. These four systems have all been combined into a single optical module that provides crystal growth process data. The module utilizes the emerging technologies of binary optics and solid optics to shrink and stabilize the system (patent-pending).
Crystal growth research over the last 15 years indicates that much of the inability of crystal growers to reach the theoretical limits of perfection in their crystals is due to gravity induced convection. Investigators worldwide are preparing experiments to test the influence of low gravity found in space on the growth of many crystalline materials. However, power limitations prevent existing space crystal growth furnaces from being able to process samples any larger than about 2 cm, and in addition, the background microgravity levels found on the Space Shuttle are not low enough to significantly benefit samples much larger than 2 cm. This paper describes a novel concept of a free-flying platform utilizing well-established solar furnace technology to enable materials processing in space experiments on large-diameter crystals. The conceptual design of this Solar Furnace Satellite is described along with its operational scenario and the anticipated g levels.