Phacoemulsification versus extracapsular cataract extraction: a comparative study of cell survival and growth on the human capsular bag in vitro

AIMS/BACKGROUND: Phacoemulsification is rapidly replacing conventional extracapsular cataract extraction (ECCE) as the method of choice for cataract surgery in the Western world. However, posterior capsule opacification (PCO) still remains the major postoperative complication, affecting 20-50% of patients, and results from persistent cell growth of epithelial cells remaining after surgery. This study aimed to compare cell survival and growth on capsular bags following ECCE and phacoemulsification surgery using an established human capsular bag culture system. METHODS: Sham ECCE and phacoemulsification cataract operations were performed on pairs of human donor eyes. Capsular bags were dissected free, pinned flat on a petri dish, and incubated with Eagle's minimum essential medium (EMEM) alone or EMEM supplemented with 10% fetal calf serum (FCS). Ongoing observations were made using phase contrast microscopy. RESULTS: Cell growth was observed across the posterior capsule of all preparations studied. It was found that there was no significant difference in the rate of cell growth on the posterior capsule with the two extraction methods, such that 50% confluency was achieved in 7.0 (SD 1.8) (n = 7) days for ECCE and 7.43 (2.1) (n = 7) days for phacoemulsification surgery. The physical changes to the capsule as a result of cell growth, such as wrinkling and capsular tensioning, were also seen in both groups. CONCLUSIONS: Cell survival and growth is dependent on the donor, rather than the surgical technique performed. There is no significant difference between phacoemulsification and ECCE surgery on the rate and nature of cell growth on the posterior capsule in vitro.     

Experimental high performance sub-0.1 μm channel nMOSFET's

Very high performance sub-0.1 μm channel nMOSFET's are fabricated with 35 Å gate oxide and shallow source-drain extensions. An 8.8-ps/stage delay at V_dd=1.5 V is recorded from a 0.08 μm channel nMOS ring oscillator at 85 K. The room temperature delay is 11.3 ps/stage. These are the fastest switching speeds reported to date for any silicon devices at these temperatures. Cutoff frequencies (f_T) of a 0.08 μm channel device are 93 GHz at 300 K, and 119 GHz at 85 K, respectively. Record saturation transconductances, 740 mS/mm at 300 K and 1040 mS/mm at 85 K, are obtained from a 0.05 μm channel device. Good subthreshold characteristics are achieved for 0.09 μm channel devices with a source-drain halo process     

Interpersonal factors in brief treatment of depression: Further analyses of the National Institute of Mental Health Treatment of Depression Collaborative Research Program.

Previous analyses of data from the National Institute of Mental Health Treatment of Depression Collaborative Research Program indicate minimal differences in therapeutic outcome among 3 brief treatments for depression, but patients' pretreatment level of perfectionism had a significant negative relationship with residualized measures of clinical improvement. The present analyses indicate that the quality of the therapeutic relationship reported by patients early in treatment contributed significantly to the prediction of therapeutic change. The quality of the therapeutic relationship was only marginally predictive of therapeutic gain at low and high levels of perfectionism, but significantly predicted therapeutic gain at moderate levels of perfectionism. These findings suggest that the extensive efforts to compare different manual-directed treatments need to be balanced by commensurate attention to interpersonal dimensions of the therapeutic process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Self-Stabilization of an Actively Mode-Locked Semiconductor-Based Fiber-Ring Laser for Ultralow Jitter

Noise characteristics are studied for a self-stabilized laser utilizing the interplay between the intracavity dispersion and the optical frequency shift. The noise suppression bandwidth of this scheme is from 0 to ~100 KHz and showed the reduction of residual timing jitter (integrated from 0.9 Hz to 1 MHz) from 2.2fs to 660 attosecond which represents, to our knowledge, the lowest timing jitter reported for an actively mode-locked laser     

Pilot task-based assessment of noise levels among firefighters

Purpose

Over one million American firefighters are routinely exposed to various occupational hazards. While efforts have been made to identify and reduce some causes of injuries and illnesses among firefighters, relatively little has been done to evaluate and understand occupational noise exposures in this group. The purpose of this pilot study was to apply a task-based noise exposure assessment methodology to firefighting operations to evaluate potential noise exposure sources, and to use collected task-based noise levels to create noise exposure estimates for evaluation of risk of noise-induced hearing loss by comparison to the 8-hr and 24-hr recommended exposure limits (RELs) for noise of 85 and 80.3 dBA, respectively.

Methods

Task-based noise exposures (n = 100 measurements) were measured in three different fire departments (a rural department in Southeast Michigan and suburban and urban departments in Northern California). These levels were then combined with time-at-task information collected from firefighters to estimate 8-hr noise exposures for the rural and suburban fire departments (n = 6 estimates for each department). Data from 24-hr dosimetry measurements and crude self-reported activity categories from the urban fire department (n = 4 measurements) were used to create 24-hr exposure estimates to evaluate the bias associated with the task-based estimates.

Results

Task-based noise levels were found to range from 82 to 109 dBA, with the highest levels resulting from use of saws and pneumatic chisels. Some short (e.g., 30 min) sequences of common tasks were found to result in nearly an entire allowable daily exposure. The majority of estimated 8-hr and 24-hr exposures exceeded the relevant recommended exposure limit. Predicted 24-hr exposures showed substantial imprecision in some cases, suggesting the need for increased task specificity and highlighting the variability of firefighting noise exposures.

Conclusions

The results indicate potential for overexposure to noise from a variety of firefighting tasks and equipment, and suggest a need for further exposure characterization and additional hearing loss prevention efforts.

Relevance to industry

Firefighters may be at risk of noise-induced hearing loss, which can affect their fitness for duty and ability to respond effectively to emergencies. The results of this study suggest that additional efforts at hearing loss prevention among firefighters are warranted.     

Lipase-catalyzed synthesis of chiral triglycerides

Under certain reaction conditions, the acidolysis of tripalmitin with oleic acid using immobilized lipase from Rhizomucor miehei resulted in a higher level of monosubstituted oleoyldipalmitoyl (OPP) triglycerides than had been predicted according to kinetic modeling. The reaction products were subjected to chiral analysis by high-performance liquid chromatography (HPLC), which indicated that the enzyme was more active at the sn-1 position of the triglyceride than at the sn-3 position, resulting in synthesis of the chiral triglyceride 1-oleoyl-2,3-dipalmitoyl-sn-glycerol. A kinetic model was developed and was correlated with the HPLC method to provide a simple means to predict the stereoselectivity of lipase-catalyzed reactions. By using the model, the stereoselectivity of immobilized Rhizomucor miehei lipase was found to depend strongly on the initial water activity (a _w) of the reaction mixture, with greater selectivity occurring at lower a _w. The sn-1 selectivity was essentially maintained using various solvents, or without solvent, when a _w was kept constantly low. Variation in the fatty acid composition of the triglyceride indicated that shorter-chain fatty acids result in greater stereoselectivity, while variation of the chainlength of the free fatty acid indicated an enhancement by the longest chainlength. The stereoselectivity of this lipase was confirmed using a new ¹³C nuclear magnetic resonance method. By using immobilized R. miehei lipase at low a _w approximately 80% of the chiral triglyceride found in the reaction mixture was the sn-1 enantiomer, at high reaction conversion.     

Pulmonary function in the early postoperative period

To the author's knowledge, an intensive investigation of pulmonary function during the first 2 postoperative days has not previously been reported. Consequently, in this study the effect of regional surgery on respiratory function, monitored every 4 h during the first 2 postoperative days, was analyzed. Hypoxaemia was a constant finding in all patients undergoing general anaesthesia. The degree and duration of hypoxaemia and spirometry changes were related to the site of surgical incision. Clinical signs of atelectasis were commonly observed during the first postoperative day and occurred after the change in PO2 and spirometry. Atelectasis was more common in patients having upper abdominal surgery. The current investigation reveals that the earliest postoperative change indicative of atelectasis is the fall in PO2; that auscultatory changes do not always occur in the presence of postoperative hypoxaemia; that auscultatory signs are not indicative of the extent of the PO2 fall; and that radiology represents a crude method of assessing postoperative atelectasis.     

Magnification and diminishing of image size and their effects on psychological states.

Examined the affective and cognitive-perceptual changes in a total of 60 undergraduates after exposure to 1 of 3 types of visual alternation: magnification (M), diminishment (D), and restriction (R) on the visual field. Comparison of pre- and posttreatment scores on the Nowlis Adjective Check List of Mood and the Clyde Mood Scale indicates that changes of image size (both M and D) were experienced as more demanding, unpleasant, and threatening than the R condition. While the M and D conditions were experienced as equally difficult and stressful, the M group experienced time as moving more slowly, and located the apparent horizontal on a posttreatment line judgment task at a significantly lower point than the D group. These changes in the M group are comparable to the changes previously reported in depression. The performance of the R group on time production and apparent horizontal was intermediate to the M and D groups, differing significantly primarily from the D group. Results offer some support for clinical observations on an association between depression and the need to maintain volume representation. Some of the limitations of experimental studies of psychopathology as a means of testing clinical observations and hypotheses are discussed. (31 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of geometric field of view on stereoscopic spatial judgments

Within a stereoscopic display the field of view (FOV) was held constant at 13.86 degrees while the geometric field of view (GFOV) was varied across four levels: 0 degrees (parallel), 13.86 degrees (veridical), 50 degrees and 100 degrees. Participants performed a distance-matching task where they adjusted the distance of a standard track from the centre of the display to match the distance of a target track from the same point. The results indicated that while the least error occurred in the veridical GFOV condition, small variations of GFOV away from the veridical have little effect. Large differences between FOV and GFOV (36 degrees and 86 degrees) increased errors markedly. A trend toward better performance in the veridical GFOV condition relative to the parallel GFOV condition suggests that the use of linear perspective information in a stereoscopic display may facilitate more accurate spatial perception. Actual or potential applications of this work include stereoscopic display design in aviation and non-aviation settings.