Postural implications of obtaining line-of-sight for seated operators of underground mining load-haul-dump vehicles

Operators of load-haul-dump (LHD) vehicles use awkward postures that may be held statically and at extreme ranges of motion for long shift periods to spot hazards in underground mining. This study examined postural variables associated with three amounts of seat rotation intended to maximize line-of-sight during forward driving. Three different models, representing the 1st, 50th and 99th percentile male for height and weight, were positioned with appropriate hand and foot constraints in the virtual LHD cab modelled in Classic JACK v4.0. A total of 15 virtual movement strategies were developed to model the postural behaviour of typical workers and each virtual subject was tested, first with the seat in a neutral 0 degrees position and then with it rotated counter-clockwise to 20 degrees and 45 degrees . Results revealed that reductions in trunk rotation, trunk lateral bend and neck rotation were associated with the seat rotation intervention. The general relationship observed was that as seat rotation increased, view of critical visual attention locations and visible line-of-sight area increased while postural load variables decreased. For the most part, 20 degres of seat rotation was beneficial but 45 dgrees produced significantly greater changes to postural load and visible visual attention locations.     

Characteristics of multiple-component defects and architectural hotspots: a large system case study

The architecture of a large software system is widely considered important for such reasons as: providing a common goal to the stakeholders in realising the envisaged system; helping to organise the various development teams; and capturing foundational design decisions early in the development. Studies have shown that defects originating in system architectures can consume twice as much correction effort as that for other defects. Clearly, then, scientific studies on architectural defects are important for their improved treatment and prevention. Previous research has focused on the extent of architectural defects in software systems. For this paper, we were motivated to ask the following two complementary questions in a case study: (i) How do multiple-component defects (MCDs)—which are of architectural importance—differ from other types of defects in terms of (a) complexity and (b) persistence across development phases and releases? and (ii) How do highly MCD-concentrated components (the so called, architectural hotspots) differ from other types of components in terms of their (a) interrelationships and (b) persistence across development phases and releases? Results indicate that MCDs are complex to fix and are persistent across phases and releases. In comparison to a non-MCD, a MCD requires over 20 times more changes to fix it and is 6 to 8 times more likely to cross a phase or a release. These findings have implications for defect detection and correction. Results also show that 20% of the subject system’s components contain over 80% of the MCDs and that these components are 2–3 times more likely to persist across multiple system releases than other components in the system. Such MCD-concentrated components constitute architectural “hotspots” which management can focus upon for preventive maintenance and architectural quality improvement. The findings described are from an empirical study of a large legacy software system of size over 20 million lines of code and age over 17 years.     

Ontogeny of gonadotropin, testosterone, and inhibin secretion in normal boys through puberty based on overnight serial sampling

To investigate hormonal changes occurring in male puberty, we measured LH, FSH, testosterone, and alpha-inhibin immunoactivity in serum samples drawn every 10 min for 8 h (2100-0500 h) from each of 50 normal prepubertal and pubertal boys, aged 8.4-18.8 yr. We measured gonadotropins with ultrasensitive immunofluorometric assays, and testosterone and alpha-inhibin with RIAs. Unlike previous studies, which indexed pubertal development with Tanner stages, we used testicular volume, a more finely graduated indicator of development, to reveal patterns that were obscured when subjects were grouped by Tanner stage. The overnight mean concentration of each hormone increased with testis volume, but the rate of increase on a logarithmic scale slowed as testes grew. Log LH rose precipitously in the late prepubertal and early pubertal periods and plateaued during mid- and late puberty. Based on fitted regression curves, LH increased about 20-fold (from 0.11 IU/L) between testis volumes of 1 and 10 mL, but only an additional 1.5-fold by 30 mL. The developmental trajectory of log testosterone was like that of log LH, but rose less steeply early in puberty. From 0.14 micrograms/L at a testis volume of 1 mL, testosterone increased about 8.5-fold by 10 mL and an additional 3-fold by 30 mL. In contrast, logarithms of overnight mean FSH and alpha-inhibin concentrations rose at a more nearly constant rate throughout puberty. From 0.62 IU/L at a testis volume of 1 mL, the FSH concentration doubled by 10 mL and increased an additional 1.7-fold by 30 mL. From 270 ng/L at a testis volume of 1 mL, inhibin increased 1.5-fold by 10 mL and an additional 1.3-fold by 30 mL. Overnight pulse amplitudes exhibited developmental trajectories similar to those of the corresponding overnight mean concentrations. The number of LH and testosterone pulses during the sampling period averaged 2.2 and 2.1, respectively, at Tanner stage 1 and increased to 4.5 and 3.2, respectively, at Tanner stage 5. The number of FSH and inhibin pulses remained constant throughout puberty, averaging 3.3 and 3.5, respectively. Pairwise correlations among hormone concentrations were strong, reflecting common increasing trends through puberty; however, after accounting for developmental trends, FSH, LH, and testosterone concentrations remained correlated, whereas inhibin was uncorrelated with each of the other three hormones. Measuring gonadotropins with ultrasensitive assays and analyzing the results on a logarithmic scale as a function of testis volume made clear the dramatic hormonal changes that begin before the clinical changes of puberty.     

Plasma and cerebrospinal fluid pharmacokinetic study of topotecan in nonhuman primates

Topotecan, a water soluble semisynthetic analogue of camptothecin, is a topoisomerase I inhibitor that has recently entered phase II clinical trials. Topotecan has shown significant preclinical activity in refractory murine tumors and in human tumor xenograft models. In addition, objective antineoplastic activity has been observed in recent adult phase I clinical trials. Topotecan is unstable in solution and is rapidly and spontaneously converted to a less active open ring form which predominates at physiological pH. This study was undertaken to better define the pharmacokinetic behavior of this highly unstable compound in both plasma and cerebrospinal fluid (CSF) and to measure the degree of CSF penetration of this novel antineoplastic agent. Three nonhuman primates with indwelling Ommaya reservoirs received 10 mg/m2 i.v. topotecan administered as a 10-min infusion. Frequent plasma and CSF samples were obtained and immediately extracted and assayed with a reverse phase high performance liquid chromatography assay to quantitate the concentration of topotecan (lactone). Samples were then acidified and reinjected to quantitate total drug (lactone ring plus open ring). Peak plasma concentrations of topotecan ranged from 0.27 to 0.45 microM. Plasma disappearance of the lactone ring was biexponential with a distribution half-life (t1/2 alpha) of 22 +/- 5 min and an elimination half-life (t1/2 beta) of 1.3 +/- 0.1 h. Total body clearance of topotecan was 72.1 +/- 15.8 liters/h/m2. The volume of distribution at steady state was 88.6 +/- 33.2 liters/m2. Peak CSF concentrations of topotecan occurred at 30 min following drug administration and ranged from 0.044 to 0.074 microM. CSF disappearance paralleled that in plasma. The mean ratio of the area under the CSF concentration-time curve to that in plasma was 0.32 (range, 0.29 to 0.37). The mean CSF penetration of topotecan exceeds 30%, which is significantly greater than the penetration of most structurally similar chemotherapeutic agents. The impact of chemotherapy on the survival of patients with primary or metastatic central nervous system malignancies is very limited. Therefore, this novel antineoplastic agent is an excellent candidate for further study in patients with high risk or refractory central nervous system tumors.     

Pharmacokinetics of the protease inhibitor KNI-272 in plasma and cerebrospinal fluid in nonhuman primates after intravenous dosing and in human immunodeficiency virus-infected children after intravenous and oral dosing

The aim of this study was to evaluate the feasibility of routine falloposcopy in infertile patients undergoing basic infertility investigations, and to determine its usefulness in comparison with other tubal investigation methods. Seventy-five infertile women were selected based on the following criteria: 2 years of infertility, age between 18 and 40 years, normal ovulation, and partner with normal spermatozoa. Based on the results of the classical means of tubal evaluation (hysterosalpingography and laparoscopy), these patients were classified in one of two groups: tubal or unexplained infertility. All patients underwent a falloposcopy under general anaesthesia. The procedures were performed by the same surgeon with the linear everting catheter. Based on the falloposcopic findings, these patients were then reclassified in one of two other groups: falloposcopic tubal or falloposcopic unexplained infertility. The mean outcome measures were catheterization rate, duration of the procedure, pregnancy rates, complication rate and predictive value of Falloposcopy. The tubal catheterization rate was 94.5%. The mean duration of falloposcopy was 19 min per tube. Based on a standard scoring system, the spontaneous pregnancy rates were 27.6% for a score <20; 11.5% for a score between 21 and 30; and 0% if the score was >30. Complication rate was 5.1% of pinpoint perforations of the tube. With Cox's statistical model, none of the parameters analysed was statistically predictive of intrauterine pregnancy. We conclude that the greater accuracy of diagnosis by falloposcopy may indicate that it should be incorporated into the initial screening of infertile patients.     

Nodular regenerative hyperplasia of the liver in hematologic disorders: a possible response to obliterative portal venopathy. A morphometric study of nine cases with an hypothesis on the pathogenesis

Nodular regenerative hyperplasia was found in nine patients who had hematological disease including polycythemia vera, agnogenic myeloid metaplasia, primary thrombocythemia, rheumatoid arthritis with thrombocytosis, multiple myeloma, and erythrocytosis associated with polycystic renal disease. Portal hypertension was suspected in three and features of hypersplenism were present in four. 2. Nodular regenerative hyperplasia occurred in livers which had widespread obliteration of portal vein radicals (obliterative portal venopathy). Morphometric analysis indicated that the portal vein lesions were predominately located in veins up to 0.2 mm in diameter and were significantly more frequent than similar lesions occurring in elderly persons. 3. The following pathogenesis of nodular regenerative hyperplasia is proposed: Thrombi, perhaps largely composed of platelet aggregates formed in the portal venous circulation or spleen, embolize to the liver and results in obliterative vascular lesions. Atrophy and regenerative nodule formation occur in response to the interruption of the portal blood supply.     

Study of the Molecule-metal Oxide Interface using Inelastic Electron Tunneling Spectroscopyt

Several examples in the application of inelastic electron tunneling spectroscopy (IETS) to study the molecular species which occur in adhesion, and in the corrosion and corrosion inhibition of aluminum in chlorinated hydrocarbons are reviewed. These examples illustrate some of the common aspects of the phenomena which occur at the metal oxide-organic interface in the areas of adhesion and corrosion. On a molecular level the concept of inhibition can be usefully applied to the areas of corrosion and adhesive failure.