A robust method for approximate visual robot localization in feature-sparse sewer pipes.

Buried sewer pipe networks present many challenges for robot localization systems, which require non-standard solutions due to the unique nature of these environments: they cannot receive signals from global positioning systems (GPS) and can also lack visual features necessary for standard visual odometry algorithms. In this paper, we exploit the fact that pipe joints are equally spaced and develop a robot localization method based on pipe joint detection that operates in one degree-of-freedom along the pipe length. Pipe joints are detected in visual images from an on-board forward facing (electro-optical) camera using a bag-of-keypoints visual categorization algorithm, which is trained offline by unsupervised learning from images of sewer pipe joints. We augment the pipe joint detection algorithm with drift correction using vision-based manhole recognition. We evaluated the approach using real-world data recorded from three sewer pipes (of lengths 30, 50 and 90 m) and benchmarked against a standard method for visual odometry (ORB-SLAM3), which demonstrated that our proposed method operates more robustly and accurately in these feature-sparse pipes: ORB-SLAM3 completely failed on one tested pipe due to a lack of visual features and gave a mean absolute error in localization of approximately 12%-20% on the other pipes (and regularly lost track of features, having to re-initialize multiple times), whilst our method worked successfully on all tested pipes and gave a mean absolute error in localization of approximately 2%-4%. In summary, our results highlight an important trade-off between modern visual odometry algorithms that have potentially high precision and estimate full six degree-of-freedom pose but are potentially fragile in feature sparse pipes, versus simpler, approximate localization methods that operate in one degree-of-freedom along the pipe length that are more robust and can lead to substantial improvements in accuracy.

Antifungal drug discovery through the study of invertebrate model hosts.

There is an urgent need for new antifungal agents that are both effective and non-toxic in the therapy of systemic mycoses. The model nematode Caenorhabditis elegans has been used both to elucidate evolutionarily conserved components of host-pathogen interactions and to screen large chemical libraries for novel antimicrobial compounds. Here we review the use of C. elegans models in drug discovery and discuss caffeic acid phenethyl ester, a novel antifungal agent identified using an in vivo screening system. C. elegans bioassays allow high-throughput screens of chemical libraries in vivo. This whole-animal system may enable the identification of compounds that modulate immune responses or affect fungal virulence factors that are only expressed during infection. In addition, compounds can be simultaneously screened for antifungal efficacy and toxicity, which may overcome one of the main obstacles in current antimicrobial discovery. A pilot screen for antifungal compounds using this novel C. elegans system identified 15 compounds that prolonged survival of nematodes infected with the medically important human pathogen Candida albicans. One of these compounds, caffeic acid phenethyl ester (CAPE), was an effective antifungal agent in a murine model of systemic candidiasis and had in vitro activity against several fungal species. Interestingly, CAPE is a potent immunomodulator in mammals with several distinct mechanisms of action. The identification of CAPE in a C. elegans screen supports the hypothesis that this model can identify compounds with both antifungal and host immunomodulatory activity.

Binding affinity and capacities for ytterbium(3+) and hafinum(4+) by chemical entities of plant tissue fragments.

The binding affinity of ytterbium (Yb3+) and hafinum (Hf4+) to ligands of chemical entities of fragments of bermudagrass tissues and their resistance to exchanging Yb with other ligands and to displacement by protons were investigated. Chemical entities of acid resistant NDF (ARNDF), 0.1 N acid detergent fiber (0.1 N ADF), and permanganate cellulose (CELL) were prepared from fragments of bermudagrass hay (Cynodon dactylon [L.] Pers.) obtained by grinding to pass a 2-mm sieve. 175Ytterbium and Yb, as YbCl3, were initially bound to each preparation by soaking for 12 h in pH 5.5 borate buffer to obtain Yb bound onto ligands having affinity constants for Yb equal to or greater than that for the weakly stable borate ligand, Yb > or = borate. The fraction of Yb > or = borate was measured and fragments then sequentially exposed to acetate, citrate, nitrotriacetate (NTA), and EDTA ions to allow exchange of Yb from Yb > or = borate with ligands having affinity constants for Yb equal to or greater than acetate (Yb > or = acetate), citrate (Yb > or = citrate), NTA (Yb > or = NTA), and EDTA (Yb > or = EDTA) ions. Binding of Yb > or = borate indicated the existence of two species of ligands: strong ligands binding essentially 100% of added Yb at levels of 1 to 1,300 ppm (0.1 N ADF) and at 1 to 7,000 ppm (ARNDF); and weaker ligands binding 4 and 8% of the Yb, respectively, at levels of added Yb greater than 1,300 ppm and 7,000 ppm. Ytterbium > or = acetate of ARNDF, but not 0.1 N ADF, was as resistant to exchange as Yb > or = citrate. Ytterbium > or = borate was exchanged extensively (85% or greater) with soluble ligands having affinity constants > or = NTA. Ytterbium resistance to proton displacement at pH of 1.5 increased with Yb > or = EDTA > Yb > or = NTA > Yb > or = citrate > Yb > or = acetate. Very efficient binding of Yb to CELL suggested that such chemical preparations are not representative of native cellulose. Hafnium (4+) was strongly bound to plant tissues rendering both Hf and Hf-bound DM insoluble at a pH of 1.5 and insoluble in a modified NDF solvent without EDTA. It is concluded that Yb specifically applied as Yb > or = acetate and Hf4+ are indelible markers for estimating sojourn time of undigested plant tissues at the normal pH of the rumen. Because of its resistance to proton displacement, Hf4+ would be an indelible marker for estimating sojourn time in more acidic postgastric segments of the gastrointestinal tract.

Selecting practice management information systems.

Despite enormous advances in information systems, the process by which most medical practices select them has remained virtually unchanged for decades: the request for proposal (RFP). Unfortunately, vendors have learned ways to minimize the value of RFP checklists to where purchasers now learn little about the system functionality. The authors describe a selection methodology that replaces the RFP with scored demos, reviews of vendor user manuals and mathematically structured reference checking. In a recent selection process at a major medical center, these techniques yielded greater user buy-in and favorable contract terms as well.

Work-related musculoskeletal disorders among physical therapists.

BACKGROUND AND PURPOSE: Increasing evidence suggests that musculoskeletal disorders are common in workers in the United States health care industry. Physical therapists, who commonly treat patients with these disorders, are also at risk for work-related musculoskeletal disorders (WMD) in the upper limbs and low back. The purpose of this study was to determine the prevalence of WMD during a 12-month period and the job factors that may be associated with these disorders in physical therapists. SUBJECTS: A four-page questionnaire was mailed to physical therapists (N = 1,160) who attended The University of Iowa between 1943 and 1993. Nine hundred twenty-eight questionnaires were returned (80% response rate) from physical therapists in 46 states. METHODS: Based on a literature review and pilot study of physical therapists, a survey instrument was constructed consisting of a symptom survey, a job-factor survey, and various demographic information. RESULTS: The highest prevalences of WMD among physical therapists were in the following anatomical areas: low back (45%), wrist/hand (29.6%), upper back (28.7%), and neck (24.7%). The job factor rated most likely to contribute to job-related musculoskeletal disorders was "lifting or transferring dependent patients." The prevalence of WMD in physical therapists also was affected by work setting, practice specialty, age of patient, and gender of therapist. CONCLUSION AND DISCUSSION: Specific strategies should be developed to reduce WMD in the practice of physical therapy.

Oxytocin in Leydig cells: an immunocytochemical study of Percoll-purified cells from rat testes.

Testicular interstitial cells, from rats aged 35 days, were dispersed with collagenase and separated through Percoll into 5 fractions (I-V); fraction I being the least dense. Measurement of basal testosterone production, histo-enzymological staining for 3 beta-hydroxysteroid dehydrogenase activity and electron microscopy indicated that the majority of Leydig cells were found in fraction IV (corresponding to a density of 1.076-1.097 g/ml). In addition, cells from this fraction responded to hCG treatment in a dose-dependent manner on day 0 and remained responsive after being cultured for 1 day. Immunostaining for oxytocin indicated that this fraction also contained the majority of the oxytocin-immunoreactive cells. On day 1 of culture, 56% of the cell population from fraction IV were positively stained for the steroidogenic enzyme and 75% immunoreactive for oxytocin. This overlap indicates that the Leydig cells were also the oxytocin immunoreactive cells.

A videomicrographic low-frequency movement analyser (VLMA) and perifusion chamber for recording and analysis of the physical behaviour of seminiferous tubules and other contractile tissues in vitro.

A method has been developed for the recording and analysis of low frequency movements such as those of the surfaces of live seminiferous tubules. The method involves time-lapse videomicrographic recording of the tubules followed by frame-by-frame measurement of the position of the edge of the tubule image in the video field. These measurements, which describe the movement of the tubule, may be analysed into a series of power spectra relating to sequential time periods through the recording. The group of spectrum plots for each tubule preparation can be plotted as isometric, pseudo three-dimensional figures, with time represented on the z-axis. The shapes of the spectra represent the contractile activity of the seminiferous tubules. Alterations in the level of activity and/or in the position of the frequency peaks, between control and experimentally treated preparations, are readily apparent. We also describe the construction and features of the perifusion chamber used with the VLMA.

Artificial insemination: a comparison of pregnancy rates with intrauterine versus cervical insemination and washed sperm versus serum swim-up sperm preparations.

A four-cycle artificial insemination protocol was undertaken, with luteinizing hormone (LH) timing, to compare washed sperm and serum swim-up sperm preparations and cervical and intrauterine insemination. Of the 75 patients entered into the protocol series, 63 finished all 4 cycles. During the treatment period, 24 patients became pregnant, 20 of whom were donor (AID) pregnancies (out of 52 patients) and 4 were husband (AIH) pregnancies (out of 11 patients). Seventy-five percent of the pregnancies were intrauterine, whereas only 25% were from cervical inseminations. Sixty-two percent of the pregnancies were due to serum swim-up sperm preparations, and 38% were due to washed sperm preparations. The data indicate substantially higher pregnancy rates can be obtained with intrauterine insemination and suggest that additional studies are necessary to determine if the method of sperm preparation significantly influences pregnancy rates.

Control of vascular reactivity in pregnancy.

Human pregnancy is characterized by a blunted pressor responsiveness to vasopressor substances. This was first reported by Dieckmann and Michel in 1937 in experiments in which they measured vascular reactivity to the pressor effects of a crude preparation of vasopressin. Recently, this has been reported to occur in response to epinephrine, norepinephrine (NE), and angiotensin II (AII). Gant and associates reported that the increasing vascular sensitivity to infused AII not only was characteristic of women who developed pregnancy-induced hypertension, but in fact preceded the development of pregnancy-induced hypertension. Although a variety of factors may mediate this blunted pressor responsiveness, the most likely candidate appears to be the localized production within endothelium and/or vascular smooth muscle of prostaglandins. Indeed, administration of indomethacin or aspirin results in an increased sensitivity to infused AII in normotensive previously AII-refractory women. Administration of the steroid hormone 5 alpha-dihydroprogesterone reverses this apparent prostaglandin-mediated response. In addition, administration of the phosphodiesterase inhibitor, theophylline, results in a restoration of vascular refractoriness to infused AII in women with pregnancy-induced hypertension or in women destined to develop pregnancy-induced hypertension. Although a variety of known and possibly unknown compounds might also effect the control of vascular reactivity during human pregnancy, the prostinoids appear to play a pivotal role in mediation of control of vascular reactivity during human pregnancy.

Ethan-1,2-dimethanesulphonate reduces testicular oxytocin content and seminiferous tubule movements in the rat.

An oxytocin-like peptide is present in the interstitial cells of the testis, and testicular concentrations of oxytocin have been shown to increase seminiferous tubule movements in vitro. We have used the drug ethan-1,2-dimethanesulphonate (EDS), which depletes the Leydig cell population of the adult rat testis, to examine further the relationships between the Leydig cell, testicular oxytocin and tubular movements. Adult rats were injected i.p. with a single dose of EDS (75 mg/kg) or of vehicle (25% dimethyl sulphoxide). Histological study 3 and 10 days after treatment with EDS showed a reduction in the number of interstitial cells, and levels of oxytocin immunoreactivity were undetectable by radioimmunoassay. Immunostaining revealed very few oxytocin-reactive cells. Spontaneous contractile activity of the seminiferous tubules in vitro was also dramatically reduced, but could be restored by the addition of oxytocin to the medium. Four weeks after EDS treatment, the interstitial cells were similar to those in the control animals both in number and in immunostaining; immunoassayable oxytocin was present and tubular movements were normal. The EDS effect, seen at 3 and 10 days, was not altered by daily treatment with testosterone. However, repopulation of the testes with oxytocin-immunoreactive cells was not seen until 6 weeks in the testosterone-treated animals. We suggest that the Leydig cells are the main source of oxytocin immunoreactivity in the testis and that this oxytocin is involved in modulating seminiferous tubule movements and the resultant sperm transport. The results also imply that testosterone does not play a major role in controlling tubular activity in the mature rat.

The effects of corn silage dry matter content and sodium bicarbonate addition on nutrient digestion and growth by lambs and calves.

One lamb and three calf trials were conducted to determine if interactions existed between the effects of dry matter (DM) content of corn silage at harvest and sodium bicarbonate supplementation on diet digestibility, nitrogen balance, rate and site of digestion and feedlot performance. Corn plants were harvested from the same field when DM content was approximately 31% (early; E) or 44% (late; L). Sodium bicarbonate (1.2% of DM intake) was added in a completely mixed ration. When lambs were offered diets ad libitum, (trial 1), intakes were greater (P less than .05) for L-silage diets, but apparent digestibilities were similar. Nitrogen balance was greater for sodium bicarbonate-supplemented diets, and was a reflection of greater (P less than .10) DM intakes for these diets. At similar diet DM intakes, N balance was greater for L-silage diets, with no effects measured due to sodium bicarbonate addition. When growing, abomasally cannulated heifers (trial 2) were offered diets 12 times per day, a significant interaction among treatments was measured for total tract and acid detergent fiber (ADF) digestion. Adding bicarbonate to the E-silage diet increased (P less than .05) digestion by 9.1 percentage units (66.4 vs 75.5%) but decreased digestibility of the L-silage diet by 4.2 percentage units (73 vs 68.8%). Grams of ADF apparently digested in the rumen followed the same pattern as for total tract digestion. In trial 3, ruminal rates of liquid and particulate passage and in situ rats of NDF digestion were determined using four rumen-cannulated heifers calves.(ABSTRACT TRUNCATED AT 250 WORDS)

LH and testosterone cause the development of seminiferous tubule contractile activity and the appearance of testicular oxytocin in hypogonadal mice.

Immunoreactive oxytocin is present in the testis and it has been shown that this hormone increases the contractility of seminiferous tubules. We have investigated the relationship between testicular oxytocin, tubular movements and the effects of LH and testosterone using, as a model, the hypogonadal (hpg/hpg) mouse, which is deficient in hypothalamic LH-releasing hormone (LHRH). Whilst both testicular oxytocin and seminiferous tubule movements, resembling those seen in the rat, can be found in normal adult mice, neither can be found in hypogonadal mice. After 2 weeks of treatment with LH (200 ng to 100 micrograms daily) low levels of testicular oxytocin and tubular movements were observed. Treatment with large doses of testosterone for 2-12 weeks led to higher concentrations of testicular oxytocin and tubular movements resembling those seen in the normal adult mouse. The results support the evidence that testicular oxytocin modulates seminiferous tubule movements. We suggest that testosterone may play a part in the accumulation of oxytocin in the testis.

Dysfunctional uterine bleeding. Clarifying its definition, mechanisms, and management.

"Dysfunctional uterine bleeding" is not a generic term for abnormal uterine bleeding. Rather, it refers solely to bleeding caused by an ovarian endocrinopathy. Estrogen withdrawal and inappropriately sustained estrogen production are the two mechanisms responsible. The latter mechanism produces estrogen breakthrough bleeding, which is common in women with chronic anovulation. Treatment of estrogen withdrawal bleeding depends on when in the menstrual cycle bleeding occurs. Anovulatory bleeding is best treated with progestin. Estrogen therapy is contraindicated, except in patients with profuse anovulatory bleeding unresponsive to progestin treatment, because it increases the risk of endometrial hyperplasia and cancer.

Limitations of a histologic assay for syn-, allo-, and xenogeneic H-Y antigen.

In view of the potential significance of the H-Y antigen in the etiology of cases of sexual ambiguity we have attempted to develop a clinically useful test for the presence of H-Y on the cells of such patients. The attempts were directed at the detection of accelerated or decelerated rejection of syngeneic skin grafts on H-Y-incompatible mice previously exposed to H-Y positive syngeneic, allogeneic, or xenogeneic cells. Using a simple and rapid histologic assay after exposure to syn- or allogeneic cells, acceleration (sensitization) as well as deceleration (tolerance) was readily demonstrable. However, the assay was not helpful with the use of xenogeneic (rabbit, human) cells.