Snakes on the watershed

We present a new approach for object boundary extraction, called the watersnake. It is a two-step snake algorithm whose energy functional is minimized by the dynamic programming method. It is more robust to local minima because it finds the solution by searching the entire energy space. To reduce the complexity of the minimization process, the watershed transformation and a coarse-to-fine strategy are used. The new technique is compared to standard methods for accuracy in synthetic data and is applied to segmentation of white blood cells in bone marrow images     

Nonmitogenic anti-CD3F(ab')2 fragments inhibit lethal murine graft-versus-host disease induced across the major histocompatibility barrier

We have investigated the in vivo administration of nonmitogenic anti-CD3F(ab')2 fragments for the prevention of lethal graft-vs-host disease (GVHD) in irradiated recipients of fully allogeneic bone marrow cells plus splenocyte (BMS) inocula. Recipients of anti-CD3F(ab')2 fragments administered for 1 mo post-bone marrow transplantation (BMT) had 100% survival without clinical or histopathological evidence of GVHD. Controls given saline injections succumbed by 39 days post-BMT. Similar results were obtained in groups of recipient mice given BMS in which T cells were depleted by in vitro anti-Thy-1.2 plus C' treatment. Further studies were undertaken to define mechanistic differences in the two approaches. Using Ly-5 congenic sources of donor bone marrow and spleen, we determined that anti-CD3F(ab')2 fragments induced TCR modulation and T cell depletion. Mature splenic-derived CD4+ cells were depleted to a greater extent than CD8+ cells. Early post-BMT, recipients receiving injections with control saline had the highest number of CD4+ and CD8+ cells (which may cause GVHD) followed by recipients of anti-CD3F(ab')2 fragments, with the fewest CD8+ cells observed in the anti-Thy-1.2 + C' treated group. CD3+CD4-CD8- cells (which may suppress GVHD generation) were present in higher numbers early post-BMT in recipients given anti-CD3F(ab')2 fragments as compared to recipients given anti-Thy-1.2 + C'-treated BMS. In long term survivors, a mononuclear T cell containing infiltrate without evidence of destruction was observed in sites of GVHD (lung and liver), consistent with a "Quilty" effect, which was not observed in either of the other two groups. Although survivors were tolerant of donor skin grafts and rejected third party grafts, recipients given anti-CD3F(ab')2 fragments but not anti-Thy-1.2 + C'-treated BMS had vigorous anti-host proliferative responses. These results demonstrate that although in vitro anti-Thy-1.2 + C' treatment of BMS (which is highly depletionary) and in vivo administration of anti-CD3F(ab')2 fragments (which is modulatory and less depletionary) are both effective strategies for GVHD, the cellular events involved in achieving GVHD prevention are indeed different.     

The supercooling dependence of the initial fold length of polyethylene crystallized from the melt: unification of melt and solution crystallization

Following the previous recognition [1], reached with the aid of real time low angle X-ray diffraction (using a synchrotron X-ray source) that in melt crystallized polyethylene the initial (primary) lamellar thickness is much smaller than hitherto envisaged, we have proceeded to construct the full relationship between primary fold length (I _g ^*) and supercooling (T) covering a wide range of crystallization temperature (T _c). The principal result of this work is the identification of supercooling as the sole factor which determinesI _g ^*. Comparison with crystallization from solution [2–4] has revealed that theI _g ^* against T curves are completely superposable thus removing the gap which has existed up to the present between melt and solution crystallization, bringing about a welcome unification of these two separate (at least as far as fold length was concerned) aspects of polymer crystallization. Further, we show that while T determinesI _g ^*, subsequent thickening is determined by the absolute temperature. Isothermal thickening in particular proceeds first by a large discontinuous step followed by a continuous logarithmic increase with time. The importance of these findings and in particular the affirmation of the unique role of supercooling for chain folding and lamellar crystallization in general is emphasized.     

High-temperature crystallization behaviour of amorphous Fe80B20

Samples of 0.003 in. round Fe₈₀B₂₀ amorphous wires were annealed in vacuo for 1 sec to 8 h periods at 780° C and the crystallinity induced in these wires from this heat treatment was studied through X-ray diffraction and field-ion microscopy. X-ray diffraction studies indicate that complete crystallinity is produced following 1 sec anneal at 780° C. However, the initial product is a primitive-tetragonal Fe₃B phase unlike the body-centred tetragonal Fe₃B observed in low-temperature isothermal transformation studies with this alloy. The Fe₃B phase is seen to persist in the diffraction patterns for annealing durations of up to 15 min. Upon annealing for periods of up to 1 h, an intermediate three-phase structure consisting of -Fe, Fe₃B, and Fe₂B is seen to result with a gradual decrease in the Fe₃B phase corresponding to longer annealing durations. Anneals of more than 1 h at 780° C are seen to result in the disappearance of the Fe₃B phase producing a two-phase microstructure consisting of -Fe(b c c) and Fe₂B (b c t). Field-ion-microscopy with a pure neon imaging gas at 78 K likewise indicates that existence of a three-stage phase structural change during the isothermal anneals, and the atomic arrangement of the various species are quite readily discernible because of the different symmetries contained in the three distinct phases.     

Annealing behaviour of amorphous Fe80B20 on continuous heating

Resistance measurements during direct heating of Fe₈₀B₂₀ amorphous alloys indicate phase changes occur at 395, 500, 720 and 840° C. Samples heated to these temperatures, and maintained for five minutes in a neutral atmosphere, show that a hardness maximum occurs at the crystallization temperature of 395° C and that annealing at 500° C produces a material with the same hardness. Above 500° C the microhardness is seen to drop below that of the amorphous alloy. Saturation magnetization measurements show a steady increase following each anneal, up to a temperature of 720° C, and the rate of increase is seen to drop in the range of 720 to 840° C. X-ray diffraction studies show that only a small fraction of the matrix is crystallized following the anneal at 395° C and the transformed phases are -Fe and Fe₃B. Following annealing at 500° C, an increased proportion of -Fe and Fe₃B are observed with complete crystallinity while samples heattreated at 720° C are seen to consist of a three-phase mixture of -Fe, Fe₂₃B₆ and Fe₂B. Annealing at 840° C is seen to produce an equilibrium phase mixture of -Fe and Fe₂B phases. Only in the sample annealed at 395° C is a fraction of the amorphous phase seen to persist, indicating that a 5 min anneal is not sufficient, at this temperature, to induce complete crystallization. These structural features are corroborated by field ion microscope analyses, made at liquid nitrogen temperature in a medium of pure neon, and scanning electron microscopy, and are also consistent with our earlier study involving the isothermal annealing, for various times, of Fe₈₀B₂₀ alloy at 780° C.     

Plasma somatomedin activity in normal and scoliotic children

In a study of plasma somatomedin activity in childhood scoliosis a group of five patients with congenital scoliosis was found to have significantly lower plasma somatomedin levels compared with a group of 20 normal children. A group of 52 patients with "idiopathic" scoliosis had normal plasma somatomedin levels. There is no apparent difference in the plasma somatomedin activity between the sexes, and no change in plasma somatomedin activity with chronologic age in these children, suggesting that normal adult somatomedin levels have been reached.     

AH-64D main transmission accessory drive spur gear installation fault detections

The US Army has launched an aggressive program to implement condition based maintenance on its rotary wing assets. Condition Based Maintenance takes advantage of technology developments in the areas of machinery monitoring, signal processing and fault modeling to reduce the cost of ownership through improved maintenance procedures. Documenting the reduction in maintenance burden, cost savings and increased safety through early detection of helicopter faults is an important step in justifying the program. This paper describes a novel technique used to detect a serious fault in the accessory section of the AH-64D Apache main transmission. The technique determines if the primary or secondary clutch system is driving the aircraft accessories through a tachometer speed ratio. The method has identified three aircraft operating on the secondary system allowing Army maintenance crews to replace the affected transmissions and quickly restore the aircraft to operational status.     

Office task effects on comfort and body dynamics in five dynamic office chairs

In the present study, we investigated the effect of office tasks on posture and movements in field settings, and the comfort rating for chair characteristics and correlation with type of task. The tasks studied were: computer work, telephoning, desk work and conversation. Postures, movements, chair part inclinations and comfort rating data were collected from 12 subjects. Computer work showed the lowest physical activity, together with upright trunk and head position and low backrest inclination. Conversation shows the highest activity of head legs and low back together with the highest cervical spine extension. In contrast, desk work provoked the most cervical spine flexion and showed the second lowest activity. The telephoning tasks showed medium activity and the highest kyphosis. Conversation showed the highest backrest inclination. Positive comfort relations were found for computer work and a "swing system" chair, for telephoning and an active longitudinal seat rotation, and for desk work and a chair with a three-dimensionally moveable seat.     

Encephalopathy during oral treatment with bismuth salts

Side effects of orally administered bismuthic salts have been known for many years. Many systems are involved, including the digestive and urinary. The authors discuss a recently discovered effect on the central nervous system, termed "bismuth encephalopathy". In the light of the medical literature reviewed, two original aspects are stressed: the clinical symptoms are stereotyped and completely reversible, and the distribution of the disease is almost epidemic, being limited in time and space. The prodromes include confusion, asthenia, slowing of mental functions and disturbance of gait. The clinical picture is dominated by four major symptoms: confusion (again), ataxia, dysarthria and, above all, myoclonic jerks. In conclusion, various pathogenetic hypotheses are considered. The purpose of this study is to enable the general practitioner to detect the development of this condition early in treatment with oral bismuthic salts. Withdrawal of the medication always results in normalization of the patient's condition.