Immune response to an intercalated enhanced inactivated polio vaccine/oral polio vaccine programme in Israel: impact on the control of poliomyelitis

A combined enhanced inactivated polio vaccine (EIPV) and oral polio vaccine (OPV) programme was introduced in Israel in 1990, with the purpose of providing a solution to the persistent polio morbidity in spite of a 30 year long OPV programme. The schedule comprised two doses of EIPV administered at the age of 2 and 4 months, intercalated with two doses of OPV at 4 and 6 months, followed by a reinforcing dose with the two vaccines simultaneously administered at 12 months. The 5-year evaluation of the programme included: the assessment of clinical suspicions of polio, early immune response in successive cohorts administered the new schedule, dynamics of the immune profile in a cohort followed up to the age of 5, and monitoring of wild poliovirus excretion in sewage specimens collected in 25 permanent sites throughout Israel as well as from the Palestinian Authority. No paralytic polio cases associated with a wild or vaccinal poliovirus strain were detected since the introduction of the programme. At the age of 4 months, one week after administration of the second EIPV and first OPV dose, 100% seropositivity and high geometric mean titres (GMTs) of neutralizing antibody (NA) to the three vaccinal and to the wild poliovirus type 1, responsible for the 1988 polio outbreak, were observed. No change in percent of seropositivity occurred between the age of 6 and 12 months. Thirty days after the IPV and OPV reinforcing doses, GMTs to each of the four poliovirus strains were > or = 3037. Up to the age of 5, the seropositivity was unchanged. After a 2.5-10-fold decline in the first year following the completion of the programme, GMTs to the three vaccinal and the wild poliovirus strain levelled off at rather high values, considered protective. Between 1990 and 1995, 16 wild poliovirus type 1 strains were isolated in three separate episodes in Gaza Strip sewage and once only in one Israeli site very close to Gaza City. The rapidly established, high and persistent NA titre to the vaccinal and wild poliovirus strains and the presence of immunological memory are indicative of high individual protection throughout the first 5 years of life. The only one-time introduction, without circulation, of a wild poliovirus strain in a single Israeli settlement suggests community protection. The intercalated programme offers a contribution to polio eradication by providing a solution to the primary and secondary failure associated with OPV, as well as to the control of vaccine-associated paralytic poliomyelitis.     

The thermogenic center in social wasps

In the social wasps Vespa orientalis and Paravespula germanica (Hymenoptera, Vespinae), a thermogenic center has been found in the dorsal part of the first thoracic segment. The temperature in this region of the prothorax is higher by 6-9 degrees C than that at the tip of the abdomen, and this in actively flying hornets outside the nest (workers, males or queens) as well as in hornets inside the nest that attend to the brood in the combs. On viewing the region from the outside, one discerns a canal or rather a fissure in the cuticle, which commences at the center of the dorsal surface of the prothorax and extends till the mesothorax. Thus the length of this canal or fissure is approximately 5-7 mm and it is seen to contain numerous thin hairs whose shape varies from that of the hairs alongside the structure. Beneath the cuticle in this region there are dorsoventral as well as longitudinal muscles in abundance, much the same as the musculature in the remaining thoracic segments (i.e. the meso- and metathorax), which activate the two pairs of wings. The canal-bearing segment is of course devoid of wings, and its dorsoventral muscles are attached to the cuticle, which in this region resembles a bowl harboring several layers of epithelium that boasts numerous butterfly-shaped tracheal branches. Additionally there are layers that display lymph-filled spaces and also perforated layers and depressions, and beneath all these is a lace-like layer that also coats the cuticle's hollows. Underneath the cuticle proper, there are numerous large mitochondria and tracheae, which occupy a considerable part of the cuticular epithelium surface. These abundant mitochondria are, most probably, the main element of heat production in the thermogenic center.     

Ni–C powder synthesis by a submerged pulsed arc in breakdown mode

Powders of Ni–C nanoparticles were synthesized using a pulsed arc between Ni electrodes submerged in pure ethanol. The arc was ignited by inter-electrode breakdown. The ethanol was arc treated for 5 min with 1 μs duration pulses, at a repetition rate of 1 kHz. The pulse energy was in a range of 0.01–0.05 J. Powder samples were obtained by extracting liquid from the treatment vessel after a pre-determined sedimentation time, or by allowing the liquid to evaporate from the vessel, and collecting the residue. The samples were examined by HRSEM, EDX and XRD.It was found that a powder of Ni–C nanoparticles was produced. The powder consisted of carbon particles and nickel–carbon alloy particles. The latter were also coated by carbon. The carbon concentration in the Ni alloy was approximately triple of the maximum equilibrium solid solubility of carbon in nickel. The production rate of carbon was greater than the erosion rate of the Ni electrodes by factors of 2–6. The ratio of carbon production rate to electrode erosion rate decreased with the discharge energy. The size distribution of the produced particles was narrow. No particles with diameter more than 0.7 μm were observed.     

Pulsed discharge production of nano- and microparticles in ethanol and their characterization

Nanoparticles were synthesized using a pulsed arc submerged in ethanol. Two electrode configurations, (a) a 1×4 mm and a 10×10 mm graphite electrodes, and (b) Ni, W, and steel rod electrode pairs, were used. The liquid was arc treated for 5 min with 100 A peak current, 20 μs duration pulses, at a repetition rate of 100 Hz. Samples were obtained by extracting liquid from the top of the treatment vessel, and by allowing the liquid to evaporate from the vessel, and collecting the residue. The samples were examined by HRTEM, HRSEM, XRD, and X-ray photoemission spectroscopy (XPS). Carbon nanoparticles with an onion-like structure, i.e., composed of concentric spherical layers, were found in the samples from the top of the liquid vessel after arcing with either C or Ni electrode pairs. These particles typically had an o.d. of 15-20 nm, and the diameter of the interior void was approximately 5-8 nm. In some cases, the onions were clustered together, such that a typical cluster size was 50-60 nm. Ni and W nanoparticles were produced by treatment with Ni and W electrodes, respectively. The particles could be electrically collected by applying a potential difference between a pair of collection electrodes submerged in the fluid. The Ni particles with sizes of ∼15 μm drifted in the direction generally towards the positive electrode with velocities of approximately ∼2.5-3.5 mm/s in a d.c. electric field of 100 V/mm.     

Confinement-guided shaping of semiconductor nanowires and nanoribbons: "writing with nanowires"

To fully exploit their full potential, new semiconductor nanowire building blocks with ab initio controlled shapes are desired. However, and despite the great synthetic advances achieved, the ability to control nanowire's geometry has been significantly limited. Here, we demonstrate a simple confinement-guided nanowire growth method that enables to predesign not only the chemical and physical attributes of the synthesized nanowires but also allows a perfect and unlimited control over their geometry. Our method allows the synthesis of semiconductor nanowires in a wide variety of two-dimensional shapes such as any kinked (different turning angles), sinusoidal, linear, and spiral shapes, so that practically any desired geometry can be defined. The shape-controlled nanowires can be grown on almost any substrate such as silicon wafer, quartz and glass slides, and even on plastic substrates (e.g., Kapton HN).     

Novel reduction of mercury (II) by mercury-sensitive dissimilatory metal reducing bacteria

The dissimilatory metal reducing bacterium (DMRB) Shewanella oneidensis MR-1 reduces ionic mercury (Hg[II]) to elemental mercury (Hg[0]) by an activity not related to the MerA mercuric reductase. In S. oneidensis, this activity is constitutive and effective at Hg(II) concentrations too low to induce mer operon functions. Reduction of Hg(II) by MR-1 required the presence of electron donors and electron acceptors. Reduction occurred with oxygen or fumarate, but had the highest rate when ferric oxyhydroxide was used as a terminal electron acceptor. Geobacter sulfurreducens PCA and Geobacter metallireducens GS-15 reduced Hg(II) to Hg(0) with activity comparable to MR-1; however, neither the DMRB Anaeromyxobacter dehalogenans 2CP-C nor the nitrate reducer Pseudomonas stutzeri OX-1 reduced Hg(II) during growth. This discovery of constitutive mercury reduction among anaerobes has implications to the mobilization of mercury and production of methylmercury in anoxic environments.     

A thermoregulatory center in hornets: IR photography

In the Oriental hornet Vespa orientalis (Hymenoptera, Vespinae), there is on the dorsal side of the thorax, beneath the mesoscutum plate of the prothorax and around the median notal suture, a lump that, in the course of hornet activity, is warmer by 9 degrees C from the surrounding milieu and by up to 6 degrees C from other body parts of the hornet. This lump is about 1 mm in diameter, butterfly-shaped, and its upper, posterior border abuts the base of the forewings. During hornet activity and via Infra Red photography one can observe heat extensions stemming from the center of the lump and proceeding forward in the direction of the head, downward toward the legs and backwards toward the bases of the wings. The warmest region is the center of the lump, with its margins showing a lower temperature. As for the legs of the hornet, their upper part is warmer than the other parts. The temperature gradients along the hornet's body are dependent on the extent and nature of hornet activity. Thus, during flight or ventilation activity, the thorax is the warmest part of the body, while the wings, legs, and antennae, as well as the posterior part of the gaster are colder, yet all these body parts are still warmer to varying degrees than the surrounding milieu. Thus, at night, when sentry worker hornets stand guard around the nest entrance and remain practically motionless, the temperature differences between the various body parts are retained unchanged. We conjecture that the described butterfly-shaped lump is a thermoregulatory center (TC), which is neurogenically activated, since the changes occurring in it are rapid, a matter of one to several seconds and do not appear to be directly dependent on the hemolymph supply. The thermoregulatory center keeps a high constant temperature apparently related to hornet activity and the environmental conditions. The temperature cascade is most probably regulated via the tracheal system. Apparently another system activated by a heat pump mechanism keeps the gaster at a lower temperature than the environment.     

Influence of pulsed arc parameters on powder production in ethanol

Powder consisting nickel and carbon particles were synthesized using a pulsed arc between Ni electrodes submerged in pure ethanol. The ethanol was arc treated for 5 min with 20 and 40 μs duration pulses, at a repetition rate of 100 Hz. The pulse energy was varied in a range of 7.7-192 mJ. Powder samples were obtained by extracting liquid from the treatment vessel after a pre-determined sedimentation time, or by allowing the liquid to evaporate from the vessel, and collecting the residue. The samples were examined by HRSEM, EDX and XRD. Dependencies of the particle structure and size distribution, and the powder production rate and composition, on the pulse energy and duration were studied.The powder samples consisted of nickel and carbon particles. The surface of the nickel particle had a carbon coating. The Ni concentration increased from 32% to 46%, and the C concentration decreased from 68% to 54%, when the pulse energy was increased from 7.7 to 100 mJ with 20 μs pulses. For 40 μs pulses the same changes of Ni and C concentrations were obtained when the pulse energy increased from 60 to 100 mJ. The production rate of the Ni and C particles linearly increased with pulse energy.The particle quantity and size distribution width increased with pulse energy. The maximum particle diameter increased from 70 to 550 nm while its minimum diameter remained ∼ 50 nm when the pulse energy increased from 7.7 to 48 mJ with pulse duration of 20 μs.     

High-cycle fatigue of silver halide infrared fibers

The transmission of CO(2) laser radiation by silver halide infrared fibers was measured during cyclic bending of the fibers. High-cycle fatigue of the fibers was investigated. The fibers were found to transmit without significant deterioration after more than 10(7) cycles. The fatigue-stress limit, based on 10(7) bending cycles, was estimated to be approximately 75 MPa.     

Free‐Standing,Thermostable, Micrometer‐Scale Honeycomb Polymer Films and their Properties

A method of manufacturing free‐standing, micrometer‐scale honeycomb polyetherimide films is reported for the first time. Films are manufactured with a dip‐coating technique under water‐assisted self‐assembly. It is shown that the addition of poly(organosilane/siloxane)s and poly(ethylene glycol) allows the formation of regular honeycomb patterns. The films demonstrated the high thermal stability inherent for polyetherimide. The wetting properties of films are reported. The presence of nanopores was revealed with SEM imaging of the films. The makeup of the films allows their use as asymmetric membranes for reverse osmosis and ultrafiltration.