Time-Resolved Single-Particle X-ray Scattering Reveals Electron-Density Gradients As Coherent Plasmonic-Nanoparticle-Oscillation Source

Dynamics of optically excited plasmonic nanoparticles are presently understood as a series of scattering events involving the initiation of nanoparticle breathing oscillations. According to established models, these are caused by statistical heat transfer from thermalized electrons to the lattice. An additional contribution by hot-electron pressure accounts for phase mismatches between theory and experimental observations. However, direct experimental studies resolving the breathing-oscillation excitation are still missing. We used optical transient-absorption spectroscopy and time-resolved single-particle X-ray diffractive imaging to access the electron system and lattice. The time-resolved single-particle imaging data provided structural information directly on the onset of the breathing oscillation and confirmed the need for an additional excitation mechanism for thermal expansion. We developed a new model that reproduces all of our experimental observations. We identified optically induced electron density gradients as the initial driving source.

Three-dimensional femtosecond snapshots of isolated faceted nanostructures

The structure and dynamics of isolated nanosamples in free flight can be directly visualized via single-shot coherent diffractive imaging using the intense and short pulses of x-ray free-electron lasers. Wide-angle scattering images encode three-dimensional (3D) morphological information of the samples, but its retrieval remains a challenge. Up to now, effective 3D morphology reconstructions from single shots were only achieved via fitting with highly constrained models, requiring a priori knowledge about possible geometries. Here, we present a much more generic imaging approach. Relying on a model that allows for any sample morphology described by a convex polyhedron, we reconstruct wide-angle diffraction patterns from individual silver nanoparticles. In addition to known structural motives with high symmetries, we retrieve imperfect shapes and agglomerates that were not previously accessible. Our results open unexplored routes toward true 3D structure determination of single nanoparticles and, ultimately, 3D movies of ultrafast nanoscale dynamics.

The PERCIVAL detector: first user experiments

The PERCIVAL detector is a CMOS imager designed for the soft X-ray regime at photon sources. Although still in its final development phase, it has recently seen its first user experiments: ptychography at a free-electron laser, holographic imaging at a storage ring and preliminary tests on X-ray photon correlation spectroscopy. The detector performed remarkably well in terms of spatial resolution achievable in the sample plane, owing to its small pixel size, large active area and very large dynamic range; but also in terms of its frame rate, which is significantly faster than traditional CCDs. In particular, it is the combination of these features which makes PERCIVAL an attractive option for soft X-ray science.

Single-shot ptychography at a soft X-ray free-electron laser

In this work, single-shot ptychography was adapted to the XUV range and, as a proof of concept, performed at the free-electron laser FLASH at DESY to obtain a high-resolution reconstruction of a test sample. Ptychography is a coherent diffraction imaging technique capable of imaging extended samples with diffraction-limited resolution. However, its scanning nature makes ptychography time-consuming and also prevents its application for mapping of dynamical processes. Single-shot ptychography can be realized by collecting the diffraction patterns of multiple overlapping beams in one shot and, in recent years, several concepts based on two con-focal lenses were employed in the visible regime. Unfortunately, this approach cannot be extended straightforwardly to X-ray wavelengths due to the use of refractive optics. Here, a novel single-shot ptychography setup utilizes a combination of X-ray focusing optics with a two-dimensional beam-splitting diffraction grating. It facilitates single-shot imaging of extended samples at X-ray wavelengths.

Persistence of spatial memory induced by spaced training involves a behavioral-tagging process

Spaced training, which involves long inter-trial intervals, has positive effects on memories. One of the main attributes of long-term memories (LTM) is persistence. Here, to identify the process that promotes LTM persistence by spaced learning, we used the spatial object recognition (SOR) task. The protocol consisted of a first strong training session that induced LTM formation (tested 1 day after training), but not LTM persistence (tested 7 or 14 days after training); and a second weak training session that promoted memory persistence when applied 1 day, but not 7 days, after the first training. We propose that the promotion of memory persistence is based on the Behavioral Tagging (BT) mechanism operating when the memory trace is retrieved. BT involves the setting of a tag induced by learning which gives rise to input selectivity, and the use of plasticity-related proteins (PRPs) to establish the mnemonic trace. We postulate that retraining will mainly retag the sites initially activated by the original learning, where the PRPs needed for memory expression and/or induced by retrieval would be used to maintain a persistent mnemonic trace. Our results suggest that the mechanism of memory expression, but not those of memory reinforcement or reconsolidation, is necessary to promote memory persistence after retraining. The molecular mechanisms involve ERKs1/2 activity to set the SOR learning tag, and the availability of GluA2-containing AMPA receptor. In conclusion, both the synthesis of PRPs and the setting of a learning tag are key processes triggered by retraining that allow SOR memory persistence.

Pulse Energy and Pulse Duration Effects in the Ionization and Fragmentation of Iodomethane by Ultraintense Hard X Rays

The interaction of intense femtosecond x-ray pulses with molecules sensitively depends on the interplay between multiple photoabsorptions, Auger decay, charge rearrangement, and nuclear motion. Here, we report on a combined experimental and theoretical study of the ionization and fragmentation of iodomethane (CH_{3}I) by ultraintense (∼10^{19}  W/cm^{2}) x-ray pulses at 8.3 keV, demonstrating how these dynamics depend on the x-ray pulse energy and duration. We show that the timing of multiple ionization steps leading to a particular reaction product and, thus, the product's final kinetic energy, is determined by the pulse duration rather than the pulse energy or intensity. While the overall degree of ionization is mainly defined by the pulse energy, our measurement reveals that the yield of the fragments with the highest charge states is enhanced for short pulse durations, in contrast to earlier observations for atoms and small molecules in the soft x-ray domain. We attribute this effect to a decreased charge transfer efficiency at larger internuclear separations, which are reached during longer pulses.

Housing and accessibility after the COVID-19 pandemic: Rebuilding for resilience, equity and sustainable mobility

A more sustainable post COVID-19 world requires urban transport policies aiming for resilience, social equity and decarbonisation. Instead of just focusing on the transport sector, the authors propose an integrated approach to housing and mobility. This approach acknowledges the challenges posed by inadequate housing and dependence on motorised transport during the COVID-19 crisis. In contrast, adequate housing and cycling became paramount resources while confronting the pandemic. Using Santiago de Chile as a case study, this research examines how different relocation scenarios for its current housing deficit cannot only affect the ability to implement stay-at-home measures, but also the potential of cycling as a relevant commuting alternative. The current location of the families suffering this deficit is compared to three scenarios: compact, pericentral and extended. In light of the learnings from the COVID-19 crisis, a housing-cycling policy becomes a tool for resilience; equity is achieved by enforcing the right to housing, by increasing job opportunities among the poor, and by reducing the dependence on expensive motorised transport; decarbonisation is achieved by promoting active transportation and reducing the dependence on motorisation.

Characterization of the Percival detector with soft X-rays

In this paper the back-side-illuminated Percival 2-Megapixel (P2M) detector is presented, along with its characterization by means of optical and X-ray photons. For the first time, the response of the system to soft X-rays (250 eV to 1 keV) is presented. The main performance parameters of the first detector are measured, assessing the capabilities in terms of noise, dynamic range and single-photon discrimination capability. Present limitations and coming improvements are discussed.

Tissue-Sparing Outcome of Mohs Micrographic Surgery in Squamous Cell Carcinomas

BACKGROUND

Micrographic Mohs Surgery (MMS) offers the highest cure rates and healthy skin tissue sparing effect compared with standard excision.

OBJECTIVE

To quantify the tissue-sparing properties of MMS in squamous cell carcinoma (SCC) in comparison with standard excision (SE).

METHODS

A bidirectional, descriptive study, including 94 cases of SCC, was performed, on patients with histologic diagnosis of SCC (in situ, well differentiated, moderately differentiated, and undifferentiated), that where operated with MMS between 2013 and 2018 at Hospital de Clínicas Dr. Manuel Quintela in Montevideo, Uruguay. Tumor size and defect area after MMS were measured in 2 perpendicular directions. The suspected defect area was calculated with standard excision using a 4-mm margin for low risk lesions and a 10-mm margin for high risk lesions. The primary outcome of this study was the size of the defect area post MMS compared with the calculated defect area with standard excision.

RESULTS

The median tumor size was 1,41mm², and the median defect size after MMS was 4,12mm². The median defect size calculated for standard surgical excision was 8,36mm².

LIMITATIONS

We do not use all National Comprehensive Cancer Network (NCCN) criteria. We define low and high risk lesions just taking into account anatomical location, size, histopathology and whether it was a primary or recurrent tumor.

CONCLUSION

Our results show that MMS has a tissue-sparing effect of at least 52% compared to SE.

[Single-repair for primary proximal hypospadias. Lessons learned after 196 primary repairs]

PURPOSE

Proximal, scrotal and perineal hypospadias challenge the surgeon. After 40 years devoted to hypospadias surgery, the senior author summarizes her experience, share her tricks and shows that almost any hypospadias can be fully repaired in one surgery.

METHODS

Retrospective review and discussions of a large series of consecutive proximal hypospadias treated in one surgery by the same team from 1999 to 2016.

RESULTS

196 patients were operated. 68% of all patients were successfully repaired after the surgery. All hypospadias were treated using one of the following techniques: onlay double flap, tubularized preputial flap or mucosal grafts (only until 2005). Urethrocutaneous fistula was present in 25% of cases, but only 13% of patients needed other further surgical procedures.

CONCLUSION

Cutaneous incisions design is fundamental in hypospadias repair. When the incisions follow the natural folds that appear in penile and scrotal skin, it's possible to obtain optimal flaps for both urethroplasty and skin coverage (even avoiding the need for mucosal grafts). Consequently, almost all kinds of hypospadias can be repaired in one surgery with very good long-term results.

The Super Shaving Technique to Correct the Trapdoor Effect in Nasal Flaps

INTRODUCTION AND OBJECTIVES

The trapdoor effect is a possible complication in flap reconstructions, particularly those involving the face. It consists of a bulging, elevated deformity that appears 3 weeks after the intervention. To date there has been no consensus on how the trapdoor effect should be treated. The aim of this article is to report on our experience with this defect and describe how we use the 'super shaving' technique to resolve the trapdoor effect in nasal flaps.

MATERIAL AND METHODS

We performed a retrospective, descriptive study of 10 patients who developed a bulging deformity of a nasal flap that was treated surgically with the super shaving technique. We also report on postoperative management.

RESULTS

The median age of the 10 patients was 67.7 years and they all developed a bulging transposition flap in the nasal area after conventional or Mohs micrographic surgery. The complication occurred approximately 5 weeks after surgery and healing time was 4 weeks. There were no major postoperative complications and the outcome was of low aesthetic significance compared with the bulging flap. All the patients stated they were very satisfied with the aesthetic outcome.

CONCLUSIONS

In our opinion, the super shaving technique is a fast, effective, simple, and cheap outpatient procedure that offers excellent aesthetic results.

Relativistic and resonant effects in the ionization of heavy atoms by ultra-intense hard X-rays

An accurate description of the interaction of intense hard X-ray pulses with heavy atoms, which is crucial for many applications of free-electron lasers, represents a hitherto unresolved challenge for theory because of the enormous number of electronic configurations and relativistic effects, which need to be taken into account. Here we report results on multiple ionization of xenon atoms by ultra-intense (about 1019 W/cm2) femtosecond X-ray pulses at photon energies from 5.5 to 8.3 keV and present a theoretical model capable of reproducing the experimental data in the entire energy range. Our analysis shows that the interplay of resonant and relativistic effects results in strongly structured charge state distributions, which reflect resonant positions of relativistically shifted electronic levels of highly charged ions created during the X-ray pulse. The theoretical approach described here provides a basis for accurate modeling of radiation damage in hard X-ray imaging experiments on targets with high-Z constituents.

Rapid sample delivery for megahertz serial crystallography at X-ray FELs

Liquid microjets are a common means of delivering protein crystals to the focus of X-ray free-electron lasers (FELs) for serial femtosecond crystallography measurements. The high X-ray intensity in the focus initiates an explosion of the microjet and sample. With the advent of X-ray FELs with megahertz rates, the typical velocities of these jets must be increased significantly in order to replenish the damaged material in time for the subsequent measurement with the next X-ray pulse. This work reports the results of a megahertz serial diffraction experiment at the FLASH FEL facility using 4.3 nm radiation. The operation of gas-dynamic nozzles that produce liquid microjets with velocities greater than 80 m s-1 was demonstrated. Furthermore, this article provides optical images of X-ray-induced explosions together with Bragg diffraction from protein microcrystals exposed to trains of X-ray pulses repeating at rates of up to 4.5 MHz. The results indicate the feasibility for megahertz serial crystallography measurements with hard X-rays and give guidance for the design of such experiments.

CAMP@FLASH: an end-station for imaging, electron- and ion-spectroscopy, and pump-probe experiments at the FLASH free-electron laser

The non-monochromatic beamline BL1 at the FLASH free-electron laser facility at DESY was upgraded with new transport and focusing optics, and a new permanent end-station, CAMP, was installed. This multi-purpose instrument is optimized for electron- and ion-spectroscopy, imaging and pump-probe experiments at free-electron lasers. It can be equipped with various electron- and ion-spectrometers, along with large-area single-photon-counting pnCCD X-ray detectors, thus enabling a wide range of experiments from atomic, molecular, and cluster physics to material and energy science, chemistry and biology. Here, an overview of the layout, the beam transport and focusing capabilities, and the experimental possibilities of this new end-station are presented, as well as results from its commissioning.

Introduction of pharmacy technicians onto a busy oncology ward as part of the nursing team

A project was planned to explore the practicality of using pharmacy technicians to support the workload of nursing teams on a busy haematology oncology ward of 28 beds in a university acute care children's hospital of 300 beds. The question asked was, could pharmacy technicians be part of the nursing team to undertake what has traditionally been considered a nursing role? Three pharmacy technicians were trained and participated in the study. Assisting in the preparation and administration of 509 intravenous injections out of a possible 1123 (45%) of all intravenous injections prepared on the ward during the study period. The results indicated a reduction in adverse events of 1-2 a day during the study period, a reduction in work-related stress by nursing staff associated with preparing complex medication and releasing a nurse, 4 hours a day to enable them additional time to care for patients.

Spatial patterns of Anchoveta (Engraulis ringens) eggs and larvae in relation to pCO2 in the Peruvian upwelling system

Large and productive fisheries occur in regions experiencing or projected to experience ocean acidification. Anchoveta (Engraulis ringens) constitute the world's largest single-species fishery and live in one of the ocean's highest pCO₂ regions. We investigated the relationship of the distribution and abundance of Anchoveta eggs and larvae to natural gradients in pCO₂ in the Peruvian upwelling system. Eggs and larvae, zooplankton, and data on temperature, salinity, chlorophyll a and pCO₂ were collected during a cruise off Peru in 2013. pCO₂ ranged from 167–1392 µatm and explained variability in egg presence, an index of spawning habitat. Zooplankton abundance explained variability in the abundance of small larvae. Within the main spawning and larva habitats (6–10°S), eggs were found in cool, low-salinity, and both extremely low (less than 200 µatm) and high (more than 900 µatm) pCO₂ waters, and larvae were collected in warmer, higher salinity, and moderate (400–600 µatm) pCO₂ waters. Our data support the hypothesis that Anchoveta preferentially spawned at high pCO₂ and these eggs had lower survival. Enhanced understanding of the influence of pCO₂ on Anchoveta spawning and larva mortality, together with pCO₂ measurements, may enable predictions of ocean acidification effects on Anchoveta and inform adaptive fisheries management.

Selective Oestrogen Receptor Agonists Rescued Hippocampus Parameters in Male Spontaneously Hypertensive Rats

Spontaneously hypertensive rats (SHR) show pronounced hippocampus alterations, including low brain-derived neurotrophic factor (BDNF) expression, reduced neurogenesis, astrogliosis and increased aromatase expression. These changes are reverted by treatment with 17β-oestradiol. To determine which oestradiol receptor (ER) type is involved in these neuroprotective effects, we used agonists of the ERα [propylpyrazole triol (PPT)] and the ERβ [diarylpropionitrite (DPN)] given over 2 weeks to 4-month-old male SHR. Wistar Kyoto normotensive rats served as controls. Using immunocytochemistry, we determined glial fibrillary protein (GFAP)+ astrocytes in the CA1, CA3 and hilus of the dentate gyrus of the hippocampus, aromatase immunostaining in the hilus, and doublecortin (DCX)+ neuronal progenitors in the inner granular zone of the dentate gyrus. Brain-derived neurotrophic factor mRNA was also measured in the hippocampus by the quantitative polymerase chain reaction. In SHR, PPT had no effect on blood pressure, decreased astrogliosis, slightly increased BDNF mRNA, had no effect on the number of DCX+ progenitors, and increased aromatase staining. Treatment with DPN decreased blood pressure, decreased astrogliosis, increased BDNF mRNA and DCX+ progenitors, and did not modify aromatase staining. We hypothesise that, although both receptor types may participate in the previously reported beneficial effects of 17β-oestradiol in SHR, receptor activation with DPN may preferentially facilitate BDNF mRNA expression and neurogenesis. The results of the present study may help in the design of ER-based neuroprotection for the encephalopathy of hypertension.

Detector developments at DESY

With the increased brilliance of state-of-the-art synchrotron radiation sources and the advent of free-electron lasers (FELs) enabling revolutionary science with EUV to X-ray photons comes an urgent need for suitable photon imaging detectors. Requirements include high frame rates, very large dynamic range, single-photon sensitivity with low probability of false positives and (multi)-megapixels. At DESY, one ongoing development project - in collaboration with RAL/STFC, Elettra Sincrotrone Trieste, Diamond, and Pohang Accelerator Laboratory - is the CMOS-based soft X-ray imager PERCIVAL. PERCIVAL is a monolithic active-pixel sensor back-thinned to access its primary energy range of 250 eV to 1 keV with target efficiencies above 90%. According to preliminary specifications, the roughly 10 cm × 10 cm, 3.5k × 3.7k monolithic sensor will operate at frame rates up to 120 Hz (commensurate with most FELs) and use multiple gains within 27 µm pixels to measure 1 to ∼100000 (500 eV) simultaneously arriving photons. DESY is also leading the development of the AGIPD, a high-speed detector based on hybrid pixel technology intended for use at the European XFEL. This system is being developed in collaboration with PSI, University of Hamburg, and University of Bonn. The AGIPD allows single-pulse imaging at 4.5 MHz frame rate into a 352-frame buffer, with a dynamic range allowing single-photon detection and detection of more than 10000 photons at 12.4 keV in the same image. Modules of 65k pixels each are configured to make up (multi)megapixel cameras. This review describes the AGIPD and the PERCIVAL concepts and systems, including some recent results and a summary of their current status. It also gives a short overview over other FEL-relevant developments where the Photon Science Detector Group at DESY is involved.

Suppressing bacterial interaction with copper surfaces through graphene and hexagonal-boron nitride coatings

Understanding biological interaction with graphene and hexagonal-boron nitride (h-BN) membranes has become essential for the incorporation of these unique materials in contact with living organisms. Previous reports show contradictions regarding the bacterial interaction with graphene sheets on metals. Here, we present a comprehensive study of the interaction of bacteria with copper substrates coated with single-layer graphene and h-BN. Our results demonstrate that such graphitic coatings substantially suppress interaction between bacteria and underlying Cu substrates, acting as an effective barrier to prevent physical contact. Bacteria do not "feel" the strong antibacterial effect of Cu, and the substrate does not suffer biocorrosion due to bacteria contact. Effectiveness of these systems as barriers can be understood in terms of graphene and h-BN impermeability to transfer Cu(2+) ions, even when graphene and h-BN domain boundary defects are present. Our results seem to indicate that as-grown graphene and h-BN films could successfully protect metals, preventing their corrosion in biological and medical applications.

Heritability and identification of QTLs and underlying candidate genes associated with the architecture of the grapevine cluster (Vitis vinifera L.)

We have identified 19 QTLs for rachis architecture, a key and complex trait for grapevine production. Fifty out of 1,173 genes underlying these QTLs are candidates to be further explored. In the table grape industry, the rachis architecture has economic and management implications. Therefore, understanding the genetics of this trait is key for its breeding. The aim of this work was to identify genetic determinants of traits associated with the cluster architecture. Characterisations of eight traits was performed on a 'Ruby Seedless' × 'Sultanina' crossing (F1: n = 137) during three seasons, with and without gibberellic acid (GA3) applications. The genotypic effects and the genotype × GA3 interactions were significant for several traits. Rachis length (rl), lateral shoulder length and node number along the central axis were the most prominent traits. On average, the heritability of these traits was ~71 %, with heritability of rl being 76 % as estimated under different seasons. Quantitative trait loci (QTLs) analyses showed that linkage group 5 (LG5) and LG18 harboured the largest number of QTLs for these traits. According to the variance explained, the main QTL (corresponding to rl) was found on LG9. These QTLs were supported mainly by a paternal additive effect and revealed possible pleiotropic effects. Based on the grapevine reference genome, we identified 1,173 genes located under these QTL confidence intervals. Fifty of the 891 annotated genes of this list were selected for their further characterisation because of their possible participation in the rachis architecture. In conclusion, the QTLs detected indicate that these traits and their GA3 responsiveness have a clear genetic basis. Due to the percentage of the total variance explained, they are good candidates to participate in the genetic determination of the cluster architecture.

Efficacy and safety of non-operative management of blunt liver trauma

BACKGROUND

The liver is the most frequently affected organ during blunt abdominal trauma. Blunt liver trauma management has changed in the last two decades with the introduction of the computed tomography (CT) scan and non-operative management of stable patients.

OBJECTIVE

To determine the incidence, efficacy, and failure rate of blunt liver trauma non-operative management as well as the risk factors associated with such treatment in a level 1 trauma center in Colombia.

METHODS

We conducted an observational descriptive study on patients with blunt liver trauma who were admitted to a level 1 trauma center in Colombia. The evaluated outcomes were indications of immediate surgical treatment and the success of non-operative management.

RESULTS

A total of 73 patients were studied. The most common mechanism of trauma continues to be motor vehicle crashes. In 14 patients (19.2%), immediate surgical intervention was necessary and we observed a Revised Trauma Score (RTS) above 7.8 and intra-abdominal injuries as risk factors. Three patients died (21.4%). Fifty-nine patients (80.8%) received non-operative management, which failed in seven patients (11.2%). Age, severity of liver injury, and intra-abdominal injuries were not risk factors in the failure of non-operative management. Mortality in the non-operative management group was 1.7%.

CONCLUSION

Non-operative management is the treatment of choice for polytraumatized patients with blunt liver trauma who are hemodynamically stable. Non-operative management is an effective and safe treatment strategy. However, patients with an RTS score under 7.8 and other intra-abdominal non-liver injuries are at increased risk for an immediate surgical intervention.

Catheter ablation of ventricular tachycardia in Chagasic Cardiomyopathy

There is a limited experience with catheter ablation for treatment of ventricular tachycardia (VT) in Chagasic cardiomyopathy. A 30-year-old woman experienced episodes of palpitations and syncope due to attacks of VT. A diagnosis of Chagas disease was established on a biological basis. Two-dimensional echo and contrast ventriculography showed an apical aneurysm with thrombus. Surgery was indicated to resect the aneurysm and ablate the VT. Ventricular tachycardia recurred 1 month later despite therapy, including amiodarone. Two clinical frequent and well-tolerated tachycardias were identified. The site of origin was located in the right ventricular apex and in the apical-lateral wall of the left ventricle, respectively. Catheter ablation was performed at two sites with DC shocks (total energy 600 J) after unsuccessful radiofrequency ablation. Holter recordings performed during the post-operative period showed only infrequent extrasystoles. After follow-up of 24 months the patient remains asymptomatic. Drug-refractory VT in Chagasic cardiomyopathy can be ablated by medium-energy DC shocks after failure of radiofrequency ablation.

Expression of the GM-CSF receptor in ovine spermatozoa: GM-CSF effect on sperm viability and motility of sperm subpopulations after the freezing–thawing process

The granulocyte-macrophage colony stimulating factor (GM-CSF) is a pleiotropic cytokine capable of stimulating proliferation, maturation and function of haematopoietic cells. Receptors for this cytokine are composed of two subunits, alpha and beta, and are expressed in myeloid progenitors and mature mononuclear phagocytes, monocytes, eosinophils and neutrophils, as well as in other non-haematopoietic cells. We have previously demonstrated that bull spermatozoa express functional GM-CSF receptors that signal for increased glucose and vitamin-C uptake and enhance several parameters of sperm motility in the presence of glucose or fructose substrates. In this study, we have analyzed the expression of GM-CSF receptors in ovine spermatozoa and studied the effect of GM-CSF on sperm viability and motility after the freezing-thawing process. Immunolocalization and immunoblotting analyses demonstrated that ovine spermatozoa (Xisqueta race) expressed GM-CSF receptors. In addition, GM-CSF partially counteracted the impairing action of freezing/thawing on the percentage of total motility, as well as on the specific motility patterns of each of the separate, motile sperm subpopulations of ram ejaculates subjected to this protocol. These results suggest that GM-CSF can play a role in the resistance of ram spermatozoa to environmental thermal stress.

262 TISSUE-SPECIFIC ANALYSIS OF PRION EXPRESSION IN EARLY BOVINE FETUSES

The prion protein (PrP) is best known for its mis-folded, pathogenic isoform, which is widely regarded as the infectious agent in transmissable spongiform encephalopathies. However, the role of normal, cellular PrP, a host-encoded 29-kD glycoprotein tethered to the cell membrane by a phosphatidyl-inositol glycane (GPI) anchor, is poorly understood. PrP binds copper with high affinity, has antioxidant activity and may play a role in cell adhesion and/or signaling. PrP is expressed in mouse embryos on 6.5 days post-coitum in extra-embryonic tissue and at 13.5 days in the central and peripheral nervous system, intestine, and dental lamina. Our previous data revealed PrP gene expression in bovine embryos throughout pre-implantation embryo development. As part of a larger effort to map the ontogeny of cellular PrP expression in cattle, we sought here to analyze in early bovine fetuses (1) total PrP gene expression by real-time quantitative PCR (QPCR), and (2) tissue-specific PrP expression by immunohistochemistry. Fetuses were obtained from donor cattle bred by artificial insemination (AI; Day 0) and subjected to mid-ventral laparotomy on Days 32 (n = 2) and 39 (n = 2). Immediately upon recovery, one fetus from each stage was placed in RNAlater for RNA isolation and the other fixed in 10% formalin for immunohistochemistry. RNA was isolated using an RNeasy� mini kit (Qiagen, Valencia, CA, USA). cDNA was generated by reverse transcription with random hexamer priming and used the ΔΔcT method for estimation of PrP expression by QPCR. Tissue-specific expression was determined by immunohistochemistry. Formalin-fixed fetuses were embedded in paraffin, sagittally sectioned, dehydrated, and subjected to an unmasking protocol that employed Vectorlab unmasking solution and autoclaving. Tissues were then probed with a primary anti-PrP monoclonal antibody (SAF 32; Cayman Chemical Company, Ann Arbor, MI, USA). Bound primary antibody was detected with a biotinylated horse anti-mouse secondary antibody complexed to horseradish peroxidase using the ABC kit (Vector Laboratories, Burlingame, CA, USA). Probed sections were then counterstained with hematoxolin and eosin. Neighboring sections, processed identically but to which no primary antibody was added, served as controls. PrP gene expression was detected by QPCR at both stages examined and tended to be higher in Day 39 compared to Day 32 fetuses. PrP immunoreactivity was found throughout the central and peripheral nervous systems, ganglia, nerve trunks, and neural cell populations of sensory organs in both Day 32 and Day 39 fetuses. PrP immunolabeling was also observed in the mesonephric kidney, liver, and heart in the Day 39 fetus. At both stages, immunoreactivity was most intense in the nervous system. Thus, PrP is expressed in a tissue-specific pattern in early bovine fetuses. Tissue distribution of fetal PrP expression appears similar to that of adult PrP. Moreover, PrP appears to be expressed in a developmentally regulated fashion in some tissues.

Safety, immunogenecity, and efficacy of an autoclaved Leishmania amazonensis vaccine plus BCG adjuvant against New World cutaneous leishmaniasis

The safety, immunogenecity, and efficacy of two doses of an autoclaved-killed, whole cell Leishmania amazonensis vaccine (IFLA/BR/67/PH8) and BCG adjuvant (n = 750) against cutaneous leishmaniasis (CL) was compared with placebo (n = 756) in a randomized, placebo-controlled, blinded study. Systemic and local side-effects were more frequent in the vaccine than placebo group. Leishmanin skin test (LST) conversion was greater in the vaccine than placebo group 2 months after the second vaccination dose (74.4% versus 14.7%; P = 0.000001). The 26-month incidence of confirmed CL (n = 25) was similar between the vaccine (2.0%) and placebo groups (2.0% versus 1.3%; P > 0.05). LST conversion was not associated with CL protection and the vaccine did not offer significant protection against CL infection caused by L. Viannia spp. compared to placebo.

Aerobic degradation of 2,4,6-TCP content in ECF bleached effluent

Elemental chlorine-free (ECF) bleach effluents from kraft mill are characterised by: a chemical organic demand/biological organic demand (COD/BOD(5)) ratio of 4, chlorophenol content with low chlorine substitution, and toxicity. The effect of increasing the concentration of 2,4,6-trichlorophenol (2,4,6-TCP) content in ECF bleaching sequence effluent on the degradative activity of bacterial communities present in an aerobic system treatment was studied. An aerobic lagoon (AL) was used as a typical secondary treatment of kraft-mill effluent. AL displays a high performance of BOD(5) degradation (up to 90%); however, only 40% of the COD was removed. Simultaneously, the AL system shows a high ability to biodegrade 2,4,6-TCP up to 237 mg/l day. Kinetic parameters of the 2,4,6-TCP biodegradation by aerobic bacteria were determined. The K(s) and K(i) values were 34.3 and 50 mg/l 2,4,6-TCP, respectively. Moreover, the tolerance of aerobic bacteria was observed up to 1.3 g/l 2,4,6-TCP.

[Parasitic risks (bilharziosis and intestinal parasitosis) to Mboune's valley revitalisation (Senegal)]

In order to assess the parasitic risks related to M'Boune's valley water launching, a study has been carried out from September 16 to November 24, 1998 in 12 villages: four villages surrounding the Guiers lake, four villages surrounding Ferlo already water launched 10 years ago, and four villages within M'Boune not water launched. The prevalence rate of urinary bilharziosis is 0.002% in the frist area, 1.3% in the second one and 13.7% in the third area. In these areas, intestinal parasitosis are prevaling respectively at rates of 38.2%, 36.4% and 21.3%. Although, there is no reason to fear immediately a worsening of the epidemiological situation due to M'Boune's valley revitalisation project, nevertheless, appropriate steps should be taken right now aiming at tackling the extension of conditions related to hydric medium.

Evidence that the NH2 terminus of vph1p, an integral subunit of the V0 sector of the yeast V-ATPase, interacts directly with the Vma1p and Vma13p subunits of the V1 sector

The vacuolar-type H(+)-ATPase (V-ATPase) is composed of a peripherally bound (V(1)) and a membrane-associated (V(0)) complex. V(1) ATP hydrolysis is thought to rotate a central stalk, which in turn, is hypothesized to drive V(0) proton translocation. Transduction of torque exerted by the rotating stalk on V(0) requires a fixed structural link (stator) between the complexes to prevent energy loss through futile rotation of V(1) relative to V(0); this work sought to identify stator components. The 95-kDa V-ATPase subunit, Vph1p, has a cytosolic NH(2) terminus (Nt-Vph1p) and a membrane-associated COOH terminus. Two-hybrid assays demonstrated that Nt-Vph1p interacts with the catalytic V(1) subunit, Vma1p. Co-immunoprecipitation of Vma1p with Nt-Vph1p confirmed the interaction. Expression of Nt-Vph1p in a Deltavph1 mutant was necessary to recruit Vma13p to V(1). Vma13p bound to Nt-Vph1p in vitro demonstrating direct interaction. Limited trypsin digests cleaves both Nt-Vph1p and Vma13p. The same tryptic treatment results in a loss of proton translocation while not reducing bafilomycin A(1)-sensitive ATP hydrolysis. Trypsin cleaved Vph1p at arginine 53. Elimination of the tryptic cleavage site by substitution of arginine 53 to serine partially protected vacuolar acidification from trypsin digestion. These results suggest that Vph1p may function as a component of a fixed structural link, or stator, coupling V(1) ATP hydrolysis to V(0) proton translocation.

Disruption and phenotypic analysis of six open reading frames from the left arm of Saccharomyces cerevisiae chromosome VII

Six open reading frames (ORFs) from Saccharomyces cerevisiae chromosome VII were deleted using the kanMX4 module and the long-flanking homology-PCR replacement strategy in at least two different backgrounds. Among these ORFs, two of them (YGL100w and YGL094c) are now known genes which encode well-characterized proteins (Seh1p, a nuclear pore protein, and Pan2p, a component of Pab1p-stimulated poly(A) ribonuclease, respectively). The other four ORFs (YGL101w, YGL099w, YGL098w and YGL096w) code for proteins of unknown function, although the protein encoded by YGL101w has a strong similarity to the hypothetical protein Ybr242p. Gene disruptions were performed in diploid cells using the KanMX4 cassette, and the geneticin (G418)-resistant transformants were checked by PCR. Tetrad analysis of heterozygous deletant strains revealed that YGL098w is an essential gene for vegetative growth in three backgrounds, whereas the other five genes are non-essential, although we have found some phenotypes in one of them. YGL099wDelta strain did not grow at all at 15 degrees C and showed a highly impaired sporulation and a significantly lower mating efficiency. The other three deletants did not reveal any significant differences with respect to their parental strains in our basic phenotypic tests.