Scintillation light detection in the 6-m drift-length ProtoDUNE Dual Phase liquid argon TPC

DUNE is a dual-site experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. ProtoDUNE Dual Phase (DP) is a 6  ×  6  ×  6 m 3 liquid argon time-projection-chamber (LArTPC) that recorded cosmic-muon data at the CERN Neutrino Platform in 2019-2020 as a prototype of the DUNE Far Detector. Charged particles propagating through the LArTPC produce ionization and scintillation light. The scintillation light signal in these detectors can provide the trigger for non-beam events. In addition, it adds precise timing capabilities and improves the calorimetry measurements. In ProtoDUNE-DP, scintillation and electroluminescence light produced by cosmic muons in the LArTPC is collected by photomultiplier tubes placed up to 7 m away from the ionizing track. In this paper, the ProtoDUNE-DP photon detection system performance is evaluated with a particular focus on the different wavelength shifters, such as PEN and TPB, and the use of Xe-doped LAr, considering its future use in giant LArTPCs. The scintillation light production and propagation processes are analyzed and a comparison of simulation to data is performed, improving understanding of the liquid argon properties.

Early positive approaches to support for families of young children with intellectual disability: the E-PAtS feasibility RCT

Background

Parents of children with intellectual disability are 1.5–2 times more likely than other parents to report mental health difficulties. There is a lack of clinically effective and cost-effective group well-being interventions designed for family carers of young children with intellectual disability.

Aim

To examine the feasibility of a randomised controlled trial of the clinical effectiveness and cost-effectiveness of the Early Positive Approaches to Support (E-PAtS) intervention.

Design

A feasibility study (including randomisation of families into a two-arm trial), questionnaires to assess the feasibility of proposed outcome measures (including resource use and health-related quality of life) and practitioner/family carer interviews. An additional question was included in an online UK survey of families, conducted by the research team to assess usual practice, and a survey of provider organisations.

Setting

Families recruited from community contexts (i.e. third sector, local authority services, special schools) and self-referral. The E-PAtS intervention was delivered by trained community-based providers.

Participants

Families with at least one child aged 1.5–5 years with an intellectual disability. At least one parent had to have English-language ability (spoken) for E-PAtS programme participation and participants had to provide informed consent.

Interventions

E-PAtS intervention – two caregivers from each family invited to eight 2.5-hour group sessions with usual practice. Usual practice – other support provided to the family, including other parenting support.

Objectives

To assess randomisation willingness/feasibility, recruitment of providers/parents, retention, usual practice, adherence, fidelity and feasibility of proposed outcome measures (including the Warwick–Edinburgh Mental Well-Being Scale as the proposed primary outcome measure, and parent anxiety/depression, parenting, family functioning/relationships, child behavioural/emotional problems and adaptive skills, child and parent quality of life, and family services receipt as the proposed secondary outcome measures).

Results

Seventy-four families (95 carers) were recruited from three sites (with 37 families allocated to the intervention). From referrals, the recruitment rate was 65% (95% confidence interval 56% to 74%). Seventy-two per cent of families were retained at the 12-month follow-up (95% confidence interval 60% to 81%). Exploratory regression analysis showed that the mean Warwick–Edinburgh Mental Well-Being Scale well-being score was 3.96 points higher in the intervention group (95% confidence interval –1.39 to 9.32 points) at 12 months post randomisation. High levels of data completeness were achieved on returned questionnaires. Interviews (n = 25) confirmed that (1) recruitment, randomisation processes and the intervention were acceptable to family carers, E-PAtS facilitators and community staff; (2) E-PAtS delivery were consistent with the logic model; and (3) researchers requesting consent in future for routine data would be acceptable. Recorded E-PAtS sessions demonstrated good fidelity (96% of components present). Adherence (i.e. at least one carer from the family attending five out of eight E-PAtS sessions) was 76%. Health-related quality-of-life and services receipt data were gathered successfully. An online UK survey to assess usual practice (n = 673) showed that 10% of families of young children with intellectual disability received any intervention over 12 months. A provider survey (n = 15) indicated willingness to take part in future research.

Limitations

Obtaining session recordings for fidelity was difficult. Recruitment processes need to be reviewed to improve diversity and strategies are needed to improve primary outcome completion.

Conclusions

Study processes were feasible. The E-PAtS intervention was well received and outcomes for families were positive. A barrier to future organisation participation is funding for intervention costs. A definitive trial to test the clinical effectiveness and cost-effectiveness of E-PAtS would be feasible.

Trial registration

Current Controlled Trials ISRCTN70419473.

Funding

This project was funded by the National Institute for Health Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 10, No. 2. See the NIHR Journals Library website for further project information.

Early Positive Approaches to Support (E-PAtS) for Families of Young Children With Intellectual Disability: A Feasibility Randomised Controlled Trial

Background: Parents of children with intellectual disabilities are likely to experience poorer mental well-being and face challenges accessing support. Early Positive Approaches to Support (E-PAtS) is a group-based programme, co-produced with parents and professionals, based on existing research evidence and a developmental systems approach to support parental mental well-being. The aim of this study was to assess the feasibility of community service provider organisations delivering E-PAtS to parents/family caregivers of young children with intellectual disability, to inform a potential definitive randomised controlled trial of the effectiveness and cost-effectiveness of E-PAtS. Methods: This study was a feasibility cluster randomised controlled trial, with embedded process evaluation. Up to two parents/family caregivers of a child (18 months to <6 years old) with intellectual disability were recruited at research sites and allocated to intervention (E-PAtS and usual practise) or control (usual practise) on a 1:1 basis at cluster (family) level. Data were collected at baseline and 3 and 12 months' post-randomisation. The following feasibility outcomes were assessed: participant recruitment rates and effectiveness of recruitment pathways; retention rates; intervention adherence and fidelity; service provider recruitment rates and willingness to participate in a future trial; barriers and facilitating factors for recruitment, engagement, and intervention delivery; and feasibility of collecting outcome measures. Results: Seventy-four families were randomised to intervention or control (n = 37). Retention rates were 72% at 12 months post-randomisation, and completion of the proposed primary outcome measure (WEMWBS) was 51%. Recruitment of service provider organisations and facilitators was feasible and intervention implementation acceptable. Adherence to the intervention was 76% and the intervention was well-received by participants; exploratory analyses suggest that adherence and attendance may be associated with improved well-being. Health economic outcome measures were collected successfully and evidence indicates that linkage with routine data would be feasible in a future trial. Conclusions: The E-PAtS Feasibility RCT has demonstrated that the research design and methods of intervention implementation are generally feasible. Consideration of the limitations of this feasibility trial and any barriers to conducting a future definitive trial, do however, need to be considered by researchers. Clinical Trial Registration: https://www.isrctn.com, identifier: ISRCTN70419473.

An experimental approach to analyze aerosol and splatter formations due to a dental procedure

Throughout 2020 and beyond, the entire world has observed a continuous increase in the infectious spread of the novel coronavirus (SARS-CoV-2) otherwise known as COVID-19. The high transmission of this airborne virus has raised countless concerns regarding safety measures employed in the working conditions for medical professionals. Specifically, those who perform treatment procedures on patients which intrinsically create mists of fine airborne droplets, i.e., perfect vectors for this and other viruses to spread. The present study focuses on understanding the splatter produced due to a common dentistry technique to remove plaque buildup on teeth. This technique uses a high-speed dentistry instrument, e.g., a Cavitron ultrasonic scaler, to scrape along the surface of a patient's teeth. This detailed understanding of the velocity and the trajectory of the droplets generated by the splatter will aid in the development of hygiene mechanisms to guarantee the safety of those performing these procedures and people in clinics or hospitals. Optical flow tracking velocimetry (OFTV) method was employed to obtain droplet velocity and trajectory in a two-dimensional plane. Multiple data collection planes were taken in different orientations around a model of adult mandibular teeth. This technique provided pseudo-three-dimensional velocity information for the droplets within the splatter developed from this high-speed dental instrument. These results indicated that within the three-dimensional splatter produced there were high velocities (1-2 m/s) observed directly below the intersection point between the front teeth and the scaler. The splatter formed a cone-shape structure that propagated 10-15 mm away from the location of the scaler tip. From the droplet trajectories, it was observed that high velocity isolated droplets propagate away from the bulk of the splatter. It is these droplets which are concerning for health safety to those performing the medical procedures. Using a shadowgraphy technique, we further characterize the individual droplets' size and their individual velocity. We then compare these results to previously published distributions. The obtained data can be used as a first step to further examine flow and transport of droplets in clinics/dental offices.

Constraints on Lightly Ionizing Particles from CDMSlite

The Cryogenic Dark Matter Search low ionization threshold experiment (CDMSlite) achieved efficient detection of very small recoil energies in its germanium target, resulting in sensitivity to lightly ionizing particles (LIPs) in a previously unexplored region of charge, mass, and velocity parameter space. We report first direct-detection limits calculated using the optimum interval method on the vertical intensity of cosmogenically produced LIPs with an electric charge smaller than e/(3×10^{5}), as well as the strongest limits for charge ≤e/160, with a minimum vertical intensity of 1.36×10^{-7}  cm^{-2} s^{-1} sr^{-1} at charge e/160. These results apply over a wide range of LIP masses (5  MeV/c^{2} to 100  TeV/c^{2}) and cover a wide range of βγ values (0.1-10^{6}), thus excluding nonrelativistic LIPs with βγ as small as 0.1 for the first time.

Light Dark Matter Search with a High-Resolution Athermal Phonon Detector Operated above Ground

We present limits on spin-independent dark matter-nucleon interactions using a 10.6 g Si athermal phonon detector with a baseline energy resolution of σ_{E}=3.86±0.04(stat)_{-0.00}^{+0.19}(syst)  eV. This exclusion analysis sets the most stringent dark matter-nucleon scattering cross-section limits achieved by a cryogenic detector for dark matter particle masses from 93 to 140  MeV/c^{2}, with a raw exposure of 9.9 g d acquired at an above-ground facility. This work illustrates the scientific potential of detectors with athermal phonon sensors with eV-scale energy resolution for future dark matter searches.

Correlated charge noise and relaxation errors in superconducting qubits

The central challenge in building a quantum computer is error correction. Unlike classical bits, which are susceptible to only one type of error, quantum bits (qubits) are susceptible to two types of error, corresponding to flips of the qubit state about the X and Z directions. Although the Heisenberg uncertainty principle precludes simultaneous monitoring of X- and Z-flips on a single qubit, it is possible to encode quantum information in large arrays of entangled qubits that enable accurate monitoring of all errors in the system, provided that the error rate is low¹. Another crucial requirement is that errors cannot be correlated. Here we characterize a superconducting multiqubit circuit and find that charge noise in the chip is highly correlated on a length scale over 600 micrometres; moreover, discrete charge jumps are accompanied by a strong transient reduction of qubit energy relaxation time across the millimetre-scale chip. The resulting correlated errors are explained in terms of the charging event and phonon-mediated quasiparticle generation associated with absorption of γ-rays and cosmic-ray muons in the qubit substrate. Robust quantum error correction will require the development of mitigation strategies to protect multiqubit arrays from correlated errors due to particle impacts.

Impact of hydraulic retention time on phosphorus removal from wastewater using reactive media

Phosphorus (P) discharge from wastewater treatment plants into the environment contributes to eutrophication issues. Reactive media filters represent an effective, simple and cost-effective solution to decrease the P content. Previous research used various experimental designs and often synthetic wastewater, making assessment of real-world performance difficult. This study assesses the impact of the hydraulic retention time (HRT) on P removal using real wastewater to refine design criteria for full-scale installations. Four media were compared in column experiments for >200 days. Different HRTs were applied and initially the media achieved low P effluent concentrations of >0.1 mg/L PO₄-P, increasing over time. Best P removal was observed for the highest HRT with on average >99%. HRT was seen to be the driving factor for P removal rather than media capacity. Three of the four materials showed pH levels above 12 initially, decreasing over time. Water quality parameters, including organics, solids and metals, were monitored. In-depth analysis confirmed formation of calcium phosphate precipitation on the media's surface. The results suggest the importance of an optimal HRT to achieve high P removal and show that the reactive media application is an appropriate technology for P removal on small sites if the elevated pH is addressed.

Erratum: First Dark Matter Constraints from a SuperCDMS Single-Charge Sensitive Detector [Phys. Rev. Lett. 121, 051301 (2018)]

This corrects the article DOI: 10.1103/PhysRevLett.121.051301.

Constraints on Sub-GeV Dark-Matter-Electron Scattering from the DarkSide-50 Experiment

We present new constraints on sub-GeV dark-matter particles scattering off electrons based on 6780.0 kg d of data collected with the DarkSide-50 dual-phase argon time projection chamber. This analysis uses electroluminescence signals due to ionized electrons extracted from the liquid argon target. The detector has a very high trigger probability for these signals, allowing for an analysis threshold of three extracted electrons, or approximately 0.05 keVee. We calculate the expected recoil spectra for dark matter-electron scattering in argon and, under the assumption of momentum-independent scattering, improve upon existing limits from XENON10 for dark-matter particles with masses between 30 and 100  MeV/c^{2}.

Low-Mass Dark Matter Search with the DarkSide-50 Experiment

We present the results of a search for dark matter weakly interacting massive particles (WIMPs) in the mass range below 20  GeV/c^{2} using a target of low-radioactivity argon with a 6786.0 kg d exposure. The data were obtained using the DarkSide-50 apparatus at Laboratori Nazionali del Gran Sasso. The analysis is based on the ionization signal, for which the DarkSide-50 time projection chamber is fully efficient at 0.1  keVee. The observed rate in the detector at 0.5  keVee is about 1.5  event/keVee/kg/d and is almost entirely accounted for by known background sources. We obtain a 90% C.L. exclusion limit above 1.8  GeV/c^{2} for the spin-independent cross section of dark matter WIMPs on nucleons, extending the exclusion region for dark matter below previous limits in the range 1.8-6  GeV/c^{2}.

First Dark Matter Constraints from a SuperCDMS Single-Charge Sensitive Detector

We present the first limits on inelastic electron-scattering dark matter and dark photon absorption using a prototype SuperCDMS detector having a charge resolution of 0.1 electron-hole pairs (CDMS HVeV, a 0.93 g CDMS high-voltage device). These electron-recoil limits significantly improve experimental constraints on dark matter particles with masses as low as 1  MeV/c^{2}. We demonstrate a sensitivity to dark photons competitive with other leading approaches but using substantially less exposure (0.49 g d). These results demonstrate the scientific potential of phonon-mediated semiconductor detectors that are sensitive to single electronic excitations.

Energy benchmarking in wastewater treatment plants: the importance of site operation and layout

Energy benchmarking is a powerful tool in the optimization of wastewater treatment plants (WWTPs) in helping to reduce costs and greenhouse gas emissions. Traditionally, energy benchmarking methods focused solely on reporting electricity consumption, however, recent developments in this area have led to the inclusion of other types of energy, including electrical, manual, chemical and mechanical consumptions that can be expressed in kWh/m3. In this study, two full-scale WWTPs were benchmarked, both incorporated preliminary, secondary (oxidation ditch) and tertiary treatment processes, Site 1 also had an additional primary treatment step. The results indicated that Site 1 required 2.32 kWh/m3 against 0.98 kWh/m3 for Site 2. Aeration presented the highest energy consumption for both sites with 2.08 kWh/m3 required for Site 1 and 0.91 kWh/m3 in Site 2. The mechanical energy represented the second biggest consumption for Site 1 (9%, 0.212 kWh/m3) and chemical input was significant in Site 2 (4.1%, 0.026 kWh/m3). The analysis of the results indicated that Site 2 could be optimized by constructing a primary settling tank that would reduce the biochemical oxygen demand, total suspended solids and NH4 loads to the oxidation ditch by 55%, 75% and 12%, respectively, and at the same time reduce the aeration requirements by 49%. This study demonstrated that the effectiveness of the energy benchmarking exercise in identifying the highest energy-consuming assets, nevertheless it points out the need to develop a holistic overview of the WWTP and the need to include parameters such as effluent quality, site operation and plant layout to allow adequate benchmarking.

Measurement of radiative proton capture on 18F and implications for oxygen-neon novae

The rate of the 18F(p,γ)19Ne reaction affects the final abundance of the γ-ray observable radioisotope 18F, produced in novae. However, no successful measurement of this reaction exists and the rate used is calculated from incomplete information on the contributing resonances. Of the two resonances thought to play a significant role, one has a radiative width estimated from the assumed analogue state in the mirror nucleus, 19F. The second does not have an analogue state assignment at all, resulting in an arbitrary radiative width being assumed. Here, we report the first successful direct measurement of the 18F(p,γ)^19Ne reaction. The strength of the 665 keV resonance (Ex=7.076  MeV) is found to be over an order of magnitude weaker than currently assumed in nova models. Reaction rate calculations show that this resonance therefore plays no significant role in the destruction of ^{18}F at any astrophysical energy.

Apatite/amelogenin coating on titanium promotes osteogenic gene expression

Osteoblast differentiation and extracellular matrix production are pivotal processes for implant osseointegration or bone tissue engineering. We hypothesized that a biomimetic coating on titanium surfaces, consisting of apatite and amelogenin, would promote such processes. Human Embryonic Palatal Mesenchymal pre-osteoblasts were used as a model for the evaluation of cell adhesion and spreading patterns, as well as mRNA expression of certain osteoblastic gene products. Real-time PCR showed significant (p < 0.05) increase in expression of type I collagen, alkaline phosphatase, and osteocalcin from cells grown on titanium with an apatite/amelogenin composite, as compared with that from cells grown on a pure titanium or apatite coating only. Osteocalcin expression was specifically stimulated by amelogenin added to the culture media. Enhanced attachment and cell spreading were also observed. The biomimetic coating promoting cell adhesion and osteoblast differentiation may have great potential for future dental and biomedical applications.

Quantification of manual force control and tremor

Isometric impulse frequencies associated with active tremor and force regulation were examined in 10 patients with idiopathic Parkinson's disease (PD) and in 10 older adults (OAs) who performed an isometric tracing task. The authors decoupled and analyzed the data to determine whether PD-related tremor in the thumb and in the index finger during isometric force control are related and whether PD impairs the performance of volitional force control beyond the errors contributed by tremor. After decoupling, there were clear and robust differences in PD patients' control of isometric force that could not be attributed to action-tremor error. Those errors, which occurred in the absence of movement, suggest impairment in coordinated recruitment and derecruitment of motor units during a fine-motor task.

Altered Cbfa1 expression and biomineralization in an osteosarcoma cell line

Osteoblast differentiation and expression are regulated by Cbfa1 transcription factors. Recent evidence suggests that Cbfa1 may also regulate bone mineralization. The purpose of this study was to characterize Cbfa1 expression in relation to mineralization in rat UMR106-01 osteoblastic cell cultures. UMR106-01 BSP cultures consistently form bone-like mineral, whereas the UI subclone mineralize gradually. BSP and UI cultures were grown for 48 h and then treated with beta-glycerophosphate. BSP cultures had alizarin red stained calcifications and mineral-like deposits within 24 h of phosphate. Atomic absorption spectroscopy measured significantly (P<0.0001) more calcium in the phosphate-treated BSP cultures than in the UI. Cbfa1 message was detected in the BSP and UI cultures, but the Cbfa1 N-terminal isoform was deficient in UI and appeared to be up-regulated in the phosphate-treated BSP cultures. Cbfa1 protein levels were also reduced in the UI. DNA sequence from the RT-PCR products was utilized to design Taqman Real-time RT-PCR reagents. Quantitative Real-time RT-PCR analysis showed that Cbfa1 mRNA levels relative to endogenous 18 s rRNA were lower in the slower mineralizing UI cultures. Furthermore, the Cbfa1 N-terminal isoform mRNA levels were significantly (P<0.001) lower in the slower mineralizing cultures. Transfection with Cbfa1 or isoform antisense caused a significant (P<0.001) reduction in mineralization. Therefore, Cbfa1 expression may be associated with bone-like mineral formation in rat UMR106-01 osteoblastic cell cultures.

Forces exerted by a conventional dental explorer during clinical examination

PURPOSE

To measure the range of forces exerted clinically in order to determine whether research in this area uses forces that are similar to those generally seen in a clinical setting.

METHODS

A transducer was manufactured consisting of a force measurement sleeve positioned over the handle of a conventional explorer. The sleeve housed 4 strain gauges oriented to detect forces in a vertical and lateral direction. Five experienced dentists performed a full-mouth caries exam on three fully dentate caries-free subjects with the force-detecting probe.

RESULTS

The overall average force was 340 +/- 6 (SEM) g with a standard deviation of 218 g and a range of 14-1,006 g. The average number of contacts per tooth was 6.2 +/- 0.2 (SEM) with a standard deviation of 2.7.

CONCLUSIONS

The data from this study show that the forces used in previous studies were sometimes greater than the average force, but were still within the observed range of forces.

Implant surface roughness affects osteoblast gene expression

The transcription factor Cbfa1 regulates osteoblast differentiation and expression of genes necessary for the development of a mineralized phenotype. The purpose of this study was to determine if Cbfa1 and BSPII gene expression are influenced by implant surface microtopography. Osteoblasts were cultured on 600-grit (grooved) or sandblasted (roughened) cpTi implant discs. Mineralization was evaluated by Alizarin-Red-S staining. Real Time PCR was used for quantitative analysis of Cbfa1 and BSPII gene expression. Enhanced mineralization was seen in osteoblasts grown on roughened implant surfaces relative to tissue culture plastic. Real Time PCR showed significant (P < 0.05) increases in Cbfa1 gene expression in cells grown on roughened, as compared with grooved, implant surfaces. BSPII gene expression was also increased on rough surfaces in the UMR cells, but was reduced in the rat calvarial osteoblast cultures. These results suggest that osteoblast gene expression and mineralization are affected by roughened implant surface microtopographies during osseointegration of dental implants.

Early cell adhesion events differ between osteoporotic and non-osteoporotic osteoblasts

In osteoporosis, the regenerative capacity of bone is compromised, which may involve altered osteoblast (OB) activity. This could be attributed to an inappropriate synthesis and assembly of an extracellular matrix (ECM), altered cell adhesion to the ECM, or be due to inappropriate downstream activation of adhesion-mediated signaling cascades through proteins such as focal adhesion kinase (FAK). The purpose of our study was to compare early adhesion-mediated events using previously described and characterized clinically derived OBs obtained from human patients undergoing major joint arthroplasty for osteoporosis or osteoarthritis. The presence or absence of osteoporosis was established with a radiographic index. Using light microscopy and crystal violet staining, we show that OB cells derived from sites of osteoporosis do not attach and spread as well as non-osteoporotic (OP) OB cells. OP cells initially have a more rounded morphology, and show significantly less (P < 0.001) attachment to serum-coated tissue culture plastic over a 24 h time period. Immunofluorescent labeling after 24 h of attachment showed that OP OB focal adhesions (FAs) and stress fibers were less defined, and that the OP cells were smaller and had a more motile phenotype. When normalized protein lysates were Western blotted for phosphotyrosine (PY) a band corresponding to pp125FAK was identified. FAK tyrosine phosphorylation was evident at 6 h in both the OP and non-OP OBs, but decreased or was absent through 24 h in OP OBs. These results suggest early adhesion-mediated events, such as cell adhesion, attachment, and FAK signaling via PY may be altered in OP OBs.

Osteoblast integrin adhesion and signaling regulate mineralization

Integrin adhesion and signaling events may contribute to the progressive differentiation of the osteoblast and to the initiation of a mineralized matrix. The purpose of our study was to begin to analyze the role of integrin receptors, in particular alpha2beta1, alpha5beta1, and alphaVbeta3, regarding mediation of the initiation of a mineralized matrix. Integrin-perturbation assays were conducted in microdot cultures of UMR-106-01 Bone Sialoprotein (BSP) osteoblast cells. For phenotypic analysis, we performed bright-field microscopy and Aliziran Red S staining to analyze effects on mineralization initiation. Mineralization was reduced significantly (P < 0.001) following the addition of alpha5- or beta1-integrin subunit antibody by approximately 20% and 45%, respectively--alphaVbeta3 integrin by nearly 65%, and alpha2beta1 integrin by nearly 95%. This effect was reversible following the removal of the antiintegrin antibody. These results suggest that integrin adhesion and signaling events may contribute to the ability of this cell line to mediate the initiation of the mineralization phenotype biologically.

The design and testing of a force feedback dental simulator

The Iowa Dental Surgical Simulator is a haptic simulator to train dental students in the haptic skills of dentistry. The initial design emphasizes the detection of carious lesions. This work describes the software and implementation of the prototype system, the design tradeoffs' and the technical issues associated with haptic and graphics subsystems. The work also describes the current system performance, including a formal evaluation by practicing dentists and performance measures. A discussion of the limitations of the current system is followed by an analysis of opportunities to improve the quality of the simulator. The results should be of interest to designers of medical haptic simulation systems and other simulation designers.

An initial evaluation of the Iowa Dental Surgical Simulator

The University of Iowa colleges of dentistry and engineering are collaborating to build an effective but low-cost surgical simulator that uses force feedback to teach and assess the tactile skills of dentistry. A prototype simulator was built, and a formative evaluation examined the realism of the haptics and identified directions for future work. Using a cross-over design, twelve experienced practitioners probed two virtual teeth using two instruments attached to the force feedback device. The session was videotaped, the forces recorded, and a standardized questionnaire completed. Two analyses were conducted: an ANOVA examined practitioners' questionnaire responses, and a t-test analyzed the probing forces. Significant tooth order by instrument order interaction and instrument effects were found. Practitioners were generally satisfied. They preferred a standard joystick to an explorer, felt that two-dimensional graphics were sufficient, and emphasized that the existing vibration be eliminated. Random placement of caries should help teach generalized skills.

Clinical and serological studies of tuberculosis patients in Argentina receiving immunotherapy with Mycobacterium vaccae (SRL 172)

Two small, placebo-controlled studies of immunotherapy with heat killed Mycobacterium vaccae added to routine chemotherapy for pulmonary tuberculosis, together involving 40 HIV seronegative patients, were carried out in Argentina. The immunotherapy was associated with reduced sputum smear positivity of AFB at 1 month and a greater reduction in ESR at 2 months. In the first study radiological improvement was better (P < 0.05) among immunotherapy recipients. In the second study, weight regain and time to become apyrexial were measured and were found to be improved amongst immunotherapy recipients (P < 0.05). In the first month of treatment the levels of IgG to the 65 kDa and 70 kDa heat-shock proteins showed greater falls following immunotherapy (P < 0.05 and P < 0.001, respectively). On admission serum cytokine levels of interleukins 4 and 10 (IL-4, IL-10), interferon gamma (IFN-gamma) and tumour necrosis factor alpha (TNF-alpha) were grossly raised in comparison with a matched control group (P < 0.001). After 1 month. Levels of IL-4, IL-10 and TNF-alpha fell (P < 0.001, P < 0.01 and P < 0.01, respectively) and levels of IFN-gamma rose more (P = 0.005) in immunotherapy recipients than in those receiving chemotherapy alone. The results are in accord with a switch towards a TH1 immunological status and clinical benefit for immunotherapy recipients.

Studies of vaccination of persons in close contact with leprosy patients in Argentina

A total of 670 adults living or working with leprosy patients, were examined for a BCG vaccination scar, and skin-tested with four new tuberculins. Based on the results 513 were vaccinated, 65 with Bacille de Calmette et Guérin (BCG) alone, 66 with BCG plus killed Mycobacterium vaccae and 382 with killed M. vaccae alone. Skin-testing was repeated 2-3 years later on 344 subjects, when all three vaccines were found to have been highly successful in increasing responses to Tuberculin and Leprosin A (p < 0.0005) with increased immune recognition of common and species-specific antigens. Mean diameters of induration to each skin-test were greatest in recipients of BCG alone (p < 0.05), which suggests that better immuno-regulation occurs after receiving vaccines that incorporate M. vaccae. The results suggest 10(8) M. vaccae alone might prove a valuable future vaccine, which would not require selective pre-vaccination procedures.

Immunotherapy with Mycobacterium vaccae in the treatment of psoriasis

A placebo-controlled study of immunotherapy with Mycobacterium vaccae for chronic plaque psoriasis showed improvement in the psoriasis area severity index in 19 of 21 immunotherapy recipients (P<0.005). Minor improvement, not reaching statistical significance for the group, occurred in nine of 14 placebo recipients. There were losses to follow-up and the placebo used, tetanus toxoid, was not ideal. Clinical improvement after immunotherapy persisted for 6 months and another injection of the immunotherapeutic given to a few volunteers from either group resulted in benefits lasting a year. Lymphoproliferative tests were carried out at each clinic visit, and on 50 matched controls. Starting with reduced responses to mycobacterial antigens and concanavalin A, both treatment groups showed a fall after 3 months, and diverged at 6 months with M. vaccae recipients rising to values similar to those of healthy controls, whereas placebo recipients continued to fall. Conclusions reached were that immunotherapy with M. vaccae gave long-lasting clinical benefit to most patients, with minimal side effects. This accompanied a return towards normal cellular immune responsiveness to mycobacterial antigens, which did not follow the use of the placebo.

Anaerobic tissue-dissolving abilities of calcium hydroxide and sodium hypochlorite

Closed root canals likely have an oxygen-free environment; most bacteria in canals are anaerobic. These bacteria and other debris are difficult to remove. Unknown is tissue dissolution with chemicals under these anaerobic conditions. This study evaluated and compared dissolving properties of calcium hydroxide (Ca(OH)2) and sodium hypochlorite (NaOCl) on bovine pulp tissue in aerobic and anaerobic environments. Sixty bovine pulp specimens were dried, then randomly divided into six groups. Groups A and B were immersed in Ca(OH)2 + water solution, whereas group C and D were in 2.5% NaOCl. Groups E and F (controls) specimens were placed in distilled water. Groups A, C, and E were incubated anaerobically, and groups B, D, and F were incubated under regular atmospheric conditions, all for 7 days. Percentages of weight loss were compared between groups. Results showed the following: (a) both chemicals partially dissolved pulp tissue, (b) anaerobic environment did not alter tissue-dissolving properties of Ca(OH)2 or NaOCl, and (c) Ca(OH)2 and NaOCl were equal and more effective than water.

Bone acidic glycoprotein-75 is a major synthetic product of osteoblastic cells and localized as 75- and/or 50-kDa forms in mineralized phases of bone and growth plate and in serum

Anti-peptide and anti-protein antisera were produced which both recognize bone acidic glycoprotein-75 (Mr = 75,000) and an apparent fragment or biosynthetic intermediate (Mr = 50,000) in calcified tissues and/or serum. A fragment-precursor relationship is suggested from the fact that closely spaced doublet polypeptides of Mr = 50,000 could be produced by proteolysis of the purified protein upon long term storage. No reactivity was detected with osteopontin, bone sialoprotein, or small bone proteoglycans. Bone acidic glycoprotein-75 represents 0.5-1% of the total radiolabeled proteins synthesized by explant cultures of neonatal calvaria or growth plate, by calvarial outgrowth cultures, and by rat osteosarcoma cells. Amounts produced by explant cultures and calvarial outgrowth cultures were similar to that for osteopontin, a major product of osteoblasts. In osteosarcoma cultures, 80% of labeled antigens were associated with the cell layer fraction wherein specific immunoprecipitation pelleted Mr = 50,000 and 75,000 sized antigens. Bone acidic glycoprotein-75 (Mr = 75,000) is enriched in 4 M guanidine HCl/0.5 EDTA extracts of neonatal rat bone and growth plate tissues, whereas largely absent from heart, lung, spleen, liver, brain, and kidney. Explant cultures of these noncalcifying tissues also synthesized bone acidic glycoprotein-75 antigen, but the quantities produced were only 5% or less that obtained with calvaria. By immunohistochemistry, antigenicity is associated with the bony shaft and calcified cartilage of long bones, but is absent from associated soft tissues. These finding demonstrate that bone acidic glycoprotein-75 is antigenically distinct, predominantly localized to calcified tissues, represents a major product of normal osteoblastic cells and may undergo a characteristic fragmentation in vivo and in vitro.

Peripheral noradrenaline depletion does not impair extinction of food-rewarded running in the rat

To test whether the sympathetic nervous system influences the inhibition of non-rewarded running in the runway, we examined the effects of peripheral noradrenaline depletion, induced by 6-hydroxydopamine (6-OHDA HBr, 30 mg/kg, i.p.), on extinction of food-rewarded running in rats. This was done in two separate experiments. In the first, in which the inter-trial interval (ITI) was one day and rats were injected before acquisition, running times at the end of extinction did not differ. The 6-OHDA appeared to slow down running times at the end of acquisition and the start of extinction. In the second experiment (15 s ITI) therefore, rats were injected after stable running had been acquired; there was no effect on running in subsequent rewarded trials. In extinction, although the groups ran similarly at first, the 6-OHDA treated animals subsequently ran more slowly than the controls; that is they showed greater extinction. Taken together with other published evidence, the sympathetic nervous system does not appear to contribute to the extinction of continuously reinforced responses.

An amperometric enzyme electrode for monitoring brain glucose in the freely moving rat

Brain glucose concentration was measured with an amperometric enzyme electrode using glucose oxidase (EC 1.1.3.4) irreversibly adsorbed onto an organic conducting salt. The responses of the electrode and its stability both in vitro and in vivo are described. Parellel changes in brain glucose and blood glucose (measured in samples from an implanted intra-atrial cannula) following injections of insulin are reported.

The effect of peripheral noradrenaline depletion on responding on a schedule of differential reinforcement of low rates of response (DRL)

First, it was confirmed that systemic injection of the neurotoxin 6-hydroxydopamine HBr (30 mg/kg IP) depleted noradrenaline levels in rat heart, but not centrally. Losses averaged 90% of control 1 day after injection, and 50% at 42 days. The same drug and dose was then administered to 50% of a group of rats which had been trained to lever-press for food reward on continuous reinforcement (CRF). After further CRF sessions, the rats were changed to a schedule of Differential Reinforcement of Low Rates of Response with a 20-s criterion (DRL 20). The drugged rats earned fewer reinforcements during DRL than did controls, and made fewer responses. Temporal discrimination (shown by the IRT/Opp distribution) was disrupted. It is concluded that peripheral noradrenergic systems may be involved in the control over responding by temporal cues associated with reward and non-reward.

The effect of repeated mild stress on cerebral cortical adrenoceptors and noradrenaline synthesis in the rat

The effects of repeated mild stress on cortical alpha 2- and beta-adrenoceptor binding sites and on the rate of noradrenaline synthesis in cortical synaptosomes were measured. The stressful stimuli were either daily handling (1 min) or daily handling which included an i.p. saline injection. In both cases, rats killed 24 h after the last of 14 daily treatments showed an increase in noradrenaline synthesis rate and a decrease of alpha 2- and beta-adrenoceptor density. There were no changes in adrenoceptor density or the noradrenaline synthesis rate after either a single or 5 daily handlings plus saline injections. At no time was a change found in the Kd of either alpha 2- or beta-adrenoceptor binding sites. The results are discussed in relation to the effects on adrenoceptors of chronic antidepressant treatments.

The effect of chronic antidepressant administration on beta-adrenoceptor function of the rat pineal

1 The beta-adrenoceptor agonist, isoprenaline (1.5-3.0 mg kg(-1) intravenously), produced a dose-related increase in rat pineal melatonin content. This increase was prevented by pretreatment with the selective beta(1)-adrenoceptor antagonist, atenolol (2 mg kg(-1)), but not by the beta(2)-adrenoceptor antagonist, butoxamine (2 mg kg(-1)). The beta(2)-adrenoceptor agonist, terbutaline (5.0 mg kg(-1)), produced a moderate increase in pineal melatonin content.2 Repeated daily administration of desmethylimipramine (10 mg kg(-1) for 10 days) and maprotiline (10 mg kg(-1) for 10 days), antidepressants predominantly inhibiting noradrenaline (NA) uptake, reduced the isoprenaline-induced increase in pineal melatonin content. Amitriptyline (20 mg kg(-1) for 14 days), a drug which inhibits both NA and 5-hydroxytryptamine (5-HT) uptake, had a similar effect. The beta-adrenoceptor agonist, clenbuterol (5 mg kg(-1) for 14 days), also attenuated the increase in pineal melatonin produced by isoprenaline.3 In contrast, chronic administration of the selective 5-HT uptake inhibitor, fluoxetine (10 mg kg(-1) for 10 days), or the antidepressants, iprindole and mianserin (both 20 mg kg(-1) for 14 days), which do not inhibit monoamine uptake, failed to reduce the increase in pineal melatonin following isoprenaline. Repeated electroconvulsive shock was similarly without effect.4 Ten hours after the final dose of desmethylimipramine (10 mg kg(-1)) once daily for 10 days there was no change in the usual dark phase increase in pineal melatonin.5 The data suggest that repeated administration of certain antidepressant drugs results in reduced pineal beta-adrenoceptor sensitivity. However the lack of change in the dark phase increase in pineal melatonin following repeated desmethylimipramine, implies that the reduced ss-adrenoceptor sensitivity may be part of an adaptive process which maintains normal pineal function. Therefore the decrease in beta-adrenoceptor number in the brain reported after chronic antidepressant administration may not be associated with a change in overall synaptic function.

Comparison of the effects of chronic desmethylimipramine administration on alpha 2- and beta-adrenoceptors in different regions of rat brain

The effects of ten once-daily injections of desmethylimipramine (10 mg/kg i.p.) on alpha 2- and beta-adrenoceptor binding were investigated in the rat cortex, hippocampus and hypothalamus. [3H]clonidine and [3H]dihydroalprenolol were used as ligands for alpha 2- and beta-adrenoceptors, respectively. Twenty-four hours after the last injection, the density of beta-adrenoceptors was reduced in all regions studied. In contrast, there was no change in alpha 2-adrenoceptor binding in the cortex, while increased binding was found in the hypothalamus. The effects of desmethylimipramine are discussed in relation to those of other antidepressant treatments.

Noradrenaline release in rats during prolonged cold-stress and repeated swim-stress

1 Plasma noradrenaline concentration in rats was measured during prolonged cold-stress and repeated swim-stress. 2 Cold exposure for 6 h caused a rise in plasma noradrenaline which reached a peak at 4 h. 3 Administration of desmethylimipramine and normetanephrine to block neuronal and extra-neuronal uptake of noradrenaline raised plasma noradrenaline concentration without changing the pattern of the response to cold exposure. 4 Repeated cold exposure on subsequent days produced no change in the pattern of plasma noradrenaline concentration. 5 Five successive 1-min swims at 30-min intervals caused a rise in plasma noradrenaline concentration which was maximal after the third swim. 6 It is suggested that prolonged and repeated activation of sympathetic nerve terminals leads to a decline in noradrenaline release.

Changes in plasma noradrenaline concentration as a measure of release rate

1 A method is described for repeated sampling of plasma noradrenaline (NA) in freely moving rats. Na concentration does not change during the day or after adrenalectomy. 2 Exogenous NA has a half-life of 1.5 min; drugs which block neuronal and extra-neuronal uptake lengthen this to 6.3 min. 3 Swim-stress leads to a steep rise followed by a rapid decline in plasma NA concentration. 4 This method of plasma NA sampling can serve as a measure of both steady and rapid changes in release rate over long periods of time.

Semi-quantitative estimation of changes in noradrenaline content and intraneuronal distribution in the rat vas deferens by fluorescence histochemistry

A semi-quantitative histochemical assay for noradrenaline was developed, based on the assumption that the rate of reaction of noradrenaline with paraformaldehyde depends on transmitter concentration. Changes in organ noradrenaline content caused by drugs or cold-stress were associated with similar changes in fluorescence intensity of organ samples taken for microscopy. Differences in the fluorescence intensity of experimental and control tissues were also found when there was no change in total noradrenaline content, suggesting that fluorescence intensity is not a simple function of whole organ noradrenaline content. Changes in the relative fluorescence of experimental tissues with different paraformaldehyde exposures suggested that the intraneuronal distribution of noradrenaline may affect the rate of development of fluorescence. Analysis of the time course of the fluorescence reaction showed that this was best described by the sum of two first-order exponential components of different half-life. Further results suggested that the first, fast component represents vesicle-bound noradrenaline, while the slow component represents extrangranular transmitter.