We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure no-reply@cambridge.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Hydraulic fracturing generates large volumes of flowback and produced water, composed of complex mixtures of organic and inorganic constituents. The solids associated with these fluids are Fe-rich and can contain toxic organics, heavy metals and naturally occurring radioactive materials (NORMs). Despite this, only a few studies have analysed their composition and there is a lack of understanding about their interactions with microbial communities and their long-term fate in the environment. In this study, we analysed the solids associated with flowback water derived from a hydraulically fractured well in the Bowland Shale, UK. We also investigated the microbial reduction of these Fe(III)-rich materials under anaerobic conditions using anthraquinone-2.6-disulfonate (AQDS) as an electron shuttle and identified the resulting bioreduced mineral phases. XRD characterization indicated that the solids contained akaganeite (β-FeOOH, Cl) and Ba-bearing celestine (SrSO4). These Fe(III)-containing solids served as an electron acceptor for Shewanella frigidimarina and a flowback-derived Fe(III)-reducing enrichment culture. The bioreduced Fe(II)-bearing mineral phase was identified as ankerite [Ca(Fe,Mg,Mn)(CO3)2]; however, the presence of amorphous mineral phases is not ruled out. Microbial community composition was analysed using 16S rRNA gene sequencing. Amplicon sequence variants (ASVs) most closely related to Chromohalobacter, Caminicella and putative Fe(III)-reducing genera were dominant across treatments. Our findings highlight the potential of these Fe(III)-bearing sludges to be harnessed for the development of wastewater treatment strategies; for example, coupling the oxidation of toxic organics with Fe(III) reduction through either the introduction of microbial inocula or biostimulation of the native microbial communities. Furthermore, microbial processing can also be optimized to transform the Fe(III) sludges into denser materials, which are easier to handle and can immobilize toxic metals, thereby reducing the toxicity of this waste.
Since the start of the coronavirus disease 2019 pandemic, transnasal humidified rapid-insufflation ventilatory exchange (‘THRIVE’) has been classified as a high-risk aerosol-generating procedure and is strongly discouraged, despite a lack of conclusive evidence on its safety.
Methods
This study aimed to investigate the safety of transnasal humidified rapid-insufflation ventilatory exchange usage and its impact on staff members. A prospective study was conducted on all transnasal humidified rapid-insufflation ventilatory exchange cases performed in our unit between March and July 2020.
Results
During the study period, 18 patients with a variety of airway pathologies were successfully managed with transnasal humidified rapid-insufflation ventilatory exchange. For each case, 7–10 staff members were present. Appropriate personal protective equipment protocols were strictly implemented and adhered to. None of the staff involved reported symptoms or tested positive for coronavirus disease 2019, up to at least a month following their exposure to transnasal humidified rapid-insufflation ventilatory exchange.
Conclusion
With strictly correct personal protective equipment use, transnasal humidified rapid-insufflation ventilatory exchange can be safely employed for carefully selected patients in the current pandemic, without jeopardising the health and safety of the ENT and anaesthetic workforce.
Accretion discs appear in many astrophysical systems. In most cases, these discs are probably not completely axisymmetric. Discs in binary systems are often found to be misaligned with respect to the binary orbit. In this case, the gravitational torque from a companion induces nodal precession in misaligned rings of gas. We first calculate whether this precession is strong enough to overcome the internal disc torques communicating angular momentum. For typical parameters, precession torque wins. To check this result, we perform numerical simulations using the Smoothed Particle Hydrodynamics code, PHANTOM, and confirm that sufficiently thin and sufficiently inclined discs can break into distinct planes that precess effectively independently. Disc tearing is widespread and severely changes the disc structure. It enhances dissipation and promotes stronger accretion onto the central object. We also perform a stability analysis on isolated warped discs to understand the physics of disc breaking and tearing observed in numerical simulations. The instability appears in the form of viscous anti-diffusion of the warp amplitude and the surface density. The discovery of disc breaking and tearing has revealed new physical processes that dramatically change the evolution of accretion discs, with obvious implications for observed systems.
The role of the neuropeptide cholecystokinin in schizophrenia has been widely explored because of its modulating action on midbrain dopamine neurons. The recent discovery of more specific receptor subtype cholecystokinin antagonists should be considered as potential treatment for schizophrenia with fewer side effects. This paper reviews cholecystokinin/dopamine interactions in animal and human studies. Clinical trials with cholecystokinin agonists and antagonists in schizophrenia are updated.
Animal studies have suggested that exposure of the middle ear to topical local anaesthesia may be ototoxic. This study aimed to report sensorineural hearing outcomes and patients’ satisfaction in those who underwent myringotomy and ventilation tube insertion using topical local anaesthesia.
Methods
Twenty-nine patients (32 ears) were operated on. Pre- and post-operative audiology findings were compared. A Likert-type questionnaire on treatment satisfaction was completed at the end of the procedure.
Results
Median patient age was 55 years (range, 27–88 years). Pre- and post-operative bone conduction pure tone averages were 26.76 dB and 25.26 dB respectively (mean reduction of −1.22 dB, 95 per cent confidence interval of −5.91 to 8.13 dB; p = 0.7538). One ear (3 per cent) had a reduction in pure tone average of 10 dB.
Conclusion
The results suggest that sensorineural hearing loss is not a complication of ear exposure to topical local anaesthesia during myringotomy and ventilation tube insertion. The procedure was well perceived.
Plant canopy reflectance over the 0.45- to 1.25-μm wavelength (WL) of weed species and crops was recorded with a field spectroradiometer to evaluate the possible use of remote sensing to distinguish weeds from crops. Weed and weed-crop species reflectance differences were generally greater at the 0.85 μm WL in the near-infrared spectral region than at the 0.55 μm WL in the visible region, indicating that color infrared (CIR) aerial photography may be useful to detect weed populations in crops. Canopy reflectance data were more directly related to photographic differences in weed-crop images than were single leaf or inflorescence reflectance data. Aerial photography at altitudes of 610 to 3050 m distinguished climbing milkweed (Sarcostemma cyancboides ♯ SAZCY) in orange [Citrus sinensis (L.) Osbeck. ‘Valencia’) trees; ragweed parthenium (Parthenium hysterophorus L. ♯ PTNHY) in carrot (Daucus carota L., var. sativa ‘Long Imperator’); johnsongrass [Sorghum halepense (L.) Pers. ♯ SORHA) in cotton (Gossypium hirsutum L. ‘CP 3774’) and in sorghum (Sorghum bicolor L. Moench. ‘Oro’); London rocket (Sisymbrium irio L. ♯ SSYIR) in cabbage; and Palmer amaranth (Amaranthus palmeri S. Wats. ♯ AMAPA) in cotton. Johnsongrass was also detectable with CIR film in maturing grain sorghum from 18 290 m. Detection of weed species in crops was aided by differential stages of inflorescence and senescence, and by the chlorophyll content, color, area, intercellular space, and surface characteristics of the leaves. Discrete plant community areas were determined by computer-based image analyses from a 1:8000-scale positive transparency with the efficiency of 82, 81, 68, and 100% for Palmer amaranth, johnsongrass, sorghum, and cotton, respectively. The computer analyses should permit discrete aerial surveys of weed-crop communities that are necessary for integrated crop management systems.
The effectiveness of individually administered cognitive processing therapy (CPT) when compared with treatment as usual (TAU) in a community sexual assault centre was tested. Trauma survivors with acute stress disorder (ASD) following sexual assault were randomised to either CPT (n = 25) or TAU (n = 22), and assessed at pretreatment, posttreatment, and 3-, 6- and 12-month follow-up. Both groups demonstrated large reductions in PTSD and depression symptoms following treatment, and these gains were maintained over the course of follow-ups (Cohen's ds for PTSD symptom reductions ranging between 0.76 to 1.45). Although smaller and not always consistent, between-group effect sizes typically favoured CPT. Effect sizes (d) ranged between 0.13–0.50 for posttraumatic stress and 0.13–0.41 for depression over the course of follow-ups. Independent assessment of PTSD severity indicated more CPT participants reached good end-state functioning at 12-month follow-up (50%) than TAU (31%). Although both treatments were effective, there were some indications that CPT led to better outcomes relative to therapists delivering their usual therapy. The present study demonstrates that evidence-based, trauma-focused therapy such as CPT can be effective when delivered as an early intervention in a routine mental health setting.
Sarcoma of the head and neck is a rare condition that poses significant challenges in management and often requires radical multimodality treatment.
Objectives:
This study aimed to analyse current clinical presentation, evaluation, management dilemmas and oncological outcomes.
Methods:
Computer records and case notes were analysed, and 39 patients were identified. Variables were compared using Pearson's chi-square test and the log-rank test, while survival outcomes were calculated using the Kaplan–Meier method.
Results:
The histopathological diagnosis was Kaposi sarcoma in 20.5 per cent of cases, chondrosarcoma in 15.3 per cent and osteosarcoma in 10.2 per cent. A range of other sarcomas were diagnosed in the remaining patients. The site of disease was most commonly sinonasal, followed by the oral cavity and larynx.
Conclusion:
Wide local excision with clear resection margins is essential to achieve local control and long-term survival. There is a need for cross-specialty collaboration in order to accrue the evidence which will be necessary to improve long-term outcomes.
Inadvertent (or incidental) parathyroidectomy can occur during thyroidectomy. However, the factors associated with inadvertent parathyroidectomy remain unclear. This study aimed to report the rate of inadvertent parathyroidectomy during thyroidectomy and associated risk factors.
Methods:
Variables including fine needle aspiration cytology findings, age, sex, thyroid weight, concurrent neck dissection, extent of thyroidectomy, and the presence of cancer and parathyroid tissue within the specimen were recorded for 266 patients. The incidence of post-operative hypocalcaemia was also recorded. Univariate and multivariate analysis were performed to identify factors associated with inadvertent parathyroidectomy.
Results:
The inadvertent parathyroidectomy rate was 16 per cent. Univariate analysis revealed that cancer and concurrent neck dissection predicted inadvertent parathyroidectomy. On multivariate analysis, only concurrent neck dissection remained an independent predictor of inadvertent parathyroidectomy: it was associated with a fourfold increase in inadvertent parathyroidectomy.
Conclusion:
The inadvertent parathyroidectomy rate was 16 per cent and concurrent neck dissection was identified as an independent predictor of inadvertent parathyroidectomy.
Provision of non-pharmacological interventions is a common policy objective for people with dementia, and support groups are an increasingly common intervention. However, there have been few attempts to synthesize evidence on the effectiveness of support groups for people with dementia. This review investigated the outcomes of support groups for people with dementia, explored participant characteristics and reviewed group formats.
Methods:
A systematic review was undertaken and a narrative synthesis of data from 29 papers (reporting on 26 groups and a survey of a range of groups) was conducted.
Results:
Support groups seem acceptable to people with dementia. Qualitative studies report subjective benefits for participants but there is limited evidence of positive outcomes based on quantitative data. Samples have tended to be homogenous and this may limit the generalizability of findings.
Conclusions:
Although qualitative studies will remain important in this area, further mixed-methods randomized controlled trials (RCTs)or comparison group studies with longer follow-up periods are needed to strengthen the evidence base.
With the increasing use of chemoradiotherapy protocols, total laryngectomy carries increasing risks such as pharyngocutaneous fistula. There is little reference to the use of antibiotic prophylaxis in salvage surgery. This study aimed to determine the current practice in antibiotic prophylaxis for total laryngectomy in the UK.
Method:
A questionnaire was designed using SurveyMonkey software, and distributed to all ENT-UK registered head and neck surgeons.
Results:
The survey revealed that 19 surgeons (51 per cent) follow a protocol for antibiotic prophylaxis in primary total laryngectomy and 17 (46 per cent) follow a protocol in salvage total laryngectomy. Only 11 (30 per cent) use anti-methicillin-resistant Staphylococcus aureus agents in their antibiotic prophylaxis. The duration of prophylaxis varies considerably. Nineteen surgeons (51 per cent) revealed that their choice of antibiotic prophylaxis reflected non-evidence-based practices.
Conclusion:
There appears to be little evidence-based guidance on antibiotic prophylaxis in primary and salvage total laryngectomy. The survey highlights the need for more research in order to inform national guidance on antibiotic prophylaxis in primary and salvage total laryngectomy.
The prevalence of occult neck metastasis in patients undergoing salvage total laryngectomy remains unclear, and there is controversy regarding whether elective neck dissection should routinely be performed.
Method:
A retrospective case note review of 32 consecutive patients undergoing salvage total laryngectomy in a tertiary centre was performed, in order to correlate pre-operative radiological staging with histopathological staging.
Results:
The median patient age was 61 years (range, 43–84 years). With regard to lymph node metastasis, 28 patients were pre-operatively clinically staged (following primary radiotherapy or chemoradiotherapy) as node-negative, 1 patient was staged as N1, two patients as N2c and one patient as N3. Fifty-two elective and seven therapeutic neck dissections were performed. Pathological analysis up-staged two patients from clinically node-negative (following primary radiotherapy or chemoradiotherapy) to pathologically node-positive (post-surgery). No clinically node-positive patients were down-staged. More than half of the patients suffered a post-operative fistula.
Conclusion:
Pre-operative neck staging had a negative predictive value of 96 per cent. Given the increased complications associated with neck dissection in the salvage setting, consideration should be given to conservative management of the neck in clinically node-negative patients (staged following primary radiotherapy or chemoradiotherapy).
Titan's atmosphere harbors a suite of hydrocarbons and nitrogen-bearing compounds formed from the dissociation of the two main species, nitrogen (N2)and methane (CH4). It also contains oxygen compounds, likely produced from an influx of water and/or oxygen. The mixing ratios of these photochemical species vary with altitude, latitude, and time as a consequence of various chemical sources and sinks and of the atmospheric transport that redistributes them both vertically and horizontally. It is important to characterize and monitor the distribution of these chemical species because they play an important role in the radiative budget and provide insight into the seasonally varying atmospheric circulation. They can also help us understand the complex chemistry at work in Titan's atmosphere, leading to the formation of thick haze layers, which in turn affect the heat balance and general circulation. This chapter reviews the neutral composition of Titan's atmosphere, from the troposphere up to the thermosphere (~ 1400 km), and its vertical, horizontal, and temporal variations. These topics are interwoven with the origin and evolution, the general circulation, the clouds and weather, and the atmospheric chemistry of Titan that are the subjects of Chapters 1, 4, 6, and 7.
5.1.1 Historical perspective
The first unquestionable evidence for an atmosphere on Titan was the discovery of several absorption bands of methane in near-infrared spectra of the satellite (Kuiper, 1944). But it was not until the 1970s that Titan became an object of intense study.
Direct skin involvement of nodal metastasis from mucosal head and neck squamous cell carcinoma has traditionally been considered a poor prognostic indicator.
Methods:
This retrospective review identified eight patients (five with mucosal upper aerodigestive and three with occult primary squamous cell carcinoma) who presented between 2000 and 2007 with direct skin involvement of nodal metastasis.
Results:
Five patients were treated with extended radical and three with extended modified radical neck dissection. Closure was achieved directly (four cases), with local (two) or pedicled (two) flaps. Surgery was always followed by radiotherapy (pan-mucosal or to the primary site). The five-year recurrence-free and disease-specific survival rates were 100 per cent.
Conclusion:
It is exceptionally rare to encounter direct skin involvement of metastatic lymph nodes from mucosal head and neck squamous cell carcinoma without evidence of involvement of other anatomical structures. Surgical intervention is possible and combined modality treatment with curative intent is essential, as most patients can have a favourable outcome.
Cadmium (Cd) accumulates in the human food chain and poses a risk of kidney dysfunction (Fanconi Syndrome) and bone disorders in humans. The margin of safety between typical Cd intakes by humans and levels associated with toxicity is smaller than for other metals. Consumption of just one sheep kidney could cause an average adult person to exceed their Provisional Maximum Tolerable Daily Intake. However, the rate of accumulation in sheep’s liver and kidney, the primary target organs for Cd accumulation, is unclear. This makes prediction of the effects of varying Cd intake by sheep on the Cd concentration in these organs difficult. We undertook a meta-analysis of independent feeding trials, which sought to integrate previous findings in order to review existing legislation on permitted levels of Cd in animal feeds and organs. Resulting predictions on Cd accumulation in sheep liver and kidneys are applicable to the broad set of exposure situations investigated in the individual studies.
Our physical understanding of tectonic processes is predominantly influenced by evidence from crustal rocks. There are few constraints on the coupling between crust and mantle and the degree to which mantle is physically involved in orogenic events. Occurrences of alluvial diamonds in mountain belts have caused episodic speculation that some tectonically emplaced ultramafic rocks may originate from within the diamond stability field. Since the mid–1980s substantive evidence has come to light to support this view. This chapter reviews the evidence for the tectonic emplacement of large fragments of mantle (up to 300 km2) from the diamond stability field into the crust. Orogenic peridotite massifs from the Betico-Rifean tectonic belt and ophiolitic peridotite bodies from the Indian–Tibetan suture zone are discussed in detail. Constraints are placed on the origin of these ultrahigh pressure (UHP) rocks, their P-T histories are constrained by geochemical and mineralogical data and their implications for orogenesis are discussed.
Pyroxenites within the Beni Bousera and Ronda orogenic peridotite bodies contain multicrystalline aggregates of graphite as octahedra and other forms of cubic symmetry that are interpreted as graphitized diamonds. Stable and radiogenic isotope data for the Beni Bousera pyroxenites indicate that some of them originated as high pressure (HP) cumulates from melts of subducted oceanic crust. Anomalously light carbon isotope values (δ13C = –16 to –27.6%00) for the graphite suggest crystallisation of diamond from subducted kerogenous carbon.
Small, submillimeter diamonds have been recovered from two ophiolitic peridotite bodies in Tibet.
In a 33-month prospective analysis of needlestick injuries, venepuncturists working under Centers for Disease Control (CDC) guidelines for handling used needles were shown to incur a needlestick injury for every 3,175 to 4,006 needle-handling procedures. On the other hand, users of a simple device designed to reduce the risk of injury when recapping used needles were shown to incur a needlestick only once in every 16,100 venepunctures performed (P<0.00l). This represents a fourfold reduction in the rate of needlestick injuries. We thus question the effectiveness of the CDC nonrecapping policy.
The mechanisms of steady-slate creep in compression in a sintered SiC produced via sintering of β-SiC powders derived from gaseous reactants in a plasma are have been determined from (1) kinetic data within the ranges of temperature and constant stress of 1770–2020 K and 17–208 MPa, respectively, and (2) the results of transmission electron microscopy (TEM) and other microbeam characterization techniques. The stress exponent was 2.06 ± 0.04; the values of activation energy were 913 ± 13 and 630 ± 14 kJ/mol above and below, respectively, a knee of ∼∼ 1920 K. Gliding dislocations and B4C precipitates, which developed within the grains during creep, and their interaction were the dominant microstructural features of the crept material. Apparent nonmechanical pinning of the dislocations at the precipitates indicated that the latter attracted the dislocations rather than acting as classical obstacles to dislocation movement. A synthesis of this information leads to the conclusion that the controlling creep mechanisms in this SiC were grain boundary sliding accommodated by grain boundary diffusion at T < 1920 K and lattice diffusion at T > 1920 K. The parallel mechanism of dislocation glide also contributed to the total strain.