Gas spectroscopy through multimode self-mixing in a double-metal terahertz quantum cascade laser.

A multimode self-mixing terahertz-frequency gas absorption spectroscopy is demonstrated based on a quantum cascade laser. A double-metal device configuration is used to expand the laser's frequency tuning range, and a precision-micromachined external waveguide module is used to enhance the optical feedback. Methanol spectra are measured using two laser modes at 3.362 and 3.428 THz, simultaneously, with more than eight absorption peaks resolved over a 17 GHz bandwidth, which provide the noise-equivalent absorption sensitivity of 1.20×10-3 cm-1 Hz-1/2 and 2.08×10-3 cm-1 Hz-1/2, respectively. In contrast to all previous self-mixing spectroscopy, our multimode technique expands the sensing bandwidth and duty cycle significantly.

An evaluation of the experiences of academics and practice educators who supported radiography students working on the temporary HCPC register during the COVID-19 pandemic.

INTRODUCTION: The COVID-19 pandemic has had a profound impact on all those residing in the United Kingdom, resulting in unprecedented changes being made to the education and training of healthcare students. Universities and practice partners had to respond quickly and work in close collaboration with Health Education England, to ensure the changes brought in by the Health and Care Professions Council (HCPC) emergency measures were implemented. The aim of this study was to explore the experiences of staff supporting final year diagnostic and therapeutic radiography students who joined the HCPC register early during phase one of the COVID-19 pandemic. METHODS: This study was informed by a phenomenological approach, in which a purposeful sample of eight participants comprising of six practice educators (PEs) and two academics. Semi-structured interviews and focus groups were conducted to collect the data via a virtual platform. RESULTS: The results highlighted three themes, Competence and the transition to registration, Support mechanisms and Communication. Both academics and PEs described how they observed the new registrants gaining confidence and competence during their time on the temporary register and suggested that professional bodies could consider curriculum changes to encompass a final transitional placement similar to their experience. They suggested that having robust support mechanisms and communication in place are essential for the success of this initiative. CONCLUSION: The results provide insight into how PEs and academics supported new registrants to meet the necessary requirements of the HCPC register whilst working during the first phase of the COVID-19 pandemic. They highlight the importance of having robust support mechanisms and good communication in place to achieve this. IMPLICATIONS FOR PRACTICE: Some consideration could be made to changing the curriculum in the future to allow for early temporary registration and paid Band 4 final placements for students working as assistant practitioners.

An evaluation of the experiences of radiography students working on the temporary HCPC register during the COVID-19 pandemic.

INTRODUCTION: The COVID-19 pandemic has changed the world's perspective and had a profound impact on all those residing in the United Kingdom, resulting in unprecedented changes being made to the education and training of healthcare students. Universities and practice partners had to respond quickly and work in close collaboration with their wider system partners, Health Education England and the Department of Health, to ensure the changes made within the Health and Care Professions Council (HCPC) emergency measures were implemented. The aim was to explore the experiences of final year diagnostic and therapeutic radiography students who joined the HCPC temporary register during phase one of the COVID-19 pandemic. METHODS: This study was informed by a phenomenological approach, in which a purposeful sample of seventeen participants comprising of nine students, six practice educators and two academics were chosen to participate. Semi-structured interviews and focus groups were conducted to collect the data via a virtual platform. RESULTS: The results highlighted three themes, professionalism and transition to registration, benefits and challenges of working through a pandemic, and emotional impact. Students described how they gained confidence and competence during their time on the temporary register and suggested that professional bodies could consider curriculum changes to encompass a final transitional placement similar to their experience. They said they had been well supported but felt a sense of loss having been denied the normal rite of passage associated with completion of their course and graduation. CONCLUSION: The results provide insight into how students, practice educators and academics transformed their practice to meet the necessary requirements whilst working during the first phase of the COVID-19 pandemic. They highlight the importance of having good support mechanisms in place and the rewards and challenges for students joining their professional register early. IMPLICATIONS FOR PRACTICE: Some consideration could be made to changing the curriculum in the future to allow for early temporary registration and paid Band 4 final placements for students working as assistant practitioners.

A bipartite yeast SSRP1 analog comprised of Pob3 and Nhp6 proteins modulates transcription.

The FACT complex of vertebrate cells, comprising the Cdc68 (Spt16) and SSRP1 proteins, facilitates transcription elongation on a nucleosomal template and modulates the elongation-inhibitory effects of the DSIF complex in vitro. Genetic findings show that the related yeast (Saccharomyces cerevisiae) complex, termed CP, also mediates transcription. The CP components Cdc68 and Pob3 closely resemble the FACT components, except that the C-terminal high-mobility group (HMG) box domain of SSRP1 is not found in the yeast homolog Pob3. We show here that Nhp6a and Nhp6b, small HMG box proteins with overlapping functions in yeast, associate with the CP complex and mediate CP-related genetic effects on transcription. Absence of the Nhp6 proteins causes severe impairment in combination with mutations impairing the Swi-Snf chromatin-remodeling complex and the DSIF (Spt4 plus Spt5) elongation regulator, and sensitizes cells to 6-azauracil, characteristic of elongation effects. An artificial SSRP1-like protein, created by fusing the Pob3 and Nhp6a proteins, provides both Pob3 and Nhp6a functions for transcription, and competition experiments indicate that these functions are exerted in association with Cdc68. This particular Pob3-Nhp6a fusion protein was limited for certain Nhp6 activities, indicating that its Nhp6a function is compromised. These findings suggest that in yeast cells the Cdc68 partners may be both Pob3 and Nhp6, functioning as a bipartite analog of the vertebrate SSRP1 protein.

Progressive radiolucent lines following the implantation of the cemented Rimfit acetabular component in total hip arthroplasty using the rimcutter technique: cause for concern?

AIMS: The highly cross-linked polyethylene Exeter RimFit flanged cemented acetabular component was introduced in the United Kingdom in 2010. This study aimed to examine the rates of emergence of radiolucent lines observed when the Rimfit acetabular component was implanted at total hip arthroplasty (THA) using two different techniques: firstly, the 'rimcutter' technique in which the flange sits on a pre-prepared acetabular rim; and secondly, the 'trimmed flange' technique in which the flange is trimmed and the acetabular component is seated inside the rim of the acetabulum. PATIENTS AND METHODS: The radiographs of 150 THAs (75 'rimcutter', 75 'trimmed flange') involving this component were evaluated to assess for radiolucencies at the cement/bone interface by three observers. RESULTS: Rimfit acetabular components implanted using the rimcutter technique had significantly higher rates of radiolucency than those introduced using the 'trimmed flange' technique one year post-operatively (one zone: 63/75 (84%) vs 17/75 (23%); two zones 42/75 (56%) vs 0/75 (0%); all three zones 17/75 (23%) vs 0/75 (0%):(all p < 0.001). CONCLUSION: On the basis of these findings, we have stopped using the 'rimcutter' technique when implanting the Rimfit acetabular component and have reverted to the 'trimmed flange' technique. TAKE HOME MESSAGE: Surgeons should be vigilant of the performance of the Rimfit acetabular component when used alongside the rim cutter device due to an observed higher rate of progressive radiolucencies with this combination of component / technique.

The yeast protein complex containing cdc68 and pob3 mediates core-promoter repression through the cdc68 N-terminal domain.

Transcription of nuclear genes usually involves trans-activators, whereas repression is exerted by chromatin. For several genes the transcription mediated by trans-activators and the repression mediated by chromatin depend on the CP complex, a recently described abundant yeast nuclear complex of the Pob3 and Cdc68/Spt16 proteins. We report that the N-terminal third of the Saccharomyces cerevisiae Cdc68 protein is dispensable for gene activation but necessary for the maintenance of chromatin repression. The absence of this 300-residue N-terminal domain also decreases the need for the Swi/Snf chromatin-remodeling complex in transcription and confers an Spt- effect characteristic of chromatin alterations. The repression domain, and indeed the entire Cdc68 protein, is highly conserved, as shown by the sequence of the Cdc68 functional homolog from the yeast Kluyveromyces lactis and by database searches. The repression-defective (truncated) form of Cdc68 is stable but less active at high temperatures, whereas the known point-mutant form of Cdc68, encoded by three independent mutant alleles, alters the N-terminal repression domain and destabilizes the mutant protein.

Comparison of novel cannabinoid partial agonists and SR141716A in the guinea-pig small intestine.

The controversial nature of the CB(1) receptor antagonist, SR141716A, in the guinea-pig small intestine was investigated by comparing it with four analogues of Delta(8)-tetrahydrocannabinol (Delta(8)-THC): O-1184, O-1238, O-584 and O-1315. These compounds (10 - 1000 nM) inhibited the electrically-evoked contractions with a rank order of potency of O-1238>O-1184>O-584>O-1315. Log concentration-response curves for O-1238, O-1184 and O-1315 were significantly shifted to the right by SR141716A and the maxima were significantly less than that of the CB(1) agonist, WIN55212-2, an indication of partial agonism. Partial saturation of the triple bond in O-1184 to a cis double bond (O-1238) increased its potency as an agonist (pEC(50) from 6.42 to 7.63) and as an antagonist of WIN55212-2, (pK(B), from 8.36 to 9.49). Substitution of the terminal azide group by an ethyl group (O-584) or removal of the phenolic hydroxyl group (O-1315) had no significant effect on the agonist or antagonist potency. None of these analogues increased the twitch response in a manner resembling that of SR141716A. O-1184 (10 and 100 nM) shifted the log concentration-response curve of WIN55212-2 for inhibition of the twitch responses to the right with pK(B) values of 8.29 and 8.38, respectively. We conclude that these Delta(8)-THC analogues behave as partial agonists rather than silent antagonists at CB(1) binding sites in this tissue. There was no evidence of antagonism of endocannabinoids thus supporting the hypothesis that, in this tissue, SR141716A is an inverse agonist of constitutively active CB(1) receptors.

Endogenous digoxin-like immunoreactive substance in patients undergoing coronary surgery. Preliminary report.

Perioperative digoxin concentrations were measured in 20 unselected adult patients undergoing coronary surgery. None of the patients were receiving treatment with digoxin. A digoxin-like immunoreactive substance was found in 16 patients postoperatively. This substance, if pharmacologically active, may have important clinical implications in the management of patients after open heart surgery.

Mechanical considerations in impaction bone grafting.

In impaction grafting of contained bone defects after revision joint arthroplasty the graft behaves as a friable aggregate and its resistance to complex forces depends on grading, normal load and compaction. Bone mills in current use produce a distribution of particle sizes more uniform than is desirable for maximising resistance to shear stresses. We have performed experiments in vitro using morsellised allograft bone from the femoral head which have shown that its mechanical properties improve with increasing normal load and with increasing shear strains (strain hardening). The mechanical strength also increases with increasing compaction energy, and with the addition of bioglass particles to make good the deficiency in small and very small fragments. Donor femoral heads may be milled while frozen without affecting the profile of the particle size. Osteoporotic femoral heads provide a similar grading of sizes, although fewer particles are obtained from each specimen. Our findings have implications for current practice and for the future development of materials and techniques.

The pathogenesis of bone loss following total knee arthroplasty.

Bone loss following total knee arthroplasty (TKA) may be focal or diffuse. It may be caused mechanically, either by unloading of the bone leading to disuse osteoporosis, or by overloading of the bone leading to trabecular fractures and bone destruction. Osteolysis, instigated by an inflammatory reaction to particulate wear debris, is an important and common cause of bone loss after TKA. Less common, though sometimes dramatic, causes of bone loss are infection and osteonecrosis.

Reimplantation of the totally extruded talus.

We present two cases of traumatic total extrusion of the talus, leaving no soft-tissue attachment. The management of this rare injury is controversial. These cases were managed by reimplantation of the tali. The tali revascularised and survived without collapse. One patient developed posttraumatic osteoarthritis of the ankle.

Joint replacement for arthritis.

BACKGROUND: Joint replacement is most commonly performed at the hip and knee for osteoarthritis. It is also possible to replace joints such as: the shoulder, elbow, metacarpophalangeal joints and ankle, but usually only when the joint has been destroyed by rheumatoid arthritis. While the main benefit of joint replacement is the resolution of arthritic pain, range of movement and function can also be improved and the length of the limb or alignment of the joint may be restored. OBJECTIVE: In this article we address the indications for joint replacement, and how the patient is assessed. The results of joint replacements of varying joints are considered and we discuss some topical current concepts in joint replacement surgery.

Ipsilateral fractures of the proximal ulna and distal radius (Colles type).

A 43-year-old female fell backward outside her home while carrying a watering can. She sustained an ipsilateral fracture of the proximal ulna and distal radius (Colles fracture). The ulnar fracture was plated, and the Colles fracture was managed by closed reduction and percutaneous Kirschner wiring. The patient recovered without incident. This association of forearm fractures is unusual. Both fractures can be caused by a fall on the hand with the wrist in mid-extension and the elbow flexed, and they probably occurred in quick succession.

Quasi-synchronous patellar tendon rupture.

The case of a 66-year-old male who suffered from rupture of both patellar tendons within a few minutes of each other is reported. The patient was not suffering from any underlying medical problems, and made an uneventful recovery following surgical repair.

The design of the acetabular component and size of the femoral head influence the risk of revision following 34 721 single-brand cemented hip replacements: a retrospective cohort study of medium-term data from a National Joint Registry.

Despite excellent results, the use of cemented total hip replacement (THR) is declining. This retrospective cohort study records survival time to revision following primary cemented THR using the most common combination of components that accounted for almost a quarter of all cemented THRs, exploring risk factors independently associated with failure. All patients with osteoarthritis who had an Exeter V40/Contemporary THR (Stryker) implanted before 31 December 2010 and recorded in the National Joint Registry for England and Wales were included in the analysis. Cox's proportional hazard models were used to analyse the extent to which risk of revision was related to patient, surgeon and implant covariates, with a significance threshold of p < 0.01. A total of 34 721 THRs were included in the study. The overall seven-year rate of revision for any reason was 1.70% (99% confidence interval (CI) 1.28 to 2.12). In the final adjusted model the risk of revision was significantly higher in THRs with the Contemporary hooded component (hazard ratio (HR) 1.88, p < 0.001) than with the flanged version, and in smaller head sizes (< 28 mm) compared with 28 mm diameter heads (HR 1.50, p = 0.005). The seven-year revision rate was 1.16% (99% CI 0.69 to 1.63) with a 28 mm diameter head and flanged component. The overall risk of revision was independent of age, gender, American Society of Anesthesiologists grade, body mass index, surgeon volume, surgical approach, brand of cement/presence of antibiotic, femoral head material (stainless steel/alumina) and stem taper size/offset. However, the risk of revision for dislocation was significantly higher with a 'plus' offset head (HR 2.05, p = 0.003) and a hooded acetabular component (HR 2.34, p < 0.001). In summary, we found that there were significant differences in failure between different designs of acetabular component and sizes of femoral head after adjustment for a range of covariates.

Knowledge of tuberculosis transmission among recently infected patients in Glasgow.

OBJECTIVES: To examine perceptions and understanding of disease causation in tuberculosis patients with few epidemiological links detected by contact tracing. STUDY DESIGN: An exploratory qualitative study using semi-structured interviews was undertaken. Patients' beliefs were explored against a background of medical thinking about tuberculosis transmission and the current approach to contact tracing. METHODS: Interviews were undertaken with patients (n=23) or suitable next of kin (n=3). Study patients were diagnosed with tuberculosis in Glasgow, an urban area of Scotland, between 1997 and 2004. All had a genetically indistinguishable 15-banded IS6110 restriction fragment length polymorphism pattern of the Beijing family of Mycobacterium tuberculosis, suggestive of recently transmitted infection, yet few had epidemiological links detectable as a result of contact tracing (30.8%). RESULTS: Interviewees had varying levels of knowledge, but most believed that tuberculosis was caused by a pathogen, spread by person-to-person contact. Modes of transmission were thought to include airborne transmission, sharing utensils with an infected individual, consumption of contaminated foods/liquids, and exchange of bodily fluids. Prolonged contact was not thought to be required for transmission to occur. Impaired immunity, social factors and environmental factors were believed to enhance the potential for transmission. CONCLUSIONS: Patients have complex beliefs about tuberculosis transmission and causation, which do not always mirror those of health professionals. Adopting and implementing an approach to contact identification that is aligned with lay beliefs may result in improved contact tracing outcomes.

What do patients think about minimally invasive total hip arthroplasty?

INTRODUCTION: The introduction of minimally invasive techniques for hip replacement into clinical practice has been driven by the perceived benefits of smaller incisions, shorter in-patient stays and faster rehabilitation. This may be at the cost of higher complication rates. The purpose of this study was to explore the opinions and priorities of patients in relation to these techniques. PATIENTS AND METHODS: A cross-sectional survey was performed in an elective out-patient setting. RESULTS: Of 44 patients approached, 36 agreed to participate. From most important to least important, patients rated the following items in order: 'rate of complications'; 'implant survival'; 'length of rehabilitation'; 'time in hospital' and 'length of scar'. Despite this, 21 of 35 (60%) responders stated they would accept the offer of minimally invasive techniques if made. CONCLUSIONS: Patients appear to prioritise long-term outcomes and low complication rates over the shorter scars, reduced in-patient stay and reduced rehabilitation times potentially offered by minimally invasive hip arthroplasty. Despite this, the technique remains popular among patients.

Hand washing rituals in trauma theatre: clean or dirty?

INTRODUCTION: The aim of this study was to investigate the degree of contamination of a surgeon's hand following use of chlorhexidine gluconate or alcohol gel as disinfectants. MATERIALS AND METHODS: In this prospective, randomised trial, orthopaedic surgeons were allocated to one of two different hand-washing protocols using a randomisation table. The hand-washing protocol dictated that all surgeons should wash for 5 min with chlorhexidine for their first case. Thereafter, the surgeon was randomised to wash for 3 min with either alcohol gel or chlorhexidine. At the end of each procedure, the gloves of each surgeon were carefully removed and the fingertips from each hand were placed on an agar plate. The number of bacterial colonies present after 24 h and 48 h of incubation were recorded for each agar plate by a microbiologist blinded to the washing protocol used. RESULTS: Overall, 41 procedures and 82 episodes of hand washings were included in the study. Two episodes were discarded due to contamination at the time of glove removal. Four hands (8%) were contaminated in the chlorhexidine group compared to 19 (34%) in the alcohol group. Fisher's exact test confirmed a significantly higher risk of contamination using alcohol gel compared to chlorhexidine (P = 0.002). In addition, the average bacterial colony count was substantially higher in the alcohol group (20 colony forming units) compared to the chlorhexidine group (5 colony forming units). There was no relationship between the duration of surgery and the degree of contamination (P = 1.12). CONCLUSIONS: Alcohol gel disinfectant is not a suitable alternative to chlorhexidine when hand washing before surgery. This study has identified a higher risk of bacterial contamination of surgeons' hands washed with alcohol. This may lead to higher levels of postoperative infection in the event of glove perforation.

Recovery from post-operative anaemia.

Acceptance of lower transfusion thresholds and shorter post-operative stays results in patients leaving hospital after surgery with lower haemoglobin (Hb) than previously. We undertook a prospective observational study to assess the haematological response to post-operative anaemia and to determine the utility of quality of life (QoL) measures in assessing the impact of anaemia on such patients. Thirty patients undergoing unilateral hip arthroplasty had blood samples taken and QoL questionnaires administered pre-operatively and at 7, 28 and 56 days post-operatively. Increased erythropoiesis was evident at day 7 post-operatively. Approximately two-thirds of the post-operative Hb deficit was corrected by day 28. There was evidence of functional iron deficiency in more than one-quarter of patients at day 56. QoL scores used did not show any relationship with Hb in the post-operative period. Red cell 2,3-diphosphoglycerate (2,3DPG) levels increased in proportion to the degree of post-operative anaemia. We concluded that substantial recovery of Hb occurs between day 7 and day 28 post-operatively. Complete recovery of Hb may be delayed beyond day 56 due to development of iron deficiency. Patients are at significant risk of developing post-operative iron deficiency depending on operative blood loss and pre-operative iron stores. Increased red cell 2,3DPG may offset the effect of anaemia on oxygen delivery. We found no evidence that anaemia produces a measurable effect on chosen QoL scores in the post-operative period.