Room temperature plasmon laser by total internal reflection

Plasmon lasers create and sustain intense and coherent optical fields below light's diffraction limit with the unique ability to drastically enhance light-matter interactions bringing fundamentally new capabilities to bio-sensing, data storage, photolithography and optical communications. However, these important applications require room temperature operation, which remains a major hurdle. Here, we report a room temperature semiconductor plasmon laser with both strong cavity feedback and optical confinement to 1/20th of the wavelength. The strong feedback arises from total internal reflection of surface plasmons, while the confinement enhances the spontaneous emission rate by up to 20 times.Comment: 8 Page, 2 Figure

Integrated plasmonic circuitry on a vertical-cavity surface-emitting semiconductor laser platform

Integrated plasmonic sources and detectors are imperative in the practical development of plasmonic circuitry for bio- and chemical sensing, nanoscale optical information processing, as well as transducers for high-density optical data storage. Here we show that vertical-cavity surface-emitting lasers (VCSELs) can be employed as an on-chip, electrically pumped source or detector of plasmonic signals, when operated in forward or reverse bias, respectively. To this end, we experimentally demonstrate surface plasmon polariton excitation, waveguiding, frequency conversion and detection on a VCSEL-based plasmonic platform. The coupling efficiency of the VCSEL emission to waveguided surface plasmon polariton modes has been optimized using asymmetric plasmonic nanostructures. The plasmonic VCSEL platform validated here is a viable solution for practical realizations of plasmonic functionalities for various applications, such as those requiring sub-wavelength field confinement, refractive index sensitivity or optical near-field transduction with electrically driven sources, thus enabling the realization of on-chip optical communication and lab-on-a-chip devices

Near-field examination of perovskite-based superlenses and superlens-enhanced probe-object coupling

A planar slab of negative index material works as a superlens with sub-diffraction-limited imaging resolution, since propagating waves are focused and, moreover, evanescent waves are reconstructed in the image plane. Here, we demonstrate a superlens for electric evanescent fields with low losses using perovskites in the mid-infrared regime. The combination of near-field microscopy with a tunable free-electron laser allows us to address precisely the polariton modes, which are critical for super-resolution imaging. We spectrally study the lateral and vertical distributions of evanescent waves around the image plane of such a lens, and achieve imaging resolution of wavelength/14 at the superlensing wavelength. Interestingly, at certain distances between the probe and sample surface, we observe a maximum of these evanescent fields. Comparisons with numerical simulations indicate that this maximum originates from an enhanced coupling between probe and object, which might be applicable for multifunctional circuits, infrared spectroscopy, and thermal sensors.Comment: 20 pages, 6 figures, published as open access article in Nature Communications (see http://www.nature.com/ncomms/

The clinical features of the piriformis syndrome: a systematic review

Piriformis syndrome, sciatica caused by compression of the sciatic nerve by the piriformis muscle, has been described for over 70 years; yet, it remains controversial. The literature consists mainly of case series and narrative reviews. The objectives of the study were: first, to make the best use of existing evidence to estimate the frequencies of clinical features in patients reported to have PS; second, to identify future research questions. A systematic review was conducted of any study type that reported extractable data relevant to diagnosis. The search included all studies up to 1 March 2008 in four databases: AMED, CINAHL, Embase and Medline. Screening, data extraction and analysis were all performed independently by two reviewers. A total of 55 studies were included: 51 individual and 3 aggregated data studies, and 1 combined study. The most common features found were: buttock pain, external tenderness over the greater sciatic notch, aggravation of the pain through sitting and augmentation of the pain with manoeuvres that increase piriformis muscle tension. Future research could start with comparing the frequencies of these features in sciatica patients with and without disc herniation or spinal stenosis

Does patient-physiotherapist agreement influence the outcome of low back pain? A prospective cohort study

BACKGROUND: Recent research suggests that agreement between patients' and health professionals' perceptions may influence the outcome of various painful conditions. This issue has received little attention in the context of low back pain and physiotherapy interventions. The current study aimed at exploring the relationship between patient-physiotherapist agreement on baseline low back pain intensity and related functional limitations, and changes in patient outcomes four weeks later. METHODS: Seventy-eight patient-physiotherapist dyads were included in the study. At baseline, patients and physiotherapists completed a Numerical Rating Scale and the Roland-Morris Disability Questionnaire. Patients' perceptions were reassessed over the phone at follow-up. RESULTS: Using multiple regression, baseline level of patient-physiotherapist agreement on pain intensity was associated with both outcome measures at follow-up. Agreement on functional limitations had no impact on outcomes. CONCLUSION: The results of this study indicate that patient-physiotherapist agreement has some impacts on the short-term outcomes of low back pain. Further research is needed to confirm these findings

Forefoot plantar multilobular noninfiltrating angiolipoma: a case report and review of the literature

<p>Abstract</p> <p>Background</p> <p>Soft tissue tumors of the feet are uncommon and there have been very few reports of large series in the literature. These tumors continue to present the clinician with one of the most difficult problems in medicine.</p> <p>Case presentation</p> <p>We present a case of a large multilobular noninfiltrating angiolipoma at the plantar surface of the forefoot. Only three cases occurring at the foot have been previously described. We report this new case due to unusual location of the tumor, the long duration (25 years) of its existence and the unique surgical approach for the tumor excision.</p> <p>Conclusion</p> <p>Surgical excision is the treatment of choice and adjuvant radiotherapy is indicated in select cases.</p

An interdisciplinary clinical practice model for the management of low-back pain in primary care: the CLIP project

<p>Abstract</p> <p>Background</p> <p>Low-back pain is responsible for significant disability and costs in industrialized countries. Only a minority of subjects suffering from low-back pain will develop persistent disability. However, this minority is responsible for the majority of costs and has the poorest health outcomes. The objective of the Clinic on Low-back pain in Interdisciplinary Practice (CLIP) project was to develop a primary care interdisciplinary practice model for the clinical management of low-back pain and the prevention of persistent disability.</p> <p>Methods</p> <p>Using previously published guidelines, systematic reviews and meta-analyses, a clinical management model for low-back pain was developed by the project team. A structured process facilitating discussions on this model among researchers, stakeholders and clinicians was created. The model was revised following these exchanges, without deviating from the evidence.</p> <p>Results</p> <p>A model consisting of nine elements on clinical management of low-back pain and prevention of persistent disability was developed. The model's two core elements for the prevention of persistent disability are the following: 1) the evaluation of the prognosis at the fourth week of disability, and of key modifiable barriers to return to usual activities if the prognosis is unfavourable; 2) the evaluation of the patient's perceived disability every four weeks, with the evaluation and management of barriers to return to usual activities if perceived disability has not sufficiently improved.</p> <p>Conclusion</p> <p>A primary care interdisciplinary model aimed at improving quality and continuity of care for patients with low-back pain was developed. The effectiveness, efficiency and applicability of the CLIP model in preventing persistent disability in patients suffering from low-back pain should be assessed.</p

Movement control exercise versus general exercise to reduce disability in patients with low back pain and movement control impairment. A randomised controlled trial

<p>Abstract</p> <p>Background</p> <p>Non-specific low back pain (NSLBP) in subacute and chronic stages can be treated effectively with exercise therapy. Research guidelines recommend evaluating different treatments in defined subgroups of patients with NSLBP. A subgroup of patients with movement control impairment (MCI) improved significantly on patient specific function and disability in a previous case series after movement control exercises.</p> <p>Methods/Design</p> <p>In a randomised controlled trial (RCT) we will compare the effectiveness of movement control and general exercise in patients with MCI. 106 participants aged 18 - 75 will be recruited in 5 outpatient hospital departments and 7 private practices.</p> <p>Patients randomly assigned to the movement control exercise group will be instructed to perform exercises according to their MCI. The general exercise group will follow an exercise protocol aimed at improving endurance and flexibility. Patients in both groups will receive 9 - 18 treatments and will be instructed to do additional exercises at home.</p> <p>The primary outcome is the level of disability assessed using the patient specific functional scale (PSFS) which links the perceived pain to functional situations and is measured before treatment and at 6 and 12 months follow-up. Secondary outcomes concern low back pain related disability (Roland Morris questionnaire, RMQ), graded chronic pain scale (GCPS), range of motion and tactile acuity.</p> <p>Discussion</p> <p>To our knowledge this study will be the first to compare two exercise programs for a specific subgroup of patients with NSLBP and MCI. Results of this study will provide insight into the effectiveness of movement control exercise and contribute to our understanding of the mechanisms behind MCI and its relation to NSLBP.</p> <p>Trial registration</p> <p>Current Controlled Trials <a href="http://www.controlled-trials.com/ISRCTN80064281">ISRCTN80064281</a></p

Work and Health, a Blind Spot in Curative Healthcare? A Pilot Study

Introduction Most workers with musculoskeletal disorders on sick leave often consult with regular health care before entering a specific work rehabilitation program. However, it remains unclear to what extent regular healthcare contributes to the timely return to work (RTW). Moreover, several studies have indicated that it might postpone RTW. There is a need to establish the influence of regular healthcare on RTW as outcome; “Does visiting a regular healthcare provider influence the duration of sickness absence and recurrent sick leave due to musculoskeletal disorders?”. Methods A cohort of workers on sick leave for 2–6 weeks due to a-specific musculoskeletal disorders was followed for 12 months. The main outcomes for the present analysis were: duration of sickness absence till 100% return to work and recurrent sick leave after initial RTW. Cox regression analyses were conducted with visiting a general health practitioner, physical therapist, or medical specialist during the sick leave period as independent variables. Each regression model was adjusted for variables known to influence health care utilization like age, sex, diagnostic group, pain intensity, functional disability, general health perception, severity of complaints, job control, and physical load at work. Results Patients visiting a medical specialist reported higher pain intensity and more functional limitations and also had a worse health perception at start of the sick leave period compared with those not visiting a specialist. Visiting a medical specialist delayed return to work significantly (HR = 2.10; 95%CI 1.43–3.07). After approximately 8 weeks on sick leave workers visiting a physical therapist returned to work faster than other workers. A recurrent episode of sick leave during the follow up quick was initiated by higher pain intensity and more functional limitations at the moment of fully return to work. Visiting a primary healthcare provider during the sickness absence period did not influence the occurrence of a new sick leave period. Conclusion Despite the adjustment for severity of the musculoskeletal disorder, visiting a medical specialist was associated with a delayed full return to work. More attention to the factor ‘labor’ in the regular healthcare is warranted, especially for those patients experiencing substantial functional limitations due to musculoskeletal disorders