Controlling behaviour of transparency and absorption in three-coupled multiple quantum wells via spontaneously generated coherence.

This article presents a coherent phenomenon called spontaneously generated coherence (SGC) under the regime of electromagnetically induced transparency (EIT) in a three-coupled multiple quantum wells. We demonstrate that the presence of SGC in these quantum wells lead to intriguing modifications in the transparency window within the absorption spectrum. At the same time, modification of the dispersive nature is also demonstrated which enables the feasibility of the system in diverse applications based on light propagation. The absorption and dispersion responses are found to be varied by the individual strength of the first and second control fields in presence as well as in absence of SGC in the EIT regime. The positional shifting of the transparency window and simultaneous modifications in the dispersive profiles by tuning the control field detunings of both the first and second control fields are also revealed. Some absorption and dispersion contours are illustrated for getting better insights into the modifications of the optical responses via SGC. Finally, by manipulating the strength of the SGC parameter, we observe the changes in the respective position of the transparency window and dispersion curve. It is expected that the current investigations will pave novel ways for innovative applications in quantum communications, and fabrication of advanced photonic devices.

Stabilization of modulation instability by control field in semiconductor quantum wells.

This article explores the modulation instability of a continuous or quasi-continuous weak probe pulse in a three-level asymmetric double quantum wells under an electromagnetically induced transparency regime, controlled by a strong laser beam. The dynamics of modulation instability reveals that the instability gain as well as its bandwidth is greatly influenced by control field Rabi frequency. The probe pulse is found to be almost stable against modulation instability for higher values of control field Rabi frequency. The results of this investigation may potentially apply for oscillation free generation of supercontinuum in quantum well nanostructures.

Complete incorporation of long diaphyseal sequestrum without surgical intervention in chronic hematogenous osteomyelitis of tibia in an immunocompetent child.

Traditionally, the management of chronic osteomyelitis emphasizes the excision of necrotic and infected material (sequestrectomy/debridement) followed by prolonged administration of antibiotics. Most children with chronic osteomyelitis undergo surgery with the inherent risk of damage to their growth plate. Treatment regimen based on findings of imaging with emphasis on antibiotics to potentially reduce the rate of surgical interventions is being increasingly reported. An 8-year-old thin built Indian boy belonging to lower socio-economic group presented to the orthopedic department with the chief complaints of pain in the left upper leg for the last 3 months. Radiograph of the affected limb showed features of chronic osteomyelitis with a large diaphyseal sequestrum on the medial cortex of tibia with incomplete involucrum. No surgery was performed; not even incision and drainage. The sinuses healed completely in 6 weeks time with appropritate antibiotics alone. Gradually, over a period of 8 months, the large tibial diaphyseal sequestrum got fully incorporated into the healthy diaphyseal bone indistinguishable from normal bony architecture with complete clinical remission of sepsis. Our rare case is an example of the evolving notion that antibiotics and supportive care alone may be sufficient enough in the treatment of chronic osteomyelitis even with large diaphyseal sequestrum in paediatric cases where excellent healing potential of the immune-competent child may potentially make surgical intervention redundant.

Outcome of percutaneous continuous drainage of psoas abscess: A clinically guided technique.

BACKGROUND: Percutaneous aspiration of abscesses under ultrasonography (USG) and computer tomography (CT) scan has been well described. With recurrence rate reported as high as 66%. The open drainage and percutaneous continuous drainage (PCD) has reduced the recurrence rate. The disadvantage of PCD under CT is radiation hazard and problems of asepsis. Hence a technique of clinically guided percutaneous continuous drainage of the psoas abscess without real-time imaging overcomes these problems. We describe clinically guided PCD of psoas abscess and its outcome. MATERIALS AND METHODS: Twenty-nine patients with dorsolumbar spondylodiscitis without gross neural deficit with psoas abscess of size >5 cm were selected for PCD. It was done as a day care procedure under local anesthesia. Sequentially, aspiration followed by guide pin-guided trocar and catheter insertion was done without image guidance. Culture sensitivity was done and chemotherapy initiated and catheter kept till the drainage was <10 ml for 48 hours. Outcome assessment was done with relief of pain, successful abscess drainage and ODI (Oswestry Disability Index) score at 2 years. RESULTS: PCD was successful in all cases. Back and radicular pain improved in all cases. Average procedure time was 24.30 minutes, drain output was 234.40 ml, and the drainage duration was 7.90 days. One patient required surgical stabilisation due to progression of the spondylodiscitis resulting in instability inspite of successful drainage of abscess. Problems with the procedure were noticed in six patients. Multiple attempts (n = 2), persistent discharge (n = 1) for 2 weeks, blocked catheter (n = 2) and catheter pull out (n = 1) occurred with no effect on the outcome. The average ODI score improved from 62.47 to 5.51 at 2 years. CONCLUSIONS: Clinically guided PCD is an efficient, safe and easy procedure in drainage of psoas abscess.

Case report and brief review of literature on sonographic detection of accidentally implanted wooden foreign body causing persistent sinus.

Despite advances in imaging techniques, the detection of vegetative foreign bodies in soft tissues remains a difficult and sometimes even a challenging task. Clinical evaluation of such patient may present several months or even years after the initial injury and clinician may fail to elicit an antecedent skin puncture. X-ray examination will miss radiolucent foreign bodies. A 15-year-old boy presented with a draining non-healing sinus at the lateral aspect of his right thigh for 9 months. Musculoskeletal ultrasonography was ordered after ruling out chronic osteomyelitis to detect possible lesions around the thigh. High-frequency linear ultrasonic probe readily detected an elongated foreign body within the vastus lateralis muscle. A long piece of wood was confirmed at surgery. Non-healing sinus with normal finding in radiograph following old trauma should raise the suspicion of implanted radiolucent foreign body/bodies. The role of diagnostic ultrasound as a valuable screening tool for the detection of foreign body is briefly reviewed.

Double parabolic Kirschner-wires as dynamic distractor for treatment of unstable intraarticular phalangeal fractures of hand.

BACKGROUND: Treatment of complex injuries of interphalangeal joints (IPJs) is difficult. The restoration of joint stability for early joint mobility till fracture union is the key for successful outcome. Although various treatment options like dynamic splinting, external fixator, closed reduction, transarticular Kirschner (K)-wire and ORIF, etc., are available in literature, a universally accepted ideal treatment for complex intraarticular fractures of IPJs is still evolving. Open reduction is difficult because fixation of volar fragment is often impractical and radical procedures like volar plate arthroplasty, arthrodesis or joint replacement, etc., may become mandatory for salvage. We describe percutaneous technique to treat unstable fractures and dorsal fracture-dislocations of the PIP joint and report short-term postoperative results. MATERIALS AND METHODS: Ten cases of unstable or potentially unstable intraarticular fractures including pilon fractures and fracture-dislocations of IP joints were treated percutaneously by double parabolic K-wire technique (DPK). The device was used as a dynamic distraction, using the principle of ligamentotaxis. The idea was to commence early postoperative continuous active and active-assisted joint motion exercises and to carry on the frame as a definitive treatment for achieving fracture union. RESULTS: In all patients of fracture-dislocation the reduction was satisfactory and early mobility was achieved. Although there is a tendency towards over-distraction, no loss of reduction occurred. Pin tract infection occurred in one with no delayed union or nonunion. The average total range of motion for each involved IP joint was 93.5 degree and the average total active range of motion was 90.8° each at the end of 4 months followup. Excellent to good results were restored in nearly all cases without further interventions. CONCLUSION: DPK technique may be a cheap and valuable definitive treatment option in the management of unstable or potentially unstable intraarticular fractures of IPJs. The technique gave satisfactory radiological union and functional outcome in our small series. This technique may be worth considering in unstable or potentially unstable intraarticular fractures of IPJs with intact collateral ligaments and when other treatment options are impractical.

Occult renal cell carcinoma with acrometastasis and ipsilateral juxta-articular knee lesions mimicking acute inflammation.

Generally, skeletal peripheral metastases below the elbow and the knee are rare. Skeletal metastases to the hand or foot are very rare; but when they do it may be a revealing clinical finding. Purely lytic lesions are commonly seen in metastases from lung, renal, and thyroid tumors, but they are also known to occur in primary myeloma, brown tumor and lymphomas. A 70-year-old man was brought to the emergency department with acute painful swelling involving his right hand and the right knee. Due to significant accompanying soft tissue swellings cellulitis, acute osteomyelitis and gouty arthropathy were included in the initial differential diagnosis. Radiographs showed pure lytic bony lesion with complete disappearance of lower two third of the second metacarpal, trapezium and trapezoid bones of the right hand along with a lytic subarticular lesion of medial condyle of ipsilateral femur. Chest X-ray (CXR) was normal but sonography of the abdomen readily demonstrated a large renal mass, later confirmed at biopsy as renal cell carcinoma (RCC). Clinicians should be cognizant of the strong association between digital acrometastases and renal cell carcinoma in male patients with normal CXR findings. In suspected hand acrometastasis associated with a soft tissue component outside the contours of normal bone, screening the abdomen by sonography should be done prior to bone biopsy and before costly or time-consuming investigations are offered. Metastatic RCC should be included in the differential diagnosis of all unilateral expansile bony lesions of the digit. It is particularly important if such lesion/lesions are accompanied by local inflammation. Screening the abdomen by sonography may be of particular value in such elderly male patient when Chest X-ray shows no abnormality.