Optical sideband generation up to room temperature with mid-infrared quantum cascade lasers

Mid-infrared (MIR) sideband generation on a near infrared (NIR) optical carrier is demonstrated within a quantum cascade laser (QCL). By employing an externally injected NIR beam, E(NIR), that is resonant with the interband transitions of the quantum wells in the QCL, the nonlinear susceptibility is enhanced, leading to both frequency mixing and sideband generation. A GaAs-based MIR QCL (E(QCL) = 135 meV) with an aluminum-reinforced waveguide was utilized to overlap the NIR and MIR modes with the optical nonlinearity of the active region. The resulting difference sideband (E(NIR) - E(QCL)) shows a resonant behavior as a function of NIR pump wavelength and a maximum second order nonlinear susceptibility, χ((2)), of ~1 nm/V was obtained. Further, the sideband intensity showed little dependence with the operating temperature of the QCL, allowing sideband generation to be realized at room temperature.

20 THz broadband generation using semi-insulating GaAs interdigitated photoconductive antennas

We demonstrate broadband (20 THz), high electric field, terahertz generation using large area interdigitated antennas fabricated on semi-insulating GaAs. The bandwidth is characterized as a function of incident pulse duration (15-35 fs) and pump energy (2-30 nJ). Broadband spectroscopy of PTFE is shown. Numerical Drude-Lorentz simulations of the generated THz pulses are performed as a function of the excitation pulse duration, showing good agreement with the experimental data.

Metformin and Not Diabetes Influences the Survival of Resected Early Stage NSCLC Patients

BACKGROUND

Published data suggest that diabetes influences survival of patients with lung cancer. The anti-cancer effect of metformin confounds this association. We sought to study the association of diabetes and metformin with survival in patients undergoing resection of stage I non-small cell lung cancer (NSCLC).

METHODS

Pathologic stage I NSCLC patients undergoing anatomic resection from 2002 to 2011 were studied. A diagnosis of diabetes and diabetic medication use were identified through records. Univariate and multivariate analyses examined the association of diabetes and metformin usage with overall survival (OS).

RESULTS

409 eligible patients were included in the analysis - excluding patients with neoadjuvant therapy, more than one lung cancer, or resection less than lobectomy. 71 (17.4%) patients were diabetics and 41 (10.0%) used metformin. With a median follow up of 44 months, univariate analysis demonstrates that diabetes had no effect on OS (P=0.75); however, metformin use was associated with improved OS (median survival not reached vs. 60 months; P=0.02). Metformin use remained an important predictor of good survival in multivariate analysis (HR=3.08; P<0.01) after adjusting for age, gender, pathologic stage, histology and smoking status.

CONCLUSION

Metformin use rather than diabetes is associated with improved long-term survival in Stage I NSCLC patients.

Lung cancer screening update

Lung cancer is the leading cause of cancer-related mortality globally and the American cancer society estimates approximately 226,160 new cases and 160,340 deaths from lung cancer in the USA in the year 2012. The majority of lung cancers are diagnosed in the later stages which impacts the overall survival. The 5-year survival rate for pathological st age IA lung cancer is 73% but drops to only 13% for stage IV. Thus, early detection through screening and prevention are the keys to reduce the global burden of lung cancer. This article discusses the current state of lung cancer screening, including the results of the National Lung Cancer Screening Trial, the consideration of implementing computed tomography screening, and a brief overview of the role of bronchoscopy in early detection and potential biomarkers that may aid in the early diagnosis of lung cancer.

Advances in bronchoscopy for lung cancer

Bronchoscopic techniques have seen significant advances in the last decade. The development and refinement of different types of endobronchial ultrasound and navigation systems have led to improved diagnostic yield and lung cancer staging capabilities. The complication rate of these minimally invasive procedures is extremely low as compared to traditional transthoracic needle biopsy and surgical sampling. These advances augment the safe array of methods utilized in the work up and management algorithms of lung cancer.

Mode-locking of a terahertz laser by direct phase synchronization

A novel scheme to achieve mode-locking of a multimode laser is demonstrated. Traditional methods to produce ultrashort laser pulses are based on modulating the cavity gain or losses at the cavity roundtrip frequency, favoring the pulsed emission. Here, we rather directly act on the phases of the modes, resulting in constructive interference for the appropriated phase relationship. This was performed on a terahertz quantum cascade laser by multimode injection seeding with an external terahertz pulse, resulting in phase mode-locked terahertz laser pulses of 9 ps duration, characterized unambiguously in the time domain.

Detection of a possible case of pulmonary tumour thromboembolism by endobronchial ultrasound

-

Integrated injection seeded terahertz source and amplifier for time-domain spectroscopy

We used a terahertz (THz) quantum cascade laser (QCL) as an integrated injection seeded source and amplifier for THz time-domain spectroscopy. A THz input pulse is generated inside a QCL by illuminating the laser facet with a near-IR pulse from a femtosecond laser and amplified using gain switching. The THz output from the QCL is found to saturate upon increasing the amplitude of the THz input power, which indicates that the QCL is operating in an injection seeded regime.

The "silver-nitrate-oma"

This case report demonstrates and emphasises the unusual radiographic appearance of silver nitrate treatment in a 30-year-old patient, who subsequently underwent excision biopsy of a presumed potentially malignant lesion.

Estrogen inhibits NPY secretion through membrane-associated estrogen receptor (ER)-α in clonal, immortalized hypothalamic neurons

OBJECTIVE

Estrogen (E(2)) has an inhibitory effect on food intake by acting centrally in the hypothalamus, although it is not clear which hypothalamic neurons are involved in this process. Earlier studies from our lab and others have implicated neuropeptide Y (NPY) as an important central anorexigenic target of E(2). This study was designed to investigate whether E(2) can directly regulate NPY secretion and examine the cellular mechanisms and receptors responsible for this anorexigenic action of E(2).

DESIGN

Clonal, murine, hypothalamic neuronal cell models, mHypoE-42 and mHypoA-2/12, were investigated for NPY secretory responses to 17β-estradiol (E(2)) in the presence or absence of pharmacological inhibitors directed against the phosphatidylinositol-3-kinase (PI3K), mitogen-activated protein kinase (MAPK) and AMP-activated kinase (AMPK) pathways or to estrogen receptor (ER) specific agonists/antagonists.

MEASUREMENTS

The presence of hypothalamic markers and characterization of neuronal cell lines was completed with polymerase chain reaction. NPY levels were measured using an enzyme immunoassay (EIA). The expression of ER-α and caveolin-1 was analyzed using immunocytochemistry.

RESULTS

E(2) significantly decreased NPY secretion in both the mHypoE-42 and mHypoA-2/12 neurons. The E(2)-mediated repression of NPY secretion in the mHypoE-42 and mHypoA-2/12 neurons required ER-α, but not ER-β, as shown by studies using an ER-specific agonist/antagonists. Additionally, using immunocytochemistry we detected colocalization of ER-α and the membrane-associated signaling protein caveolin-1. Importantly, using E(2)-conjugated bovine serum albumin (E(2)-BSA) and ER antagonists, we were able to show that the E(2)-mediated decrease in NPY secretion occurred through membrane-bound ER-α. Finally, using a combination of pharmacological inhibitors, we found that inhibition of the PI3K or AMPK pathway blocked the E(2)-mediated decrease in NPY secretion.

CONCLUSION

These findings indicate that the central anorexigenic action of E(2) occurs at least partially through hypothalamic NPY-synthesizing neurons. This regulation of NPY secretion occurs through rapid signaling mechanisms through membrane bound ER-α.

Simulating the influence of vernalization, photoperiod and optimum temperature on wheat developmental rates

BACKGROUND AND AIMS

Accurately representing development is essential for applying crop simulations to investigate the effects of climate, genotypes or crop management. Development in wheat (Triticum aestivum, T. durum) is primarily driven by temperature, but affected by vernalization and photoperiod, and is often simulated by reducing thermal-time accumulation using vernalization or photoperiod factors or limiting accumulation when a lower optimum temperature (T(optl)) is exceeded. In this study T(optl) and methods for representing effects of vernalization and photoperiod on anthesis were examined using a range of planting dates and genotypes.

METHODS

An examination was made of T(optl) values of 15, 20, 25 and 50 degrees C, and either the most limiting or the multiplicative value of the vernalization and photoperiod development rate factors for simulating anthesis. Field data were from replicated trials at Ludhiana, Punjab, India with July through to December planting dates and seven cultivars varying in vernalization response.

KEY RESULTS

Simulations of anthesis were similar for T(optl) values of 20, 25 and 50 degrees C, but a T(optl) of 15 degrees C resulted in a consistent bias towards predicting anthesis late for early planting dates. Results for T(optl) above 15 degrees C may have occurred because mean temperatures rarely exceeded 20 degrees C before anthesis for many planting dates. For cultivars having a strong vernalization response, anthesis was more accurately simulated when vernalization and photoperiod factors were multiplied rather than using the most limiting of the two factors.

CONCLUSIONS

Setting T(optl) to a high value (30 degrees C) and multiplying the vernalization and photoperiod factors resulted in accurately simulating anthesis for a wide range of planting dates and genotypes. However, for environments where average temperatures exceed 20 degrees C for much of the pre-anthesis period, a lower T(optl) (23 degrees C) might be appropriate. These results highlight the value of testing a model over a wide range of environments.

Anatomical study comparing the thickness of the volar and dorsal cortex of cadaveric adult distal radii using digital photography

INTRODUCTION

Dorsally displaced fractures of the distal radius fractures are one of the commonest in day-to-day practice. There is still no consensus among surgeons regarding the suitability of using volar or the dorsal cortex as basis for internal fixation for dorsally displaced fractures.

BACKGROUND

We report an anatomical study, which compares the thickness of the volar and dorsal cortices of cadaveric adult radii using digital photography.

RESULTS

Results of this study show that the volar cortex was statistically, significantly thicker than the dorsal cortex. We believe that the volar cortex may behave as the calcar of the distal radius and hence internal fixation devices applied to the volar cortex may provide a more stable internal fixation compared to those based on the dorsal cortex.

Patellar tendon ruptures in a pair of brothers

The patellar tendon does not easily rupture due to its considerable high tensile strength. Therefore, in normal individuals, ruptures of the patellar tendon are uncommon. We report three episodes of patellar tendon ruptures in two normally fit and healthy brothers; postulating the possibility of inherent weakness. The treatment options for these injuries are discussed.

Palmar cortical angle of the distal radius: a radiological study

Fifty lateral radiographs of normal wrists were viewed to determine the palmar cortical angle of the distal radius. The palmar cortical angle is different to its previously described palmar tilt or angulation. The mean value for the palmar cortical angle was 37 degrees (range, 26-50 degrees). This may be clinically important in the design of palmar plates for the distal radius.

Transitional cell carcinoma manifesting as acute cor pulmonale: cause of microscopic tumor embolism

Acute cor pulmonale is an uncommon manifestation of microscopic pulmonary tumor embolism. We describe the case of an 84-year-old man with a history of transitional cell carcinoma (TCC) of the urinary bladder who had acute cor pulmonale and died within a few hours after the onset of dyspnea. Autopsy showed that the right ventricle was dilated without hypertrophy. Microscopic examination of the lung showed that the small arteries, arterioles, and capillaries were filled with micrometastases of TCC. Microscopic pulmonary tumor embolism has rarely been reported with TCC, and to the best of our knowledge, such a fulminant course has not been previously described in the English language.

Lumbosacral plexopathy after dual kidney transplantation

A 58-year-old man underwent dual kidney transplantation. He was unable to move his right leg after surgery. This was caused by extensive lumbosacral plexopathy on the side of surgery. Lumbosacral plexopathy after kidney transplantation is uncommon, because the plexus has rich anastomotic blood supply, and ischemic injury is unlikely. However, isolated femoral neuropathy after renal transplantation has been reported, as the distal portion of this nerve is supplied by branches of internal iliac artery only and is more prone to ischemic injury during surgery. Dual-kidney transplantation involves a larger dissection, and the procedure takes 60 to 90 minutes longer than single-kidney transplantation. It involves more vascular reconstruction. This may predispose the lumbosacral plexus to ischemic injury. To the best of our knowledge, this is the first reported case of lumbosacral plexopathy after a dual kidney transplantation, and this may be seen more frequently because this procedure is becoming more common.

Pneumococcal bacteremia associated with an infected central venous catheter

Pneumococcus (Streptococcus pneumoniae) bacteremia is a serious infection. Pneumococcus has never been implicated as a cause of a central venous catheter-related bacteremia. It has been isolated from the catheter tip only twice before, and in one case caused the infection of an infusion port device. We report case of a 41-year-old woman who developed pneumococcal bacteremia after 6 days of an indwelling central venous catheter. The catheter tip grew > 300 cfu of S pneumoniae by the roll-plate method described by Maki and colleagues. No other focus of infection could be found in this patient. To the best of our knowledge, this is the first reported case of pneumococcal bacteremia associated with an infected central venous catheter.

Lady Windermere syndrome: middle lobe bronchiectasis and Mycobacterium avium complex infection due to voluntary cough suppression

An 81-year-old woman who presented with middle lobe bronchiectasis and Mycobacterium avium complex infection is described. She had a history of habitual suppression of cough, as in Lady Windermere syndrome. She was thin and had mild kyphoscoliosis but had no history of smoking or connective tissue disease. The middle lobe and lingula are predisposed to chronic inflammation because of their particular anatomic structures. Inability to clear the secretions from the airway due to voluntary cough suppression may predispose to bronchiectasis and M. avium complex infection.