First demonstration and detailed characterization of a multimode amplifier for Space Division Multiplexed transmission systems

We present the first demonstration of a multimode (two mode-group) erbium-doped fiber amplifier for Space Division Multiplexed (SDM) applications and demonstrate various design and performance features of such devices. In particular we experimentally demonstrate that differential modal gains can be controlled and reduced both by fiber design and control of the pump field distribution. Using a suitably designed fiber we demonstrate simultaneous modal gains of ~20 dB for different pair-wise combinations of spatial and polarization modes in an EDFA supporting amplification of 6 distinct modes.

Protein stability and folding kinetics in the nucleus and endoplasmic reticulum of eucaryotic cells

We measure the stability and folding relaxation rate of phosphoglycerate kinase (PGK) Förster resonance energy transfer (FRET) constructs localized in the nucleus or in the endoplasmic reticulum (ER) of eukaryotic cells. PGK has a more compact native state in the cellular compartments than in aqueous solution. Its native FRET signature is similar to that previously observed in a carbohydrate-crowding matrix, consistent with crowding being responsible for the compact native state of PGK in the cell. PGK folds through multiple states in vitro, but its folding kinetics is more two-state-like in the ER, so the folding mechanism can be modified by intracellular compartments. The nucleus increases PGK stability and folding rate over the cytoplasm and ER, even though the density of crowders in the nucleus is no greater than in the ER or cytoplasm. Nuclear folding kinetics (and to a lesser extent, thermodynamics) vary less from cell to cell than in the cytoplasm or ER, indicating a more homogeneous crowding and chemical environment in the nucleus.

A United Kingdom inflammatory bowel disease database: making the effort worthwhile

BACKGROUND

Inflammatory bowel disease (IBD), a paradigm of chronic illness, requires for its safe clinical management ready access to complete information, not always possible using paper records.

AIM

To develop an IBD database (DB) for both individual patient management and collating information across centres.

METHODS

Access® based, with a minimum dataset.

RESULTS

Prospectively collected data for 11,432 patients from 21 centres. PROFILE DIAGNOSIS: Ulcerative colitis (UC) 56%, Crohn's disease (CD) 40%, indeterminate colitis 4%. M:F ratio: UC 1.08:1, CD 0.72:1. Median age at diagnosis: UC 39, CD 30 years. Operated: UC 16%, CD 47%. Thiopurine use: UC 16%, CD 29%. IBD related mortality: 0.74%.

DISCUSSION

A snapshot of this large IBD cohort shows the disease profile across the UK is similar to other large series. Unexpected gaps, sometimes large emerged (e.g. data on smoking and immunosuppression) highlighting the need for clear definition, consistency and completeness of data collection. Clinical management is made easier by the 'at a glance' summary, automated clinic letters, and facility for monitoring and audit, but the time required limited its 'real-time' use.

CONCLUSION

Our experience shows it is possible to collect data from centres across the country which truly reflects clinical practice. We have learned as much from the process itself as from the data, principally, information needs to be well defined, validated at entry, and updated at every visit, a time consuming sequence which we had underestimated. Our lessons learned may help inform the development of a national database, and support national IBD standards and audit.

The CCN family proteins in carcinogenesis

The CCN (Cyr61 (cysteine-rich protein 61), CTGF (connective tissue growth factor), Nov (nephroblastoma overexpressed)) family consists of six members that belong to matricellular proteins of extracellular matrix (ECM). Like other matricellular proteins, CCN members do not primarily have a structural role; however, they modulate cell-ECM interactions. In general, CCN proteins are formed by four characteristic domain structures and thought to participate in various biological phenomena such as organ development, wound healing, angiogenesis, fibrosis, etc. In cancer, CCN proteins family expresses aberrantly; probably depending on the sites and types, expressions of different CCN proteins have been documented to be linked with either progression or inhibition of the pathological processes of cancer. Through various mechanisms like cell survival, apoptosis, inflammation, cell adhesion and migration and connection with several cytokines, CCN proteins perhaps influence the disease course including tumor metastasis. A majority of the above-mentioned effects are believed to be mediated by binding with integrins, a class of receptors that mediate cell-cell and cell-ECM interactions. Furthermore, the members of CCN family modulate the functions of several important growth factors and related pathways such as insulin-like growth factor (IGF), transforming growth factor-beta (TGF-beta) and Wnt signaling. Interestingly, a variety of factors/proteins linked with these signaling systems are reported to be associated with the carcinogenic process. Nevertheless, a precise knowledge about the pathophysiological activities including signaling pathways of CCN proteins would be helpful to identify molecular targets in order to design therapeutic strategies in the management of cancer.

Silicon dioxide embedded germanium nanocrystals grown using molecular beam epitaxy for floating gate memory devices

SiO2/Ge nanocrystals/SiO2 trilayer memory structure has been fabricated by oxidizing and subsequent annealing of self assembled SiGe nanoislands grown by molecular beam epitaxy. The optical and charge storage characteristics of trilayer structures have been studied through Raman spectroscopy and capacitance-voltage measurements, respectively. An anti-clockwise hysteresis in the C-V characteristics indicated the net electron trapping in the floating gate containing Ge nanocrystals. Frequency dependent measurements of device characteristics indicate that neither interface defects nor deep traps are dominant for the charging or discharging processes of nanocrystal floating gates.

Shape and size distribution of molecular beam epitaxy grown self-assembled Ge islands on Si (001) substrates

We have performed a series of annealing experiments with Ge islands on Si (001) grown by molecular beam epitaxy, in order to clarify issues related to island stability and coarsening. The shape and size distribution of nanoislands as a function of annealing time at a temperature of 650 degrees C have been studied. Optical phonons from Raman spectra have been used as efficient probes to study the evolution of Si(1-x)Ge(x) islands. Both the alloy composition and residual strain in the islands have been determined from the phonon frequencies and Raman intensities. The experimental results are in good agreement with the strain relaxation estimated using X-ray rocking curves. The results indicate that the shape and size distribution of Ge islands are controlled via structural and compositional changes through strain relaxation by the periodic creation and extinction of tiny nanocrystals.

Memory effect in a junction-like CdS nanocomposite/conducting polymer poly[2-methoxy-5-(2-ethylhexyloxy)1,4-phenylene-vinylene] heterostructure

The operation of a nonvolatile memory device is demonstrated using junction-like CdS nanocomposites embedded in a polymer matrix. The capacitance-voltage characteristics of Al/conducting polymer poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene-vinylene]/CdS nanocomposites in a polyvinyl alcohol matrix/indium tin oxide device exhibit hysteresis, which is attributed to the trapping, storage, and emission of holes in the quantized valence band energy levels of isolated CdS nanoneedles. The characteristics at different operating frequencies show that the hysteresis is due to trapping of charge carriers in CdS nanocomposites rather than in the interfacial states. The memory behavior in the inorganic/organic heterostructure is explained on the basis of a simple energy band diagram.

Residential health near major construction projects: unexplored hazards

Few studies have been made of the impact of major construction on the health of nearby residents. We conducted a feasibility study in one zip code (02111; Chinatown, Boston, MA, USA) in which four large buildings (20-30 stories) were built between 1999 and 2004 and adjacent to which a major highway construction project was in progress. Information about major construction project start and end dates were obtained from a variety of sources. Three sets of health data--emergency department and mortality-were obtained from the Massachusetts Department of Public Health for the years of 1998 - 2004. We used ICD-9 and ICD-10 disease codes to aggregate selected pulmonary and cardiac-related categories that could reasonably be expected to be aggravated by air pollution released from construction sites, including diesel and dust, and noise and vibration. We propose that larger-scale studies are possible and needed using approaches similar to ours.

Evidence-based management of Mastalgia: A meta-analysis of randomised trials

Several agents have been utilised for therapy of mastalgia based on data from small trials. No meta-analysis of trials on mastalgia exists. We have conducted a meta-analysis on trials on mastalgia published in the English language. Study was restricted to randomised controlled trials comparing Bromocriptine, Danazol, Evening primrose oil (EPO) and Tamoxifen with placebo. The analysis was carried out on the REVMAN statistical package. Weighted mean difference in the pain score in favour of Bromocriptine was -16.31(95% CI -26.35 to -6.27). Danazol produced a significant benefit with a mean pain score difference -20.23(95% CI -28.12 to -12.34). EPO did not offer any advantage over placebo in pain relief, mean pain score difference being -2.78 (95% CI -7.97 to 2.40). Tamoxifen achieved a relative risk (RR) of pain relief of 1.92 (95% CI 1.42-2.58). Tamoxifen is associated with least side effects and should be the drug of first choice.

Biodegradable-polymer-based, paclitaxel-eluting Infinnium stent: 9-Month clinical and angiographic follow-up results from the SIMPLE II prospective multi-centre registry study

BACKGROUND

SIMPLE II was a multi-centre, prospective registry study aimed at investigating the safety and efficacy of the Infinnium (Sahajanand Medical Technologies Pvt. Ltd, India) paclitaxel-eluting stent for the treatment of single de novo lesions in the native coronary arteries.

METHODS

One hundred and three patients with symptomatic coronary artery disease were treated for single de novo native coronary artery lesions using the Infinnium stent (paclitaxel concentration 1.4 mcg/mm2 released over 48 days) in a multi-centre, prospective study performed on 3 continents (Asia, Europe and South America). The primary safety endpoint was major adverse cardiac events at 30 days (MACE 30d) and efficacy was assessed by in-stent binary restenosis as measured by quantitative coronary angiography (QCA) at six-month follow-up. A clinical follow-up was scheduled at nine months.

RESULTS

The mean patient age was 58.5 years; 70.9% were males; 43.7% had unstable angina and 38.8% previous myocardial infarction. Risk factors included hypertension in 62.1%, hypercholesterolemia in 52.4%, current smoking in 32.0% and diabetes in 28.2%. Stent implantation was successful in all patients, with more than one stent being implanted in 9 patients (8.7%). Hierarchical MACE 30d was 2.9%. At nine months, 101 patients had clinical follow-up (1 patient had died and 1 refused). There was one death (1.0%), one Q-wave myocardial infarction (Q MI) (1.0%), three non-Q MIs (2.9%), one clinically-driven target lesion Coronary Artery Bypass Grafting (CABG) (1.0%), and one clinically-driven target lesion repeat percutaneous coronary intervention (re-PCI) (1.0%). The overall event-free rate at nine months was 93.2%. QCA revealed in-stent and in-segment late loss of 0.38+/-0.49 mm and 0.18+/-0.46 mm, resulting in binary restenosis rates of 7.3% and 8.3%, respectively. There was one case of late stent thrombosis in the patient experiencing the Q MI and subsequent re-PCI.

CONCLUSIONS

The Infinnium paclitaxel-eluting stent appears to be safe and efficacious for the treatment of single de novo lesions in coronary arteries in a patient population with symptomatic coronary artery disease (CAD).

Second echelon node predicts metastatic involvement of additional axillary nodes following sentinel node biopsy in early breast cancer

BACKGROUND

In many patients with early breast cancer, the sentinel lymph node (SLN) is the sole site of regional nodal metastasis. This subgroup of patients may not benefit from completion axillary lymph node dissection (CALND).

AIMS

This pilot study evaluates the status of 2nd echelon (station) lymph nodes in the axilla as a predictor of additional positive nodes in the axilla in the presence of sentinel node metastasis.

SETTINGS AND DESIGN

Cross-sectional study of 40 breast cancer patients.

MATERIALS AND METHODS

Forty patients with invasive breast cancer underwent SLN biopsy followed by 2nd echelon lymph node biopsy in the same sitting. SLN mapping was performed using a combined technique of isosulfan blue and 99 mTc-sulfur colloid. SLNs (Station I) were defined as blue and/or hot nodes. These nodes were then injected with 0.1 ml of blue dye using a fine needle and their efferent lymphatic was traced to identify the Station II nodes. Then a complete ALND was performed. All the specimens were sent separately for histopathological evaluation.

RESULTS

SLNs (Station I nodes) were successfully identified in 98% (39/40) patients. Of the 17 patients with a positive SLN, 8 (47%) patients had no further positive nodes in the axilla, 9 (53%) patients had additional metastasis in nonsentinel lymph nodes upon CALND. Station II nodes were identified in 76% (13/17) patients with a positive SLN. Station II nodes accurately predicted the status of the remaining axilla in 92% patients (12/13).

STATISTICAL ANALYSIS

We calculated the Sensitivity, Negative predictive value, Positive predictive value, False negative rate and Identification rate.

CONCLUSION

Station II nodes may predict metastatic involvement of additional nodes in the axilla.

Neuroprotective effects of FeTMPyP: a peroxynitrite decomposition catalyst in global cerebral ischemia model in gerbils

Peroxynitrite involvement has been implicated in the neuronal damage. In the present study, we have investigated the neuroprotective effects of peroxynitrite decomposition catalyst (FeTMPyP) on global cerebral ischemia. Global cerebral ischemia-reperfusion (IR) injury was produced by 5 min occlusion of both common carotid arteries followed by reperfusion of 96 h in the adult male Mongolian gerbils. The extent of injury was assessed behaviorally by measuring neurological functions, locomotor activity, passive avoidance test and by histopathological evaluation of extent of damage to CA1 hippocampal pyramidal region. FeTMPyP (1 and 3 mgkg(-1), i.p., administered 30 min prior to ischemia) treatment improved the neurological functions, reduced the hyperlocomotion and memory impairment in IR challenged gerbils. The loss of neurons from the pyramidal layer of the CA1 region caused by global IR injury was attenuated with FeTMPyP. FeTMPyP also inhibited lipid peroxidation as evident from reduction in brain malondialdehyde levels. These results suggest that peroxynitrite decomposition catalyst may be effective neuroprotective agent for global cerebral ischemia.

Comparison of cardiac output in OPCAB: bolus thermodilution technique versus pulse contour analysis

The study was designed to evaluate the clinical agreement between intermittent bolus thermodilution technique and pulse contour analysis technique. Sixty patients with normal left ventricular function undergoing elective off-pump coronary bypass surgery were included in this prospective study. In addition to routine monitoring, a 7.5F pulmonary artery thermodilution catheter via right internal jugular vein and a 4F arterial thermodilution catheter into femoral artery were also placed. Cardiac output measurements were compared before induction, after induction, after sternotomy, during the various anastomoses, post-protamine and post-sternal closure. Statistical analysis was performed using analysis of agreement to assure bias distribution of differences between the two methods by using Bland and Altman analysis. The cardiac output values obtained at preinduction, post-induction, and post-sternal closure time points showed good agreement, whereas the values obtained during the various anastomoses showed significant differences (p <0.05). Therefore it was concluded that pulse contour analysis cannot be relied upon completely whenever there is a change in the position of heart or alteration in systemic vascular resistance. But the trends in cardiac output were in complete agreement during the entire procedure.

Spin glasses in the limit of an infinite number of spin components

We consider spin glass models in which the number of spin components m is infinite. In the formulation of the problem appropriate for numerical calculations proposed by several authors, we show that the order parameter defined by the long-distance limit of the correlation functions is actually zero and there is only "quasi-long-range order" below the transition temperature. Nonetheless, there can be a finite temperature phase transition where the decay of correlations changes from exponential to power law. We also show that the spin glass transition temperature is zero in three dimensions so power-law behavior only occurs at T=0 in this case. We also argue that the order of limits, m-->infinity and N-->infinity is important, where N is the number of spins.

Endometrioid carcinoma of uterus and ovary

A thirty-two-year-old married woman presented with pain abdomen and polymenorrhoea. Her uterus was bulky and one of the fornices was full. USG of abdomen revealed unilateral ovarian tumour associated with a mass in the uterus. Histopathological report revealed synchronous endometrioid carcinoma of the uterus and the ovary with morphological evidences in favour of independent primary carcinomas. With these perspectives the present case is reported where endometrioid carcinomas of uterus and ovary are two separate primary tumours.

Diverticular disease of the colon: ethnic differences in frequency

BACKGROUND

Colonic diverticular disease is more common in Western populations than in developing countries.

AIM

To determine whether the frequency of colonic diverticular disease is different in British patients of Indian-subcontinent Asian origin compared with other ethnic groups.

METHODS

All colonoscopies performed over a 3-year period in a London hospital were studied. Patients of Indian-subcontinent Asian origin were identified by name.

RESULTS

Five of 134 Indian-subcontinent Asian males (4%) had colonic diverticular disease, compared with 278 of 1268 patients of other ethnic groups (22%; P < 0.001). Five of 91 Indian-subcontinent Asian females (6%) had colonic diverticular disease, compared with 333 of 1486 patients of other ethnic groups (23%; P < 0.001). Although patients of Indian-subcontinent Asian origin (54.8 +/- 15.8 years) were younger than those of other ethnic groups (60.3 +/- 17.8 years; P < 0.0001), the ethnic difference in the frequency of diverticular disease persisted even when age was taken into account.

CONCLUSION

There is a lower frequency of colonic diverticular disease in Indian-subcontinent Asians presenting for colonoscopy, compared with other ethnic groups. This cannot be explained by sex or age differences. Our findings require confirmation, but may provide opportunities for research into the aetiology of colonic diverticular disease.

Purification and characterization of a Galactomyces reessii hydratase that converts 3-methylcrotonic acid to 3-hydroxy-3-methylbutyric acid

Cell free extracts of Galactomyces reessii contain a hydratase as the key enzyme for the transformation of 3-methylcrotonic acid to 3-hydroxy-3-methylbutyric acid. Highest levels of hydratase activity were obtained during growth on isovaleric acid. The enzyme, an enoyl CoA hydratase, was purified 147-fold by precipitation with ammonium sulphate and successive chromatography over columns of DE-52, Blue Sepharose CL-6B and Sephacryl S-200. During purification, hydratase activity was measured spectrophotometrically (OD change at 263 nm) for 3-methylcrotonyl CoA and crotonyl CoA as substrates. The enzyme displayed highest activity with crotonyl CoA with a Kcat of 1,050,000 min(-1). The ratio of crotonyl CoA to 3-methylcrotonyl CoA activities was constant (20:1) during all steps of purification. The Kcat for crotonyl CoA was also about 20 times greater than the Kcat for 3-methylcrotonyl CoA (51,700 min(-1). The enzyme had pH and temperature optima at 7.0 and 35 degrees C, a native Mr of 260 +/- 4.5 kDa and a subunit Mr of 65 kDa, suggesting that the enzyme was a homotetramer. The pI of the purified hydratase was 5.5, and the N-terminal amino acid sequence was VPEGYAEDLLKGKMMRFFDS. Hydratase activity for 3-methylcrotonyl CoA was competitively inhibited by acetyl CoA, propionyl CoA and acetoacetyl CoA.

Topological phases near a triple degeneracy

We study the pattern of three-state topological phases that appears in systems with real Hamiltonians and wave functions. We give a simple geometric construction for representing these phases. We then apply our results to understand previous work on three-state phases. We show that the "mirror symmetry" of wave functions noticed in microwave experiments can be simply understood in our framework.