Robust manipulation of light using topologically protected plasmonic modes.

We propose using a topological plasmonic crystal structure composed of an array of nearly parallel nanowires with unequal spacing for manipulating light. In the paraxial approximation, the Helmholtz equation that describes the propagation of light along the nanowires maps onto the Schrödinger equation of the Su-Schrieffer-Heeger (SSH) model. Using a full three-dimensional finite difference time domain solution of the Maxwell equations, we verify the existence of topological defect modes, with sub-wavelength localization, bound to domain walls of the plasmonic crystal. We show that by manipulating domain walls we can construct spatial mode filters that couple bulk modes to topological defect modes, and topological beam-splitters that couple two topological defect modes. Finally, we show that the structures are tolerant to fabrication errors with an inverse length-scale smaller than the topological band gap.

Isolation, characterization, and evaluation of three Citrus sinensis-derived constitutive gene promoters.

KEY MESSAGE: Regulatory sequences from the citrus constitutive genes cyclophilin (CsCYP), glyceraldehyde-3-phosphate dehydrogenase C2 (CsGAPC2), and elongation factor 1-alpha (CsEF1) were isolated, fused to the uidA gene, and qualitatively and quantitatively evaluated in transgenic sweet orange plants. The 5' upstream region of a gene (the promoter) is the most important component for the initiation and regulation of gene transcription of both native genes and transgenes in plants. The isolation and characterization of gene regulatory sequences are essential to the development of intragenic or cisgenic genetic manipulation strategies, which imply the use of genetic material from the same species or from closely related species. We describe herein the isolation and evaluation of the promoter sequence from three constitutively expressed citrus genes: cyclophilin (CsCYP), glyceraldehyde-3-phosphate dehydrogenase C2 (CsGAPC2), and elongation factor 1-alpha (CsEF1). The functionality of the promoters was confirmed by a histochemical GUS assay in leaves, stems, and roots of stably transformed citrus plants expressing the promoter-uidA construct. Lower uidA mRNA levels were detected when the transgene was under the control of citrus promoters as compared to the expression under the control of the CaMV35S promoter. The association of the uidA gene with the citrus-derived promoters resulted in mRNA levels of up to 60-41.8% of the value obtained with the construct containing CaMV35S driving the uidA gene. Moreover, a lower inter-individual variability in transgene expression was observed amongst the different transgenic lines, where gene constructs containing citrus-derived promoters were used. In silico analysis of the citrus-derived promoter sequences revealed that their activity may be controlled by several putative cis-regulatory elements. These citrus promoters will expand the availability of regulatory sequences for driving gene expression in citrus gene-modification programs.

Quantum entanglement between an optical photon and a solid-state spin qubit.

Quantum entanglement is among the most fascinating aspects of quantum theory. Entangled optical photons are now widely used for fundamental tests of quantum mechanics and applications such as quantum cryptography. Several recent experiments demonstrated entanglement of optical photons with trapped ions, atoms and atomic ensembles, which are then used to connect remote long-term memory nodes in distributed quantum networks. Here we realize quantum entanglement between the polarization of a single optical photon and a solid-state qubit associated with the single electronic spin of a nitrogen vacancy centre in diamond. Our experimental entanglement verification uses the quantum eraser technique, and demonstrates that a high degree of control over interactions between a solid-state qubit and the quantum light field can be achieved. The reported entanglement source can be used in studies of fundamental quantum phenomena and provides a key building block for the solid-state realization of quantum optical networks.

Nanoscale magnetic sensing with an individual electronic spin in diamond.

Detection of weak magnetic fields with nanoscale spatial resolution is an outstanding problem in the biological and physical sciences. For example, at a distance of 10 nm, the spin of a single electron produces a magnetic field of about 1 muT, and the corresponding field from a single proton is a few nanoteslas. A sensor able to detect such magnetic fields with nanometre spatial resolution would enable powerful applications, ranging from the detection of magnetic resonance signals from individual electron or nuclear spins in complex biological molecules to readout of classical or quantum bits of information encoded in an electron or nuclear spin memory. Here we experimentally demonstrate an approach to such nanoscale magnetic sensing, using coherent manipulation of an individual electronic spin qubit associated with a nitrogen-vacancy impurity in diamond at room temperature. Using an ultra-pure diamond sample, we achieve detection of 3 nT magnetic fields at kilohertz frequencies after 100 s of averaging. In addition, we demonstrate a sensitivity of 0.5 muT Hz(-1/2) for a diamond nanocrystal with a diameter of 30 nm.

Proposal for a continuous wave laser with linewidth well below the standard quantum limit.

Due to their high coherence, lasers are ubiquitous tools in science. We show that by engineering the coupling between the gain medium and the laser cavity as well as the laser cavity and the output port, it is possible to eliminate most of the noise due to photons entering as well as leaving the laser cavity. Hence, it is possible to reduce the laser linewidth by a factor equal to the number of photons in the laser cavity below the standard quantum limit. We design and theoretically analyze a superconducting circuit that uses Josephson junctions, capacitors and inductors to implement a microwave laser, including the low-noise couplers that allow the design to surpass the standard quantum limit. Our proposal relies on the elements of superconducting quantum information, and thus is an example of how quantum engineering techniques can inspire us to re-imagine the limits of conventional quantum systems.

An embryogenic suspension cell culture system for Agrobacterium-mediated transformation of citrus.

A method for the genetic transformation of several citrus cultivars is described, including cultivars observed to be recalcitrant to conventional epicotyl-mediated transformation. Embryogenic cell suspension cultures, established from unfertilized ovules were used as target tissues for Agrobacterium-mediated transformation. Several modifications were made to the culture environment to investigate factors required for efficient transfer of the T-DNA and the subsequent regeneration of transgenic citrus plants. It was determined that co-cultivation of citrus cells and Agrobacterium in EME medium supplemented with maltose (EME-M) and 100 µM acetosyringone for 5 days at 25°C was optimum for transformation of each of the citrus cultivars. Efficient selection was obtained and escapes were prevented when the antibiotic hygromycin B was used as a selection antibiotic following transformation with an Agrobacterium strain containing hptII in the T-DNA region. Transgenic embryo regeneration and development was enhanced in medium that contained a liquid overlay consisting of a 1:2 mixture of 0.6 M BH3 and 0.15 M EME-M media. PCR and Southern blot analyses confirmed the presence of the T-DNA and the stable integration into the genome of regenerated plants, while RT-PCR demonstrated variable amounts of RNA being transcribed in different transgenic lines. This protocol can create an avenue for insertion of useful traits into any polyembryonic citrus cultivar that can be established as embryogenic cell suspension cultures, including popular specialty mandarins and seedless cultivars.

Larvicidal activity of neem and karanja oil cakes against mosquito vectors, Culex quinquefasciatus (say), Aedes aegypti (L.) and Anopheles stephensi (L.).

Larvicidal effect of neem (Azadirachta indica) and karanja (Pongamia glabra) oil cakes (individuals and combination) was studied against mosquito species. Both the oil cakes showed larvicidal activity against the mosquito species tested. The combination of neem and karanja oil cakes in equal proportion proved to have better effect than the individual treatments. The combination of the two oil cakes recorded an LC95 of 0.93, 0.54 and 0.77% against the mosquitoes, Culex quinquefasciatus, Aedes aegypti and Anopheles stephensi respectively The increase in efficacy of the combination treatment over individuals in all the mosquito larvae tested was found to range about 4 to 10 fold in terms of LC50 and 2 to 6 fold in terms of LC95.

Coronary risk factors in a rural community.

A cross-sectional health examination survey was carried out among a random sample of 406 people of 30 years and above from a rural community to investigate the prevalence of coronary heart disease risk factors. Prevalence of smoking and tobacco use was 16%, alcohol intake 9.4 %, daily Salt intake (> or = 5 gram) 34.2%, daily saturated fat intake ( > or =10 % of daily energy intake) 47.0 % and physical inactivity 18.5 %. BMI was > or =25 Kg /m(2) in 18 percent and it was > or =30 Kg / m(2) in 3.2 percent population. Truncal obesity (WHR: men> 0.9; women > 0.8) was found 18.5 percent more in case of males (20.7). Abdominal obesity(men > or =102; women > or = 88)was found 15.7 percent more in case of males (20.6).18.5 percent population was found suffering from systolic hypertension> or =140 mm Hg )and 15 percent from diastolic hypertension(> or =90 mm Hg). Awareness of CHD risk factors was present in 30.0 percent population. Differences in prevalence of riskfactor in male and female were found statistically significant in case of smoking, alcohol consumption and abdominal obesity. The present study shows that prevalence of CHD risk factors increases significantly in men and women having BMI equal or more than 25 Kg /m(2) so this cutoff, should be used to determine obesity in Indian population.

Proteomic analysis.

The field of proteomics is becoming increasingly important as genome sequences are being completed and annotated. Recent advances in proteomics include experimental and mathematical proofs of the need to complement microarray analysis with protein analysis, improved sensitivity for mass spectrometric analysis of separated proteins, better informatic tools for gel analysis and protein spot annotation, first steps towards automated experimental procedures, and new technology for quantitation of protein changes.

Computed tomography and EEG in herpes simplex encephalitis. Their value in diagnosis and prognosis.

Herpes simplex encephalitis (HSE) is associated with high mortality and morbidity, but these rates may be reduced by early administration of vidarabine. In six of 11 patients with the disease, the computed tomographic (CT) scan was of diagnostic value and showed low-density areas primarily in the temporal lobes; in only two of these six patients did the EEG point to the true diagnosis. Two of the six died. In the other five patients, the CT scan was normal or showed minor changes but the EEG was grossly abnormal. All five of these patients died. Information from CT scanning and the EEG should be combined for early diagnosis in HSE.

Unconjugated bilirubin in human bile: the nucleating factor in cholesterol cholelithiasis?

AIMS: To investigate the concentrations of bilirubin, bilirubin conjugates, phospholipid, and cholesterol in the gall bladder bile obtained at surgery from patients with and without cholesterol gallstones. METHODS: Gall bladder bile was collected during surgery, by puncture, from 20 patients with gallstones undergoing routine cholecystectomy and from eight patients with normal liver blood tests. Concentrations of bilirubin, bilirubin conjugates, phospholipid, and cholesterol were measured using standard procedures. RESULTS: The proportion of total bilirubin that was unconjugated was significantly higher in the bile from patients with stones than in bile from control patients, whether or not the bile from either group was saturated with cholesterol or not. Indeed, the mean concentration of cholesterol was significantly higher in control bile samples. CONCLUSION: The presence of stones was more closely related to the proportion of unconjugated bilirubin than to the degree of saturation of bile with cholesterol. Bilirubin and its metabolites probably play an important part in the formation of cholesterol gallstones.

A severe bullous eruption occurring in a patient with chronic active hepatitis and glomerulonephritis.

A patient with chronic active hepatitis and membranous glomerulonephritis acquired an acute, fatal illness characterized by a toxic erythematous desquamative dermatitis with bulla formation, fever, diarrhea, and hepatic and renal failure. The cutaneous histopathologic appearance resembled that found in erythema multiforme, toxic epidermal necrolysis, and the acute graft vs host reaction. The cutaneous eruption may have been part of a widespread atuoimmune reaction, possibly triggered by drugs or infection.

Sustained release of isoniazid from a single injectable dose of poly (DL-lactide-co-glycolide) microparticles as a therapeutic approach towards tuberculosis.

Drug delivery strategies to achieve a sustained drug release and increased bioavailability involve the use of biodegradable polymeric drug carriers. Poly (DL-lactide-co-glycolide) (PLG) microparticles were investigated as carriers for isoniazid (INH). In vitro and in vivo release of INH from different formulations of PLG microparticles was examined. In vitro experiments showed a sustained release of INH up to 6 days from non-porous microparticles while porous microparticles released INH over 3 days. Both porous and non-porous microparticles released INH in plasma for up to 2 days. Hardened PLG microparticles sustained release of INH for up to 7 weeks both in vitro and in vivo. The concentrations of INH obtained at all times were much higher than the minimum inhibitory concentration (MIC) of INH. Controls injected with free INH showed release of INH in plasma for up to 12 h and in organs for up to 24 h. There was no hepatotoxicity induced as compared with control animals. Taken together these results suggest that PLG-based antitubercular drugs may serve as ideal therapeutic agents for the treatment of tuberculous infections.

Liposomes and PLG microparticles as sustained release antitubercular drug carriers--an in vitro-in vivo study.

Liposomes and PLG microparticles were investigated as sustained release antitubercular drug carriers for isoniazid (INH) and rifampicin (RIF). In vitro release of drugs from liposomes showed a sustained release of INH and RIF up to 4 weeks. PLG microparticles exhibited a sustained release of INH and RIF up to 6 and 49 days, respectively. In vivo drug disposition studies from liposomes indicated a sustained release of INH in plasma and various tissues up to 24 h and 5 days, respectively, while release of rifampicin was obtained for 24 and 72 h in plasma and various tissues. In vivo drug disposition studies from PEG-PLG microparticles indicated a sustained release of INH up to 9 and 27 days in plasma and various tissues, while rifampicin was detected in plasma and lungs up to 12 h and 27 days. Hepatotoxicity studies revealed no toxicity induced using biochemical tests. PLG microparticles exhibited a more sustained release of antitubercular drugs than a liposomal carrier system.

Nitrate consumption and the incidence of gastric cancer in Singapore.

The nitrate content of a wide variety of vegetables, fruits and meat purchased in Singapore were determined by high-pressure liquid chromatography. From the 1982 statistical figures of retained imports and local production of these items the average per capita daily consumption of nitrates was calculated and found to be 215 mg, one of the highest reported figures in the world. Two vegetables are not so popular with the Malays and Indians who comprise 21% of the population. If their consumption of these vegetables is ignored then the per capita daily nitrate consumption of the Chinese population amounts to 250 mg and those of the Malays and Indians to 113 mg. Although these may be overestimates they do appear to show an association with the male gastric cancer incidence rates (age-adjusted) of 44.8 for the Chinese, 10.3 for Malays and 19.4 for the Indians. This could, however, be a chance association.

Sampling variability of liver biopsy in inflammatory bowel disease.

Sampling errors may occur when hepatic needle biopsy specimens are obtained for histologic examination. We obtained biopsy specimens from the right and left lobes of the livers of 29 patients who were to undergo surgery for inflammatory bowel disease. The histologic appearances of Kupffer's cell hyperplasia, fatty change, portal tract inflammation, and focal necrosis, but not giant cell granulomas, were well represented by a single specimen. The incidence of minor hepatic abnormalities was high and is likely to reflect the severity of the disease leading to surgery, but serious lesions were uncommon.

Feulgen staining of mammalian tissues fixed in picro-formol-acetic acid.

The paper describes a highly satisfactory method for in situ localization of DNA in tissues fixed in picro-formol-acetic acid or picro-formol-acetic-chromic acid mixtures following a technique in the Feulgen procedure as devised by the author. Mammalian tissues fixed in these fixatives can be hydrolysed in 6N HCl at 35 degrees C for 10 min, rinsed in water, stained with Schiff reagent after exposing the sections under UV light for 10 min, washed in water, dehydrated through a graduated series of ethanol, cleared in xylol and mounted in DPX. Sections of tissues fixed in picro-formol-acetic-chromic acid mixtures after acid hydrolysis when stained with an aqueous solution of basic fuchsin are also found to be very satisfactory for in situ localization of DNA.

Selective staining of animal chromosomes with synthetic dyes following iodine-dye-procedure.

The paper embodies results of the use of 51 synthetic dyes, belonging to different chemical groups for staining of animal chromosomes following iodine-dye procedure. It has been found that some of these dyes can replace gentian violet, crystal violet and safranin when used after this procedure. It has further been found that the fluorescent dyes, acriflavine and acridine yellow can also be used to stain animal chromosomes and that some of the dyes belonging to one chemical group can be successfully used whereas others of the same group are of no use. Dyes of the monoazo group are absolutely useless. Amongst the dyes successfully used, the preparations remain stable when stained with most of them except methyl green, malachite green, brillant green, iodine green and cresyl violet and amongst acid dyes, acid fuchsin. Cytochemical studies presented herein indicate that the components of the animal chromosomes stainable with crystal violet are the nucleic acids and that these substances should be highly polymerised and should not be even in a semi-degraded state. Removal of any one of these nucleic acids makes the chromosomes unstainable with iodine-crystal violet.

Recent progress in the staining of DNA-aldehyde in cell nuclei.

The paper is a review of studies on Feulgen staining of nuclear DNA. For convenience, the paper is split into several sections, such as (a) the characteristic of the dyes used for the manufacture of Schiff reagent (b) preparations of Schiff reagent (c) fixation of the material (d) hydrolysis (e) staining with Schiff reagent (f) Schiff-type dyes and (g) use of Schiff-type dyes in quantitative cytochemistry. Barring the section on preparation of Schiff reagent that includes the classical methods, all other sections contain a comprehenside account showing progress made during the last 15 years. Under each section interpretations of new findings as far as possible, and in the section on staining with Schiff reagent, new approaches to its study have been presented. The section on Schiff-type dyes includes dyes with and without primary amino group.

Saline flush: a simple method of reducing diazepam-induced thrombophlebitis.

Five hundred outpatients undergoing endoscopy were admitted into a controlled trial comparing the incidence of thrombophlebitis following intravenous diazepam administered in the way, with the effects of either a saline flush following the diazepam or diluting the drug with the patient's own blood before injection ('barbotage'). The results were assessed using a questionnaire completed by patients two weeks after endoscopy; 80% replied. A saline flush reduced the incidence of side effects, particularly pain (P less than 0.05). 'Barbotage' gave the highest incidence of side effects. Saline flush is therefore recommended as a means of reducing the thrombophlebitis which may follow intravenous diazepam.