Fabrication and characterization of talipot starch-based biocomposite film using mucilages from different plant sources: A comparative study

Biocomposite films were prepared by formulating talipot starch with plant mucilage derived from shoeblack leaves, okra, and seeds of basil, fenugreek, and flax, which were identified as SBM-TSF, OKM-TSF, BSM-TSF, FGM-TSF, and FXM-TSF, respectively. The plant mucilages enhanced the crosslinking of the filmogenic solutions, which increased the film's relative crystallinity. Upon topographical investigation, the biocomposite films exhibited the same compact and homogeneous structures as the native talipot starch film (NTSF), but with finer corrugations. When compared to NTSF, the addition of plant mucilage decreased the moisture content while increasing the thickness and opacity. SBM-TSF showed significantly reduced (p ≤ 0.05) solubility and water vapor permeability, indicating that increased crosslink formation in the film obstructed the water vapor passage. Among all the biocomposite films, the BSM-TSF had the greatest tensile strength, making it more resistant to stretching. Among the studied biocomposite films, SBM-TSF and BSM-TSF demonstrated improved thermal and biodegradation stability.

Interferenceless coded aperture correlation holography with synthetic point spread holograms

Lensless, interferenceless coded aperture correlation holography (LI-COACH) is an incoherent computational optical technique for three-dimensional (3D) imaging. In direct imaging, the image of the object is generated by a lens, whereas the LI-COACH is an indirect imaging technique that consists of two steps: one-time point spread hologram (PSH) training and then many times imaging of multiple-point objects. In the one-time training step, a point object moves in the object space along the optical axis. Light emitted from the point is modulated by a quasi-random phase mask, and the PSH library is recorded. In the imaging step, an object is mounted within the axial boundaries of the PSH library, and the object holograms are recorded using the same quasi-random phase masks. The 3D image of the object is reconstructed by the cross correlation of the object holograms with the PSH library. In this study, the entire PSH library is digitally synthesized from a single PSH, recorded at one plane only. The recorded PSH is scaled by magnification factors corresponding to the various axial planes. The reconstruction results from the synthetic PSH library are comparable with those from the recorded PSH library. The proposed approach can reduce the time of the training step in LI-COACH.

Spatial light modulator aided noninvasive imaging through scattering layers

We propose and demonstrate a new imaging technique to noninvasively see through scattering layers with the aid of a spatial light modulator (SLM). A relay system projects the incoherent light pattern emitting from the scattering layer onto the SLM. Two coded phase masks are displayed, one after another, on the SLM to modulate the projected scattered field and the two corresponding intensity patterns are recorded by a digital camera. The above procedure helps to achieve two goals. Firstly, since the coded phase masks are digitally synthesized, the point spread function of the imaging system can be engineered such that the image retrieval becomes more reliable. Secondly, the two recorded intensity patterns are subtracted one from the other and by that the background noise of the recovered image is minimized. The above two advantages along with a modified phase retrieval algorithm enable a relatively easier and accurate convergence to the image of the covered object.

Implementation of a speckle-correlation-based optical lever with extended dynamic range

A speckle-correlation-based optical lever (SC-OptLev) is constructed for the measurement of small changes in the orientation angle of a surface. The dynamic range of SC-OptLev is found to be twice that of a conventional OptLev for the same experimental configurations. Different filtering mechanisms are implemented, and the correlation results are compared. Two types of computer-automated SC-OptLevs, an open-source-based computing system with a low-cost image sensor and a commercial computing system, are presented with assistive computational modules.

Superresolution beyond the diffraction limit using phase spatial light modulator between incoherently illuminated objects and the entrance of an imaging system

We present a superresolution technique for imaging objects beyond the diffraction limit imposed by the limited numerical aperture (NA) of a general optical system. A coded phase mask (CPM) displayed on a spatial light modulator is introduced between the object and the input aperture of an ordinary lens-based imaging system. Consequently, the effective NA is increased beyond the inherent NA of the optical imaging system. Unlike conventional systems, the imaging in our proposed method is not direct from an object to a sensor, and the system requires a one-time calibration. In the calibration mode, a point object is mounted in the object plane, and the point spread intensity pattern is recorded. Following the calibration, the system is ready for imaging an arbitrary number of 2D objects. The intensity pattern from any object placed at the same axial location of the point object, and modulated by the same CPM, is recorded once by a digital camera. The superresolved image of the object is reconstructed by a nonlinear cross-correlation between the abovementioned two intensity patterns. The effective NA and the new resolution limit can be tuned by changing the scattering degree of the CPM.

Generation of structured light by multilevel orbital angular momentum holograms

Structured light has been created by a myriad of near-and far-field techniques and has found both classical and quantum applications. In the case of orbital angular momentum (OAM), continuous spiral phase patterns in dynamic or geometric phase are often employed with the phase patterns existing across the entire transverse plane. Here, we exploit the uncertain relationship between OAM and angle in order to create structured OAM fields by using multilevel OAM holograms. We show theoretically and experimentally that only a multilevel angular phase contour in the near-field is needed to create structured OAM light in the far-field, exploiting the reciprocal nature of angular momentum and angle. We use this approach to demonstrate exotic 3D structured light control to show the Poynting vector's evolution in such fields and to highlight the physics underlying this phenomenon.

Synthesis, Optical, Morphological and Magnetic Properties of Hematite Nanorods in Deep Eutectic Solvent with its Antibacterial and Photocatalytic Applications

Deep eutectic solvent comprising of choline chloride and D(+)-glucose was synthesized by mixing in the molar ratio 2:1. Iron oxide nanoparticles were successfully synthesized by co-precipitation method. Deep eutectic solvent consisting of D(+)-glucose acts as a promising reducing agent for the synthesis of iron oxide nanoparticles. Direct optical band gap of iron oxide nanoparticles was found to be 2.262 eV. Powder X-ray diffraction technique was used to identify the crystalline phases. Surface morphology analysis by Field emission scanning electron microscopy and high resolution transmission electron microscopy confirmed the rod shape structure of the iron oxide nanoparticles. Selected area electron diffraction pattern revealed the identity of lattice planes with the XRD data. The antibacterial and photocatalytic activities of the iron oxide nanoparticles were also studied. The synthesized iron oxide nanoparticles showed appreciable antibacterial and photocatalytic activities

Resolution enhancement in nonlinear interferenceless COACH with point response of subdiffraction limit patterns

Interferenceless coded aperture correlation holography (I-COACH) is a non-scanning, motionless, incoherent digital holography technique for 3D imaging. The lateral and axial resolutions of I-COACH are equivalent to those of conventional direct imaging with the same numerical aperture. The main component of I-COACH is a coded phase mask (CPM) used as the system aperture. In this study, the CPM has been engineered using a modified Gerchberg-Saxton algorithm to generate a random distribution of subdiffraction spot arrays on the digital camera as a system response to a point source illumination. A library of point object holograms is created to calibrate the system for imaging different lateral sections of a 3D object. An object is placed within the calibrated 3D space and an object hologram is recorded with the same CPM. The various planes of the object are reconstructed by a non-linear cross-correlation between the object hologram and the point object hologram library. A lateral resolution enhancement of about 25% was noted in the case of I-COACH compared to direct imaging.

Non-linear adaptive three-dimensional imaging with interferenceless coded aperture correlation holography (I-COACH)

Interferenceless coded aperture correlation holography (I-COACH) is an incoherent digital holography technique for imaging 3D objects without two-wave interference. In I-COACH, the object beam is modulated by a pseudorandom coded phase mask (CPM) and propagates to the camera where its intensity pattern is recorded. The image of the object is reconstructed by a cross-correlation of the object intensity pattern with a point intensity response of the system, whereas the light from both the object and the point, are modulated by the same CPM. In order to recover the image of the object without bias level and background noise, multiple intensity recordings are necessary for both objects as well as the point object, which in turn significantly reduces the time resolution of imaging. In this study, a non-linear reconstruction technique is developed to reconstruct the image of the object with only a single camera shot. Furthermore, the proposed technique is adaptive to different experimental conditions in the sense of finding different optimal parameters for each experiment. The new method has been implemented on a regular I-COACH system in both transmission as well as reflection illumination modes.

A selective and sensitive high performance liquid chromatography assay for the determination of cycloserine in human plasma

BACKGROUND

Cycloserine (CYC) is a second line antitubercular drug that is used for the treatment of multidrug resistant tuberculosis (MDR-TB) along with other antitubercular agents and is often used in developing countries. Monitoring CYC levels in plasma could be useful in the clinical management of patients with MDR-TB. A high performance liquid chromatography method for the determination of CYC in human plasma was developed.

METHODS

The method involved extraction of the sample using solid phase extraction cartridges and analysis of the extracted sample using a reverse phase T3 column (150mm) and detection at 240nm with Photo Diode Array (PDA) detector. The chromatogram was run for 15min at a flow rate of 0.4ml/min at 30°C.

RESULTS AND CONCLUSION

The assay was specific for CYC and linear from 5.0 to 50.0μg/ml. The relative standard deviations of within- and between-day assays were less than 10%. Recovery of CYC ranged from 102% to 109%. The interference of other second line anti-TB drugs in the assay of CYC was ruled out. The assay spans the concentration range of clinical interest. The specificity and sensitivity of this assay makes it highly suitable for pharmacokinetic studies.

Extending the field of view by a scattering window in an I-COACH system

Interferenceless coded aperture correlation holography (I-COACH) is an incoherent digital holography technique developed to record and reconstruct 3D images of objects without two-wave interference. Herein, we introduce a novel technique to extend the field of view (FOV) of I-COACH beyond the limit imposed by the ratio between the finite area of the image sensor and the magnification of the optical system. Light diffracted from a point object located on the optical axis is modulated by a pseudorandom coded phase mask, and the central part of the point spread hologram (PSH) on the image sensor is recorded. The point object is shifted laterally to predetermined lateral locations in order to collect the exterior parts of the PSH. The recorded PSHs are stitched together to produce a synthetic PSH (SPSH) with an area nine times that of any individual PSH recorded by the image sensor. An object with a lateral extent beyond the FOV limit of the image sensor is placed at the same axial location as the point object, and the object hologram is recorded. The object is reconstructed by a cross-correlation between the zero-padded object hologram and the SPSH. Hence, the object parts beyond the FOV limit of the image sensor are recovered. An SPSH library is created for different axial planes, and the corresponding axial planes of the object are reconstructed.

Pharmacokinetics of thrice-weekly rifampicin, isoniazid and pyrazinamide in adult tuberculosis patients in India

OBJECTIVE

To study the pharmacokinetics of rifampicin (RMP), isoniazid (INH) and pyrazinamide (PZA) in adult tuberculosis (TB) patients and examine factors that influence drug pharmacokinetics.

METHODS

Adult TB patients (n = 101) receiving thrice-weekly anti-tuberculosis treatment in the Revised National TB Control Programme (RNTCP) were studied. The study was conducted at steady state after directly observed drug administration. RMP, INH and PZA concentrations were estimated using high-performance liquid chromatography and NAT2 genotyping by real-time polymerase chain reaction.

RESULTS

RMP peak concentration (Cmax) was sub-therapeutic (<8 μg/ml) in 88% of the patients. The Cmax of RMP, INH and PZA at 2 h was observed in respectively 83.2%, 97.0% and 92.1% of the patients. The Cmax and area under the curve from 0 to 8 h (AUC0-8) of PZA was lower in TB patients with diabetes mellitus than in non-diabetics. Significant associations were observed between the Cmax and the AUC0-8 of RMP, INH and PZA with drug doses; RMP with category of treatment; INH with smoking, body mass index and N-acetyl transferase 2 genotype; and PZA with sex and smoking.

CONCLUSIONS

Several risk factors for drug concentration variations were identified. Two-hour post-dosing drug concentrations mimicked Cmax. A high proportion of TB patients had RMP Cmax below the expected range, which is a matter of concern.

3D Imaging through Scatterers with Interferenceless Optical System

Imaging through a scattering medium is a challenging task. We propose and demonstrate an interferenceless incoherent opto-digital technique for 3D imaging through a scatterer with a single lens and a digital camera. The light diffracted from a point object is modulated by a scattering mask. The modulated wavefront is projected on an image sensor using a spherical lens and the impulse response is recorded. An object is placed at the same axial location as the point object and another intensity pattern is recorded with identical experimental conditions and with the same scattering mask. The image of the object is reconstructed by a cross-correlation between a reconstructing function and the object hologram. For 3D imaging, a library of reconstructing functions are created corresponding to different axial locations. The different planes of the object are reconstructed by a cross-correlation of the object hologram with the corresponding reconstructing functions.

Single camera shot interferenceless coded aperture correlation holography

We propose a new scheme for recording an incoherent digital hologram by a single camera shot. The method is based on a motionless, interferenceless, coded aperture correlation holography for 3D imaging. Two random-like coded phase masks (CPMs) are synthesized using the Gerchberg-Saxton algorithm with two different initial random phase profiles. The two CPMs are displayed side by side and used as the system aperture. Light from a pinhole is introduced into the system, and two impulse responses are recorded corresponding to the two CPMs. The two impulse responses are subtracted, and the resulting intensity profile is used as a reconstructing hologram. A library of reconstructing holograms is created corresponding to all possible axial locations. Following the above training stage, an object is placed within the axial limits of the library, and the intensity patterns of a single shot, corresponding to the same two CPMs, are recorded under identical conditions to generate the object hologram. The image of the object at any plane is reconstructed by a cross-correlation between the object hologram and the corresponding reconstructing hologram from the library.

Incoherent digital holograms acquired by interferenceless coded aperture correlation holography system without refractive lenses

We present a lensless, interferenceless incoherent digital holography technique based on the principle of coded aperture correlation holography. The acquired digital hologram by this technique contains a three-dimensional image of some observed scene. Light diffracted by a point object (pinhole) is modulated using a random-like coded phase mask (CPM) and the intensity pattern is recorded and composed as a point spread hologram (PSH). A library of PSHs is created using the same CPM by moving the pinhole to all possible axial locations. Intensity diffracted through the same CPM from an object placed within the axial limits of the PSH library is recorded by a digital camera. The recorded intensity this time is composed as the object hologram. The image of the object at any axial plane is reconstructed by cross-correlating the object hologram with the corresponding component of the PSH library. The reconstruction noise attached to the image is suppressed by various methods. The reconstruction results of multiplane and thick objects by this technique are compared with regular lens-based imaging.

Interferenceless coded aperture correlation holography-a new technique for recording incoherent digital holograms without two-wave interference

Recording digital holograms without wave interference simplifies the optical systems, increases their power efficiency and avoids complicated aligning procedures. We propose and demonstrate a new technique of digital hologram acquisition without two-wave interference. Incoherent light emitted from an object propagates through a random-like coded phase mask and recorded directly without interference by a digital camera. In the training stage of the system, a point spread hologram (PSH) is first recorded by modulating the light diffracted from a point object by the coded phase masks. At least two different masks should be used to record two different intensity distributions at all possible axial locations. The various recorded patterns at every axial location are superposed in the computer to obtain a complex valued PSH library cataloged to its axial location. Following the training stage, an object is placed within the axial boundaries of the PSH library and the light diffracted from the object is once again modulated by the same phase masks. The intensity patterns are recorded and superposed exactly as the PSH to yield a complex hologram of the object. The object information at any particular plane is reconstructed by a cross-correlation between the complex valued hologram and the appropriate element of the PSH library. The characteristics and the performance of the proposed system were compared with an equivalent regular imaging system.

Coded aperture correlation holography system with improved performance [Invited]

Coded aperture correlation holography (COACH) is a recently introduced technique for recording incoherent digital holograms of general three-dimensional scenes. In COACH, a random-like coded phase mask (CPM) is used as a coded aperture. Even though the CPM is optimized to reduce background noise, there is still a substantial amount of noise, mitigating the performance of COACH. In order to reduce the noise, we first modify the hologram reconstruction method. Instead of computing the correlation between a complex hologram of the entire object and a hologram of a source point, in this study the numerical correlation is performed with a phase-only filter. In other words, the phase function of the Fourier transform of the source point hologram is used as the spatial filter in the correlation process. Furthermore, we propose and demonstrate two additional methods for reducing the background noise in COACH. The first is based on the integration of a quadratic phase function, as used in Fresnel incoherent correlation holography (FINCH), with the CPM of COACH. This hybrid COACH-FINCH system enables a dynamic trade-off between the amount of background noise and the axial resolution of the system. The second method is employed by recording COACH holograms with multiple independent CPMs and averaging over the reconstructed images. The results of the above two techniques are compared with FINCH and with a regular imaging system.

Experimental demonstration of square Fresnel zone plate with chiral side lobes

In this study, we introduce what we believe is a novel holographic optical element called a chiral square Fresnel zone plate (CSFZP). The chirality is imposed on a square Fresnel zone plate (SFZP) using a nonclassical technique by rotating the half-period zones relative to one another. The rotation of the half-period zones, in turn, twists the side lobes of the diffraction pattern without altering the focusing properties inherent to a SFZP. As a consequence, the beam profile is hybrid, consisting of a strong central Gaussian focal spot with gradient force similar to that generated by a lens and twisted side lobes with orbital angular momentum. The optical fields at the focal plane were calculated and found to possess a whirlpool-phase profile and a twisted intensity profile. Analysis of the field variation along the direction of propagation revealed a spiraling phase and amplitude distribution. Poynting vector plot of the fields revealed the presence of angular momentum in the regions of chiral side lobes. The phase of the CSFZPs were displayed on a phase-only reflective spatial light modulator and illuminated using a laser. The intensity patterns recorded in the experiment match the calculated ones, with a strong central focal spot and twisted side lobes. The beam pattern was implemented in an optical trapping experiment and was found to possess particle trapping capabilities.

Spectrum and space resolved 4D imaging by coded aperture correlation holography (COACH) with diffractive objective lens

In this Letter, we present an advanced optical configuration of coded aperture correlation holography (COACH) with a diffractive objective lens. Four-dimensional imaging of objects at the three spatial dimensions and with an additional spectral dimension is demonstrated. A hologram of three-dimensional objects illuminated by different wavelengths was recorded by the interference of light diffracted from the objects with the light diffracted from the same objects, but through a random-like coded phase mask (CPM). A library of holograms denoted point spread function (PSF) holograms were prerecorded with the same CPM, and under identical conditions, using point objects along different axial locations and for the different illuminating wavelengths. The correlation of the object hologram with the PSF hologram recorded using a particular wavelength, and at a particular axial location, reconstructs only the object corresponding to the particular axial plane and to the specific wavelength. The reconstruction results are compared with regular imaging and with another well-established holographic technique called Fresnel incoherent correlation holography.

Coded aperture correlation holography-a new type of incoherent digital holograms

We propose and demonstrate a new concept of incoherent digital holography termed coded aperture correlation holography (COACH). In COACH, the hologram of an object is formed by the interference of light diffracted from the object, with light diffracted from the same object, but that passes through a coded phase mask (CPM). Another hologram is recorded for a point object, under identical conditions and with the same CPM. This hologram is called the point spread function (PSF) hologram. The reconstructed image is obtained by correlating the object hologram with the PSF hologram. The image reconstruction of multiplane object using COACH was compared with that of other equivalent imaging systems, and has been found to possess a higher axial resolution compared to Fresnel incoherent correlation holography.

Enhanced super resolution using Fresnel incoherent correlation holography with structured illumination

The structured illumination (SI) technique has already been well established as a resolution enhancer in many studies and well demonstrated in many optical imaging systems during the past decade. The ability to use the SI in incoherent imaging systems was also introduced, especially in fluorescence microscopy. In this Letter, we propose and demonstrate a new approach to combine the SI technique with the recently innovated motionless incoherent holographic system, called Fresnel incoherent correlation holography (FINCH), in order to enhance the resolution beyond the limits achieved in regular imaging with SI. The results obtained by use of SI-FINCH were compared against regular imaging, regular FINCH and SI-imaging.

A clinical study on drug-related problems associated with intravenous drug administration

Background:

Infusion therapy through intravenous (IV) access is a therapeutic option used in the treatment of many hospitalized patients. IV therapy is complex, potentially dangerous and error prone. The objectives were to ascertain the drug-related problems (DRPs) involved in IV medication administration and further to develop strategies to reduce and prevent the occurrence of DRPs during IV administration.

Materials and Methods:

A prospective observational study was carried out for a period of 4 months. Patients receiving more than two medications through IV route were included and studied.

Results:

Of 110 patients, 76 (69.09%) were male and the rest were female. Nearly, half of the patients (46.3%, n = 51) were reported with DRPs. Of the 80 DRPs (72.72%) documented, 61 problems (55.4%) were seen in patients given IV medications through peripheral line. Among the DRPs majority seen were incompatibilities (40.9%, n = 45), followed by complications developed (12.7%, n = 14), errors in rate of administration (10.9%), and dilution errors (8%). To study the association of DRPs among gender, statistical analysis was performed and significant association was seen between DRPs and gender (P = 0.03).

Conclusion:

Among the reported DRPs, simultaneous IV administration of two incompatible drugs was the main predicament faced.

Quasi-achromatic Fresnel zone lens with ring focus

The phase of a standard Fresnel zone lens (FZL) is periodically modulated in the radial direction using the phase of a binary fraxicon. The resulting element (rf-FZL) focuses light into a ring. The ring is found to be quasi-achromatic, in that the diameter is wavelength independent but its location is not. The binary rf-FZL is fabricated using electron beam direct writing. Experimental results confirm the generation of a wavelength-independent ring pattern at the focus of the rf-FZL. An efficiency of 24% was obtained. The variation in radius of ring pattern was reduced from 61 μm to less than 10 nm for a corresponding wavelength variation from 532 to 633 nm.

Characterization and correction of spherical aberration due to glass substrate in the design and fabrication of Fresnel zone lenses

As with a conventional lens, a Fresnel zone lens (FZL) can be used to image objects at infinity or nearby. In the latter case, the FZL converts a diverging spherical wavefront into a converging spherical wavefront. The glass substrate on which the FZL is fabricated introduces spherical aberration resulting in a shift of the image plane and blurring of the image. Two novel schemes for correction of this spherical aberration are proposed and studied in this paper. To demonstrate them, FZLs are designed with and without aberration correction. They are fabricated using electron beam direct writing. The devices are evaluated and the accuracy of the proposed aberration correction schemes is validated.

Current knowledge and future direction of research on soy isoflavones as a therapeutic agents

Isoflavones, the most abundant phytoestrogens in Soy beans, are structurally similar to 17beta-estradiol. The antioxidant property of the soy isoflavones, namely, genistein and daidzein is well established in different experimental models and also in clinical studies. The compounds have been found effective in the management of diabetes by acting on peroxisome proliferator-activated receptors. It reduces the risk of coronary heart disease by reducing the level of low-density lipoprotein and triglycerides. Soy isoflavones have the potential in the treatment of osteoporosis to act on osteoclasts further to inhibit tyrosine kinase. Among the soy isoflavones, genistein is the potential compound found effective in the treatment of cancer by acting on androgen receptor further to inhibit tyrosine kinases. In this article, various aspects of the diverse biological activities of soy isoflavones and their potential clinical implications with mechanism of action, especially in the treatment and prevention of diabetes, cardiovascular diseases, cancer, osteoporosis, neuroprotection, and also future area of research on soy isoflavones are reviewed and discussed.

Design, fabrication, and evaluation of a multilevel spiral-phase Fresnel zone plate for optical trapping

A compact optics configuration for the generation of donut beams for trapping atoms at the micrometer scale using a multilevel spiral-phase Fresnel zone plate (FZP) and a semiconductor laser is proposed. A FZP is designed and a multilevel spiral phase is integrated into it. A spiral-phase FZP with a radius of 1 mm and with more than 1300 half-period zones is designed with multiple angular levels for integer and fractional topological charges, and the device is fabricated using electron-beam lithography direct writing. The performance of the device is evaluated, and the generation of symmetric and asymmetric donut beams is successfully demonstrated.

Phase-shifted Fresnel axicon

We propose an optical element: a phase-shifted Fresnel axicon for generation of multiple Bessel beams. By giving a binary phase modulation to the standard Fresnel axicon, the proposed element is generated. The phase profile of the binary phase modulation is engineered to generate two and three Bessel beams of equal intensities. This composite optical element is fabricated using electron beam direct writing. The performance of the fabricated device is evaluated using a semiconductor laser, and the generation of two and three Bessel beams is successfully demonstrated.

Physical and functional interaction between polyoma virus middle T antigen and insulin and IGF-I receptors is required for oncogene activation and tumour initiation

Polyoma virus middle T antigen (PyVmT) is a powerful viral oncogene; however, the mechanisms of PyVmT activation are poorly understood. The insulin-like growth factor I receptor (IGF-IR) and the insulin receptor (IR) are known to be implicated in the development of many cancers. Furthermore, PyVmT-overexpressing mouse mammary carcinoma Met-1 cells are highly responsive to IGF-I and insulin. Herein, we demonstrate that PyVmT physically interacts with IGF-IR and IR in Met-1 cells. Insulin and IGF-I increase association of the IR and IGF-IR with PyVmT, enhance tyrosine phosphorylation of PyVmT and augment the recruitment of Src and PLCgamma(1) to PyVmT. This is accompanied by robust and sustained phosphorylation of Akt and ERK1/2, which are implicated in both PyVmT and IGF-IR/IR signalling. Both ligands significantly increase proliferation, survival, migration and invasion of Met-1 cells. Furthermore, orthotopic inoculation of Met-1 cells with shRNAmir-mediated knockdown of IR or IGF-IR fails to initiate tumour growth in recipient mice. In conclusion, our data indicate that the physical and functional interaction between PyVmT and cellular receptor tyrosine kinases, including IR and IGF-IR, is critical for PyVmT activation and tumour initiation. These results also provide a novel mechanism for oncogene activation in the host cell.

Obesity and type 2 diabetes are associated with an increased risk of developing cancer and a worse prognosis; epidemiological and mechanistic evidence

Both obesity and Type 2 diabetes are independently associated with an increased risk of developing cancer and an increased mortality. The etiology is yet to be determined but insulin resistance and hyperinsulinemia maybe important factors. Hyperglycemia, hyperlipidemia and inflammatory cytokines in addition to the insulin-like growth factors are also possible factors involved in the process.

Insulin-like growth factor-I protects cells from ER stress-induced apoptosis via enhancement of the adaptive capacity of endoplasmic reticulum

Disruption of endoplasmic reticulum (ER) homeostasis causes accumulation of unfolded and misfolded proteins in the ER, triggering the ER stress response, which can eventually lead to apoptosis when ER dysfunction is severe or prolonged. Here we demonstrate that human MCF-7 breast cancer cells, as well as murine NIH/3T3 fibroblasts, are rescued from ER stress-initiated apoptosis by insulin-like growth factor-I (IGF-I). IGF-I significantly augments the adaptive capacity of the ER by enhancing compensatory mechanisms such as the IRE1 alpha-, PERK- and ATF6-mediated arms of ER stress signalling. During ER stress, IGF-I stimulates translational recovery and induces expression of the key molecular chaperone protein Grp78/BiP, thereby enhancing the folding capacity of the ER and promoting recovery from ER stress. We also demonstrate that the antiapoptotic activity of IGF-I during ER stress may be mediated by a novel, as yet unidentified, signalling pathway(s). Application of signal transduction inhibitors of MEK (U1026), PI3K (LY294002 and wortmannin), JNK (SP600125), p38 (SB203580), protein kinases A and C (H-89 and staurosporine) and STAT3 (Stattic) does not prevent IGF-I-mediated protection from ER stress-induced apoptosis. Taken together, these data demonstrate that IGF-I protects against ER stress-induced apoptosis by increasing adaptive mechanisms through enhancement of ER stress-signalling pathways, thereby restoring ER homeostasis and preventing apoptosis.

Neuronal spike trains with exponential decay

Stochastic models for the spike discharge activity of neurons are analyzed. Model I treats only excitatory impulses occurring as Poisson events with exponential density of the jump magnitude, and, in the absence of these events, the subthreshold potential decays exponentially. A closed solution for the Laplace transform of the renewal density of the discharge is obtained by the imbedding method. Model III takes care of both excitatory and inhibitory impulses with exponential decay of the subthreshold potential between the jumps. Analytical closed solutions for the first passage problem are obtained in this care also. The mean interval time between the spikes and the stationary density of firing are obtained.

Mercury concentrations in recent and ninety-year-old benthopelagic fish

Several species of bottom-dwelling fish from 2500 meters with similar feeding habits had mercury concentrations that differed by an order of magnitude. Within one species there was a correlation between size and concentration, with the larger individuals having mercury concentrations as high as 0.8 part per million (wet weight). The mercury content of the water in the deep-ocean habitat of these fish appears not to determine the mercury content of a particular fish; species-specific factors and size do appear to determine this concentration. The species-specific variation between the recent fish also existed between the same two species in specimens collected 90 years ago from a depth of 2000 meters, and a 90-year-old specimen fit closely the size-concentration regression curve for nine recent individuals of the same species.