Author Correction: Towards 5G: A Photonic Based Millimeter Wave Signal Generation for Applying in 5G Access Fronthaul.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The impact of ZnO configuration as an external layer on the sensitivity of a bi-layer coated polymer optical fiber probe.

Salinity magnitude changes are a critical factor for determining the chemistry of natural water bodies and biological processes. Label-free refractive index sensors are promising devices for detecting these changes. A polymer optical fiber (POF) sensor modified with cladding treatment and a bi-layer zinc oxide/silver (ZnO/Ag) nanostructure coating to determine sodium chloride concentration changes through refractive index variations in water is experimentally demonstrated. The use of three ZnO nanostructure shapes, nanoparticles and horizontally and vertically oriented nanorods, as an external layer and a broad spectrum light source from the visible (Vis) to the near infrared (NIR) region are investigated to achieve optimum sensitivity. The rms roughness, optical band-gap and zeta potential (ZP) value for the vertically oriented sample are 148 nm, 3.19 eV and 5.96 mV, respectively. In the NIR region the wavelength-intensity sensitivity values of probes coated with ZnO nanoparticles and horizontally and vertically oriented nanorods are 104 nm RIU-1-12 dB RIU-1, 63 nm RIU-1-10 dB RIU-1 and 146 nm RIU-1-22 dB RIU-1, respectively, and in the Vis area the values are 65 nm RIU-1-14 dB RIU-1, 58 nm RIU-1-11 dB RIU-1 and 89 nm RIU-1-23 dB RIU-1, respectively. The maximum amplitude sensitivity is obtained for the probe coated with vertically aligned ZnO nanorods in the NIR area due to the deeper penetration of evanescent waves, a higher surface-volume ratio, better crystallinity, more adhesive interactions with salt molecules, larger surface roughness and higher-order dispersion compared to the other coated ZnO nanostructures.

Multifunction interferometry using the electron mobility visibility and mean free path relationship.

A conventional Michelson interferometer is modified and used to form the various types of interferometers. The basic system consists of a conventional Michelson interferometer with silicon-graphene-gold embedded between layers on the ports. When light from the monochromatic source is input into the system via the input port (silicon waveguide), the change in optical path difference (OPD) of light traveling in the stacked layers introduces the change in the optical phase, which affects to the electron mean free path within the gold layer, induces the change in the overall electron mobility can be seen by the interferometer output visibility. Further plasmonic waves are introduced on the graphene thin film and the electron mobility occurred within the gold layer, in which the light-electron energy conversion in terms of the electron mobility can be observed, the gold layer length is 100 nm. The measurement resolution in terms of the OPD of ∼ 50 nm is achieved. In applications, the outputs of the drop port device of the modified Michelson interferometer can be arranged by the different detectors, where the polarized light outputs, the photon outputs, the electron spin outputs can be obtained by the interference fringe visibility, mobility visibility and the spin up-down splitting output energies. The modified Michelson interferometer theory and the detection schemes are given in details.

Effect of organic ligand-decorated ZnO nanoparticles as a cathode buffer layer on electricity conversion efficiency of an inverted solar cell.

Efficiency improvement of the industrial scale solar cells to capture sunlight as an important renewable energy source is attracting significant attention to prevent the consumption of a finite supply of unsustainable fossil fuels. ZnO nanoparticles decorated with an imine-linked receptor have been used in the fabrication of a photocathode based on dye-sensitized solar cells for the purpose of photovoltaic efficiency enhancement. Various characterization techniques have been employed to investigate the structural, morphological, and optical behaviors of the solar cell having ZnO nanoparticles and ZnO nanoparticles decorated with an organic ligand as a photocathode layer. The decorated nanoparticles have a stable wurtzite structure and an average grain size of ∼45 nm, confirmed by the TEM image and XRD through the Scherrer equation. The ZnO sample emits wide peaks in the visible range, and the emission intensity of the ZnO-DOL sample increases along with a red-shift (0.38 eV) in the band gap. This shift can be explained using deep level transition, surface plasmon energy of a surfactant, and coupling of ZnO with local surface plasmon energy. UV-vis absorption spectra together with photoluminescence spectra confirm the higher absorption rate due to organic ligand decoration on ZnO nanoparticles. The greatest solar power-to-electricity conversion efficiency (η) of 3.48% is achieved for the ZnO-DOL sample. It is enhanced by 3.13% as compared to that of the ZnO-based solar cell. The ZnO-DOL device exhibits a higher external quantum efficiency (EQE), responsivity (R λ), and photocurrent-to-dark current ratio; this confirms the improvement in the solar cell performance.

Towards 5G: A Photonic Based Millimeter Wave Signal Generation for Applying in 5G Access Fronthaul.

5G communications require a multi Gb/s data transmission in its small cells. For this purpose millimeter wave (mm-wave) RF signals are the best solutions to be utilized for high speed data transmission. Generation of these high frequency RF signals is challenging in electrical domain therefore photonic generation of these signals is more studied. In this work, a photonic based simple and robust method for generating millimeter waves applicable in 5G access fronthaul is presented. Besides generating of the mm-wave signal in the 60 GHz frequency band the radio over fiber (RoF) system for transmission of orthogonal frequency division multiplexing (OFDM) with 5 GHz bandwidth is presented. For the purpose of wireless transmission for 5G application the required antenna is designed and developed. The total system performance in one small cell was studied and the error vector magnitude (EVM) of the system was evaluated.

A Stable Dual-wavelength Thulium-doped Fiber Laser at 1.9 µm Using Photonic Crystal Fiber.

A stable dual-wavelength thulium-doped fiber laser operating at 1.9 µm using a short length of photonic crystal fiber (PCF) has been proposed and demonstrated. The photonics crystal fiber was 10 cm in length and effectively acted as a Mach-Zehnder interferometry element with a free spectral range of 0.2 nm. This dual-wavelength thulium-doped fiber laser operated steadily at room temperature with a 45 dB optical signal-to-noise-ratio.

Increment of Access Points in Integrated System of Wavelength Division Multiplexed Passive Optical Network Radio over Fiber.

This paper describes a novel technique to increase the numbers of access points (APs) in a wavelength division multiplexed-passive optical network (WDM-PON) integrated in a 100 GHz radio-over-fiber (RoF). Eight multi-carriers separated by 25 GHz intervals were generated in the range of 193.025 to 193.200 THz using a microring resonator (MRR) system incorporating an add-drop filter system. All optically generated multi-carriers were utilized in an integrated system of WDM-PON-RoF for transmission of four 43.6 Gb/sec orthogonal frequency division multiplexing (OFDM) signals. Results showed that an acceptable BER variation for different path lengths up to 25 km was achievable for all four access points and thus the transmission of four OFDM channels is feasible for a 25 km standard single mode fiber (SSMF) path length.

Effects of hydrostatic pressure on mouse sperm.

OBJECTIVES: The objective of this study was to investigate the abnormalities in sperm after exposure to hydrostatic pressure. BACKGROUND: Hydrostatic pressure acting on the cells is one of the fundamental environmental mechanical forces. Disorders of relationship between the cells and this mechanical force, such as when pressure varies beyond physiological limits, can lead to disease or pathological states. Sperm exposed to different range of hydrostatic pressure within male reproductive system and after entering the female reproductive system. METHODS: Sexually mature male NMRI mice, 8-12 weeks-old were sperm donors. Sperms were separated from the caudal epididymis and maintained in Ham's F-10 culture medium supplemented with 10 % FBS and divided into control and treatments. Sperm suspensions in the treatments were placed within pressure chamber and were subjected to increased hydrostatic pressure of 25, 50 and 100 mmHg (treatment I, II and III) above atmospheric pressure for 2 and 4 h. Sperm viability, motility, morphology, DNA integrity and fertilizing ability were assessed and compared with control. RESULTS: Results showed that hydrostatic pressure dependent on ranges and time manner reduced sperm quality due to adverse effect on viability, motility , morphology, DNA integrity and fertilizing ability in all of treatments, especially after 4h (p<0.05). CONCLUSION: Our data revealed hydrostatic pressure reduces sperm quality as a consequence of adverse effects on sperm parameters and may cause male infertility or subfertility (Tab. 5, Ref. 5).

Generation and transmission of 3 × 3 W-Band multi-input multi-output orthogonal frequency division multiplexing-radio-over-fiber signals using micro-ring resonators.

Using the micro-ring resonator (MRR) system, the single and multi-carriers at frequencies of f(1)=192.898, f(2)=192.990, f(3)=193.1, f(4)=193.315, and f(5)=193.537 THz with a free spectral range (FSR) of 92, 110, 215, and 222 GHz, respectively, are generated to be suitable for a radio-over-fiber (RoF) system based on multi-input multi-output (MIMO) with orthogonal frequency division multiplexing (OFDM). Demonstrated are the concepts of all-optical MIMO signal generation and its transmission over a 50 km single mode fiber (SMF) optical link and an up to 3 m wireless link. Sixty-four multi-carriers are used in the all-optical generation of three MIMO W-Band RF signals, where the single carriers (f(3)-f(5)) transport the signals over the RoF link. The bit error rate (BER) of the overall system performance is discussed; thus, the transmission of MIMO signals is feasible for up to an SMF path 50 km long and a wireless distance of 3 m.

Increased receptor for advanced glycation end products in spermatozoa of diabetic men and its association with sperm nuclear DNA fragmentation.

Although the majority of patients with diabetes have disorders in sexual function, associations between diabetes mellitus and sperm function at the molecular level are largely unknown. As receptor for advanced glycation end products plays a key role in many diabetic complications, we hypothesised that it may be involved in sperm nuclear DNA fragmentation. RAGE levels were determined using ELISA and western blot analysis in sperm samples from 32 diabetic and 35 nondiabetic men. Sperm DNA fragmentation was assessed using TUNEL assay. Diabetic men had significantly higher mean levels of RAGE protein (P < 0.001) and DNA fragmentation (P < 0.001) in spermatozoa. Sperm RAGE was directly correlated to sperm DNA fragmentation in diabetic men (r = 0.81, P < 0.001). The high positive correlation between RAGE levels and nuclear DNA fragmentation in spermatozoa of diabetic men suggests a central role of RAGE in disturbances in sexual function of diabetic men.

Relationship between advanced glycation end products and increased lipid peroxidation in semen of diabetic men.

AIMS: Majority of diabetic male patients have disturbances in their reproductive systems. However, the mechanisms underlying these disturbances are largely unknown. Since advanced glycation end products (AGE) have a key role in oxidative stress and cell damage in diabetic complications, we hypothesize that AGEs may be involved sperm lipid peroxidation. METHODS: total AGEs in seminal plasma of 32 diabetic and 35 non-diabetic men was determined by spectrofluorimetric method and carboxy methyl lysine (CML) level was assayed using ELISA. Contents of lipid peroxidation in sperm and seminal plasma were determined by thiobarbituric acid reaction. Total antioxidant capacity (TAC) was measured by a colorimetric assay. RESULTS: total AGEs were found significantly higher in seminal plasma of diabetic men than non-diabetic group (p<0.001) whereas no significant differences in seminal plasma CML values between two groups was observed. Moreover, sperm and seminal plasma lipid peroxidation were significantly higher in diabetic subjects than non-diabetic men and a significantly lower TAC was detected in diabetic group compare to non-diabetics. CONCLUSIONS: these results showed an increment in AGEs in seminal plasma of diabetic subjects and may suggest a key role for glycation process and increased oxidative stress in reproductive system dysfunction.

L-carnitine level in seminal plasma of fertile and infertile men.

BACKGROUND: To determine any correlation between infertility and semen quality with concentrations of L-carnitine in human seminal plasma. METHODS: This case-control study performed in Fatemieh Hospital in Hamadan, Iran. Seminal plasma of 72 infertile men and 80 men with proved fertility as a control group was investigated and L-carnitine level was determined using UV enzymatic test at 340 nm. RESULTS: The concentration of L-carnitine was significantly lower in the infertile group compared with control group (80.59±56.43 mg/l versus 108.43±42.26 mg/l; P= 0.0009). There was also a statistically significant positive correlation between seminal plasma L-carnitine concentration, total sperm count, and the percentage of motile sperm (P= 0.0009, and P= 0.0000, respectively). CONCLUSION: These finding suggest that the determination of seminal plasma L-carnitine level may be a useful test in evaluation of male infertility.

The complete amino acid sequence of the pathogenesis-related (PR2) protein induced in chemically stressed bean leaves.

We have established the complete sequence of the 155 amino acid residues of the pathogenesis-related protein PR2 accumulating in bean leaves treated with a mercuric chloride solution. Bean PR2 whose biological function remains to be elucidated, represents a structurally unfamiliar protein in which sequence arginine, cysteine, methionine and tryptophan residues are missing. This sequence is identical to that of bean PvPR1.

Clostridium difficile toxin B: characterization and sequence of three peptides.

The cytotoxin, also named toxin B, was isolated from a toxigenic strain of Clostridium difficile, purified to homogeneity and partially characterized. The purification procedure included ultrafiltration followed by anion-exchange chromatography. We noticed that a non-specific nucleic material eluted with the protein during the purification. The presence of these nucleic acids appeared to be important for the toxic activity of the protein. Some characteristics of the cytotoxin were examined, especially the amino acid composition and the sequence of three tryptic fragments.

Amino acid composition and proteolytic generated domains of higher plant tubulin.

The molecular architecture of tubulin from higher plant remains unknown. In this report we have made an attempt to identify higher plant tubulin domains using total and limited proteolysis of Haemanthus endosperm tubulin. The tubulin was previously purified and characterized (Picquot and Lambert 1988). The amino acid composition revealed a high content of basic residues, such as arginine and lysine. Tubulin domains were probed by tryptic and chymotryptic cleavage and analyzed by immunoblotting using specific monoclonal antibodies against alpha or beta subunits. These data shed light on specific properties of the higher plant tubulin.

Isolation and structure of a pseudopeptide gamma-L-glutamyl-L-aspartic acid from Datura stramonium that impairs learning retention in mice.

Datura stramonium contains a compound that impairs learning retention in mice. It has been purified to homogeneity and its structure has been established as that of a gamma-L-glutamyl-L-aspartate. The biological activity of this pseudodipeptide has been found to be identical with that of the corresponding synthetic one. It has also been compared to those of various synthetic di- and tripeptides containing L- and/or D-enantiomers of the constitutive amino acids. The results show that the activity is associated with a peptidic structure containing only one type of enantiomer.

gamma-L-glutamyl-L-aspartate induces specific deficits in long-term memory and inhibits [3H]glutamate binding on hippocampal membranes.

gamma-L-Glutamyl-L-aspartic acid (gamma-LGLA) has been isolated from Datura stramonium; its structure has been determined and it was then synthesized. In male Swiss mice intraperitoneal administration of the natural peptide (125 nmol/kg) or of the synthetic peptide (25-2500 nmol/kg) 24 h after acquisition of a Y-maze avoidance task induced a dose-dependent deficit in retention performance 48 h later. gamma-LGLA had no effect on locomotor activity or emotional reactivity at the doses used. Separate or simultaneous administration of aspartate or glutamate (each at 250 nmol/kg) had no effect on learning retention, indicating that deficit induced by gamma-LGLA was specific to the peptide. gamma-LGLA impaired learning acquisition in a time-dependent manner when administered from 3 min to 24 h post-training, but had no effect when administered 3 days following acquisition. gamma-LGLA administered just after the training session did not affect retention performance during the first 3 h, but suppressed the retention improvement observed in control animals from 6 to 24 h after acquisition; this deficit was still evident 7 days after the treatment. gamma-LGLA partially inhibited L-[3H]glutamate binding on crude hippocampal or striatal membrane preparations; this inhibition was not observed on cerebellar membrane preparations. These results suggest a specific action of gamma-LGLA on excitatory amino acid systems which may be responsible for its effects on learning retention.

Amino acid sequence of the ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit from Euglena.

The amino acid sequence of the ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) small subunit (SSU) from Euglena has been established by alignment of the sequence of peptides obtained by cleavage with chymotrypsin, trypsin, Staphylococcus aureus protease or formic acid. The Euglena SSU has 138 amino acids and thus represents longest SSU sequence described so far. Homology is only 41% with cyanobacteria SSU and about 51% with higher plant SSU, whereas it is around 75% between higher plants. The largest homologous portion between all the known SSU sequences is localized in the second half and covers about 20 amino acids. The phylogenetic tree based on known SSU sequences has been established and the rate of amino acid substitution for SSU is estimated to be about 1.35×10(-9) per year and per site. Despite heterogeneity in amino acid sequence, we found that the overall secondary structure is fairly well conserved.

The complete amino acid sequence of cytoplasmic aspartyl-tRNA synthetase from Saccharomyces cerevisiae.

The crystallizable cytoplasmic aspartyl-tRNA synthetase from Saccharomyces cerevisiae is a dimer made up of identical subunits (Mr 63 000). Its primary structure was established using peptide sequences from four different digests of the native and citraconylated enzyme with trypsin, cyanogen bromide and staphylococcal protease. The oligonucleotide sequence of the structural gene was used as a template for the final alignment of the various peptides in the correct order.

A home-made solid-phase sequencer operating at the nanomole level.

The building and functioning of a fully automated solid-phase sequencer is described. The peptide is coupled via its alpha-carboxyl end to activated glass beads and successively reacted with Chang's and Edman's reagents. All operations are electronically controlled by the automated programmer. All components necessary to build the machine are commercially available. This sequencer has been used at a nanomole level in the final phase of a protein sequence determination. The overall cost as well as the sensitivity and efficiency of the final product compare favourably to those of commercial machines.