Universal all-optical zero-bias logic gates in silicon photonics.

Universal all-optical (optical input - optical output) logic gates, realized in a commercial foundry silicon photonics process, are reported. Microring resonator modulator and zero-biased stacked photodiodes are used to create the required optical input-output nonlinear transfer function for optical gate realizations. Several logic gate functions, specifically NOR which is a universal logic gate that can be used to implement any logic, are demonstrated.

A machine learning framework for spatio-temporal vulnerability mapping of groundwaters to nitrate in a data scarce region in Lenjanat Plain, Iran.

The temporal aspect of groundwater vulnerability to contaminants such as nitrate is often overlooked, assuming vulnerability has a static nature. This study bridges this gap by employing machine learning with Detecting Breakpoints and Estimating Segments in Trend (DBEST) algorithm to reveal the underlying relationship between nitrate, water table, vegetation cover, and precipitation time series, that are related to agricultural activities and groundwater demand in a semi-arid region. The contamination probability of Lenjanat Plain has been mapped by comparing random forest (RF), support vector machine (SVM), and K-nearest-neighbors (KNN) models, fed with 32 input variables (dem-derived factors, physiography, distance and density maps, time series data).

Adaptive beam forming across temperature variation in optical phased array enabled with deep neural network.

Integrated optical phased arrays (OPA) require calibration to account for mismatches amongst the channels. Furthermore, beams emitted from an OPA tend to distort when the chip's temperature changes. We propose to utilize a deep neural network (DNN) to adaptively control the phase modulator voltages of the OPA and create a desired beam pattern in the presence of process mismatches and temperature changes.

Transport and retention of functionalized graphene oxide nanoparticles in saturated/unsaturated porous media: Effects of flow velocity, ionic strength and initial particle concentration.

The widespread use of nanomaterials has raised the threat of nanoparticles (NPs) infection of soils and groundwater resources. This research aims to investigate three parameters including flow velocity, ionic strength (IS), and initial particle concentration effects on transport behavior and retention mechanism of functionalization form of graphene oxide with polyvinylpyrrolidone (GO-PVP). The transport of GO-PVP was investigated in a laboratory-scale study through saturated/unsaturated (Saturation Degree = 0.

Optically biased and controlled signal processing in silicon photonics.

Optically biased and controlled signal processing is demonstrated in a commercial foundry silicon photonics integrated circuit process. Data and control signals are carried by different wavelengths in a WDM format. Optical signals on bias and control channels are converted to electrical voltages using series stacked photodiodes operating in photoconductive mode.

Can river flow prevent land subsidence in urban areas?

Land subsidence, a silent death, occurs due to various factors like significant reduction in groundwater (GW) levels. It is a widespread phenomenon with irreparable consequences on buildings, infrastructures, and, in severe cases, groundwater aquifers. This study aims to assess the impact of river flow on the acceleration and control of land subsidence in an arid and semi-arid region.

Hydro-meteorological droughts across the Baltic Region: The role of the accumulation periods.

Based on the physical and geographical conditions, the Baltic Region is categorised as a humid climate zone. This means that, there is usually more precipitation than evaporation throughout the year, suggesting that droughts should not occur frequently in this region. Despite the humid climate in the region, the study focused on assessing the spatio-temporal patterns of droughts.

COVID-19 research in management: An updated bibliometric analysis.

The unprecedented impact of COVID-19 on the global economy as well as on the academic literature. Since early 2020, management researchers have made exceptional efforts to extend our understanding of the pandemic's effect on consumption, sourcing, the workplace, and corporate strategies. The present study uses a bibliometric design to analyze the extensive database of COVID-19 studies in management literature generated over a 2-year period.

Human-induced arsenic pollution modeling in surface waters - An integrated approach using machine learning algorithms and environmental factors.

In recent years, assessment of sediment contamination by heavy metals, i.e., arsenic, has attracted the interest of scientists worldwide.

Experimental demonstration of remotely powered, controlled, and monitored optical switching based on laser-delivered signals.

We experimentally demonstrate remotely powered, controlled, and monitored optical switching. The control signal of the switch is modulated on an optical wave and sent from a transmitter. At the switch location, the control signal is converted from an optical to an electrical signal to drive the switch.

A Bidirectional Neural Interface SoC With Adaptive IIR Stimulation Artifact Cancelers.

We present a 180-nm CMOS bidirectional neural interface system-on-chip that enables simultaneous recording and stimulation with on-chip stimulus artifact cancelers. The front-end cancellation scheme incorporates a least-mean-square engine that adapts the coefficients of a 2-tap infinite-impulse-response filter to replicate the stimulation artifact waveform and subtract it at the front-end. Measurements demonstrate the efficacy of the canceler in mitigating artifacts up to 700 mV and reducing the front-end amplifier saturation recovery time in response to a 2.

Soil moisture change analysis under watershed management practice using in situ and remote sensing data in a paired watershed.

Soil moisture, vegetation cover, and land surface temperature are vital variables in water-energy balance, eco-hydrological processes, and water resources management, which can be influenced by watershed management activities. This research focused on the spatial and temporal variability of soil moisture, vegetation cover, land surface temperature, and Temperature-Vegetation Dryness Index (TVDI) under a biological watershed management practice in the Taleghan paired watershed, namely, treated (TW) and control watersheds (CW), in Alborz province, Iran. In this research, along with the remote sensing techniques, the soil moisture and vegetation cover data were measured and statistically analyzed in the three aspects of both TW and CW during a growth period from May to October 2017.

Assessment of hydro-geochemical properties of groundwater under the effect of desalination wastewater discharge in an arid area.

Desalination to increase irrigation water supply for agricultural production is becoming important in water-scarce regions. While desalination has positive effects on the potential irrigation water quantity and quality, the technique may also be a considered potential source of groundwater pollution. The present study investigated the effects of desalination wastewater discharge on groundwater quality in an arid area in southern Iran for the 2012-2017 period.

Carbon nanomaterials against pathogens; the antimicrobial activity of carbon nanotubes, graphene/graphene oxide, fullerenes, and their nanocomposites.

Recently, antibiotic resistance of pathogens has grown given the excessive and inappropriate usage of common antimicrobial agents. Hence, producing novel antimicrobial compounds is a necessity. Carbon nanomaterials (CNMs) such as carbon nanotubes, graphene/graphene oxide, and fullerenes, as an emerging class of novel materials, can exhibit a considerable antimicrobial activity, especially in the nanocomposite forms suitable for different fields including biomedical and food applications.

Evaluation of a new X-band weather radar for operational use in south Sweden.

The performance of a new type of X-band weather radar (WR) for Sweden during a pilot run is studied. Compared to the conventional C-band WRs, the X-band WR covers a smaller area but with a higher spatiotemporal resolution, making it suitable for urban hydrological applications. Rainfall estimations from different elevation angles of the radar (levels) are compared at one-minute and single-event timescales with the observations of several rain gauges at different ranges using hyetographs.

Very high resolution, altitude-corrected, TMPA-based monthly satellite precipitation product over the CONUS.

The Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) product provided over 17 years of gridded precipitation datasets. However, the accuracy and spatial resolution of TMPA limits the applicability in hydrometeorological applications. We present a dataset that enhances the accuracy and spatial resolution of the TMPA monthly product (3B43).

Rapid differential diagnosis of vaginal infections using gold nanoparticles coated with specific antibodies.

Vaginal infections caused by bacteria, Candida and Trichomonas vaginalis, affect millions of women annually worldwide. Symptoms and signs have limited value in differential diagnosis of three causes of vaginitis. Current laboratory methods for differential diagnosis are either expensive or time consuming.

Low-power thermo-optic silicon modulator for large-scale photonic integrated systems.

Silicon platform enables the monolithic realization of large-scale photonic integrated systems. Many emerging applications facilitated by silicon photonics such as optical biosensing, optical neurostimulation, optical phased arrays, holographic displays, 3D cameras, optical machine learning, and optical quantum information processing systems require the integration of a large number of optical phase modulators with modest modulation speed. Classical optical modulators are not suitable for such large-scale integration because of their inability to provide low optical loss, compact size, high efficiency, and wide optical bandwidth, all at the same time.

A Chopper-Stabilized, Current Feedback, Neural Recording Amplifier.

Advanced neural prosthetics requires high density neural recording and stimulation electrodes interfacing with the tissue. For an implantable device, area, power consumption, and noise performance are the key design metrics. Due to the low-frequency nature of the recorded signals, chopping technique is inevitable to satisfy the noise requirement while maintaining a small area and low power consumption.

Iran's Land Suitability for Agriculture.

Increasing population has posed insurmountable challenges to agriculture in the provision of future food security, particularly in the Middle East and North Africa (MENA) region where biophysical conditions are not well-suited for agriculture. Iran, as a major agricultural country in the MENA region, has long been in the quest for food self-sufficiency, however, the capability of its land and water resources to realize this goal is largely unknown. Using very high-resolution spatial data sets, we evaluated the capacity of Iran's land for sustainable crop production based on the soil properties, topography, and climate conditions.

The effects of extended conjugation length of purely organic phosphors on their phosphorescence emission properties.

We synthesized a series of purely organic phosphors, bromobenzaldehyde derivatives, with varying conjugation length to investigate the effects of conjugation length on their phosphorescence emission properties. As the conjugation length increases phosphorescence efficiency decreases with a redshift in the emission color at 77 K. Our computational results imply that this correlation is related to the intersystem crossing rate and that the rate is determined by spin-orbit coupling strength rather than by simply the energy difference between the lowest lying singlet and triplet states.

Epidemiological study of gastrointestinal helminthes of canids in chaharmahal and bakhtiari province of iran.

Background: The present study was carried out to describe the epidemiological aspects of gastrointestinal helminthic infections of canids in Chaharmahal and Bakhtiari Province, the central western part of Iran.

Methods: Forty nine canid species including, dogs, jackals, foxes and wolves were included in this study. The contents of their alimentary canal were inspected in order to isolate and identify the parasitic helminthes of this system.

Monolithic optical phased-array transceiver in a standard SOI CMOS process.

Monolithic microwave phased arrays are turning mainstream in automotive radars and high-speed wireless communications fulfilling Gordon Moores 1965 prophecy to this effect. Optical phased arrays enable imaging, lidar, display, sensing, and holography. Advancements in fabrication technology has led to monolithic nanophotonic phased arrays, albeit without independent phase and amplitude control ability, integration with electronic circuitry, or including receive and transmit functions.

Wideband tunable laser phase noise reduction using single sideband modulation in an electro-optical feed-forward scheme.

A wideband laser phase noise reduction scheme is introduced where the optical field of a laser is single sideband modulated with an electrical signal containing the discriminated phase noise of the laser. The proof-of-concept experiments on a commercially available 1549 nm distributed feedback laser show linewidth reduction from 7.5 MHz to 1.

PEGylated nanoparticles bind to and alter amyloid-beta peptide conformation: toward engineering of functional nanomedicines for Alzheimer's disease.

We have demonstrated that the polyethylene glycol (PEG) corona of long-circulating polymeric nanoparticles (NPs) favors interaction with the amyloid-beta (Aβ(1-42)) peptide both in solution and in serum. The influence of PEGylation of poly(alkyl cyanoacrylate) and poly(lactic acid) NPs on the interaction with monomeric and soluble oligomeric forms of Aβ(1-42) peptide was demonstrated by capillary electrophoresis, surface plasmon resonance, thioflavin T assay, and confocal microscopy, where the binding affected peptide aggregation kinetics. The capture of peptide by NPs in serum was also evidenced by fluorescence spectroscopy and ELISA.