Classification of heart rate signals of healthy and pathological subjects using threshold based symbolic entropy

The dynamical fluctuations of biological signals provide a unique window to construe the underlying mechanism of the biological systems in health and disease. Recent research evidences suggest that a wide class of diseases appear to degrade the biological complexity and adaptive capacity of the system. Heart rate signals are one of the most important biological signals that have widely been investigated during the last two and half decades. Recent studies suggested that heart rate signals fluctuate in a complex manner. Various entropy based complexity analysis measures have been developed for quantifying the valuable information that may be helpful for clinical monitoring and for early intervention. This study is focused on determining HRV dynamics to distinguish healthy subjects from patients with certain cardiac problems using symbolic time series analysis technique. For that purpose, we have employed recently developed threshold based symbolic entropy to cardiac inter-beat interval time series of healthy, congestive heart failure and atrial fibrillation subjects. Normalized Corrected Shannon Entropy (NCSE) was used to quantify the dynamics of heart rate signals by continuously varying threshold values. A rule based classifier was implemented for classification of different groups by selecting threshold values for the optimal separation. The findings indicated that there is reduction in the complexity of pathological subjects as compared to healthy ones at wide range of threshold values. The results also demonstrated that complexity decreased with disease severity.

Reproductive Performance of Arabian and Thoroughbred Mares under Subtropical Conditions of Pakistan

Breeding records of 57 Arabian and 66 Thoroughbred mares were analysed to assess their reproductive performance under the subtropical conditions of Pakistan. The Arabian mares showed significantly higher conception rates (p<0.05) in second mated oestrus and foal heat mated oestrus compared to Thoroughbred mares. However, conception rates for first lifetime mated oestrus were similar in both breeds of mares. Age at first mating (1,301±40 vs 1,500±32 days) was significantly (p<0.05) less in Arabian compared to Thoroughbred mares. Both breeds of mares showed significantly (p<0.05) higher frequencies of oestrous cycles and conception rates during the winter (October to March) compared to summer (June to August) months. Age of mares affected the conception rates, as mares at ages 3 to 7 and 8 to 12 years of ages had significantly higher conception rates (p<0.05) than those ≥18 years old in both breeds. This study demonstrates that i) reproductive performance in Arabians is better than Thoroughbred mares under the subtropical conditions of Pakistan, ii) mares remain cyclic throughout the year and iii) conception rates were higher in mares bred during winter compared to summer months.

Development of radiochemistry in Pakistan – 1960 to 2010

With the inception of Pakistan Atomic Energy Commission (PAEC) in 1956, peaceful uses of atomic energy commenced for the benefit of scientific community as well as masses of Pakistan. Radiochemistry played a vital role right from the beginning. The research and development in this field accelerated soon after the criticality of the first research reactor named as Pakistan Research Reactor (PARR- 1) at the Pakistan Institute of Nuclear Science and Technology (PINSTECH), Islamabad. The first radioisotope produced at PARR-1 for application in nuclear medicine was 131I. Later on, many other radioisotopes were prepared and radiopharmaceuticals were synthesised for their use in industry and hospitals. Besides providing pure radioactive tracers for nuclear medicine, radiochemistry also enhanced the detection limit of impurities at all stages of nuclear fuel cycle for power generation. In 1983, research in the field of nuclear data measurement began. The main aim was to identify suitable conditions for the production of radionuclides for cancer diagnostics, treatment and therapy. With the establishment of a second research reactor (PARR-2) at PINSTECH, research in neutron activation analysis, radioisotope production and separation studies gained more momentum and many research articles were published. Solvent extraction, adsorption and ion-exchange were the main routes of separation in those studies. Separation of heavy metals and treatment of waste generated in a nuclear power plant are other important aspects related to environmental restoration and nuclear waste management, where radiochemistry is required. In future, work in radiochemistry will be continued on similar lines to develop novel radiopharmaceuticals, identify indigenous schemes for nuclear waste management and work out intelligent procedures for material characterization for benefit to mankind, especially the people of Pakistan.

Primer modification improves rapid and sensitive in vitro and field-deployable assays for detection of high plains virus variants

A high consequence pathogen, High plains virus (HPV) causes considerable damage to wheat if the crop is infected during early stages of development. Methods for the early, accurate, and sensitive detection of HPV in plant tissues are needed for the management of disease outbreaks and reservoir hosts. In this study, the effectiveness of five methods-real-time SYBR green and TaqMan reverse transcription-quantitative PCR (RT-qPCR), endpoint RT-PCR, RT-helicase dependent amplification (RT-HDA) and the Razor Ex BioDetection System (Razor Ex)-for the broad-range detection of HPV variants was evaluated. Specific PCR primer sets and probes were designed to target the HPV nucleoprotein gene. Primer set HPV6F and HPV4R, which amplifies a product of 96 bp, was validated in silico against published sequences and in vitro against an inclusivity panel of infected plant samples and an exclusivity panel of near-neighbor viruses. The primers were modified by adding a customized 22 nucleotide long tail at the 5' terminus, raising the primers' melting temperature (Tm; ca. 10°C) to make them compatible with RT-HDA (required optimal Tm = 68°C), in which the use of primers lacking such tails gave no amplification. All of the methods allowed the detection of as little as 1 fg of either plasmid DNA carrying the target gene sequence or of infected plant samples. The described in vitro and in-field assays are accurate, rapid, sensitive, and useful for pathogen detection and disease diagnosis, microbial quantification, and certification and breeding programs, as well as for biosecurity and microbial forensics applications.

Sudden loss of vision in an Acute Medical Unit

We present a case report of young man with Type 1 diabetes who developed acute visual loss after initially presenting with diabetic ketoacidosis. The diagnosis of invasive paranasal sinusoidal aspergillosis was made following CT and biopsy. Although uncommon, visual loss is a recognised complication of disseminated aspergillosis and is more likely in immune-compromised patients and those with diabetes. Early investigation with appropriate sinus imaging and involvement of the Ear Nose and Throat team in recommended when patients with diabetes develop acute visual loss in the context of a non-specific infective illness.

Assessment of fluoride level in groundwater and prevalence of dental fluorosis in Didwana block of Nagaur district, Central Rajasthan, India

BACKGROUND

In India, for the high concentration of fluoride in groundwater, people are at risk of dental fluorosis. The problem is common in various states of India. The condition in Rajasthan is worse where all districts have such a problem.

OBJECTIVE

To study the fluoride concentration in groundwater and prevalence of dental fluorosis in Didwana block of Nagaur district, Central Rajasthan, India.

METHODS

The fluoride concentration in water of 54 villages was measured electrochemically, using fluoride ion selective electrode. Dental fluorosis was assessed in 1136 people residing in study area by Dean's classification for dental fluorosis.

RESULTS

The fluoride concentration in groundwater in studied sites ranged from 0.5 to 8.5 mg/L. The concentration of fluoride was more than the maximum permissible limit set by WHO and Bureau of Indian Standards (1 mg/L) in 48 groundwater sources. Of 1136 people studied, 788 (69.4%; 95% CI: 66.7%-72.1%) had dental fluoros---252 had mild and 74 had severe dental fluorosis.

CONCLUSION

High level of fluoride in drinking water of Didwana block of Nagaur district, Central Rajasthan, India, causes dental fluorosis in most people in the region and is an important health problem that needs prompt attention.

ADHD matures: time for practitioners to do the same?

Attention deficit and hyperactivity disorder (ADHD) is not restricted to children. Abundant evidence from follow-up studies accumulated since the 1970s supports the concept of ADHD in adulthood. Genetic research points to a heritability of 76%, and neuroimaging studies have reported structural and functional brain abnormalities in patients with ADHD. Contrary to popular belief, ADHD is not a culturally bound disorder and has been described worldwide. ADHD has a cost for society, as adults with this disorder suffer from increased rates of unemployment and psychiatric comorbidity, including substance use disorders. Studies undertaken in forensic populations describe high rates of ADHD in these groups, particularly amongst young offenders. One of the main issues in the diagnosis of ADHD in the adult is the fact that most clinicians have not been educated to diagnose and treat ADHD. Effective pharmacological treatments for ADHD are available and should be prescribed for these patients. The National Institute for Health and Clinical Excellence (NICE) and the British Association for Psychopharmacology (BAP) guidelines established a benchmark for service development required to treat ADHD adequately in the adult population. However, the implementation of new services has been slow. More resources are needed to effectively assess and treat ADHD in the adult.

Fluoride in the drinking water of Nagaur tehsil of Nagaur District, Rajasthan, India

Fluoride concentration of groundwater samples from 100 villages of Nagaur tehsil was determined, 85 villages were found to have fluoride concentration more than 1.5 mg/L. The maximum fluoride concentration was recorded 6.6 mg/L in groundwater of Singhani village, while the minimum was recorded in Kurchhi village. As per the desirable and maximum permissible limit for fluoride in drinking water, determined by World Health Organization, the groundwater of about 85 villages of the studied sites is unfit for drinking purpose.

Experimental realization of decoherence-free subspace in neutron interferometry

A decoherence-free subspace (DFS) is an important class of quantum-error-correcting (QEC) codes that have been proposed for fault-tolerant quantum computation. The applications of QEC techniques, however, are not limited to quantum-information processing (QIP). Here we demonstrate how QEC codes may be used to improve experimental designs of quantum devices to achieve noise suppression. In particular, neutron interferometry is used as a test bed to show the potential for adding quantum error correction to quantum measurements. We built a five-blade neutron interferometer that incorporates both a standard Mach-Zender configuration and a configuration based on a DFS. Experiments verify that the DFS interferometer is protected against low-frequency mechanical vibrations. We anticipate these improvements will increase the range of applications for matter-wave interferometry.

Engineering broad-spectrum resistance against RNA viruses in potato

RNA silencing technology has become the tool of choice for inducing resistance against viruses in plants. A significant discovery of this technology is that double-stranded RNA (dsRNA), which is diced into small interfering RNAs (siRNAs), is a potent trigger for RNA silencing. By exploiting this phenomenon in transgenic plants, it is possible to confer high level of virus resistance by specific targeting of cognate viral RNA. In order to maximize the efficiency and versatility of the vector-based siRNA approach, we have constructed a chimeric expression vector containing three partial gene sequences derived from the ORF2 gene of Potato virus X, Helper Component Protease gene of Potato virus Y and Coat protein gene of Potato leaf roll virus. Solanum tuberosum cv. Desiree and Kuroda were transformed with this chimeric gene cassette via Agrobacterium tumefaciens-mediated transformation and transgenic status was confirmed by PCR, Southern and double antibody sandwich ELISA detection. Due to simultaneous RNA silencing, as demonstrated by accumulation of specific siRNAs, the expression of partial triple-gene sequence cassette depicted 20% of the transgenic plants are immune against all three viruses. Thus, expression of a single transgene construct can effectively confer resistance to multiple viruses in transgenic plants.

PCR-Based Identification and Characterization of Fusarium sp. Associated with Mango Malformation

Mango malformation is the most serious disease of mango causing considerable damage to the mango orchards worldwide. It is a major threat for mango cultivation in north Indian belt. In recent years, Fusarium sp. is finding wide acceptability in scientific community as a causal agent of this disease. However, little information is known about the variability in Fusarium isolates from malformed mango tissues. Therefore, the major objective of present study was the identification and analysis of genetic diversity among Fusarium isolates collected from malformed mango tissues. Two texon selective primers, ITS-Fu-f and ITS-Fu-r, were used for quick identification of Fusarium spp. The fungal genomic DNA was extracted from using CTAB method and was utilized as template for PCR amplification. Total 224 bands were amplified by 18 RAPD primers at an average of 12.44 bands per primer. The size of the obtained amplicons ranged from 0.264 kb (minimum) to 3.624 kb (maximum). Data scored from 25 isolates of Fusarium sp. with 18 RAPD primers were used to generate similarity coefficients. The similarity coefficient ranged from 0.17 to 0.945. Based on DNA fingerprints, all isolates were categorized into two major clusters. This study indicated a wide variability among different isolates of Fusarium.

High performance organic phototransistor based on regioregular poly(3-hexylthiophene)

We fabricated solution processed organic phototransistors (OPT) by drop casting regioregular poly 3-hexylthiophene (P3HT) from three different solvents: p-xylene, dichlorobenzene and chloroform. The best performance was obtained for films drop-casted from p-xylene with a maximum photosensitivity (P) of 3.8 x 10(3) and responsivity (R) of 250 A W(-1) under white light illumination. For films deposited from dichlorobenzene and chloroform the values of P were 1.1 x 10(3) and 30, respectively, while the values of R were 150 and 35, respectively. The maximum responsivity value reported here is at least one order of magnitude higher than that of previously reported solution processed OPT devices. By analyzing the absorption spectra of different films, we conclude that the better device performance of OPT from p-xylene is due to better crystallinity of P3HT. Demonstration of high performance OPTs is a significant step forward in integrating these devices in various optoelectronic circuits.

Fossil evidence for the origin of aquatic locomotion in archaeocete whales

Recent members of the order Cetacea (whales, dolphins, and porpoises) move in the water by vertical tail beats and cannot locomote on land. Their hindlimbs are not visible externally and the bones are reduced to one or a few splints that commonly lack joints. However, cetaceans originated from four-legged land mammals that used their limbs for locomotion and were probably apt runners. Because there are no relatively complete limbs for archaic archaeocete cetaceans, it is not known how the transition in locomotory organs from land to water occurred. Recovery of a skeleton of an early fossil cetacean from the Kuldana Formation, Pakistan, documents transitional modes of locomotion, and allows hypotheses concerning swimming in early cetaceans to be tested. The fossil indicates that archaic whales swam by undulating their vertebral column, thus forcing their feet up and down in a way similar to modern otters. Their movements on land probably resembled those of sea lions to some degree, and involved protraction and retraction of the abducted limbs.

Pulse compression of harmonic chirp signals using the fractional fourier transform

In ultrasound harmonic imaging with chirp-coded excitation, a harmonic matched filter (HMF) is typically used on the received signal to perform pulse compression of the second harmonic component (SHC) to recover signal axial resolution. Designing the HMF for the compression of the SHC is a problematic issue because it requires optimal window selection. In the compressed second harmonic signal, the sidelobe level may increase and the mainlobe width (MLW) widen under a mismatched condition, resulting in loss of axial resolution. We propose the use of the fractional Fourier transform (FrFT) as an alternative tool to perform compression of the chirp-coded SHC generated as a result of the nonlinear propagation of an ultrasound signal. Two methods are used to experimentally assess the performance benefits of the FrFT technique over the HMF techniques. The first method uses chirp excitation with central frequency of 2.25 MHz and bandwidth of 1 MHz. The second method uses chirp excitation with pulse inversion to increase the bandwidth to 2 MHz. In this study, experiments were performed in a water tank with a single-element transducer mounted coaxially with a hydrophone in a pitch-catch configuration. Results are presented that indicate that the FrFT can perform pulse compression of the second harmonic chirp component, with a 14% reduction in the MLW of the compressed signal when compared with the HMF. Also, the FrFT provides at least 23% reduction in the MLW of the compressed signal when compared with the harmonic mismatched filter (HMMF). The FrFT maintains comparable peak and integrated sidelobe levels when compared with the HMF and HMMF techniques.

The electronic transport properties of ternary Cd(1-x)Zn(x)S nanowire networks

We present the electronic transport characteristics of ternary alloy Cd(1-x)Zn(x)S nanowire networks in the dark and under white light illumination. Compared to the negligible dark current, we observed a photocurrent enhancement of up to four orders of magnitude at an intensity of 460 mW cm(-2). The time constant of the dynamic photoresponse is approximately 5 s. The current-voltage characteristics at different intensities show Ohmic behavior at low bias and space charge limited conduction (SCLC) at higher bias voltages. The SCLC behavior and slow time response indicate that the charge transport is dominated by tunneling at the percolating inter-nanowire junctions.

Determination of natural radioactivity in building materials used in the Karachi area by γ-ray spectrometry and INAA

Samples of sand, stone and manufactured building materials collected from Karachi area have been analyzed for the primordial natural radionuclides 238U, 232Th and 40K using γ-ray spectrometry. The uranium and thorium contents have also been determined by instrumental neutron activation analysis (INAA). The specific activities in these materials, having a radium equivalent activity less than 370 Bq kg–1, when evaluated for radiological effects show that all materials meet the external γ-ray dose limitation of 1.5 mSv y–1. The γ-ray spectrometric and INAA techniques complemented each other well in this study.

Fission spectrum averaged cross section measurements of some neutron threshold reactions of relevance to medical radionuclide production

A resume is given of radiochemical measurements of nuclear reaction cross sections relevant to the production of some medically important radionuclides carried out at PINSTECH during the last decade. Systematic studies on fission neutron spectrum averaged cross sections of several threshold reactions, like (n, 2n), (n, p) and (n, α), on titanium, ruthenium, europium and dysprosium for the production of 45Ti, 96Tc, 153Sm and 153Gd are described.

Radiochemical neutron activation analysis of trace impurities in high purity titanium and tungsten

Rapid radiochemical neutron activation analysis (RNAA) procedures were developed and employed to the determination of 36 trace impurities in high purity titanium and tungsten. Anion–exchange column chromatography procedures were developed for the sequential group chemical separation of various elements, which helped in reducing the spectral interferences and improving the sensitivity of the method. The procedure is simple and requires a very short time to separate the elements in three groups for radiometric assay. To determine very low contents of uranium and thorium, 239Np and 233Pa as activation products were separated using anion–exchange and coprecipitation methods. The impurity contents were found to be low; therefore, their deleterious effects would be negligible.