Effect of mechanical and chemical treatments of arecanut (areca catechu L.) fruit husk on husk and its fibre.

Arecanut husk, a biomass is generated during extraction of nut and is stored in heaps in the backyards of processing units. Arecanut husk presently has no industrial/commercial applications and is a cause of major environmental hazards. Arecanut husk is rich in good quality lingo-cellulosic fibres which have potential applications in various fields. Presently there is no proper process and machinery available to extract these fibres on a mass scale. Designing such machinery requires characterisation of husks, bonding force between fibres and the shell, etc. The aim of the present study is develop suitable mechanical and chemical treatments to facilitate easy extraction of fibres and also to study the effects of theses pretreatments on tensile property of fibres. The variety used was Shreevardhini. It was noticed that the pretreatments of husk had significant effect on fibre separation. Highest fibre recovery of about 57% was achieved with pressed husks soaked in water for 24 h. Detachment force required for fibre / fibres separation from husk was least in 2.5% KOH treated husks. There was no adverse effect of pretreatments on tensile strength of fibres. Pressing of husks resulted in maximum fibre recovery due to weakening of bonds, hence pressing of arecanut husk before mechanical fibre extraction is recommended, whereas chemical pretreatment of husks with KOH is not recommended.

Neural control of finger movement via intracortical brain-machine interface.

OBJECTIVE: Intracortical brain-machine interfaces (BMIs) are a promising source of prosthesis control signals for individuals with severe motor disabilities. Previous BMI studies have primarily focused on predicting and controlling whole-arm movements; precise control of hand kinematics, however, has not been fully demonstrated. Here, we investigate the continuous decoding of precise finger movements in rhesus macaques. APPROACH: In order to elicit precise and repeatable finger movements, we have developed a novel behavioral task paradigm which requires the subject to acquire virtual fingertip position targets. In the physical control condition, four rhesus macaques performed this task by moving all four fingers together in order to acquire a single target. This movement was equivalent to controlling the aperture of a power grasp. During this task performance, we recorded neural spikes from intracortical electrode arrays in primary motor cortex. MAIN RESULTS: Using a standard Kalman filter, we could reconstruct continuous finger movement offline with an average correlation of ρ = 0.78 between actual and predicted position across four rhesus macaques. For two of the monkeys, this movement prediction was performed in real-time to enable direct brain control of the virtual hand. Compared to physical control, neural control performance was slightly degraded; however, the monkeys were still able to successfully perform the task with an average target acquisition rate of 83.1%. The monkeys' ability to arbitrarily specify fingertip position was also quantified using an information throughput metric. During brain control task performance, the monkeys achieved an average 1.01 bits s-1 throughput, similar to that achieved in previous studies which decoded upper-arm movements to control computer cursors using a standard Kalman filter. SIGNIFICANCE: This is, to our knowledge, the first demonstration of brain control of finger-level fine motor skills. We believe that these results represent an important step towards full and dexterous control of neural prosthetic devices.

Characterization of Ty1/copia-like retrotransposon families from pigeonpea genome.

Retrotransposons contribute significantly to the size, organization, and genetic diversity of their host genomes. To characterize novel retrotransposon families in pigeonpea and develop retrotransposon-based sequence-specific amplification polymorphic markers, in silico homology sequence search was carried out against the whole genome shotgun sequence of pigeonpea variety Asha (ICPL87119). For homology searching, 5 copia-like retro elements belonging to soybean, common bean, mungbean, chickpea, and field pea were used as query sequences. Contigs with at least 80% query coverage and >70% similarity were searched for retroelements using the long terminal repeat finder. A total of 28 copia-like retroelements were identified using this method. Multiple sequence alignment for the reverse transcriptase domain indicated conserved reverse transcriptase domains in all 28 elements compared with other reported elements. Phylogenetic analysis based on reverse transcriptase domains revealed 11 families. The copy number per family ranged from 1 (for B, J, and K family) to 8 (I). The sequence-specific amplification polymorphic marker-based insertion site profiling for one of the retrotransposon families (G) confirmed multiple insertions of this element across the pigeonpea genome. This study showed that our in silico homology search strategy was efficient for identifying and characterizing the Ty1/copia-like retrotransposon. The results of this study are useful for developing retrotransposon-based sequence-specific amplification polymorphic markers for pigeonpea crop improvement.

Comparative evaluation of effect of polymerizable and non-polymerizable desensitizing agents on crown-retentive-strength of zinc-phosphate, glass-ionomer and compomer cements.

The Purpose of this study was to evaluate the effect of polymerizable and non-polymerizable dentine desensitizers on retention of complete cast crowns cemented with three different types of cements. Freshly extracted human molars (n = 90) were prepared for standardized crown preparation (6-degree taper 4-mm height). The axial surface area of each preparation was determined and specimens were distributed equally among groups (n = 10). Dentine desensitizers, cementing agents, glass ionomer cement and compomer cement. Teeth were prepared and individual castings were made using high noble porcelain-metal alloy. Castings were cemented, thermo-cycled and removed along the path of insertion using a universal testing machine. Tooth surface as well as inner surface of the casting was examined and nature of cement failure was determined. Compomer cement exhibited the highest retentive strength and all dentine treatments resulted in significantly different retentive values. Zinc phosphate was the least retentive. Crown retentive values of Compomer cement were improved with Prime & Bond NT and Gluma Desensitizer Retentive values of zinc phosphate cement with Prime & Bond NT were decreased and not affected with Gluma Desensitizer Retentive values of Glass ionomer cement were not affected by any of the desensitizers used in the study.

A protocol for high-quality genomic DNA extraction from legumes.

Current DNA extraction protocols, which require liquid nitrogen, lyophilization and considerable infrastructure in terms of instrumentation, often impede the application of biotechnological tools in less researched crops in laboratories in developing countries. We modified and optimized the existing CTAB method for plant genomic DNA extraction by avoiding liquid nitrogen usage and lyophilization. DNA was extracted directly from freshly harvested leaves ground in pre-heated CTAB buffer. Chloroform:isoamyl alcohol (24:1) and RNase treatments followed by single-purification step decontaminated the samples thereby paving way for selective extraction of DNA. High molecular weight DNA yield in the range of 328 to 4776 ng/µL with an average of 1459 ng/µL was obtained from 45 samples of cultivated and wild Cajanus species. With an absorbance ratio at 260 to 280 nm, a range of 1.66 to 2.20, and a mean of 1.85, very low levels of protein and polysaccharide contamination were recorded. Forty samples can be extracted daily at a cost between 1.8 and US$2.0 per plant sample. This modified method is suitable for most plants especially members of the Leguminosae. Apart from Cajanus, it has been extensively applied in DNA extraction from Cicer and Vigna species.

Self retentive partial silicone auricular prosthesis: a case report.

An auricular prosthesis may be required for a number of conditions including congenital abnormalities, malignancy and trauma, which result in disfigurement of the pinna. Whatever the cause of the absence of the pinna, it is a significant loss of a prominent part of the face for the person involved. This article describes a simple and cost effective technique for retention of a silicone partial auricular prosthesis. A Fish-bone shaped substructure (FSS) designed and fabricated using orthodontic wire and autopolymerizing acrylic resin, was embedded into the silicone elastomer of a self-retentive silicone prosthesis. The prosthesis is designed to overcome the disadvantages associated with traditionally fabricated prostheses; namely poor structural strength, inadequate retention, poor adaptation and durability over time.

Multidisciplinary treatment approach with one piece implants for congenitally missing maxillary lateral incisors: a case report.

Congenitally missing lateral incisors are a common clinical occurrence. Dental Implants have become a primary treatment option for replacement of these teeth. Many times in prosthodontic treatment planning a multidisciplinary approach is needed for a comprehensive out come. Prosthodontic treatment planning is needed prior to the patient's consultation and following treatment acceptance; the prosthodontist may need to coordinate treatment needs with other specialists, including an orthodontist and an implant surgeon. This article describes multidisciplinary management of a case presenting with spaced maxillary anteriors due to the congenitally missing lateral incisors. Treatment consisted of initial orthodontic space management to obtain adequate space for missing lateral incisors. Single piece, narrow diameter implants were placed in edentulous spaces on both sides. Aesthetic crown lengthening procedure was performed with all anterior teeth along with tissues surrounding the implants. Metal-ceramic crowns were given as definitive restorations, resulting into an acceptable aesthetic outcome.

Tissue concentration, systemic distribution and toxicity of clofazimine--an autopsy study.

There are very few autopsy studies available on systemic distribution of clofazimine, a drug with anti-mycobacterial activity, used in multidrug therapy (MDT) regimen of leprosy and in erythema nodosum leprosum (ENL). An autopsy study was done on a 45 year old female of lepromatous leprosy (LL) on MDT and long term high dosage of clofazimine. Patient succumbed to intractable abdominal pain, diarrhoea, hypokalemia following clofazimine treatment. Autopsy study revealed yellowish brown discoloration of skin, viscera and body fluids. Chemical extraction of the drug revealed the highest concentration of the drug in jejunum (1.5mg/gm),followed by spleen (1.2mg/gm), pancreas (0.4mg/gm), adrenal (0.25mg/gm), liver (0.21mg/gm), and less than 0.2mg/gm in lung, fat, large intestine and stomach. It can be inferred from the present study that the drug is absorbed from the jejunum and gets deposited in fat, reticulo-endothelial cells (R-E cells) and hepatocytes. The drug is best demonstrated in cryostat sections and is lost partly during tissue processing and staining. The drug toxicity can be fatal as seen in the present case.

Differential occurrence of reluctant openings in G-protein-inhibited N- and P/Q-type calcium channels.

Voltage-dependent inhibition of N- and P/Q-type calcium channels by G proteins is crucial for presynaptic inhibition of neurotransmitter release, and may contribute importantly to short-term synaptic plasticity. Such calcium-channel modulation could thereby impact significantly the neuro-computational repertoire of neural networks. The differential modulation of N and P/Q channels could even further enrich their impact upon synaptic tuning. Here, we performed in-depth comparison of the G-protein inhibition of recombinant N and P/Q channels, expressed in HEK 293 cells with the m2 muscarinic receptor. While both channel types display classic features of G-protein modulation (kinetic slowing of activation, prepulse facilitation, and voltage dependence of inhibition), we confirmed previously reported quantitative differences, with N channels displaying stronger inhibition and greater relief of inhibition by prepulses. A more fundamental, qualitative difference in the modulation of these two channels was revealed by a modified tail-activation paradigm, as well as by a novel "slope" analysis method comparing time courses of slow activation and prepulse facilitation. The stark contrast in modulatory behavior can be understood within the context of the "willing-reluctant" model, in which binding of G-protein betagamma subunits to channels induces a reluctant mode of gating, where stronger depolarization is required for opening. Our experiments suggest that only N channels could be opened in the reluctant mode, at voltages normally spanned by neuronal action potentials. By contrast, P/Q channels appear to remain closed, especially over these physiological voltages. Further, the differential occurrence of reluctant openings is not explained by differences in the rate of G-protein unbinding from the two channels. These two scenarios predict very different effects of G-protein inhibition on the waveform of Ca(2+) entry during action potentials, with potentially important consequences for the timing and efficacy of synaptic transmission.

Preferential closed-state inactivation of neuronal calcium channels.

We have investigated the inactivation mechanism of neuronal N-, P/Q-, and R-type calcium channels. Although channels inactivate slowly during square-pulse depolarization, as observed previously, we now find that they inactivate profoundly during a train of action potential (AP) waveforms. The apparent paradox arises from a voltage-dependent mechanism in which channels inactivate preferentially from intermediate closed states along the activation pathway. Inactivation can therefore extend beyond the brief duration of AP waveforms to continue between spikes, as the channel undergoes repetitive cycles of activation and deactivation. The extent of inactivation during a train is strongly affected by the subunit composition of channels. Preferential closed-state inactivation of neuronal calcium channels could produce widely variable depression of Ca2+ entry during a train of APs.

Bursts of action potential waveforms relieve G-protein inhibition of recombinant P/Q-type Ca2+ channels in HEK 293 cells.

1. A variety of neurotransmitters act through G-protein-coupled receptors to decrease synaptic transmission, largely by inhibiting the voltage-gated calcium channels that trigger neurotransmitter release. However, these presynaptic calcium channels are typically inaccessible to electrophysiological characterization. We have reconstituted a part of this inhibition using recombinant P/Q-type calcium channels and M2 acetylcholine receptors in HEK 293 cells. 2. One of the most interesting features of G-protein inhibition of calcium channels is that strong step depolarization transiently relieves the inhibition. We have found that short bursts of action potential voltage waveforms can also relieve the inhibition, increasing calcium current through G-protein-inhibited channels but not through uninhibited channels. 3. The extent of this relief increased linearly with the duration of the action potential waveforms. 4. This result provides the strongest evidence to date favouring the possibility that relief of G-protein inhibition can occur during high frequency trains of action potentials. This effect may constitute a novel form of short-term synaptic plasticity that is sensitive to action potential timing and duration.

G-protein modulation of N-type calcium channel gating current in human embryonic kidney cells (HEK 293).

1. Voltage-dependent inhibition of N-type calcium currents by G-proteins contributes importantly to presynaptic inhibition. To examine the effect of G-proteins on key intermediary transitions leading to channel opening, we measured both gating and ionic currents arising from recombinant N-type channels (alpha 1B, beta 1b and alpha 2) expressed in transiently transfected human embryonic kidney cells (HEK 293). Recombinant expression of a homogeneous population of channels provided a favourable system for rigorous examination of the mechanisms underlying G-protein modulation. 2. During intracellular dialysis with GTP gamma S to activate G-proteins, ionic currents demonstrated classic features of voltage-dependent inhibition, i.e. strong depolarizing prepulses increased ionic currents and produced hyperpolarizing shifts in the voltage-dependent activation of ionic current. No such effects were observed with GDP beta S present to minimize G-protein activity. 3. Gating currents were clearly resolved after ionic current blockade with 0.1 mM free La3+, enabling this first report of gating charge translocation arising exclusively from N-type channels. G-proteins decreased the amplitude of gating currents and produced depolarizing shifts in the voltage-dependent activation of gating charge movement. However, the greatest effect was to induce a approximately 20 mV separation between the voltage-dependent activation of gating charge movement and ionic current. Strong depolarizing prepulses largely reversed these effects. These modulatory features provide telling clues about the kinetic steps affected by G-proteins because gating currents arise from the movement of voltage sensors that trigger channel activation. 4. The mechanistic implications of concomitant G-protein-mediated changes in gating and ionic currents are discussed. We argue that G-proteins act to inhibit both voltage-sensor movement and the transduction of voltage-sensor activation into channel opening.

Elementary events underlying voltage-dependent G-protein inhibition of N-type calcium channels.

Voltage-dependent G-protein inhibition of N-type calcium channels reduces presynaptic calcium entry, sharply attenuating neurotransmitter release. Studies in neurons demonstrate that G-proteins have multiple modulatory effects on N-type channels. The observed changes may reflect genuine complexity in G-protein action and/or the intricate interactions of multiple channels and receptors in neurons. Expression of recombinant M2-muscarinic receptors and N-type channels in HEK 293 cells allowed voltage-dependent inhibition to be studied in isolation. In this system, receptor-activated G-proteins had only one effect: a 10-fold increase in the time required for channels to first open following membrane depolarization. There were no changes in gating after the channel first opened, and unitary currents were not detectably altered by modulation. Despite its simplicity, this single change successfully accounts for the complex alterations in whole-cell current observed during G-protein inhibition in neurons.

Midazolam does not influence intravenous fentanyl-induced analgesia in healthy volunteers.

The effects of saline and intravenous midazolam (0.5, 1, and 2 mg per 70 kg) in combination with intravenous fentanyl (0.1 mg/70 kg) were examined on pain induced by a cold pressor test. Healthy volunteers (six females, six males) were enrolled in a prospective, double-blind, randomized, crossover trial in which mood and psychomotor performance were also examined. Five minutes and 135 min postinjection subjects immersed their forearm in ice cold water for 3 min while assessments of pain were recorded. During the first immersion, subjects reported significantly lower pain intensity and bothersomeness ratings after having been injected with fentanyl, relative to the saline condition, but the addition of midazolam neither increased nor decreased pain reports. During the second immersion (approximately 2.5 h postinjection) pain ratings did not differ between the drug and saline conditions. Mood-altering and psychomotor-impairing effects of the drug combination were dose related. We conclude that midazolam at the doses and route of administration tested neither potentiates nor decreases the analgesia produced by fentanyl in a cold-pressor pain assay.

Effects of a cold-water stressor on psychomotor and cognitive functioning in humans.

The effects of an acute stressful and painful stimulus, cold water, on psychomotor and cognitive functioning, was assessed in 14 healthy volunteers. Subjects immersed their forearm in ice-cold water (2-3 degrees C) and luke-warm water (37 degrees C) for 3 min, and during this time period a psychomotor or cognitive test was performed. These immersions were done over the course of two experimental sessions, spaced at least 2 days apart, with six trials in each session. Within each session, cold and warm water immersions alternated. Results indicated that flicker-from-fusion threshold from the critical flicker frequency test was higher in the cold-water condition than in the luke-warm-water condition, indicative of increased alertness from the cold stimulus. Short-term memory was attenuated, however, in the cold-water condition. Performance on other tests including those that required speed and/or concentration were not affected by the manipulation. Subjects rated the cold-water stimulus as painful and bothersome, and their blood pressure was significantly elevated by the stimulus. We conclude that a painful stimulus may affect psychomotor and/or cognitive functioning, but the relationship is somewhat complex and depends on the particular tests used.