Siddharth Tiwari | Massachusetts Institute of Technology (MIT) (original) (raw)

Papers by Siddharth Tiwari

Journal of Biological Control, Jun 3, 2003

Frontiers in pain research, Apr 8, 2022

Previous research reports suggest greater baseline variability is associated with greater pain re... more Previous research reports suggest greater baseline variability is associated with greater pain relief in those who receive a placebo. However, studies that evidence this association do not control for confounding effects from regression to the mean and natural history. In this report, we analyzed data from two randomized clinical trials (Placebo I and Placebo II, total N = 139) while adjusting for the effects of natural history and regression to the mean via a no treatment group. Results agree between the two placebo groups in each study: both placebo groups showed negligible semi-partial correlations between baseline variability and adjusted response [r sp (CI 95%) = 0.22 (0.03, 0.42) and 0 (−0.07, 0.07) for Placebo I and II, respectively]. The no treatment group in Placebo I showed a negative correlation [−0.22 (−0.43, −0.02)], but the no treatment and drug groups in Placebo II's correlations were negligible [−0.02 (−0.08, 0.02) and 0.00 (−0.10, 0.12) for the no treatment and drug groups, respectively]. When modeled as a linear covariate, baseline pain variability accounted for <1% of the variance in post-intervention pain across both studies. Even after adjusting for baseline pain and natural history, the inability of baseline pain variability to account for substantial variance in pain response highlights that previous results concerning pain variability and treatment response may be inconsistent. Indeed, the relationship appears to be neither consistently specific nor sensitive to improvements in the placebo group. More work is needed to understand and establish the prognostic value of baseline pain variability-especially its placebo specificity and generalizability across patient populations.

Frontiers in pain research, Nov 2, 2021

Pain relief, or a decrease in self-reported pain intensity, is frequently the primary outcome of ... more Pain relief, or a decrease in self-reported pain intensity, is frequently the primary outcome of pain clinical trials. Investigators commonly report pain relief in one of two ways: using raw units (additive) or using percentage units (multiplicative). However, additive and multiplicative scales have different assumptions and are incompatible with one another. In this work, we describe the assumptions and corollaries of additive and multiplicative models of pain relief to illuminate the issue from statistical and clinical perspectives. First, we explain the math underlying each model and illustrate these points using simulations, for which readers are assumed to have an understanding of linear regression. Next, we connect this math to clinical interpretations, stressing the importance of statistical models that accurately represent the underlying data; for example, how using percent pain relief can mislead clinicians if the data are actually additive. These theoretical discussions are supported by empirical data from four longitudinal studies of patients with subacute and chronic pain. Finally, we discuss self-reported pain intensity as a measurement construct, including its philosophical limitations and how clinical pain differs from acute pain measured during psychophysics experiments. This work has broad implications for clinical pain research, ranging from statistical modeling of trial data to the use of minimal clinically important differences and patient-clinician communication.

Frontiers in Pain Research

Insect Pest Management, 2004

Hypocotyls of three species of Citrus were cultured on different fortifications of MS media to as... more Hypocotyls of three species of Citrus were cultured on different fortifications of MS media to assess their in vitro response. Higher in vitro morphogenesis (somatic embryogenesis and/or embryogenesis) leading to plantlet regeneration was varied considerably due to species and inoculation medium. Induction medium MS4D.5B (MS+ 4.0 mg/l 2, 4-D + 0. 5 mg/l BAP) proved well for callus initiation. Nutrient medium MS4B.5N (MS + 4.0 mg/l, BAP + 0.5 mg.l-1 NAA) performed commandingly for formation of morphogenic calli and plantlet regeneration. Higher root proliferating efficiency was recorded on rooting medium MS.5I (MS + 0.5 mg. l-1 IBA). Roots in higher numbers were attained from culture medium MS2I.5Kn (MS + 2. 0 mg. l-1 IBA + 0. 5 mg/l Kn), while culture media MS.5I.5B (MS + 0.5 mg/l IBA + 0.5 mg/l BAP) supported for enhancing mean root length. In terms of inter specific in vitro response, in general, Acid lime followed by Mandarin and Sweet orange responded decisively for the most of ...

Journal of Biological Control, 2003

Corcyra cephalonica (Stainton) is a laboratory host for mass production of Trichogramma spp. and ... more Corcyra cephalonica (Stainton) is a laboratory host for mass production of Trichogramma spp. and other biocontrol agents. In the present study for rearing Corcyra , three diets were used as broken maize alone, broken maize + yeast (2%) and broken maize + protinex (2%). Maize + yeast combination gave the best results in terms of mean total adults emergence (2211), mean total females (985), mean fecundity (397.85) and mean duration of moths emergence (52.31 days), while average developmental period was lowest (36 days) when compared with other two diets. The effect of egg laying on parasitization by T. chilonis revealed that highest mean per cent parasitization of 51.96 (mean of 1 st to 6 th day laying) was obtained on eggs laid by moths reared on maize + yeast diet. The highest mean per cent parasitization (73.9) was obtained on 2 nd day egg laying.

3 Biotech, 2019

Key message Rubus ellipticus is a wild crop having less number of EST-SSR markers. First attempt ... more Key message Rubus ellipticus is a wild crop having less number of EST-SSR markers. First attempt was made towards the transcriptomics data analysis and generation of EST-SSR markers which were used in genetic diversity and transferability studies. Abstract Rubus ellipticus is a raspberry with yellow fruits, native to tropical and subtropical India and Asia. Leaves of Rubus ellipticus 'Kumarhatti' collection were utilized for cDNA library construction. More than 15 million sequencing reads were generated using NextSeq 500 Illumina RNA-seq technology. The DNASTAR software was used for de novo assembly from which 7777 unigenes with an average length of 500 bp was obtained. These unigenes were annotated using public databases, including NCBI non-redundant and gene ontology. De novo assembly of R. ellipticus unigenes found the highest similarity to apple than to other members of Rosaceae. This is the first attempt to use the Illumina platform of RNA sequencing and de novo assembly for R. ellipticus without a reference genome. In this study, unigenes were used for SSR marker development. ESTs containing SSR motifs were extracted using an online Microsatellite Identification Tool (MISA). SSR primers were designed from the SSR containing 704 EST sequences using the Websat software. Total 304 EST-SSRs primers were successfully designed, out of which 68 randomly selected primer pairs were custom synthesized and used for validation. Real-time PCR was also performed to analyze the relationship of transcriptional factors with fruit ripening. Out of 68 primer pairs, 61 were found to be informative in R. ellipticus, whereas 65 primer pairs were informative in the five tested genera of Rosaceae, i.e., pear, peach, apple, rose, and strawberry with 95.3% and 93.5% polymorphism, leading to the conclusion that these marker systems are very efficient to carryout diversity and cross transferability study in Rosaceae genera.

Indian Journal of Plant Physiology, 2018

Iron (Fe) uptake is a highly regulated process in plants. In cereals, like wheat and rice, dietar... more Iron (Fe) uptake is a highly regulated process in plants. In cereals, like wheat and rice, dietary Fe concentration in seeds is very low because it is primarily localized as iron-phytate in vacuoles in aleurone layer. Fe transport into vacuoles and vacuolar sequestration are mediated by Vacuolar Iron Transporter (VIT) genes. In wheat seed, TaVIT2D was expressed at higher level in aleurone (removed as bran during milling) as compared to endosperm (makes dietary flour). The constitutive expression of VIT2D of wheat in the vit1 mutant of Arabidopsis thaliana increased Fe accumulation in the root, leaf, and seed during growth in low Fe medium. Expression of genes related to metal uptake and intercellular transport were induced in the complementation lines. The interaction between the vacuolar Fe sequestration and its long-distance transport may be important to address iron biofortification of cereal grains.

Journal of Computational Electronics, 2016

Double-gate (DG) MOSFETs are regarded as leading front runners in the semiconductor industry. To ... more Double-gate (DG) MOSFETs are regarded as leading front runners in the semiconductor industry. To alleviate the short-channel effects (SCEs) in DG MOSFET, a new underlap dual-material (DM) DG FinFET device structure is proposed, which has the advantages of an underlapped device as well as of a dual-material gate device (DMG). A 2D analytical surface potential and subthreshold current modelling of the proposed device has been done by solving the Poisson's equation. It has also been found that the results obtained analytically are in good agreement with numerical simulation results. As the underlap length (L un) increases, a substantial reduction of subthreshold current due to enhanced gate control over channel regime is observed. The DMG used in the structure improves average velocity of the carriers which leads to superior drive current of the device. The proposed device structure has been compared with underlap single-metal (SM) DG FinFET structures in terms of electrical characteristics, such as drain-induced barrier lowering (DIBL). The comparison confirms the suppression of SCEs with increasing L un in both the structures, but it is more significant in the case of underlap DMDG FinFET structures. Keywords Drain-induced barrier lowering (DIBL) • Dualmaterial double-gate (DMDG) • FinFET • Short channel effects (SCEs) • Subthreshold current • Underlap B Vadthiya Narendar

Indian Veterinary Journal, 2009

Indian Journal of Entomology, 2010

Ninety six entries of plant hopper screening trial (PHS-05 and PHS-06) were evaluated under glass... more Ninety six entries of plant hopper screening trial (PHS-05 and PHS-06) were evaluated under glass house conditions for their resistance to brown plant hopper, Nilaparvata lugens. PHS-05 entries KAUM MO 8 20 KR and PTB 33 were found highly resistant, while ARC 6650 and CB 21006 were rated as resistant and moderately resistant, respectively. PHS-06 entries CRAc 34997, 9412–13 and PTB 33 were identified as highly resistant, resistant and moderately resistant.

Plant Gene, 2015

Biochemical characterization and spatio-temporal expression of myo-inositol oxygenase (MIOX) from... more Biochemical characterization and spatio-temporal expression of myo-inositol oxygenase (MIOX) from wheat (Triticum aestivum L.

The Asian citrus psyllid, Diaphorina citri Kuwayama, is the most important pest of citrus worldwi... more The Asian citrus psyllid, Diaphorina citri Kuwayama, is the most important pest of citrus worldwide because of its ability to vector Candidatus Liberibacter (Ca. Las) species, the presumed causal agents of huanglongbing (HLB). Pathogen-infected trees may exhibit altered volatile production and thus be differentially attractive to the D. citri vector as compared with healthy trees. We conducted a series of behavioral experiments to investigate whether HLB-infected citrus plants were differentially attractive to D. citri as compared with healthy citrus plants. We also examined if psyllids known to be infected with the pathogen behaved differently from uninfected controls in response to both healthy and HLB-infected plants. HLB-infected citrus plants were more attractive to D. citri adults than healthy plants in two-choice olfactometer experiments. In open-air cage experiments, more D. citri were attracted to HLB-infected plants than to healthy plants. However, subsequent dispersal of ...

PLoS ONE, 2014

Silencing of genes through RNA interference (RNAi) in insects has gained momentum during the past... more Silencing of genes through RNA interference (RNAi) in insects has gained momentum during the past few years. RNAi has been used to cause insect mortality, inhibit insect growth, increase insecticide susceptibility, and prevent the development of insecticide resistance. We investigated the efficacy of topically applied dsRNA to induce RNAi for five Cytochrome P 450 genes family 4 (CYP4) in Diaphorina citri. We previously reported that these CYP4 genes are associated with the development of insecticide resistance in D. citri. We targeted five CYP4 genes that share a consensus sequence with one dsRNA construct. Quantitative PCR confirmed suppressed expression of the five CYP4 genes as a result of dsRNA topically applied to the thoracic region of D. citri when compared to the expression levels in a control group. Western blot analysis indicated a reduced signal of cytochrome P 450 proteins (45 kDa) in adult D. citri treated with the dsRNA. In addition, oxidase activity and insecticide resistance were reduced for D. citri treated with dsRNA that targeted specific CYP4 genes. Mortality was significantly higher in adults treated with dsRNA than in adults treated with water. Our results indicate that topically applied dsRNA can penetrate the cuticle of D. citri and induce RNAi. These results broaden the scope of RNAi as a mechanism to manage pests by targeting a broad range of genes. The results also support the application of RNAi as a viable tool to overcome insecticide resistance development in D. citri populations. However, further research is needed to develop grower-friendly delivery systems for the application of dsRNA under field conditions. Considering the high specificity of dsRNA, this tool can also be used for management of D. citri by targeting physiologically critical genes involved in growth and development.

Indian Journal of Small Ruminants (The), 2015

To study the effect of supplementing zinc and chromium on growth performance and nutrient utiliza... more To study the effect of supplementing zinc and chromium on growth performance and nutrient utilization, twenty-four indigenous non-descript goat kids (3–5 months old, average body weight of 5.1 kg) were allocated to four groups Gr I (control) was fed ad libitum basal complete feed which constituted sola (Aeschynomene indica) - hay (60 parts) and concentrate mixture (40 parts). The kids of Gr II, IIIand IV were fed as in control with a combined supplement of Zn-methionine and Crpicolinate at the rates of 20 and 0.5 ppm, 35 and 1 ppm and 50 and 1.5 ppm, respectively. The experiment lasted for 90 days. Significantly (P<0.05) higher body weight gain and lower feed conversion ratio (FCR) was recorded in Gr IV than the control. The study showed significantly (P<0.05) increased total nitrogen, trichloroacetic acid precipitable nitrogen (TCA-ppt -N) and microbial protein in Gr II, III, IV in the strained rumen liquor (SRL) at 45-day than the control whereas no significant change was observed in protozoan spp. due to mineral supplementation in different groups.

Pesticide Formulation and Delivery Systems: 32^ndVolume, Innovating Legacy Products for New Uses, 2012

In a laboratory investigation, the effect of spray droplet size on the mortality of three life st... more In a laboratory investigation, the effect of spray droplet size on the mortality of three life stages (eggs, nymphs, and adults) of the Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, was determined. Six spray droplets of nearly uniform size (diameter) (D 10 ¼ 40:5, 52.0, 101.5, 147.9, 174.0, and 264.7 lm) of fenpropathrin, a synthetic pyrethroid, were generated using a piezo-electric droplet generator. The formulation active ingredient (AI) was applied at spray delivery rates of 0.38 or 0.58 mg AI/min (168.9 and 253.4 g AI/ha), which were equivalent to 1/2 and 3/4 of the recommended field rates, respectively. The desired rates were achieved by moving the target plants across the spray stream at speeds of 7.2 or 27.2 cm/s. These operating parameters resulted in a high droplet density of 81.3 to 327.2 droplets/cm 2 and a low droplet density of 20.8 to 130.7 droplets/cm 2. The ACP populations were counted at 3 and 7 days after spray (DAS). In general, the percent mortality of ACP eggs, nymphs, and adults decreased at 3 and 7 DAS as the droplet size increased, regardless of the spray discharge rate or droplet density. Smaller droplet sizes (40.5 and 52.0 lm) resulted in significantly greater ACP mortality than the remaining droplet sizes, with few exceptions. The intermediate droplet sizes (101.5 and 147.9 lm) resulted in ACP mortalities ranging from 40 % to 92 %, and larger droplets (174.