Search

Microcontrollers are found in many everyday devices and will only become more prevalent as the Internet of Things (IoT) gains momentum. As such, it is increasingly important that they are reasonably secure from known vulnerabilities. If we do not improve the security posture of these devices, then attackers will find ways to exploit vulnerabilities for their own gain. Due to the security protections in modern systems which prevent execution of injected shellcode, Return Oriented Programming (ROP) has emerged as a more reliable way to execute malicious code following such attacks. ROP is a method used to take over the execution of a program by causing the return address of a function to be modified through an exploit vector, then returning to small segments of otherwise innocuous code located in executable memory one after the other to carry out the attacker’s aims. It will be shown that the Tiva TM4C123GH6PM microcontroller, which utilizes a Cortex-M4F processor, can be fully controlled with this technique. Sufficient code is pre-loaded into a ROM on Tiva microcontrollers to erase and rewrite the flash memory where the program resides. Then, that same ROM is searched for a Turing-complete gadget set which would allow for arbitrary execution. This would allow an attacker to re-purpose the microcontroller, altering the original functionality to his own malicious end.

The etiology of schizophrenia's cognitive symptoms may have its basis in prenatal alterations of glutamate N-methyl-D-aspartate (NMDA) receptor functioning. Therefore, the current study investigated the effects of ketamine (an NMDA receptor blocking drug) on both a conditioned taste aversion (CTA) and latent inhibition (LI; a model of attentional capacity) in rat fetuses. We first sought to determine if a CTA could be diminished by nonreinforced preexposure to a CS in fetal rats (i.e., LI). We injected E18 pregnant Sprague–Dawley rats with 100% allicin (garlic taste) or an equal volume of saline. Some of the pregnant dams also received ketamine (100 mg/kg, i.p.). One day later (E19), the dams received a second injection of the CS, followed by either lithium chloride (the US) or saline. Finally, on E21 pups received oral lavage with allicin and observations of ingestive orofacial motor responses were recorded. When allicin had been paired with LiCl in utero, E21 fetuses exhibited a conditioned suppression of orofacial movements, indicative of an aversion to this taste. Preexposure to the garlic taste on E18 produced a LI of this CTA. Ketamine significantly disrupted the formation of the CTA and had some impact on LI. However, the direct effect of ketamine on LI is less certain since the drug also blocked the original CTA. © 2013 Wiley Periodicals, Inc. © 2013 Wiley Periodicals, Inc. Dev Psychobiol 56: 435–447, 2014.

Tetraploid sour cherry (Prunus cerasus) has an S-RNase-based gametophytic self-incompatibility (GSI) system; however, individuals can be either self-incompatible (SI) or self-compatible (SC). Unlike the situation in the Solanaceae, where self-compatibility accompanying polyploidization is often due to the compatibility of heteroallelic pollen, the genotype-dependent loss of SI in sour cherry is due to the compatibility of pollen containing two nonfunctional S haplotypes. Sour cherry individuals with the S4S6S36aS36b genotype are predicted to be SC, as only pollen containing both nonfunctional S36a and S36b haplotypes would be SC. However, we previously found that individuals of this genotype were SI. Here we describe four nonfunctional S36 variants. Our molecular analyses identified a mutation that would confer loss of stylar S function for one of the variants, and two alterations that might cause loss of pollen S function for all four variants. Genetic crosses showed that individuals possessing two nonfunctional S36 haplotypes and two functional S haplotypes have reduced self-fertilization due to a very low frequency of transmission of the one pollen type that would be SC. Our finding that the underlying mechanism limiting successful transmission of genetically compatible gametes does not involve GSI is consistent with our previous genetic model for Prunus in which heteroallelic pollen is incompatible. This provides a unique case in which breakdown of SI does not occur despite the potential to generate SC pollen genotypes.

An important aspect of synthesizing designer nanostructures is fine-tuning their size, composition, and surface area. These parameters often dictate the unique properties of nanoparticles relative to their bulk counterpart. This paper reports the synthesis of porous metal nanorods with well-controlled dimensions, porosity, and photonic properties. The growth of each nanostructure is directed by a polycrystalline sacrificial template of silver with well-defined, tunable dimensions. This template can be selectively etched to isolate a porous hollow nanostructure. The porosity, composition, and photonic characteristics of this nanostructure are adjustable by controlling the reaction conditions.

Bowel signal monitoring finds numerous applications in medical and pathological fields. A portable bowel sound monitoring system requires front end amplifiers, data converters, signal processors and power efficient operation. In this paper, a low power integrated bowel sound monitoring system has been proposed and implemented. The system consists of a tunable charge amplifier, a feature extraction block, a bowel sound detection unit and a bowel sound occurrence rate count block. The system is implemented in a standard 6 metal 1 poly 180nm CMOS process. The developed integrated system consumes 52µW of power from a 1V supply.

The transition from self-incompatibility (SI) to self-compatibility (SC) is regarded as one of the most prevalent transitions in Angiosperm evolution, having profound impacts on the genetic structure of populations. Yet, the identity and function of mutations that result in the breakdown of SI in nature are not well understood. This work provides the first detailed genetic description of the breakdown of S-RNase-mediated gametophytic self-incompatibility (GSI) in a polyploid species that exhibits genotype-dependent loss of SI. Genetic analyses of six natural sour cherry (Rosaceae, Prunus cerasus) selections identified seven independent, nonfunctional S-haplotypes with disrupted pistil component (stylar-S) and/or pollen component (pollen-S) function. A genetic model demonstrating that the breakdown of SI in sour cherry is due to the accumulation of a minimum of two nonfunctional S-haplotypes within a single individual is developed and validated. Our finding that sour cherry is SI when only one nonfunctional S-haplotype is present has significant evolutionary implications since nonfunctional S-haplotypes would be maintained in the population without causing an abrupt shift to SC. Furthermore, we demonstrate that heteroallelic sour cherry pollen is self-incompatible, which is counter to the well-documented phenomenon in the Solanaceae where SC accompanying polyploidization is frequently due to the SC of heteroallelic pollen.

[reaction: see text] A family of dendritic amphiphiles were synthesized from the natural metabolites of glycerol, succinic acid, and myristic acid. The surfaces of these dendrimers display different numbers of alkyl chains and carboxylic acids, varying the hydrophobic-to-hydrophilic ratio over a relatively broad range. In solution these dendritic amphiphiles form supramolecular structures, and these aggregates have been characterized by light microscopy, transmission electron microscopy, and tensiometry. These aggregates can entrap the hydrophobic species pyrene.

S4′ is a pollen-part mutant in sweet cherry (Prunus avium L.) that is extensively used to develop self-compatible cultivars. The S4′-haplotype is known to have a functional stylar component and a nonfunctional pollen component. The pollen component in sweet cherry necessary for the specificity of the pollen reaction is believed to be an S-haplotype specific F-box protein gene, called SFB. This study describes two molecular markers that distinguish between SFB4 and SFB4′ by taking advantage of a four base pair deletion in the mutant allele. The resulting polymerase chain reaction (PCR) products can either be separated directly on a polyacrylamide gel or they can be subjected to restriction enzyme digestion and the different sized products can be visualized on an agarose gel. The latter technique utilizes restriction sites created in the PCR products from the SFB4′ allele, but not the SFB4 allele. Because the primer sets created differential restriction sites, these primer sets were termed dCAPS (derived cleaved amplified polymorphism sequence) markers. These molecular assays can be used to verify self-compatibility conferred by the S4′-haplotype.

Research on dendrimers continues to expand as further advances in synthetic methodology and characterization techniques translate to additional applications. Recently, dendritic polymers composed of the natural metabolites glycerol and succinic acid were synthesized, functionalized, and evaluated as new medical materials. The design and synthesis of poly(glycerol-succinic acid) dendritic polymers are discussed, including comparing and contrasting the convergent versus the divergent methodologies for preparing such macromolecules. Finally, a photocrosslinkable dendritic macromolecule was prepared and successfully used to close linear corneal lacerations as well as to secure LASIK flaps.

The high-yield convergent synthesis of dendrons, dendrimers, and dendritic-linear hybrid macromolecules composed of succinic acid, glycerol, and poly(ethylene glycol) (PEG) is described. This convergent synthesis relies on two orthogonal protecting groups; namely, the benzylidene acetal (bzld) for the protection of the 1,3-hydroxyls of glycerol and the tert-butyldiphenylsilyl (TBDPS) ester for protection of the carboxylic acid of succinic acid. These novel polyester dendritic macromolecules are composed entirely of building blocks known to be biocompatible or degradable in vivo to give natural metabolites. Derivatization of the dendritic periphery with a methacrylate affords a polymer that can be subsequently photo-cross-linked. The three-dimensional cross-linked gels formed by ultraviolet irradiation are optically transparent, with mechanical properties dependent on the initial cross-linkable dendritic macromolecule.

Glycerol monostearate (GMS) can serve as an anti-fogging agent by increasing the hydrophilic nature of a film surface. In this study, blends of GMS and LLDPE were extruded into film and the GMS was allowed to migrate to the surface over time. The surface was characterized by measuring the static water contact angle, which was then used to calculate the surface free energy of the film. Results showed that the equilibrium wettability of the film deviated dramatically from that of neat LLDPE when the GMS concentrations were greater than about 1900 ppm. Time-dependent studies demonstrated that the rate of surface-energy change was significantly influenced by the GMS concentration.

The modern power grid makes extensive use of automated data collection and control. These supervisory control and data acquisition (SCADA) systems often use communication protocols that were developed for isolated networks. However, the underlying SCADA systems often use the Internet for data transit, exposing these SCADA devices to remote, malicious adversaries. Unfortunately, these protocols are often vulnerable to impersonation attacks, and the devices can be susceptible to cryptographic key compromise. This allows adversaries to pollute the protocols with misinformation. In this paper, we propose an approach to authenticate the underlying SCADA protocols that combines a different approach to data authenticity and hardware-protected key distribution approach. Unlike prior work, our approach does not require modification to the SCADA end-points themselves, allowing the technique to be combined with legacy devices.

Correct assignment of self-incompatibility alleles (S-alleles) in sweet cherry (Prunus avium L.) is important to assure fruit set in field plantings and breeding crosses. Until recently, only six S-alleles had been assigned. With the determination that the stylar product of the S-locus is a ribonuclease (RNase) and subsequent cloning of the S-RNases, it has been possible to use isoenzyme and DNA analysis to genotype S-alleles. As a result, numerous additional S-alleles have been identified; however, since different groups used different strategies for genotype analysis and different cultivars, the nomenclature contained inconsistencies and redundancies. In this study restriction fragment-length polymorphism (RFLP) profiles are presented using HindIII, EcoRI, DraI, or XbaI restriction digests of the S-alleles present in 22 sweet cherry cultivars which were chosen based upon their unique S-allele designations and/or their importance to the United States sweet cherry breeding community. Twelve previously published alleles (S1, S2, S3, S4, S5, S6, S7, S9, S10, S11, S12, and S13) could be differentiated by their RFLP profiles for each of the four restriction enzymes. Two new putative S-alleles, both found in `NY1625', are reported, bringing the total to 14 differentiable alleles. We propose the adoption of a standard nomenclature in which the sweet cherry cultivars `Hedelfingen' and `Burlat' are S3S5 and S3S9, respectively. Fragment sizes for each S-allele/restriction enzyme combination are presented for reference in future S-allele discovery projects.

There existed an aging electrical system that needed to be upgraded. An upgrade was necessary for this system because the cost to maintain the aging technology was becoming too great. There were, however, no available schematics or technical papers describing this system. In order to upgrade the system, it first needed to be reverse engineered. The system to be upgraded was a device that would pass data back and forth from a personal computer to a proprietary storage device. The device to be upgraded communicated with the personal computer over a standard Small Computer System Interface (SCSI) interface and with the proprietary storage device through a non-standard 92-pin interface. The SCSI interface needed to be replaced by an Ethernet interface. The 92-pin interfaced needed to be reverse engineered so that it could continue to interface with the storage device as that was not going to be changed in any way. This report describes this process from the beginning to the end. It includes the different phases needed to reverse engineer the custom interface and the design and testing of the newly designed electrical system to replace the aging technology.

Vascular plants possess multiple mechanisms for defending themselves against pathogens. One well-characterized defense mechanism is systemic acquired resistance (SAR). In SAR, a plant detects the presence of a pathogen and transmits a signal throughout the plant, inducing changes in the expression of various pathogenesis-related (PR) genes. Once SAR is established, the plant is capable of mounting rapid responses to subsequent pathogen attacks. SAR has been characterized in numerous angiosperm and gymnosperm species; however, despite several pieces of evidence suggesting SAR may also exist in non-vascular plants6–8, its presence in non-vascular plants has not been conclusively demonstrated, in part due to the lack of an appropriate culture system. Here, we describe and use a novel culture system to demonstrate that the moss species Amblystegium serpens does initiate a SAR-like reaction upon inoculation with Pythium irregulare, a common soil-borne oomycete. Infection of A. serpens gametophores by P. irregulare is characterized by localized cytoplasmic shrinkage within 34 h and chlorosis and necrosis within 7 d of inoculation. Within 24 h of a primary inoculation (induction), moss gametophores grown in culture became highly resistant to infection following subsequent inoculation (challenge) by the same pathogen. This increased resistance was a response to the pathogen itself and not to physical wounding. Treatment with β-1,3 glucan, a structural component of oomycete cell walls, was equally effective at triggering SAR. Our results demonstrate, for the first time, that this important defense mechanism exists in a non-vascular plant, and, together with previous studies, suggest that SAR arose prior to the divergence of vascular and non-vascular plants. In addition, this novel moss – pathogen culture system will be valuable for future characterization of the mechanism of SAR in moss, which is necessary for a better understanding of the evolutionary history of SAR in plants.

Elevation of brain magnesium enhances synaptic plasticity and extinction of conditioned fear memories. This experiment examined the generalizability of this phenomenon by studying the effects of a novel magnesium compound, magnesium-L-threonate (MgT), on conditioned taste aversion (CTA) extinction and spontaneous recovery (SR). Adult male Sprague-Dawley rats were maintained on a 23-hour water deprivation cycle and acquired a CTA following the taste of a CS [0.3% saccharin + 16mg/ml MgT (SAC+MgT)] paired with a US [81 mg/kg (i.p.) Lithium Chloride (LiCl)]. Following CTA acquisition, rats drank a water + MgT solution for up to 1 hour/day over the next 31 days. For 14 additional days, some animals continued water + MgT treatment, but others drank water only to allow MgT to be eliminated from the body. We then employed 2 different extinction paradigms: (1) CS-Only (CSO), in which SAC was presented, every-other day, or (2) Explicitly Unpaired (EU), in which both SAC and LiCl were presented, but on alternate days. EU extinction procedures have been shown to speed CTA extinction and reduce spontaneous recovery of the aversion. Throughout extinction, half of the rats in each group continued to drink MgT (now in SAC or supplemental water+MgT solution), whereas the other half drank SAC only/water only until SAC drinking reached ≥ 90% of baseline (asymptotic extinction). Rats receiving MgT just before/during extinction drank less SAC on the first day of extinction suggesting that they had retained a stronger CTA. MgT enhanced the rate of extinction. Furthermore, the MgT-treated rats showed a relatively modest SR of the CTA 30 days later – indicating that the extinction procedure was more effective for these animals. Our data suggest that long-term dietary MgT may enhance the consolidation/retention of a CTA, speed extinction, and inhibit SR of this learned aversion.

The etiology of schizophrenia's cognitive symptoms may have its basis in prenatal alterations of glutamate N-methyl-D-aspartate (NMDA) receptor functioning. Therefore, the current study investigated the effects of ketamine (an NMDA receptor blocking drug) on both a conditioned taste aversion (CTA) and latent inhibition (LI; a model of attentional capacity) in rat fetuses. We first sought to determine if a CTA could be diminished by nonreinforced preexposure to a CS in fetal rats (i.e., LI). We injected E18 pregnant Sprague-Dawley rats with 100% allicin (garlic taste) or an equal volume of saline. Some of the pregnant dams also received ketamine (100 mg/kg, i.p.). One day later (E19), the dams received a second injection of the CS, followed by either lithium chloride (the US) or saline. Finally, on E21 pups received oral lavage with allicin and observations of ingestive orofacial motor responses were recorded. When allicin had been paired with LiCl in utero, E21 fetuses exhibited a conditioned suppression of orofacial movements, indicative of an aversion to this taste. Preexposure to the garlic taste on E18 produced a LI of this CTA. Ketamine significantly disrupted the formation of the CTA and had some impact on LI. However, the direct effect of ketamine on LI is less certain since the drug also blocked the original CTA.

An anionic amphiphilic dendrimer is reported that possesses increased cytotoxicological potency against prokaryotic cells compared to eukaryotic cells. The half-maximal effective concentration (EC50) for the dendrimer against Bacillus subtilis, a Gram-positive bacterial strain, was measured to be 4.1 x 10(-5) M, while that against human umbilical vein endothelial cells (HUVEC) was more than 36x greater at a value of 1.5 x 10(-3) M. EC50 ratios for two commercial amphiphiles, sodium dodecyl sulfate (SDS) and Triton X-100, in addition to a similar synthesized dendritic structure were at most only 3.8x greater. Furthermore, the observed EC50 values appear to be correlated to the critical aggregation constant (CAC) in solution suggesting a mechanism of action for these anionic amphiphilic dendrimers related to their supramolecular structures.

Gametophytic self-incompatibility (GSI) is an outcrossing mechanism in flowering plants that is genetically controlled by 2 separate genes located at the highly polymorphic S-locus, termed S-haplotype. This study characterizes a pollen part mutant of the S(1)-haplotype present in sour cherry (Rosaceae, Prunus cerasus L.) that contributes to the loss of GSI. Inheritance of S-haplotypes from reciprocal interspecific crosses between the self-compatible sour cherry cultivar Ujfehertoi Furtos carrying the mutated S(1)-haplotype (S(1)'S(4)S(d)S(null)) and the self-incompatible sweet cherry (Prunus avium L.) cultivars carrying the wild-type S(1)-haplotype revealed that the mutated S(1)-haplotype confers unilateral incompatibility with a functional pistil component and a nonfunctional pollen component. The altered sour cherry S(1)-haplotype pollen part mutant, termed S(1)', contains a 615-bp Ds-like element within the S(1)-haplotype-specific F-box protein gene (SFB(1)'). This insertion generates a premature in-frame stop codon that would result in a putative truncated SFB(1) containing only 75 of the 375 amino acids present in the wild-type SFB(1). S(1)' along with 2 other previously characterized Prunus S-haplotype mutants, S(f) and S(6m), illustrate that mobile element insertion is an evolutionary force contributing to the breakdown of GSI.

Tetraploid sour cherry (Prunus cerasus) exhibits a genotype-dependent loss of gametophytic self-incompatibility that is caused by the accumulation of non-functional S-haplotypes with disrupted pistil component (stylar-S) and/or pollen component (pollen-S) function. Genetic studies using diverse sour cherry germplasm identified non-functional S-haplotypes for which an equivalent wild-type S-haplotype was present in sweet cherry (Prunus avium), a diploid progenitor of sour cherry. In all cases, the non-functional S-haplotype resulted from mutations affecting the stylar component S-RNase or Prunus pollen component S-haplotype-specific F-box protein (SFB). This study determines the molecular bases of three of these S-haplotypes that confer unilateral incompatibility, two stylar-part mutants (S(6m2) and S(13m)) and one pollen-part mutant (S(13)'). Compared to their wild-type alleles, S(6m2)-RNase has a 1 bp deletion, S(13m) -RNase has a 23 bp deletion and SFB(13)' has a 1 bp substitution that lead to premature stop codons. Transcripts were identified for these three alleles, S(6m2)-RNase, S(13m)-RNase, and SFB(13)', however, these transcripts presumably result in altered proteins with a resulting loss of activity. Our characterization of natural pollen-part and stylar-part mutants in sour cherry along with other natural S-haplotype mutants identified in Prunus supports the view that loss of pollen specificity and stylar rejection evolve independently and are caused by structural alterations affecting the S-haplotype. The prevalence of non-functional S-haplotypes in sour cherry but not in sweet cherry (a diploid) suggests that polyploidization and gene duplication were indirectly responsible for the dysfunction of some S-haplotypes and the emergence of self-compatibility in sour cherry. This resembles the specific mode of evolution in yeast where accelerated evolution occurred to one member of the duplicated gene pair.

Multiple techniques have been developed to assemble micro- or nanostructured materials into well-defined patterns. These techniques are, however, often dependent on the size, shape, composition and/or surface chemistry of the structures being patterned. We have developed a general approach to pattern materials with a wide range of physical and chemical characteristics. We are able to assemble these materials into isolated or interconnected patterns covering areas up to ∼1 mm2.

Many Prunus species, including sweet cherry and Japanese apricot, of the Rosaceae, display an S-RNase-based gametophytic self-incompatibility (GSI). The specificity of this outcrossing mechanism is determined by a minimum of two genes that are located in a multigene complex, termed the S locus, which controls the pistil and pollen specificities. SFB, a gene located in the S locus region, encodes an F-box protein that has appropriate S haplotype-specific variation to be the pollen determinant in the self-incompatibility reaction. This study characterizes SFBs of two self-compatible (SC) haplotypes, S(4') and S(f), of Prunus. S(4') of sweet cherry is a pollen-part mutant (PPM) that was produced by X-ray irradiation, while S(f) of Japanese apricot is a naturally occurring SC haplotype that is considered to be a PPM. DNA sequence analysis revealed defects in both SFB(4') and SFB(f). A 4 bp deletion upstream from the HVa coding region of SFB(4') causes a frame-shift that produces transcripts of a defective SFB lacking the two hypervariable regions, HVa and HVb. Similarly, the presence of a 6.8 kbp insertion in the middle of the SFB(f) coding region leads to transcripts for a defective SFB lacking the C-terminal half that contains HVa and HVb. As all reported SFBs of functional S haplotypes encode intact SFB, the fact that the partial loss-of-function mutations in SFB are present in SC mutant haplotypes of Prunus provides additional evidence that SFB is the pollen S gene in GSI in Prunus.

This study characterizes the S 6m -haplotype, a mutated S 6 -haplotype with an altered HindIII cut site, of sour cherry (Prunus cerasus). Inheritance and pollination studies of S-haplotypes from reciprocal crosses between ‘Erdi Botermo’ (EB; S 4 S 6m S a ) and ‘Rheinische Schattenmorelle’ (RS; S 6 S a S b S c ) revealed that the S 6m -haplotype conferred unilateral incompatibility with a non-functional pistil component and a functional pollen component. Expression analyses of S 6 -RNase and SFB 6 , a candidate gene for pollen-S ,i n the S 6m -haplotype showed that SFB 6 was transcribed in EB pollen, but S 6 -RNase was not transcribed in EB styles. These results were consistent with data from the inheritance and pollination studies. Inverse PCR for the flanking regions of S 6 -RNase in the S 6 - and S 6m -haplotypes revealed an approximately 2600 bp insertion present at approximately 800 bp upstream of the S 6 -RNase in the S 6m -haplotype, which is responsible for the alternation of the HindIII cut site and a possible cause of inhibition of the transcription of S 6 -RNase. SFB 6 was present downstream of S 6 -RNase in both the S 6 - and S 6m -haplotypes and expressed in the same way, supporting the idea that SFB is a good candidate for pollen-S in Prunus.