Genetic Screening for EMS-Induced Maize Embryo-Specific Mutants Altered in Embryo Morphogenesis.

We have previously identified embryo-specific (emb) mutations that resulted in maize kernels containing abnormal embryos with normal-appearing endosperm among the progeny of active Robertson's Mutator stocks. Our rationale for the mutant screen described here is that it should be possible to produce ethyl methane sulfonate (EMS)-induced emb mutations at a frequency higher than that obtained by transposon mutagenesis and with greater ease. This proved to be the case when we screened for mutations that are embryo-specific among progeny of materials generated with EMS-treated pollen. The EMS-induced emb mutation frequency reported here is nearly three times the 4.5% we obtained with the transposable element stocks. The 45 mutants reported here were all tested for germination capacity and nearly all were lethal. The embryo phenotypes of 34 mutations were examined by dissection of the mature embryos. All were found to be retarded in development and morphologically abnormal. Half of the mutants in this group were blocked in the proembryo and transition stages. They likely include mutations in nuclear genes coding for plastid proteins. The other 17 are mainly blocked in the coleoptilar stage, or in later stages with a low frequency. This group likely includes mutations in genes regulating the completion of shoot apical meristem (SAM) development and accompanying morphogenetic events. Most of the complementation tests using 19 of the mutations in 35 unique combinations complimented each other, except for two pairs of mutations with similar phenotypes. Our results provide additional evidence for the presence of many emb loci in the maize genome.

A method of external fixation to offload and protect the foot following reconstruction in high-risk patients: the SALSAstand.

INTRODUCTION: The course of wound healing in high-risk patients with diabetes, particularly those with peripheral arterial disease and renal failure, is often prolonged and fraught with complications. Traditional methods of offloading the posterior foot or holding correction in place following diabetic foot reconstruction include various padded and bolstering devices. METHODS: In this article, we describe a method (SALSAstand) to effectively elevate, offload, and protect the foot with an external fixation device, while also promoting flap healing, maintaining tendon correction, and limiting the tendon retraction and contracture that is commonly seen following a foot-salvage procedure in high-risk patients. RESULTS: Not applicable. DISCUSSION: The SALSAstand device has been successfully utilized on many patients in our service to accomplish the aforementioned goals in this most challenging patient population.

Increasing on-task behavior in every student in a second-grade classroom during transitions: validating the Color Wheel system.

A single-case (B-C-B-C) experimental design was used to evaluate the effects of the Color Wheel classroom management system (CWS) on on-task (OT) behavior in an intact, general-education, 2nd-grade classroom during transitions. The CWS included three sets of rules, posted cues to indicate the rules students are expected to be following at that time, and transition procedures for altering activities and rules. Class-wide data analysis showed large, immediate, and sustained increases in OT behavior when the CWS was applied, with OT behavior returning to baseline levels when typical classroom management (TCM) procedures were reinstated. Each student's average phase data also showed increases in OT behavior when the CWS was applied and re-applied, and showed reductions when the CWS was withdrawn. Discussion focuses on evaluating the internal, external, and contextual validity of class-wide remediation and prevention procedures.