Crystalline silicon (c-Si) photovoltaics are robust, manufacturable, and Earth-abundant. However, barriers exist for c-Si modules to reach US$0.50-0.75/W p fabrication costs necessary for subsidy-free utility-scale adoption. We evaluate the potential of c-Si photovoltaics to reach this goal by developing a bottom-up cost model for c-Si wafer, cell, and module manufacturing; performing a sensitivity analysis to determine research domains that provide the greatest impact on cost; and evaluating the cost-reduction potential of line-of-sight manufacturing innovation and scale, as well as advanced technology innovation. We identify research domains with large cost reduction potential, including improving efficiencies, improving silicon utilization, and streamlining manufacturing processes and equipment, and briefly review ongoing research and development activities that impact these research domains. We conclude that multiple technology pathways exist to enable US$0.50/W p module manufacturing in the United States with silicon absorbers. More broadly, this work presents a usertargeted research and development framework that prioritizes research needs based on market impact.

PurposeIn treating schwannoma patients, it is critical to determine the origin of the tumor to preserve nerve function. We evaluated the validity of preoperative imaging studies in distinguishing the neurological origin of the schwannomas of the head and neck, and the efficacy of intracapsular enucleation in preserving nerve function.Materials and MethodsIn 7 cases of schwannomas in the head and neck region, we predicted whether the tumor originated from the vagus nerve or the cervical sympathetic chain through imaging studies including computed tomography (CT) and magnetic resonance imaging (MRI). All patients were performed intracapsular enucleation, and the function of the vagus nerve and the sympathetic nerve was evaluated preoperatively and postoperatively.ResultsPreoperative imaging studies showed 6 cases where the tumor was located between the carotid artery and the internal jugular vein, and 1 case where the tumor was located posteriorly, displacing the carotid artery and the internal jugular vein anteriorly. At the time of operation, we confirmed schwannoma originating from the vagus nerve on the first 6 cases, and schwannoma originating from the sympathetic nervous system on the last case. All patients went through successful intracapsular enucleation, and of the seven schwannoma cases, 6 patients maintained normal postoperative neurological function (85.7%).ConclusionPreoperative imaging studies offer valuable information regarding the location and origination of the tumor, and intracapsular enucleation helped us to preserve the nerve function.

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Fundamental frequency is controlled by contraction of the thyroarytenoid (TA) and cricothyroid (CT) muscles. While activity of the CT muscle is known to tense and thin the vocal folds, little is known about the effect of the TA muscle on vocal fold vibration. An in vivo canine laryngeal model was used to examine the role of the TA muscle in controlling phonation. Isolated TA muscle activation was obtained by stimulating sectioned terminal TA branches through small thyroid cartilage windows. Subglottic pressure measures, electroglottographic and photoglottographic signals, and acoustic signals were obtained in 5 mongrel dogs during dynamic and static variations in TA muscle activity. Results indicated that TA muscle activation is a major determinant in sudden shifts from high-frequency to modal phonation. Subglottic pressure increased and open quotient decreased gradually with increasing TA activation.

Cowden's disease, or multiple hamartoma syndrome, is an uncommon condition with characteristic mucocutaneous lesions associated with abnormalities of the breast, thyroid, and gastrointestinal tract. We describe a 32-year-old man with oral mucosal papillomatosis and plantar hyperkeratosis as a definite case of Cowden's disease according to the criteria proposed by Salem and Steck. The patient also had a thyroid mass and numerous gastrointestinal polyps endoscopically. Histologically the polyps were hamartomatous or hyperplastic polyps. The oral papillary lesions were fibroepithelial polyps and the thyroid mass was a follicular adenoma. We review the literature on this entity and summarize the pertinent findings. To the best of our knowledge, this is the first documented case of Cowden's disease in a Korean.

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We found PDL glottoplasty to be beneficial in the treatment of sulcus vocalis. Objective measurements of voice quality and normalization of vocal fold vibration improved after PDL treatment in most cases. Our results warrant further studies with larger numbers of participants and longer follow-up periods.

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