(+)-Limonene-Lactam: Synthesis of a Sustainable Monomer for Ring-Opening Polymerization to Novel, Biobased Polyamides.

In this work, the synthesis of limonene lactam starting from limonene epoxide and its subsequent ring-opening polymerization (ROP) to novel polyamides is presented. Sustainable, biobased materials are gaining interest as replacements of conventional, petroleum-based materials, and even more important, as high-performance materials for new applications. Terpenes-structurally advanced biobased compounds-are therefore of great interest. In this research, limonene lactam, a novel biobased monomer for preparing sustainable polyamides via ROP, can be synthesized. Limonene lactam possesses an isopropylene and a methyl side group, thus stereocenters posing special challenges and requirements for synthesis, analysis and polymerization. However, these difficult-to-synthesize structural elements can generate novel polymers with unique properties, e.g., functionalizability. In this work, a sustainable monomer synthesis is established, and simplified to industrial needs. For the sterically demanding in-bulk ROP to limonene polyamides, various initiators and conditions are tested. Polyamides with more than 100 monomer units are successfully synthesized and confirmed via nuclear magnetic resonance (NMR) spectroscopy and gel permeations chromatography (GPC). Differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) are used to analyze its thermal properties. In summary, a sustainable monomer synthesis is established, and promising polyamides with intact double bond and interesting thermal properties are achieved.

Biobased chiral semi-crystalline or amorphous high-performance polyamides and their scalable stereoselective synthesis.

The use of renewable feedstock is one of the twelve key principles of sustainable chemistry. Unfortunately, bio-based compounds often suffer from high production cost and low performance. To fully tap the potential of natural compounds it is important to utilize their functionalities that could make them superior compared to fossil-based resources. Here we show the conversion of (+)-3-carene, a by-product of the cellulose industry into ε-lactams from which polyamides. The lactams are selectively prepared in two diastereomeric configurations, leading to semi-crystalline or amorphous, transparent polymers that can compete with the thermal properties of commercial high-performance polyamides. Copolyamides with caprolactam and laurolactam exhibit an increased glass transition and amorphicity compared to the homopolyamides, potentially broadening the scope of standard polyamides. A four-step one-vessel monomer synthesis, applying chemo-enzymatic catalysis for the initial oxidation step, is established. The great potential of the polyamides is outlined.

New Bio-Polyamides from Terpenes: α-Pinene and (+)-3-Carene as Valuable Resources for Lactam Production.

The synthesis and polymerization of two ß-lactams and two ε-lactams derived from the terpenes α-pinene and (+)-3-carene are reported. The new biopolymers can be considered as polyamide 2 (PA2) and polyamide 6 (PA6)-types with aliphatic stereoregular side chains, which lead to remarkable new properties. The macromolecules are investigated by gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), and infrared (IR). The (+)-3-carene-derived PA6-type is of particular interest, since it reaches a molecular weight of over 30 kDa, which is the highest value for lactam-based polyamides derived from terpenes reported to date. Additionally, a glass transition temperature (Tg ) of 120 °C is observed, surpassing the glass transition temperature of PA6 by 60 °C. The absence of a melting point (Tm ) indicates high amorphicity, another novelty for terpene-based polyamides, which might give transparent bio-polyamides access to new fields of application.

A case of chest pain and hemoptysis in a young child.

Endobronchial atypical carcinoid tumors are rare in young children and can have a varied presentation. Early diagnosis and surgical resection provide an excellent outcome and good long-term survival. However, due to the risk of recurrence and later metastasis, long-term follow-up is necessary.

Consider benign Müllerian papilloma: a rare cause of vaginal bleeding in children.

Vaginal bleeding in young girls is a distressing symptom. Due to the potential for malignancy, thorough investigation is needed. Though rare, Müllerian papillomas are a benign cause of such symptoms. We report the case of a 2-year-old female who presented with acute onset of vaginal bleeding. She had another episode of bleeding during admission and was taken to the operating room for vaginoscopy under general anesthesia. A single friable lesion with active bleeding was visualized near the anterior vagina or cervix, which was biopsied. Histopathologic examination demonstrated characteristic features of benign Müllerian papilloma of infancy. Müllerian papillomas require examination under anesthesia and vaginoscopy with biopsies for efficient and accurate diagnosis. Treatment consists of complete local excision. Local recurrences are not uncommon, though prognosis for primary or recurrent disease is excellent.

Airway and ventilation management during repair of a large acquired tracheoesophageal fistula: the novel use of a readily available tool.

Acquired tracheoesophageal fistula (TEF) is a life-threatening disorder of the airway that requires early diagnosis and treatment. The case of an infant who had delayed development of a TEF following endoscopic removal of a disc battery lodged in the midesophagus is reported. A repeat bronchoscopy, performed for respiratory distress 4 days later, showed a large defect in the posterior wall of the distal trachea, including the carina. A Foley catheter was used for airway management in the repair of the acquired TEF.

Positron emission tomography in subcutaneous panniculitis-like T-cell lymphoma.

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL), an uncommon disorder, was diagnosed in a 17-year-old female when she presented with multiple hard subcutaneous masses that developed over 3 years. She was treated on chemotherapy consisting of cyclophosphamide, doxorubicin, vincristine, and prednisone. Pre- and post-treatment positron emission tomography study demonstrated dramatic resolution of the subcutaneous lesions indicating its usefulness in SPTCL staging and treatment response monitoring.

Changes in amplitude-integrated electroencephalography in neonates treated with extracorporeal membrane oxygenation: a pilot study.

Neonates (n = 20) treated with extracorporeal membrane oxygenation were evaluated with serial amplitude-integrated electroencephalography (aEEG). There was no acute change in aEEG during extracorporeal membrane oxygenation cannulation, nor were there lateralizing effects. An abnormal aEEG predicted death or moderate to severe intracranial neuropathology with sensitivity = 1.0, specificity = 0.75, positive predictive value = 0.86, and negative predictive value = 1.0.