chemically by, for example, glycosylation reactions. [3,4] Cellulose can be converted to the corresponding orthoesters by reaction with acetobromoglucose in presence of triethylamine. [5] However, the methods described so far require the use of hazardous reagents. The copper-catalyzed azide-alkyne cycloaddition was found to be advantageous for the preparation of numerous cellulose derivatives. [6,7] This reaction proceeds under mild conditions and even in aqueous media. In addition to a proof of principle, for example, [8,9] this type of click reaction has been utilized for the synthesis of highlyengineered cellulose derivatives. Dendron-like moieties could be attached to cellulose, [10] where either the azide [11] or the alkyne moiety was attached to the complementarily modified polymer backbone. [12] Moreover, azide group containing cellulose derivative could be crosslinked with propargyl modified cyclodextrin to obtain biocompatible gels. [13] The surface of cellulose fibers was modified as well, for example, by copoly merization of alkyne-containing monomers, [14] by silane chemistry, [15,16] or by tosylation of the paper surface followed by nucleophilic displacement with azide ions. [17] The functionalities attached can possess photomicrobicidal properties [18-20] or increase the strength of pulp fibers. [21] Maltose derivatives bearing N-and O-linked propargyl moieties attached to cellulose by azide-alkyne click chemistry increase the water solubility of the polymer. [22,23] This approach of click chemistry enabled the preparation of cellulose block copolymers by using cellulose derivatives bearing alkyne-or azide groups at position 1 of the reducing end of the oligosaccharide chain. [24] The reactive groups can be introduced regioselectively by, for example, 3-O-azidopropoxypoly(ethylene glycol)-2,6-di-O-thexyldimethylsilyl cellulose [25] or 3-O-propargyl cellulose. [26] In the context of plastic waste including the micro-plastic problems, biobased and biodegradable polymers are highly desirable. In this respect, solubility is an interesting parameter to enhance the biocompability of polymers. Moreover, functional polymers synthesized completely based on renewable resource (polymeric and monomeric carbohydrates) are important in order to save fossil resources. In the present paper the synthesis and structural characterization of cellulose derivatives bearing sugar moieties is reported that impart solubility to the polymer by taking advantages of the click chemistry approach. Cellulose is functionalized with different monosaccharides by the azide-alkyne click chemistry approach. Either azide or alkyne moieties are attached to the cellulose backbone and allowed to react with sugar moieties bearing the opposite clickable groups. Between 16% and 100% of the reactive sites at the polymer can be functionalized with sugar molecules and a clear correlation between steric demand and DS Sugar is observed. The polymers remain soluble in aprotic dipolar media like dimethyl sulfoxide. Products with a sufficient hydroph...

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BACKGROUND: Hip fracture is a common disease in the elderly. Among these patients, surgical intervention for hip fracture should be carefully considered because of old age and multiple comorbidities. There are still insufficient comparisons between patients treated with surgery and those treated non-surgically.OBJECTIVES: We studied hip fracture patients >90 years of age to compare the different outcomes between surgical and non-surgical treatments.DESIGN: Retrospective observational study.METHODS: Patients aged > 90 years who visited the emergency department with hip fractures between March 2010 and October 2019 were identified. Overall survival was estimated using multivariate Cox proportional hazards models. We compared the mortality rates at 30 days, 1 year, and 2 years between surgical and non-surgical patients. We also recorded the length of hospital stay, intra-admission, and 30-day complication and readmission rates.RESULTS: A total of 152 patients who underwent surgery (OP group) and 32 who received conservative treatment (non-OP group) were included. The estimated median survival time was 58.47 months in the OP group, which was significantly higher than the 24.28 months in the non-OP group. After adjusting for covariates, including age, sex, Charlson Comorbidity Index (CCI), injury severity score, and fracture type, the risk of death was reduced by surgery (hazard ratio [HR]=0.427; 95% confidence interval [CI]: 0.207-0.882; p=0.021). CCI was also an independent risk factor for poor survival rate (HR=1.3; 95% CI: 1.115-1.515; p=0.001). After adjusting for several factors, surgery within 48 h improved overall survival (HR: 2.518; 95% CI: 1.299-4.879; p=0.006).CONCLUSION: Our study suggests that surgery is likely to provide better outcomes for extremely old patients with hip fractures. Operative management should be recommended because it decreases the short-term complication rate and provides better long-term survival than non-operative management. Operation performed within 48 h of admission has better overall survival than that performed after >48 hours.

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Background Obesity is associated with adverse outcomes after major operations. The role of operative rib fixation (RF) in obese patients with flail chest is not clear. The presence of other associated injuries may complicate the interpretation of outcomes. This study compared outcomes after RF to nonoperative management (NOM) in obese patients with isolated flail chest injury. Methods Adult obese patients (BMI > 29.9) with flail chest were identified from the Trauma Quality Improvement Program (TQIP) database (2016–2018). Hospital transfers, death within 72 h, and extrathoracic injuries were excluded. RF patients were propensity score matched (1:2) to similar NOM patients. Multivariate regression identified independent factors predicting adverse outcomes. Results Overall, 367 patients with isolated flail chest who underwent RF were matched with 734 in the NOM group. After matching, the mortality rate was significantly lower in the RF group (1.4% vs. 3.7%; p < 0.05). RF had longer HLOS (15.7 days vs. 12.8 days; p < 0.05) and ICU LOS (10.1 days vs. 8.6 days; p < 0.05), shorter ventilator days (9.2 days vs. 11.5 days; p < 0.05), and a higher rate of venous thromboembolism (7.1% vs. 3.5%, p < 0.05). On multivariate analysis, RF was associated with decreased mortality (OR 0.27; p < 0.05). Early RF (≤ 72 h) was associated with shorter ICU stay and mechanical ventilation. Conclusion RF for isolated flail chest in obese patients is associated with decreased mortality and fewer ventilator days. When performed early, fixation decreases the need for prolonged ventilator use and ICU stay. A more aggressive VTE prophylaxis should be considered in patients undergoing RF.