A Comparative analysis of PESC and PPSC copolyesters: Insights into viscosity, thermal behavior, crystallinity, and biodegradability

The study examined various properties of synthesized copolyesters PESC and PPSC. Inherent viscosities of the copolyesters, measured in 1,4-dioxane at 32 °C, were 0.65 dL/g for PESC and 0.73 dL/g for PPSC. Fourier-Transform Infrared Spectroscopy (FT-IR) revealed distinct absorption bands associated with ester carbonyl stretching, C-H bending vibration, C-H group symmetry stretching, and C-O stretching vibrations. 1H and 13C Nuclear magnetic Resonance (NMR) spectroscopy were used to identify specific protons and carbon groups in the polymer chain, revealing the molecular structure of the copolyesters. Differential Scanning Calorimetry (DSC) identified the glass transition, melting, and decomposition temperatures for both copolyesters, indicating variations in the crystalline nature of the copolymers. XRD Spectral studies further elaborated on the crystalline nature, indicating that PPSC is less amorphous than PESC. Biodegradation analysis showed that PESC degrades more quickly than PPSC, with degradation decreasing as the number of methylene groups increase. Scanning Electron Microscopy (SEM) images depicted the surface morphology of the copolyesters before and after degradation, revealing a more roughened surface with pits post-degradation. These findings provide comprehensive insights into the structural and degradable properties of PESC and PPSC copolyesters.

Unpacking Land Degradation Neutrality (LDN), An Emerging Paradigm to Conserve Land Systems’ Sustainability in the 21st Century? Meta-analysis of Challenges and Opportunities

The UN Sustainable Development Goals specifically note the growing importance of land degradation management and mitigation strategies, advocating for global collaboration and innovative research and policy outlook. In this reflective summary, we synthesize the current worldview (post-2000) on land degradation neutrality (LDN), an emerging concept in the field of environmental sustainability that advocates a dynamic balance between degradation and restoration, to ensure no net loss in productive land resources. We first introduce the LDN Causal Framework (theoretical framework of LDN), followed by the Logic Model – guideline for on-ground LDN method implementation (comprising preparatory activities, followed by Integrated Land Use Planning (ILUP), and LDN Response Hierarchy (Avoid-Reduce-Reverse)). We draw attention to growing concerns about LDN technical problems: restore vs. rehabilitate; selecting indicator variables, and establishing a baseline. In the final section, we reflect on the social-ecological aspect of LDN – harnessing participatory action (multi-stakeholder engagement) and gender mainstreaming. Overall, LDN presents an umbrella vision for environmental regeneration and land capital management, that requires seamless integration of natural with social sciences, the policy with law, and requires strategic community mobilization.

Right Living Donor Nephrectomies: Retroperitoneoscopic vs Laparoscopic Transperitoneal Approach

Retroperitoneoscopic right living donor nephrectomy (RLDN) provides direct access to the renal hilum without the need to mobilize the colon. However, factors such as lack of anatomic landmarks to guide orientation, smaller working space, and steep learning curve provided a debate against this approach. In this retrospective study, we reviewed our single-center experience of retroperitoneoscopic RLDN.

MATERIALS AND METHODS

Between January 2015 and January 2017, 10 patients underwent retroperitoneoscopic RLDN by a single surgeon at the National University Hospital, Singapore. Baseline demographics, intraoperative parameters, and both donor and recipient outcomes were retrieved from the database.

RESULTS

Mean (SD) age was 52.7 (13.8) years, mean (SD) body mass index was 25.2 (2.9) kg/m², mean (SD) operating time was 196.8 (38.0) minutes, mean (SD) warm ischemic time was 5.1 (2.1) minutes, and mean (SD) blood loss was 43 (25.0) mL. Mean (SD) renal vein length was 10 (2.5) mm, and mean (SD) renal artery length was 6 (1.8 mm). One patient had to be converted to laparoscopic transperitoneal nephrectomy. No donors developed complications. Mean (SD) hospital stay was 3.5 (1.1) days. All transplanted right kidneys had immediate graft function with no complications. Mean (SD) serum creatinine (at 1 year) was 103.6 (20.3) μmol/L. There is no graft loss among the recipient after 1 year.

CONCLUSIONS

Right donor nephrectomy can be performed safely using retroperitoneoscopic approach. Retroperitoneoscopy offers advantages, especially in a patient who previously had transabdominal surgery or high body mass index. However, transperitoneal approach may be preferable in anomalous situations because it provides instinctive orientation from anatomic landmarks and a greater working space.