Gels of Semiconducting Polymers in Benign Solvents.

Gels of semiconducting polymers have many potential applications, including biomedical devices and sensors. Here, we report a self-assembled gel system consisting of isoindigo-based semiconducting polymers with galactose side chains in benign, alcohol-based solvents. Because of the carbohydrate side chains, the modified isoindigo polymers are soluble in alcohols. We obtained thermoreversible gels in 1-propanol using these polymers and di-Fmoc-l-lysine, a molecular gelator. The polymers and molecular gelators have been selected in such a way that they do not have significant physical interactions. The molecular gelator self-assembled to form a fibrous structure that confines the polymer chains in the interstitial spaces of the fibers. The polymer chains formed local aggregations and increased the shear moduli of the gels significantly. Bulky galactose side chains and the less planar nature of the polymer backbone hindered the formation of long-range assembled structures of the polymers. However, the dispersion of polymers throughout the gel samples resulted in a percolated structure in the dried gel films. The bulk electrical conductivity of dried gels confirmed the presence of such percolated structures. Our results demonstrated that carbohydrate-containing conjugated polymers can be combined with molecular gelators to obtain gels in eco-friendly solvents.

Using molecular straps to engineer conjugated porous polymer growth, chemical doping, and conductivity.

Controlling network growth and architecture of 3D-conjugated porous polymers (CPPs) is challenging and therefore has limited the ability to systematically tune the network architecture and study its impact on doping efficiency and conductivity. We have proposed that π-face masking straps mask the π-face of the polymer backbone and therefore help to control π-π interchain interactions in higher dimensional π-conjugated materials unlike the conventional linear alkyl pendant solubilizing chains that are incapable of masking the π-face. Herein, we used cycloaraliphane-based π-face masking strapped monomers and show that the strapped repeat units, unlike the conventional monomers, help to overcome the strong interchain π-π interactions, extend network residence time, tune network growth, and increase chemical doping and conductivity in 3D-conjugated porous polymers. The straps doubled the network crosslinking density, which resulted in 18 times higher chemical doping efficiency compared to the control non-strapped-CPP. The straps also provided synthetic tunability and generated CPPs of varying network size, crosslinking density, dispersibility limit, and chemical doping efficiency by changing the knot to strut ratio. For the first time, we have shown that the processability issue of CPPs can be overcome by blending them with insulating commodity polymers. The blending of CPPs with poly(methylmethacrylate) (PMMA) has enabled them to be processed into thin films for conductivity measurements. The conductivity of strapped-CPPs is three orders of magnitude higher than that of the poly(phenyleneethynylene) porous network.

Correction: Temperature- and strain-dependent transient microstructure and rheological responses of endblock-associated triblock gels of different block lengths in a midblock selective solvent.

Correction for 'Temperature- and strain-dependent transient microstructure and rheological responses of endblock-associated triblock gels of different block lengths in a midblock selective solvent' by Rosa Maria Badani Prado et al., Soft Matter, 2022, 18, 7020-7034, https://doi.org/10.1039/D2SM00567K.

Multicolor Nitrogen-Doped Carbon Quantum Dots for Environment-Dependent Emission Tuning.

Carbon quantum dots (CQDs) have potential applications in many fields such as light-emitting devices, photocatalysis, and bioimaging due to their unique photoluminescence (PL) properties and environmental benignness. Here, we report the synthesis of nitrogen-doped carbon quantum dots (NCQDs) from citric acid and m-phenylenediamine using a one-pot hydrothermal approach. The environment-dependent emission changes of NCQDs were extensively investigated in various solvents, in the solid state, and in physically assembled PMMA-PnBA-PMMA copolymer gels in 2-ethyl-hexanol. NCQDs display bright emissions in various solvents as well as in the solid state. These NCQDs exhibit multicolor PL emission across the visible region upon changing the environment (solutions and polymer matrices). NCQDs also exhibit excitation-dependent PL and solvatochromism, which have not been frequently investigated in CQDs. Most CQDs are nonemissive in the aggregated or solid state due to the aggregation-caused quenching (ACQ) effect, limiting their solid-state applications. However, NCQDs synthesized here display a strong solid-state emission centered at 568 nm attributed to the presence of surface functional groups that restrict the π-π interaction between the NCQDs and assist in overcoming the ACQ effect in the solid state. NCQD-containing gels display significant fluorescence enhancement in comparison to the NCQDs in 2-ethyl hexanol, likely because of the interaction between the polar PMMA blocks and NCQDs. The application of NCQDs-Gel as a solid/gel state fluorescent display has been presented. This research facilitates the development of large-scale, low-cost multicolor phosphor for the fabrication of optoelectronic devices, sensing, and bioimaging applications.

Persistent Immune Thrombocytopenia Resistant to Immunosuppressive Therapy: What Is the Way Forward?

Immune thrombocytopenia purpura (ITP) involves autoimmune induced platelet destruction and decreased platelet production in part due to autoantibody destruction mechanisms. Most autoantibodies involved in its pathogenesis invoke autoreactive T cells and cytokine imbalance, and most drug therapies target these mechanisms. We describe a man in his late 40s, with a medical history of ITP, who presented with blood blisters on his mucosal surfaces and bruises on all four limbs with petechial rashes. He subsequently developed epistaxis and hemoptysis. In the recent past, he had been camping in Malta and felt feverish and nauseous on return. This was his first relapse of the disease in six years, and was unresponsive to prednisolone, IV immunoglobulins, and methylprednisolone, subsequently requiring romiplostim to recover platelet counts and reduce bleeding. When investigating the underlying causes of thrombocytopenia, aspects of virology and rickettsial serology were positive, requiring precautionary measures with long-term maintenance immunosuppression to prevent reactivation of infection.

An unusual indication for splenectomy in hairy cell leukaemia: a report of three cases with persistent splenomegaly after chemoimmunotherapy.

We describe three cases of relapsed hairy cell leukaemia (HCL) treated with pentostatin plus rituximab. All three achieved bone marrow complete remission but had persistent splenomegaly and hypersplenism. Because of the clinical uncertainty of its significance, they were all splenectomized. The spleen histology showed no evidence of HCL, but a five-fold thickening of the splenic capsule and areas of fibrosis in the red pulp. This process may have contributed to the lack of elasticity and caused the persistent splenomegaly. We discuss the clinical implications for future patient management. The three patients remain in remission at 1 + , 5 + and 9 + years.

Role of injecting bone marrow aspiration injection in treating delayed union and non-union.

OBJECTIVE: To access the role of bone marrow injection in the management of delayed union and non-union. METHODS: The prospective study was conducted at the Department of Orthopaedic Surgery and Traumatology, Mayo Hospital, Lahore, from January 2012 to December 2013, and comprised patients who had long bone fractures that resulted in delayed or non-union and were treated with bone marrow injections. Aspiration of bone marrow was done from tibial tuberosity and was injected percutaneously at the fracture site. The whole procedure was carried out as a day case. Fracture site mobility, tenderness and radiological features were assessed using the Union Scale score. RESULTS: Of the 25 patients, 18(72%)were male and 7(28%) were female with an overall mean age of 38±12.96SD years (range: 17-61 years). There were 19(76%) tibial shaft fractures, 4(16%) had shaft of femur fracture, and 2(8%) had humeral shaft fracture. Mean time duration between the injury and the procedure was 34 ±3.46 SD weeks (range: 30-42 weeks). Overall, 23 (92%) patients showed union and the mean time of healing was 15 ±2.73SD weeks (range: 12-22 weeks) after the procedure. CONCLUSIONS: Percutaneous bone marrow injection provided an alternative to open bone grafting, having least complications, especially for early intervention in the fracture-healing process.

Rituximab with pentostatin or cladribine: an effective combination treatment for hairy cell leukemia after disease recurrence.

The purine analogs pentostatin and cladribine are effective treatments for hairy cell leukemia (HCL). However, alternative treatments are needed for patients with recurrent disease. We reviewed retrospectively data from 18 patients who were retreated with either pentostatin (n = 12) or cladribine (n = 6) in combination with rituximab, after 1-6 (median 2) previous treatments with either purine analog as a single agent. All 18 patients responded to therapy, with a complete response (CR) rate of 89%. This compared favorably with CR rates of 68% after second-line therapy and 47% after third-line therapy in 88 patients retreated one or more times with a purine analog alone. Toxicity with the combination treatment was minimal. At a median follow-up of 36 months (range 5-83 months) all 16 complete responders remained in CR, while one partial responder developed recurrent disease at 10 months. The estimated recurrence rate at 3 years was 7%. This compares with 21% after second-line therapy and 42% after third-line therapy in the 88 patients retreated with a purine analog alone. Furthermore, it was a marked improvement on the 55% recurrence at 3 years previously seen in these same 18 patients after their own first-line treatment with single-agent pentostatin or cladribine (p = 0.006). The combination of a purine analog with rituximab was safe and effective for patients with recurrent HCL. The results suggest an added benefit compared with single-agent purine analog therapy.

Mycophenolate mofetil in a case of relapsed, refractory thrombotic thrombocytopenic purpura.

A case of relapsing and refractory thrombotic thrombocytopenic purpura received mycophenolate mofetil (MMF) to attempt to maintain remission. The possible use of MMF in thrombotic thrombocytopenic purpura is discussed.