High-Performance Wearable Organic Photodetectors by Molecular Design and Green Solvent Processing for Pulse Oximetry and Photoplethysmography.

White-light detection from the visible to the near-infrared region is central to many applications such as high-speed cameras, autonomous vehicles, and wearable electronics. While organic photodetectors (OPDs) are being developed for such applications, several challenges must be overcome to produce scalable high-detectivity OPDs. This includes issues associated with low responsivity, narrow absorption range, and environmentally friendly device fabrication. Here, an OPD system processed from 2-methyltetrahydrofuran (2-MeTHF) sets a record in light detectivity, which is also comparable with commercially available silicon-based photodiodes is reported. The newly designed OPD is employed in wearable devices to monitor heart rate and blood oxygen saturation using a flexible OPD-based finger pulse oximeter. In achieving this, a framework for a detailed understanding of the structure-processing-property relationship in these OPDs is also developed. The bulk heterojunction (BHJ) thin films processed from 2-MeTHF are characterized at different length scales with advanced techniques. The BHJ morphology exhibits optimal intermixing and phase separation of donor and acceptor moieties, which facilitates the charge generation and collection process. Benefitting from high charge carrier mobilities and a low shunt leakage current, the newly developed OPD exhibits a specific detectivity of above 1012  Jones over 400-900 nm, which is higher than those of reference devices processed from chlorobenzene and ortho-xylene.

Additive-free molecular acceptor organic solar cells processed from a biorenewable solvent approaching 15% efficiency.

We report on the use of molecular acceptors (MAs) and donor polymers processed with a biomass-derived solvent (2-methyltetrahydrofuran, 2-MeTHF) to facilitate bulk heterojunction (BHJ) organic photovoltaics (OPVs) with power conversion efficiency (PCE) approaching 15%. Our approach makes use of two newly designed donor polymers with an opened ring unit in their structures along with three molecular acceptors (MAs) where the backbone and sidechain were engineered to enhance the processability of BHJ OPVs using 2-MeTHF, as evaluated by an analysis of donor-acceptor (D-A) miscibility and interaction parameters. To understand the differences in the PCE values that ranged from 9-15% as a function of composition, the surface, bulk, and interfacial BHJ morphologies were characterized at different length scales using atomic force microscopy, grazing-incidence wide-angle X-ray scattering, resonant soft X-ray scattering, X-ray photoelectron spectroscopy, and 2D solid-state nuclear magnetic resonance spectroscopy. Our results indicate that the favorable D-A intermixing that occurs in the best performing BHJ film with an average domain size of ∼25 nm, high domain purity, uniform distribution and enhanced local packing interactions - facilitates charge generation and extraction while limiting the trap-assisted recombination process in the device, leading to high effective mobility and good performance.

Green-Solvent-Processed High-Performance Broadband Organic Photodetectors.

Solution-processed organic photodetectors with broadband activity have been demonstrated with an environmentally benign solvent, ortho-xylene (o-xylene), as the processing solvent. The organic photodetectors employ a wide band gap polymer donor PBDB-T and a narrow band gap small-molecule non-fullerene acceptor CO1-4F, both dissolvable in o-xylene at a controlled temperature. The o-xylene-processed devices have shown external quantum efficiency of up to 70%, surpassing the counterpart processed with chlorobenzene. With a well-suppressed dark current, the device can also present a high specific detectivity of over 1012 Jones at -2 V within practical operation frequencies and is applicable for photoplethysmography with its fast response. These results further highlight the potential of green-solvent-processed organic photodetectors as a high-performing alternative to their counterparts processed in toxic chlorinated solvents without compromising the excellent photosensing performance.

Resolving Atomic-Scale Interactions in Nonfullerene Acceptor Organic Solar Cells with Solid-State NMR Spectroscopy, Crystallographic Modelling, and Molecular Dynamics Simulations.

Fused-ring core nonfullerene acceptors (NFAs), designated "Y-series," have enabled high-performance organic solar cells (OSCs) achieving over 18% power conversion efficiency (PCE). Since the introduction of these NFAs, much effort has been expended to understand the reasons for their exceptional performance. While several studies have identified key optoelectronic properties that govern high PCEs, little is known about the molecular level origins of large variations in performance, spanning from 5% to 18% PCE, for example, in the case of PM6:Y6 OSCs. Here, a combined solid-state NMR, crystallography, and molecular modeling approach to elucidate the atomic-scale interactions in Y6 crystals, thin films, and PM6:Y6 bulk heterojunction (BHJ) blends is introduced. It is shown that the Y6 morphologies in BHJ blends are not governed by the morphology in neat films or single crystals. Notably, PM6:Y6 blends processed from different solvents self-assemble into different structures and morphologies, whereby the relative orientations of the sidechains and end groups of the Y6 molecules to their fused-ring cores play a crucial role in determining the resulting morphology and overall performance of the solar cells. The molecular-level understanding of BHJs enabled by this approach will guide the engineering of next-generation NFAs for stable and efficient OSCs.

Identification of rare variants causing urea cycle disorders: A clinical, genetic, and biophysical study.

Urea cycle disorders (UCDs) are a group of rare metabolic conditions characterized by hyperammonemia and a broad spectrum of phenotypic severity. They are caused by the congenital deficiency in the eight biomolecules involved in urea cycle. In the present study, five cases of UCD were recruited and submitted to a series of clinical, biochemical, and genetic analysis with a combination of high throughput techniques. Moreover, in silico analysis was conducted on the identified missense genetic variants. Various clinical and biochemical indications (including profiles of amino acids and urinary orotic acids) of UCD were manifested by the five probands. Sequence analysis revealed nine diagnostic variants, including three novel ones, which caused Argininosuccinic aciduria (ASA) in one case, Carbamoyl phosphate synthetase 1deficiency (CPS1D) in two cases, Ornithine transcarbamylase deficiency (OTCD) in one case, and Citrin deficiency in 1case. Results of in silico biophysical analysis strongly suggested the pathogenicity of each the five missense variants and provided insight into their intramolecular impacts. In conclusion, this study expanded the genetic variation spectrum of UCD, gave solid evidence for counselling to the affected families, and should facilitate the functional study on the proteins in urea cycle.

A High-Performance Solution-Processed Organic Photodetector for Near-Infrared Sensing.

Sensitive detection of near-infrared (NIR) light enables many important applications in both research and industry. Current organic photodetectors suffer from low NIR sensitivity typically due to early absorption cutoff, low responsivity, and/or large dark/noise current under bias. Herein, organic photodetectors based on a novel ultranarrow-bandgap nonfullerene acceptor, CO1-4Cl, are presented, showcasing a remarkable responsivity over 0.5 A W-1 in the NIR spectral region (920-960 nm), which is the highest among organic photodiodes. By effectively delaying the onset of the space charge limited current and suppressing the shunt leakage current, the optimized devices show a large specific detectivity around 1012 Jones for NIR spectral region up to 1010 nm, close to that of a commercial Si photodiode. The presented photodetectors can also be integrated in photoplethysmography for real-time heart-rate monitoring, suggesting its potential for practical applications.

Relevance of clinical features in the prognosis of bronchopulmonary dysplasia in premature infants.

The aim of this study is to determine the accuracy rate of bronchopulmonary dysplasia (BPD) diagnosis and risk factors of short-term poor prognosis for premature infants. This study analyzed the clinical data of 81 premature infants (<32 weeks gestational age) with BPD, who were on oxygen therapy >28 days, and survived >36 weeks (corrected age). Outcome measures included treatments, conditions on the 28th day after birth, oxygen therapy conditions at the 36th week, occurrence of any serious complications during hospital stay. The major risk factors affecting prognosis were ventilation duration, duration of oxygen therapy, application of steroids, hypothyroidism and severity of BPD (all P<0.05). Interventions for complications (n=53) resulted in ceased inhalation of oxygen in 12 infants, improvement of symptoms in 26 infants, and were ineffective in 15 infants. BPD prognosis can be improved by shortening the duration of invasive ventilation and correcting thyroid function.

A quick response fluorescent probe based on coumarin and quinone for glutathione and its application in living cells.

We have designed and synthesized a simple but effective fluorescent probe for sensing glutathione (GSH) by PET process based on coumarin and quinone, which worked as fluorophore and reaction site, respectively. The probe could discriminate GSH from cysteine and homocysteine within 1 min in PBS-buffered solution. The sensing mechanism was confirmed by density functional theory (DFT), viscosity test, fluorescence spectrum analysis and HRMS, respectively. The probe has a low limit of detection (0.1 µM) and finally been used in cell imaging successfully.

A colorimetric, ratiometric and water-soluble fluorescent probe for simultaneously sensing glutathione and cysteine/homocysteine.

A chlorinated coumarin-aldehyde was developed as a colorimetric and ratiometric fluorescent probe for distinguishing glutathione (GSH), cystenine (Cys) and homocysteine (Hcy). The GSH-induced substitution-cyclization and Cys/Hcy-induced substitution-rearrangement cascades lead to the corresponding thiol-coumarin-iminium cation and amino-coumarin-aldehyde with distinct photophysical properties. The probe can be used to simultaneously detect GSH and Cys/Hcy by visual determination based on distinct different colors - red and pale-yellow in PBS buffer solution by two reaction sites. From the linear relationship of fluorescence intensity and biothiols concentrations, it was determined that the limits of detection for GSH, Hcy and Cys are 0.08, 0.09 and 0.18 µM, respectively. Furthermore, the probe was successfully used in living cell imaging with low cell toxicity.

An effective colorimetric and ratiometric fluorescent probe for bisulfite in aqueous solution.

We have developed the first two-photon colorimetric and ratiometric fluorescent probe, BICO, for the detection of bisulfite (HSO3(-)) in aqueous solution. The probe contains coumarin and benzimidazole moieties and can detect HSO3(-) based on the Michael addition reaction with a limit of detection 5.3 × 10(-8) M in phosphate-buffered saline solution. The probe was used to detect bisulfite in tap water, sugar and dry white wine. Moreover, test strips were made and used easily. We successfully applied the probe to image living cells, using one-photon fluorescence imaging. BICO overcomes the limitations in sensitivity of previously reported probes and the solvation effect of bisulfite, which demonstrates its excellent value in practical application.

[Imatinib is effective in a 12-month-old boy with chronic myelogenous leukemia: case report and literature review].

OBJECTIVE: To summarize the clinical characteristics of an infant with chronic myelogenous leukemia (CML) and the effects of imatinib on the case. METHOD: The clinical features of an infant with CML, who was treated with imatinib in the Norman Bethune International Peace Hospital at June 2009, were retrospectively analyzed and the reports in literature were reviewed. The 1-year-old boy suffered from recurrent low-degree fever and pallor. He had a moderate anemia, distended abdomen and marked splenomegaly. Bone marrow aspiration revealed CML in chronic phase)CP). The t (9; 22))q34; q11) could be detected and BCR-ABL (p210) was positive. The boy was diagnosed as CML-CP and treated with imatinib 100 mg per day. There were 10 related papers and more than 100 child CML patients were reported as retrieved from CNKI)from its establishment to August 2014) and Wanfang Database)from its establishment to August 2014) when "Child", " Chronic" and "Leukemia" were used as keywords. And there were 30 related papers including 400 cases from PubMed Database (from its establishment to August 2014) and one detailed report of an infant with CML was retrieved when "childhood" and "chronic myeloid leukemia" "imatinib" were used as keywords. The clinical effects of imatinib in infant CML cases were analyzed and summarized based on the literature. RESULT: The boy obtained a complete hematologic response (CHR) at the 6th week of diagnosis, a complete cytogenetic response (CCyR) at the 3rd month and a complete molecular response)CMR) at the 12th month without side effect. This boy grows very well and after a 62-month follow-up, his disease was stable. According to the domestic literature, 5 children CML cases aged 6 -12 years were treated with imatinib without side effects and got complete hematologic response (CHR) after 2-month-therapy. The dose, metabolic characteristics and clinical observation of imatinib can be found in foreign literature and imatinib showed good response with good tolerance in children with CML. Imatinib is regarded as the first line drug for children CML. But it may affect the development of the children. CONCLUSION: The children with CML-CP had a good response to imatinib, but more experience in the treatment of children with CML with iniatinib is needed.

[Clinical and imaging features of premature infants with different degrees of bronchopulmonary dysplasia].

OBJECTIVE: To study the clinical and imaging features of premature infants with different degrees of bronchopulmonary dysplasia (BPD). METHODS: A prospective study was performed on the clinical data of 59 premature infants (gestational age <32 weeks) with BPD. Among the 59 premature infants, 37 cases had mild BPD and the other 22 cases had moderate to severe BPD. The clinical and imaging data were compared between these premature infants with different degrees of BPD. RESULTS: The durations of mechanical ventilation, oxygen therapy, antibiotic therapy, parenteral nutrition, and hospitalization in the moderate to severe group were significantly longer than those in the mild group (P<0.05). The incidence of nosocomial infection and number of times of red blood cell transfusion in the moderate to severe group were significantly higher than that in the mild group. The rates of X-ray changes, including grade I respiratory distress syndrome (1 day after birth) and hypolucency of lungs (4-10 days and ≥ 28 days after birth) were significantly higher in the mild group than in the moderate to severe group. The rates of X-ray changes in classical BPD stage III (4-10 days after birth) and IV (≥ 28 days after birth) were significantly higher in the moderate to severe group than in the mild group. CONCLUSIONS: The durations of mechanical ventilation, oxygen therapy, and antibiotic therapy and the incidence of nosocomial infection are correlated with the severity of BPD. The premature infants with severer BPD need a longer duration of parenteral nutrition and more times of red blood cell transfusion and have more typical imaging changes of BPD. Imaging examination has a predictive value for the severity of BPD.

Dynamic changes of cerebral-specific proteins in full-term newborns with hypoxic-ischemic encephalopathy.

The aim of this study was to observe the dynamic changes of serum brain-derived neurotrophic factor (BDNF), S-100B, and Tau proteins levels in full-term newborns with hypoxic-ischemic encephalopathy (HIE) and to discuss their significance in brain damage. Serum samples of 28 full-term newborns diagnosed with HIE and 20 controls were obtained in the first 24 h of life. Another serum samples were also taken, respectively, at 3 and 7 days of life in HIE group. The concentrations of BDNF, S-100B, and Tau proteins were measured by the enzyme-linked immunosorbent assay method. Mean concentrations of BDNF, S-100B, and Tau proteins among different time period and in different grades of HIE group were calculated and compared. Compared with the control group, serum BDNF and proteins S-100B levels in HIE group were significantly elevated in 24 h after birth (P < 0.05) and their concentrations were also significantly higher among patients with mod-severe HIE compared to those with mild HIE at 24 h and 7 days after asphyxia (P < 0.05). Regardless of whether mod-severe HIE or mild HIE, there were no significant difference of serum BDNF and proteins S-100B among the three different time periods. There was no difference in Tau protein levels between HIE group and control group, also no difference between mod-severe HIE group and mild HIE group. BDNF and proteins S-100B are up-regulated early in asphyxia neonates with HIE; and the released amount of BDNF and proteins S-100B from nerve center system correlate with the extent of encephalopathy.

Ultrasound measurement of the corpus callosum and neural development of premature infants.

Length and thickness of 152 corpus callosa were measured in neonates within 24 hours of birth. Using ultrasonic diagnostic equipment with a neonatal brain-specific probe, corpus callosum length and thickness of the genu, body, and splenium were measured on the standard mid-sagittal plane, and the anteroposterior diameter of the genu was measured in the coronal plane. Results showed that corpus callosum length as well as thickness of the genu and splenium increased with tional age and birth weight, while other measures did not. These three factors on the standard mid-sagittal plane are therefore likely to be suitable for real-time evaluation of corpus callosum velopment in premature infants using cranial ultrasound. Further analysis revealed that thickness of the body and splenium and the anteroposterior diameter of the genu were greater in male infants than in female infants, suggesting that there are sex differences in corpus callosum size during the neonatal period. A second set of measurements were taken from 40 premature infants whose gestational age was 34 weeks or less. Corpus callosum measurements were corrected to a gestational age of 40 weeks, and infants were grouped for analysis depending on the outcome of a neonatal behavioral neurological assessment. Compared with infants with a normal neurological assessment, corpus callosum length and genu and splenium thicknesses were less in those with abnormalities, indicating that corpus callosum growth in premature infants is associated with neurobehavioral development during the early extrauterine stage.

[Relationship between the growth rate of corpus callosum and neuromotor delay in premature infants].

OBJECTIVE: To study the relationship between the growth rate of the corpus callosum and neurological motor development in premature infants. METHODS: Fifty infants whose gestational ages were less than 34 weeks and who were admitted to the neonatal intensive care unit from March 2007 to August 2007 were enrolled. From 0 to 6 weeks of postnatal age, the sagittal midline cranial sonography via anterior fontanel was performed, once weekly. The length and the morphology of the corpus callosum were measured. The 52-neuromotor examinations were performed at 3 months of corrected gestational age. RESULTS: The mean length of the corpus callosum was 39.16 mm at birth. The mean growth rate of the corpus callosum during the first 6 weeks of life was 1.05 mm/week. Fourteen infants showed abnormal neuromotor development and 36 had normal-neuromotor function at 3 months of corrected gestational age. A decreased growth rate of the corpus callosum was observed in the abnormal nervimotion group between 2 and 3 weeks (0.68 mm/week vs 1.17 mm/week) and between 4 and 5 weeks (0.86 mm/week vs 1.12 mm/week) after birth compared with that in normal nervimotion group (p<0.05). The total growth rate of the corpus callosum from 2 to 6 weeks after birth in the abnormal nervimotion group was also lower than that in the normal nervimotion group (0.91 mm/week vs 1.15 mm/week; p<0.01). CONCLUSIONS: A neuromotor delay at 3 months of corrected gestational age may be associated with the decreased growth rate of the corpus callosum between 2 and 6 weeks of life in premature infants.