Probing the degradation and homogeneity of embedded perovskite semiconducting layers in photovoltaic devices by Raman spectroscopy.

The key challenges for perovskite solar cells include their poor stability and film homogeneity. Studying the degradation and homogeneity of perovskite layers within device structures can be challenging but critical to the understanding of stability and effect of processing in real life conditions. We show that Raman spectroscopy (RS) is a unique and powerful method (simple and fast) to probe the degradation of the perovskite film within the device structure and image perovskite formation. We demonstrate that RS can be used to directly probe chemical (PbI2) and physical (dihydrated phase) degradation of a perovskite film, and estimate the relative amount of the degradation species formed, mapping its distribution with ∼1 µm spatial resolution. This has been applied to mapping a large area perovskite module to characterise the efficacy of PbI2 to perovskite conversion. We also use RS to study the degradation species and kinetics under diverse accelerated degradation conditions (temperature and humidity) in situ. These capabilities are difficult to achieve with other methods, presenting RS as an important tool to gain understanding of the degradation and effect of processing on perovskite-based photovoltaic devices.

Cyclosporin A for persistent or chronic immune thrombocytopenia in children.

Twenty percent of children with immune thrombocytopenia (ITP) develop a chronic course where treatment strategy is less established. Cyclosporin A (CSA) has been shown to be effective in small series of children with chronic ITP and might reduce the need for chronic steroid therapy and/or splenectomy. We reviewed consecutive patients below 18 years old with persistent or chronic ITP treated with CSA in our unit between January 1998 and June 2015. Thirty patients (14 boys and 16 girls) were included. The median age at initial diagnosis of ITP was 5 years (range 0.5-16.2 years). CSA was started at a median of 13.9 months (range 3.4-124 months) after initial diagnosis and given for a median duration of 9.3 months (range 0.2-63.9 months). The median platelet count before commencement was 12 × 10(9)/L (range 4-199 × 10(9)/L). The median dose of CSA was 6 mg/kg/day (range 2.4-7.5 mg/kg/day). Complete response (CR) or response (R) was achieved in 17 patients (57 %), and 7 (23 %) had sustained response. Side effects (most commonly hirsutism) were tolerable and reversible. CSA appeared effective in about half of persistent or chronic ITP patients and safe as a second-line agent in managing these children.

A study of the predonation hemoglobin and iron status among Hong Kong Chinese blood donors.

BACKGROUND: Predonation hemoglobin (PDH) is used to safeguard donors' welfare, and low hemoglobin (Hb) is known to be the most frequent reason for donor deferral. A study was initiated to assess the PDH and iron status of blood donors in Hong Kong. STUDY DESIGN AND METHODS: This observational study was designed with four groups of whole blood donors invited (group 1-eligible first time donors, group 2-eligible repeat donors with zero or one donation in preceding 12 months, group 3-eligible repeat donors with at least two donations in preceding 12 months, group 4-repeat donors being deferred for low PDH). Predonation blood samples were obtained for blood counts and iron status. Mann-Whitney test, Kruskal-Wallis test, and chi-square test for trend were applied for statistical analysis. RESULTS: A total of 836 donors were recruited, of which 35 were excluded because of hemoglobinopathy. An inverse relationship between serum ferritin level and number of donations in the preceding 12 months was observed in both sexes. Iron deficiency was significantly seen in 35.1% of male and 65.3% of female deferred donors. More importantly, up to 7.2, 5.8, and 29.5% of the female donors in groups 1, 2, and 3 were found to be iron deficient despite having a high enough PDH. CONCLUSION: This is the first study to assess PDH and iron status in Chinese blood donors. Iron depletion is noted with increasing number of blood donations in the preceding 12 months. Advice on iron repletion is a necessary step for donor welfare and strategies should be developed to ensure that donors have adequate PDH.

Long-term clinical outcomes after Streptococcus bovis isolation in asymptomatic blood donors in Hong Kong.

BACKGROUND: Risk of transfusion-transmitted bacterial sepsis has been substantially reduced by a bacterial surveillance program (BST). However, new problems emerge as asymptomatic bacteremia is detected in blood donors. Streptococcus bovis bacteremia, which is known to associate with infective endocarditis and colonic carcinoma, is an example. STUDY DESIGN AND METHODS: A retrospective study was conducted to examine the demographic and clinical outcome of this group of donors. All confirmed culture-positive cases under the BST were retrieved and those donors with S. bovis bacteremia were contacted for follow-up. Viable culture samples were sent for detailed microbiologic analysis. RESULTS: From 1998 to 2012, a total of 16 donors were found to have S. bovis bacteremia, giving an estimated prevalence of 1 in 110,800 donations. They consisted of nine men and seven women with median age of 43.5 years. Eight donors had undergone colonoscopy with colonic carcinoma detected in two and benign adenoma in four. Five of the 16 isolates could be retrieved for 16S DNA sequencing. Four were identified as S. gallolyticus ssp. pasteurianus and one as S. gallolyticus ssp. gallolyticus. The two patients with colonic carcinoma had one each of subspecies pasteurianus and gallolyticus. CONCLUSION: The findings highlight a close association of S. bovis and colonic carcinoma. We recommend prompt donor follow-up if S. bovis bacteremia is detected. Besides, all confirmed S. bovis should be fully characterized by molecular technique.

Risk factor analysis of hepatitis C virus infection among Chinese blood donors in Hong Kong.

BACKGROUND: Hepatitis C virus (HCV) infection can result in serious hepatic complications and hence potentially significant burden to the society. Despite advances in technology, transfusion-transmitted HCV infection still exists. To further minimise the risk, a review on the epidemiology of HCV infection among Chinese blood donors in Hong Kong was conducted. METHODS: All donations associated with HCV infection confirmed by positive serologic diagnosis with or without molecular confirmation during the period from 2003 to 2010 were studied. Demographic data were retrieved and risk factors were identified. RESULTS: HCV infection was more commonly seen in first time donors and donors with blood transfusion history before the availability of HCV testing, whereas its association with intravenous drug use was noted to be decreasing. Interestingly, half of the HCV positive donors in 2008-2010 were young donors aged below 21, which was also the group with the highest rate of no known source of infection. CONCLUSION: A subgroup of younger age donors was found to have no known risk factor. To develop better screening strategy, it is recommended that a more detailed analysis of this group of donors is required.

Significant bacterial contamination risk reduction with the use of diversion pouch.

BACKGROUND: Significant efforts have been made towards bacterial risk minimization by limiting the chance of bacteria entering into collected blood, detecting its presence and eliminating them by pathogen reduction technology. Improved skin disinfection and the use of diversion pouch are effective upstream measures to reduce the risk of bacterial sepsis. Here we report on our experience with the use of blood bags with diversion pouch. MATERIALS AND METHODS: An observational study was performed to compare the bacterial contamination rate for two periods of time, i.e. before and after introduction of diversion pouch into blood bags. The incidence of bacterial contamination was monitored by the existing bacterial surveillance programme using pooled samples from 5 units of random donor platelets underwent aerobic culture in the BacT/ALERT 3D system. RESULTS: Between 1 June 2004 and 31 May 2006 (blood bag without diversion pouch), 50 (0·0213%) out of 234,252 units of random donor platelets were found to have bacteria on culture whereas 15 (0·0057%) isolates out of 262,156 units were found from 1 June 2007 to 31 May 2009 (after diversion pouch was introduced). Overall, there was an 85% reduction in bacterial contaminated risk due to skin flora (P < 0·0001) but an increasing trend of detection of non skin flora such as Streptococcus bovis was noted. CONCLUSION: Integration of diversion pouch into blood bags to divert the first 30 mL blood during blood collection on top of the current skin disinfection protocol can significantly reduce the risk of bacterial contamination.

Inventory management.

A critical aspect of blood transfusion is the timely provision of high quality blood products. This task remains a significant challenge for many blood services and blood systems reflecting the difficulty of balancing the recruitment of sufficient donors, the optimal utilization of the donor's gift, the increasing safety related restrictions on blood donation, a growing menu of specialized blood products and an ever-growing imperative to increase the efficiency of blood product provision from a cost perspective. As our industry now faces questions about our standard practices including whether or not the age of blood has a negative impact on recipients, it is timely to take a look at our collective inventory management practices. This International Forum represents an effort to get a snap shot of inventory management practices around the world, and to understand the range of different products provided for patients. In addition to sharing current inventory management practices, this Forum is intended to foster an exchange of ideas around where we see our field moving with respect to various issues including specialty products, new technologies, and reducing recipient risk from blood transfusion products.

Value of anaerobic culture in bacterial surveillance program for platelet concentrates.

BACKGROUND: Short-term aerobic bacterial culture (STABC) has been used routinely in Hong Kong since 1998 to reduce bacterial contamination in platelet concentrates (PCs) with good results. With more countries implementing routine aerobic and anaerobic cultures of PCs, a prospective study was conducted to determine the value of anaerobic culture to STABC. STUDY DESIGN AND METHODS: PC tested by STABC was used as control. Twenty milliliters of the PC selected for this study was aliquoted and pooled for 7 days aerobic and anaerobic culture. If the initial culture was positive, samples retrieved from the original PC and their associated components were cultured for confirmation and microbiologic identification. RESULTS: A total of 10,035 PC units (2007 pools) were tested. The confirmed positive rates by aerobic and anaerobic cultures per pool were 3 (0.15%) and 13 (0.65%), respectively, which was equivalent to an increased yield from 0.03 to 0.13 percent of PC if anaerobic culture was added. Of the 10 bacteria detected by anaerobic culture only, 9 were found to be Propionibacterium acnes and the remaining one Peptostreptococcus sp. Their mean detection time from inoculation was 92.16 hours (range, 50.4-124.8 hr). CONCLUSION: Addition of anaerobic culture to our routine STABC would significantly increase the detection rate of bacterial contaminated PC. However, since only slow-growing bacteria were detected, and because their clinical significance was uncertain, it is concluded that there was no clear justification to introduce anaerobic culture locally if 5-day shelf life for PCs was to be maintained.

Cord blood collection before and after placental delivery: levels of nucleated cells, haematopoietic progenitor cells, leukocyte subpopulations and macroscopic clots.

The number of nucleated cells infused into the recipient of a cord blood (CB) transplant has emerged as the most important factor affecting the probability and speed of engraftment. At present, there is no international consensus on the procedure of CB collection in the maternity ward. In order to maximise the yield of viable cells in a CB unit, we aimed to investigate the efficiency of CB collection, with respect to the time of delivery of the placenta. We analysed stem and progenitor cells in terms of CD34+ cell content and colony-forming activities, lymphocyte subpopulations and the presence of macroscopic clots in 93 paired CB samples, collected before and after the delivery of the placenta. Our results demonstrated that the median concentrations of nucleated cells and total colony-forming unit (CFU) were significantly lower in CB collected after placenta delivery by 9.5% (P < 0.001) and 11.6% (P = 0.015), respectively, when compared to their counterparts collected before placental delivery. A reduction of granulocytes (P < 0.001), monocytes (P < 0.001) and CD19+ B lymphocytes (P = 0.031) was observed, with no significant change in the proportion of T cell subsets (CD4+, CD8+ cells) or activated T cells (CD25+, CD45RO+ cells) in samples collected after placenta delivery. The incidence of macroscopic clots was also higher in these samples (31% vs 1%, P < 0.001). The reduction of stem and progenitor cells correlated significantly with that of major cell populations, indicating a general cell loss, possibly due to clotting activities developed with time. Our study has documented strong evidence for recommending the collection of CB before the delivery of the placenta.

A more immunosuppressive pre-transplant conditioning may be required for Chinese patients with thalassaemia.

Bone marrow transplantation was performed on 14 Chinese patients with transfusion dependent thalassaemia major (n = 13) and haemoglobin H disease (n = 1). The donors were HLA identical siblings. The source of haematopoietic stem cells were from bone marrow (n = 13) and umbilical cord blood (n = 1). The pre-transplant conditioning regimens were (1) busulphan 14 mg/kg and cyclophosphamide 200 mg/kg in two patients; (2) busulphan 16 mg/kg, cyclophosphamide 200 mg/kg and anti-thymocyte globulin 110 mg/kg in five patients; (3) busulphan 16 mg/kg, cyclophosphamide 150 mg/kg and anti-thymocyte globulin 110 mg/kg in seven patients. Graft-versus-host disease prophylaxis was cyclosporin A and methotrexate. All patients engrafted and achieved stable haematopoiesis except the one who underwent the umbilical cord blood transplant, who had autologous marrow recovery. One patient who had stable engraftment rejected the marrow graft and developed aplastic anaemia 4 months after BMT. This patient had a second BMT but rejection recurred again. She eventually died of septicaemia. The other 12 patients were transfusion independent and disease free. The majority have gone back to school or work. Disease-free and actuarial survival probability were 85 and 93%, respectively with a median follow-up time of 30 months (13 to 42 months). Our data suggest that BMT from HLA identical siblings for transfusion dependent thalassaemia gives a high chance of cure with acceptable mortality and morbidity, and that a more immunosuppressive pre-transplant conditioning schedule may be required to prevent rejection.

Small cell variant of Ki-1 lymphoma associated with myelofibrosis and a novel constitutional chromosomal translocation t(3;4) (q13;q12).

An unusual case of small cell variant of Ki-1 non-Hodgkin's lymphoma diagnosed one year after an original diagnosis of idiopathic myelofibrosis is reported. On the second occasion, the patient presented with fever, lymphadenopathy and hepatosplenomegaly. A lymph node biopsy specimen confirmed a diagnosis of small cell variant of Ki-1 lymphoma. A repeat bone marrow biopsy specimen showed myelofibrosis with no evidence of lymphomatous infiltration, but cytogenetic studies on blood, bone marrow and skin fibroblasts revealed a novel chromosomal translocation t(3,4)(q13;q12).

Heparin therapy in the Chinese--lower doses are required.

Warfarin requirements are lower in the Chinese, but it is not known if this applies to heparin. We investigated the optimal dose for heparin therapy in Chinese patients, and to assess relationship between i.v. heparin dosage and anticoagulation efficacy. One hundred Chinese patients requiring intravenous heparin therapy were given an initial bolus followed by continuous intravenous infusion. The main outcome measures were: (i) Efficacy of anticoagulation assessed by blood coagulation studies (APTT) compared to heparin dosage, (ii) Determinants of dosage variation-age, gender, body weight, height, indication for heparin therapy and number of medications, other disease, and serum albumin level. It was found that the mean therapeutic infusion dose requirement of heparin was 848.7 +/- 274.7 units/h, 79% required a dose of 1000 units/h or less. Heparin dose correlated negatively with age (r = -0.40; p < 0.001) and positively with weight (r = 0.44 p < 0.001) and height (r = 0.49; p < 0.001). Chinese subjects require lower heparin doses (about 800 units/h) than usually recommended for Caucasians (usual dose 1000-1500 units/h). This can be partly explained by the lower body weight in Chinese patients.

Association between t(2;9)(p12;p23) and early B-precursor acute lymphoblastic leukemia.

We report the occurrence of t(2;9)(p12;p23) in a 20-month-old girl with early B-precursor acute lymphoblastic leukemia (ALL). This translocation has only been reported once before in an adult case of early B-precursor ALL with t(4;11)(q21;q23). We suggest that t(2;9)(p12;p23) may be associated with this particular phenotype of ALL.

Plasma cells with iron inclusions in two non-alcoholic Chinese women.

Plasma cells with iron granules are rare, especially among non-alcoholic individuals. We report two teetotaller Chinese women with nasopharyngeal carcinoma and non-Hodgkin's lymphoma, whose bone marrow studies revealed plasma cells with inclusions morphologically compatible with iron granules. The iron nature of the granules was confirmed by elemental analysis. The clinical significance and the exact mechanism of formation of these iron inclusions in plasma cells remain unknown.