RESUMEN
The wide tunability of the energy bandgap of colloidal lead sulfide (PbS) quantum dots (QDs) has uniquely positioned them for the development of single junction and tandem solar cells. While there have been substantial advancements in moderate and narrow bandgap PbS QDs-ideal for single junction solar cells and the bottom cell in tandem solar cells, respectively; progress has been limited in high-bandgap PbS QDs that are ideally suited for the formation of the top cell in tandem solar cells. The development of appropriate high bandgap PbS QDs would be a major advancement toward realizing efficient all-QD tandem solar cells utilizing different sizes of PbS QDs. Here, we report a comprehensive approach encompassing synthetic strategy, ligand engineering, and hole transport layer (HTL) modification to implement high-bandgap PbS QDs into solar cell devices. We achieved a greater degree of size homogeneity in high-bandgap PbS QDs through the use of a growth retarding agent and a partial passivation strategy. By adjusting the ligand polarity, we successfully grow HTL over the QD film to fabricate solar cells. With the aid of an interface modifying layer, we incorporated an organic HTL for the realization of high-performance solar cells. These solar cells exhibited an impressive open-circuit voltage of 0.824 V and a power conversion efficiency of 10.7%, marking a 360% improvement over previous results.
RESUMEN
Eppin (epididymal protease inhibitor [SPINLW1]) is present in a protein complex on the human sperm surface that contains lactotransferrin, clusterin, and semenogelin (SEMG1). During ejaculation the presence of semenogelin inhibits sperm progressive motility until semenogelin is hydrolyzed by prostate-specific antigen (PSA). Although eppin binds all three components in its protein complex, the binding of semenogelin to eppin appears to be critical for the inhibition of progressive motility. The effect of the originally identified seminal plasma motility inhibitor fragment has not been clearly defined on live spermatozoa. Therefore, we have used recombinant semenogelin (rSEMG1) and its fragments, including a semenogelin mutant in which cysteine 239 was changed to glycine, coupled with a computer assisted sperm analysis assay to study the motility inhibitory properties of semenogelin. Each fragment and the mutant were tested for their effects on motility. Recombinant semenogelin significantly inhibited sperm progressive motility in a dose- and time-dependent manner. The C-terminal semenogelin fragment (amino acids 164-283) containing cysteine 239 significantly inhibited sperm progressive motility, whereas the N-terminal fragment (amino acids 24-163), a short C-terminal fragment (amino acids 172-215) without cysteine 239, and the mutant fragment (amino acids 24-283 with glycine 239) did not inhibit motility. After treatment with recombinant semenogelin, spermatozoa could be washed and treated with PSA, partially reversing the inhibition of progressive motility. Cysteine 239 of rSEMG1 appears to be the critical amino acid for both binding to eppin and inhibiting sperm motility.
Asunto(s)
Proteínas de Secreción de la Vesícula Seminal/farmacología , Motilidad Espermática/efectos de los fármacos , Sitios de Unión/genética , Relación Dosis-Respuesta a Droga , Regulación hacia Abajo/efectos de los fármacos , Humanos , Masculino , Mutagénesis Sitio-Dirigida , Unión Proteica/genética , Unión Proteica/fisiología , Estructura Terciaria de Proteína/genética , Proteínas Inhibidoras de Proteinasas Secretoras/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/farmacología , Proteínas de Secreción de la Vesícula Seminal/química , Proteínas de Secreción de la Vesícula Seminal/genética , Espermatozoides/efectos de los fármacos , Espermatozoides/metabolismo , Espermatozoides/fisiología , Factores de TiempoRESUMEN
BACKGROUND & OBJECTIVE: Analysis of the microdeletions in the azoospermia factor (AZF) region of Y chromosome by PCR is an important screening tool in the work-up of infertile males opting for assisted reproductive techniques. In the present study, the Y chromosome microdeletions were analyzed by PCR using primers corresponding to 16 sequence tagged sites (STS) and three genes of the AZF region in infertile Indian men. Feasibility of developing a simplified multiplex PCR for screening of the Y chromosome microdeletions has been explored. METHODS: A total of 271 male subjects were analyzed, of which, 170 were infertile patients (51 oligospermic and 119 azoospermic) and 101 were fertile controls. Subjects showing normal karyotype only were included in the study. The semen analysis was done and plasma follicle stimulating hormone (FSH) concentrations were determined by radioimmunoassay. Testicular histopathology was analyzed by fine needle aspiration cytology (FNAC). RESULTS: Y chromosome microdeletions were observed in nine out of 170 (5.29%) infertile males all of whom were azoospermic. Of the nine subjects, two had deletions in AZFa, one in AZFb, three in AZFc and three in AZFb+c regions. No deletions were observed in the infertile severe oligospermic men (< 5 million sperm/ml semen) and fertile controls. No difference in the FSH concentrations of infertile patients with and without deletions (18.36 and 18.10 mIU/ml respectively) was observed. A clear relationship between Y chromosome microdeletions and testicular phenotypes could not be established. Two multiplex PCRs were designed using 7 STSs markers, which could detect Y chromosome microdeletions in infertile male subjects as efficiently as PCR based on larger number of PCR reactions. INTERPRETATION & CONCLUSION: The multiplex PCRs described in the present study may be a suitable, cost-effective and less time consuming method for screening the Y chromosome deletions in infertile males in routine clinical diagnosis and counselling prior to assisted reproduction.
Asunto(s)
Cromosomas Humanos Y/ultraestructura , Eliminación de Gen , Infertilidad Masculina/genética , Adulto , Azoospermia/genética , Estudios de Casos y Controles , Cromosomas Humanos Y/genética , Hormona Folículo Estimulante/metabolismo , Humanos , India , Cariotipificación , Masculino , Oligospermia/genética , Radioinmunoensayo/métodos , Lugares Marcados de Secuencia , Aberraciones Cromosómicas SexualesRESUMEN
BACKGROUND: Azoospermia due to obstruction of the vaso-epididymal junction is one of the few surgically correctable causes of male infertility. In patients where all clinical and laboratory parameters suggest a vaso-epididymal junction block amenable to surgery, failure to find normal spermatogenesis on fine-needle aspiration cytology (FNAC) of the testis may necessitate a change in treatment modality to the more expensive intracytoplasmic sperm injection. We evaluated the validity of FNAC findings in predicting failure of surgical exploration when clinical parameters suggest otherwise. METHODS: Infertile, azoospermic men in whom the semen volume and fructose content, testis size, follicle-stimulating hormone level were normal and the vas deferens was palpable with no evident cause for obstruction, underwent FNAC of the testis to confirm the presence of normal spermatogenesis before surgical exploration. Men with hypospermatogenesis or maturation arrest on FNAC and a normal karyotype with absence of Y chromosome microdeletion were offered assisted reproduction or surgical exploration to identify a reconstructable obstruction. Men who chose surgery were included in the study and the findings on exploration were compared with the FNAC reports. RESULTS: Of the 10 men who satisfied the inclusion criteria, 6 had hypospermatogenesis and in 4 FNAC showed maturation arrest. On surgical exploration, none had sperm in the epididymis. A biopsy of the testis taken at the time of exploration confirmed the FNAC findings. CONCLUSION: Clinical parameters are insufficient for diagnosing obstructive azoospermia. FNAC can accurately evaluate the testicular pathology and predict whether or not surgical exploration should be undertaken.
Asunto(s)
Biopsia con Aguja Fina , Infertilidad Masculina/diagnóstico , Testículo/patología , Adolescente , Adulto , Conductos Eyaculadores/patología , Epidídimo/patología , Humanos , Infertilidad Masculina/patología , Masculino , Oligospermia/diagnóstico , Oligospermia/patologíaRESUMEN
AIM: To study the occurrence of Y chromosome microdeletions in azoospermic patients with Klinefelter's syndrome (KFS). METHODS: Blood and semen samples were collected from azoospermic patients with KFS (n = 14) and a control group of men of proven fertility (n = 13). Semen analysis was done according to World Health Organization (WHO) guidelines. Blood samples were processed for karyotyping, fluorescent in situ hybridization (FISH) and measurement of plasma follicle stimulating hormone (FSH) by radioimmunoassay. To determine Y chromosome microdeletions, polymerase chain reaction (PCR) of 16 sequence tagged sites (STS) and three genes (DFFRY, XKRY and RBM1Y) was performed on isolated genomic DNA. Testicular fine needle aspiration cytology (FNAC) was done in selected cases. RESULTS: Y chromosome microdeletions spanning the azoospermia factor (AZF)a and AZFb loci were found in four of the 14 azoospermic patients with KFS. Karyotype and FISH analysis revealed that, of the four cases showing Y chromosome microdeletion, three cases had a 47,XXY/46,XY chromosomal pattern and one case had a 46,XY/47,XXY/48,XXXY/48,XXYY chromosomal pattern. The testicular FNAC of one sample with Y chromosome microdeletion revealed Sertoli cell-only type of morphology. However, no Y chromosome microdeletions were observed in any of the 13 fertile men. All patients with KFS had elevated plasma FSH levels. CONCLUSION: Patients with KFS may harbor Y chromosome microdeletions and screening for these should be a part of their diagnostic work-up, particularly in those considering assisted reproductive techniques.